cachepc-linux

iqs7222.c (58919B)

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Azoteq IQS7222A/B/C Capacitive Touch Controller
 *
 * Copyright (C) 2022 Jeff LaBundy <jeff@labundy.com>
 */

#include <linux/bits.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/ktime.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/property.h>
#include <linux/slab.h>
#include <asm/unaligned.h>

#define IQS7222_PROD_NUM			0x00
#define IQS7222_PROD_NUM_A			840
#define IQS7222_PROD_NUM_B			698
#define IQS7222_PROD_NUM_C			863

#define IQS7222_SYS_STATUS			0x10
#define IQS7222_SYS_STATUS_RESET		BIT(3)
#define IQS7222_SYS_STATUS_ATI_ERROR		BIT(1)
#define IQS7222_SYS_STATUS_ATI_ACTIVE		BIT(0)

#define IQS7222_CHAN_SETUP_0_REF_MODE_MASK	GENMASK(15, 14)
#define IQS7222_CHAN_SETUP_0_REF_MODE_FOLLOW	BIT(15)
#define IQS7222_CHAN_SETUP_0_REF_MODE_REF	BIT(14)
#define IQS7222_CHAN_SETUP_0_CHAN_EN		BIT(8)

#define IQS7222_SLDR_SETUP_0_CHAN_CNT_MASK	GENMASK(2, 0)
#define IQS7222_SLDR_SETUP_2_RES_MASK		GENMASK(15, 8)
#define IQS7222_SLDR_SETUP_2_RES_SHIFT		8
#define IQS7222_SLDR_SETUP_2_TOP_SPEED_MASK	GENMASK(7, 0)
#define IQS7222_SLDR_SETUP_3_CHAN_SEL_MASK	GENMASK(9, 0)

#define IQS7222_GPIO_SETUP_0_GPIO_EN		BIT(0)

#define IQS7222_SYS_SETUP			0xD0
#define IQS7222_SYS_SETUP_INTF_MODE_MASK	GENMASK(7, 6)
#define IQS7222_SYS_SETUP_INTF_MODE_TOUCH	BIT(7)
#define IQS7222_SYS_SETUP_INTF_MODE_EVENT	BIT(6)
#define IQS7222_SYS_SETUP_PWR_MODE_MASK		GENMASK(5, 4)
#define IQS7222_SYS_SETUP_PWR_MODE_AUTO		IQS7222_SYS_SETUP_PWR_MODE_MASK
#define IQS7222_SYS_SETUP_REDO_ATI		BIT(2)
#define IQS7222_SYS_SETUP_ACK_RESET		BIT(0)

#define IQS7222_EVENT_MASK_ATI			BIT(12)

#define IQS7222_COMMS_HOLD			BIT(0)
#define IQS7222_COMMS_ERROR			0xEEEE
#define IQS7222_COMMS_RETRY_MS			50
#define IQS7222_COMMS_TIMEOUT_MS		100
#define IQS7222_RESET_TIMEOUT_MS		250
#define IQS7222_ATI_TIMEOUT_MS			2000

#define IQS7222_MAX_COLS_STAT			8
#define IQS7222_MAX_COLS_CYCLE			3
#define IQS7222_MAX_COLS_GLBL			3
#define IQS7222_MAX_COLS_BTN			3
#define IQS7222_MAX_COLS_CHAN			6
#define IQS7222_MAX_COLS_FILT			2
#define IQS7222_MAX_COLS_SLDR			11
#define IQS7222_MAX_COLS_GPIO			3
#define IQS7222_MAX_COLS_SYS			13

#define IQS7222_MAX_CHAN			20
#define IQS7222_MAX_SLDR			2

#define IQS7222_NUM_RETRIES			5
#define IQS7222_REG_OFFSET			0x100

enum iqs7222_reg_key_id {
	IQS7222_REG_KEY_NONE,
	IQS7222_REG_KEY_PROX,
	IQS7222_REG_KEY_TOUCH,
	IQS7222_REG_KEY_DEBOUNCE,
	IQS7222_REG_KEY_TAP,
	IQS7222_REG_KEY_AXIAL,
	IQS7222_REG_KEY_WHEEL,
	IQS7222_REG_KEY_NO_WHEEL,
	IQS7222_REG_KEY_RESERVED
};

enum iqs7222_reg_grp_id {
	IQS7222_REG_GRP_STAT,
	IQS7222_REG_GRP_CYCLE,
	IQS7222_REG_GRP_GLBL,
	IQS7222_REG_GRP_BTN,
	IQS7222_REG_GRP_CHAN,
	IQS7222_REG_GRP_FILT,
	IQS7222_REG_GRP_SLDR,
	IQS7222_REG_GRP_GPIO,
	IQS7222_REG_GRP_SYS,
	IQS7222_NUM_REG_GRPS
};

static const char * const iqs7222_reg_grp_names[] = {
	[IQS7222_REG_GRP_CYCLE] = "cycle",
	[IQS7222_REG_GRP_CHAN] = "channel",
	[IQS7222_REG_GRP_SLDR] = "slider",
	[IQS7222_REG_GRP_GPIO] = "gpio",
};

static const unsigned int iqs7222_max_cols[] = {
	[IQS7222_REG_GRP_STAT] = IQS7222_MAX_COLS_STAT,
	[IQS7222_REG_GRP_CYCLE] = IQS7222_MAX_COLS_CYCLE,
	[IQS7222_REG_GRP_GLBL] = IQS7222_MAX_COLS_GLBL,
	[IQS7222_REG_GRP_BTN] = IQS7222_MAX_COLS_BTN,
	[IQS7222_REG_GRP_CHAN] = IQS7222_MAX_COLS_CHAN,
	[IQS7222_REG_GRP_FILT] = IQS7222_MAX_COLS_FILT,
	[IQS7222_REG_GRP_SLDR] = IQS7222_MAX_COLS_SLDR,
	[IQS7222_REG_GRP_GPIO] = IQS7222_MAX_COLS_GPIO,
	[IQS7222_REG_GRP_SYS] = IQS7222_MAX_COLS_SYS,
};

static const unsigned int iqs7222_gpio_links[] = { 2, 5, 6, };

struct iqs7222_event_desc {
	const char *name;
	u16 mask;
	u16 val;
	u16 enable;
	enum iqs7222_reg_key_id reg_key;
};

static const struct iqs7222_event_desc iqs7222_kp_events[] = {
	{
		.name = "event-prox",
		.enable = BIT(0),
		.reg_key = IQS7222_REG_KEY_PROX,
	},
	{
		.name = "event-touch",
		.enable = BIT(1),
		.reg_key = IQS7222_REG_KEY_TOUCH,
	},
};

static const struct iqs7222_event_desc iqs7222_sl_events[] = {
	{ .name = "event-press", },
	{
		.name = "event-tap",
		.mask = BIT(0),
		.val = BIT(0),
		.enable = BIT(0),
		.reg_key = IQS7222_REG_KEY_TAP,
	},
	{
		.name = "event-swipe-pos",
		.mask = BIT(5) | BIT(1),
		.val = BIT(1),
		.enable = BIT(1),
		.reg_key = IQS7222_REG_KEY_AXIAL,
	},
	{
		.name = "event-swipe-neg",
		.mask = BIT(5) | BIT(1),
		.val = BIT(5) | BIT(1),
		.enable = BIT(1),
		.reg_key = IQS7222_REG_KEY_AXIAL,
	},
	{
		.name = "event-flick-pos",
		.mask = BIT(5) | BIT(2),
		.val = BIT(2),
		.enable = BIT(2),
		.reg_key = IQS7222_REG_KEY_AXIAL,
	},
	{
		.name = "event-flick-neg",
		.mask = BIT(5) | BIT(2),
		.val = BIT(5) | BIT(2),
		.enable = BIT(2),
		.reg_key = IQS7222_REG_KEY_AXIAL,
	},
};

struct iqs7222_reg_grp_desc {
	u16 base;
	int num_row;
	int num_col;
};

struct iqs7222_dev_desc {
	u16 prod_num;
	u16 fw_major;
	u16 fw_minor;
	u16 sldr_res;
	u16 touch_link;
	u16 wheel_enable;
	int allow_offset;
	int event_offset;
	int comms_offset;
	struct iqs7222_reg_grp_desc reg_grps[IQS7222_NUM_REG_GRPS];
};

static const struct iqs7222_dev_desc iqs7222_devs[] = {
	{
		.prod_num = IQS7222_PROD_NUM_A,
		.fw_major = 1,
		.fw_minor = 12,
		.sldr_res = U8_MAX * 16,
		.touch_link = 1768,
		.allow_offset = 9,
		.event_offset = 10,
		.comms_offset = 12,
		.reg_grps = {
			[IQS7222_REG_GRP_STAT] = {
				.base = IQS7222_SYS_STATUS,
				.num_row = 1,
				.num_col = 8,
			},
			[IQS7222_REG_GRP_CYCLE] = {
				.base = 0x8000,
				.num_row = 7,
				.num_col = 3,
			},
			[IQS7222_REG_GRP_GLBL] = {
				.base = 0x8700,
				.num_row = 1,
				.num_col = 3,
			},
			[IQS7222_REG_GRP_BTN] = {
				.base = 0x9000,
				.num_row = 12,
				.num_col = 3,
			},
			[IQS7222_REG_GRP_CHAN] = {
				.base = 0xA000,
				.num_row = 12,
				.num_col = 6,
			},
			[IQS7222_REG_GRP_FILT] = {
				.base = 0xAC00,
				.num_row = 1,
				.num_col = 2,
			},
			[IQS7222_REG_GRP_SLDR] = {
				.base = 0xB000,
				.num_row = 2,
				.num_col = 11,
			},
			[IQS7222_REG_GRP_GPIO] = {
				.base = 0xC000,
				.num_row = 1,
				.num_col = 3,
			},
			[IQS7222_REG_GRP_SYS] = {
				.base = IQS7222_SYS_SETUP,
				.num_row = 1,
				.num_col = 13,
			},
		},
	},
	{
		.prod_num = IQS7222_PROD_NUM_B,
		.fw_major = 1,
		.fw_minor = 43,
		.event_offset = 10,
		.comms_offset = 11,
		.reg_grps = {
			[IQS7222_REG_GRP_STAT] = {
				.base = IQS7222_SYS_STATUS,
				.num_row = 1,
				.num_col = 6,
			},
			[IQS7222_REG_GRP_CYCLE] = {
				.base = 0x8000,
				.num_row = 10,
				.num_col = 2,
			},
			[IQS7222_REG_GRP_GLBL] = {
				.base = 0x8A00,
				.num_row = 1,
				.num_col = 3,
			},
			[IQS7222_REG_GRP_BTN] = {
				.base = 0x9000,
				.num_row = 20,
				.num_col = 2,
			},
			[IQS7222_REG_GRP_CHAN] = {
				.base = 0xB000,
				.num_row = 20,
				.num_col = 4,
			},
			[IQS7222_REG_GRP_FILT] = {
				.base = 0xC400,
				.num_row = 1,
				.num_col = 2,
			},
			[IQS7222_REG_GRP_SYS] = {
				.base = IQS7222_SYS_SETUP,
				.num_row = 1,
				.num_col = 13,
			},
		},
	},
	{
		.prod_num = IQS7222_PROD_NUM_B,
		.fw_major = 1,
		.fw_minor = 27,
		.reg_grps = {
			[IQS7222_REG_GRP_STAT] = {
				.base = IQS7222_SYS_STATUS,
				.num_row = 1,
				.num_col = 6,
			},
			[IQS7222_REG_GRP_CYCLE] = {
				.base = 0x8000,
				.num_row = 10,
				.num_col = 2,
			},
			[IQS7222_REG_GRP_GLBL] = {
				.base = 0x8A00,
				.num_row = 1,
				.num_col = 3,
			},
			[IQS7222_REG_GRP_BTN] = {
				.base = 0x9000,
				.num_row = 20,
				.num_col = 2,
			},
			[IQS7222_REG_GRP_CHAN] = {
				.base = 0xB000,
				.num_row = 20,
				.num_col = 4,
			},
			[IQS7222_REG_GRP_FILT] = {
				.base = 0xC400,
				.num_row = 1,
				.num_col = 2,
			},
			[IQS7222_REG_GRP_SYS] = {
				.base = IQS7222_SYS_SETUP,
				.num_row = 1,
				.num_col = 10,
			},
		},
	},
	{
		.prod_num = IQS7222_PROD_NUM_C,
		.fw_major = 2,
		.fw_minor = 6,
		.sldr_res = U16_MAX,
		.touch_link = 1686,
		.wheel_enable = BIT(3),
		.event_offset = 9,
		.comms_offset = 10,
		.reg_grps = {
			[IQS7222_REG_GRP_STAT] = {
				.base = IQS7222_SYS_STATUS,
				.num_row = 1,
				.num_col = 6,
			},
			[IQS7222_REG_GRP_CYCLE] = {
				.base = 0x8000,
				.num_row = 5,
				.num_col = 3,
			},
			[IQS7222_REG_GRP_GLBL] = {
				.base = 0x8500,
				.num_row = 1,
				.num_col = 3,
			},
			[IQS7222_REG_GRP_BTN] = {
				.base = 0x9000,
				.num_row = 10,
				.num_col = 3,
			},
			[IQS7222_REG_GRP_CHAN] = {
				.base = 0xA000,
				.num_row = 10,
				.num_col = 6,
			},
			[IQS7222_REG_GRP_FILT] = {
				.base = 0xAA00,
				.num_row = 1,
				.num_col = 2,
			},
			[IQS7222_REG_GRP_SLDR] = {
				.base = 0xB000,
				.num_row = 2,
				.num_col = 10,
			},
			[IQS7222_REG_GRP_GPIO] = {
				.base = 0xC000,
				.num_row = 3,
				.num_col = 3,
			},
			[IQS7222_REG_GRP_SYS] = {
				.base = IQS7222_SYS_SETUP,
				.num_row = 1,
				.num_col = 12,
			},
		},
	},
	{
		.prod_num = IQS7222_PROD_NUM_C,
		.fw_major = 1,
		.fw_minor = 13,
		.sldr_res = U16_MAX,
		.touch_link = 1674,
		.wheel_enable = BIT(3),
		.event_offset = 9,
		.comms_offset = 10,
		.reg_grps = {
			[IQS7222_REG_GRP_STAT] = {
				.base = IQS7222_SYS_STATUS,
				.num_row = 1,
				.num_col = 6,
			},
			[IQS7222_REG_GRP_CYCLE] = {
				.base = 0x8000,
				.num_row = 5,
				.num_col = 3,
			},
			[IQS7222_REG_GRP_GLBL] = {
				.base = 0x8500,
				.num_row = 1,
				.num_col = 3,
			},
			[IQS7222_REG_GRP_BTN] = {
				.base = 0x9000,
				.num_row = 10,
				.num_col = 3,
			},
			[IQS7222_REG_GRP_CHAN] = {
				.base = 0xA000,
				.num_row = 10,
				.num_col = 6,
			},
			[IQS7222_REG_GRP_FILT] = {
				.base = 0xAA00,
				.num_row = 1,
				.num_col = 2,
			},
			[IQS7222_REG_GRP_SLDR] = {
				.base = 0xB000,
				.num_row = 2,
				.num_col = 10,
			},
			[IQS7222_REG_GRP_GPIO] = {
				.base = 0xC000,
				.num_row = 1,
				.num_col = 3,
			},
			[IQS7222_REG_GRP_SYS] = {
				.base = IQS7222_SYS_SETUP,
				.num_row = 1,
				.num_col = 11,
			},
		},
	},
};

struct iqs7222_prop_desc {
	const char *name;
	enum iqs7222_reg_grp_id reg_grp;
	enum iqs7222_reg_key_id reg_key;
	int reg_offset;
	int reg_shift;
	int reg_width;
	int val_pitch;
	int val_min;
	int val_max;
	bool invert;
	const char *label;
};

static const struct iqs7222_prop_desc iqs7222_props[] = {
	{
		.name = "azoteq,conv-period",
		.reg_grp = IQS7222_REG_GRP_CYCLE,
		.reg_offset = 0,
		.reg_shift = 8,
		.reg_width = 8,
		.label = "conversion period",
	},
	{
		.name = "azoteq,conv-frac",
		.reg_grp = IQS7222_REG_GRP_CYCLE,
		.reg_offset = 0,
		.reg_shift = 0,
		.reg_width = 8,
		.label = "conversion frequency fractional divider",
	},
	{
		.name = "azoteq,rx-float-inactive",
		.reg_grp = IQS7222_REG_GRP_CYCLE,
		.reg_offset = 1,
		.reg_shift = 6,
		.reg_width = 1,
		.invert = true,
	},
	{
		.name = "azoteq,dead-time-enable",
		.reg_grp = IQS7222_REG_GRP_CYCLE,
		.reg_offset = 1,
		.reg_shift = 5,
		.reg_width = 1,
	},
	{
		.name = "azoteq,tx-freq-fosc",
		.reg_grp = IQS7222_REG_GRP_CYCLE,
		.reg_offset = 1,
		.reg_shift = 4,
		.reg_width = 1,
	},
	{
		.name = "azoteq,vbias-enable",
		.reg_grp = IQS7222_REG_GRP_CYCLE,
		.reg_offset = 1,
		.reg_shift = 3,
		.reg_width = 1,
	},
	{
		.name = "azoteq,sense-mode",
		.reg_grp = IQS7222_REG_GRP_CYCLE,
		.reg_offset = 1,
		.reg_shift = 0,
		.reg_width = 3,
		.val_max = 3,
		.label = "sensing mode",
	},
	{
		.name = "azoteq,iref-enable",
		.reg_grp = IQS7222_REG_GRP_CYCLE,
		.reg_offset = 2,
		.reg_shift = 10,
		.reg_width = 1,
	},
	{
		.name = "azoteq,iref-level",
		.reg_grp = IQS7222_REG_GRP_CYCLE,
		.reg_offset = 2,
		.reg_shift = 4,
		.reg_width = 4,
		.label = "current reference level",
	},
	{
		.name = "azoteq,iref-trim",
		.reg_grp = IQS7222_REG_GRP_CYCLE,
		.reg_offset = 2,
		.reg_shift = 0,
		.reg_width = 4,
		.label = "current reference trim",
	},
	{
		.name = "azoteq,rf-filt-enable",
		.reg_grp = IQS7222_REG_GRP_GLBL,
		.reg_offset = 0,
		.reg_shift = 15,
		.reg_width = 1,
	},
	{
		.name = "azoteq,max-counts",
		.reg_grp = IQS7222_REG_GRP_GLBL,
		.reg_offset = 0,
		.reg_shift = 13,
		.reg_width = 2,
		.label = "maximum counts",
	},
	{
		.name = "azoteq,auto-mode",
		.reg_grp = IQS7222_REG_GRP_GLBL,
		.reg_offset = 0,
		.reg_shift = 2,
		.reg_width = 2,
		.label = "number of conversions",
	},
	{
		.name = "azoteq,ati-frac-div-fine",
		.reg_grp = IQS7222_REG_GRP_GLBL,
		.reg_offset = 1,
		.reg_shift = 9,
		.reg_width = 5,
		.label = "ATI fine fractional divider",
	},
	{
		.name = "azoteq,ati-frac-div-coarse",
		.reg_grp = IQS7222_REG_GRP_GLBL,
		.reg_offset = 1,
		.reg_shift = 0,
		.reg_width = 5,
		.label = "ATI coarse fractional divider",
	},
	{
		.name = "azoteq,ati-comp-select",
		.reg_grp = IQS7222_REG_GRP_GLBL,
		.reg_offset = 2,
		.reg_shift = 0,
		.reg_width = 10,
		.label = "ATI compensation selection",
	},
	{
		.name = "azoteq,ati-band",
		.reg_grp = IQS7222_REG_GRP_CHAN,
		.reg_offset = 0,
		.reg_shift = 12,
		.reg_width = 2,
		.label = "ATI band",
	},
	{
		.name = "azoteq,global-halt",
		.reg_grp = IQS7222_REG_GRP_CHAN,
		.reg_offset = 0,
		.reg_shift = 11,
		.reg_width = 1,
	},
	{
		.name = "azoteq,invert-enable",
		.reg_grp = IQS7222_REG_GRP_CHAN,
		.reg_offset = 0,
		.reg_shift = 10,
		.reg_width = 1,
	},
	{
		.name = "azoteq,dual-direction",
		.reg_grp = IQS7222_REG_GRP_CHAN,
		.reg_offset = 0,
		.reg_shift = 9,
		.reg_width = 1,
	},
	{
		.name = "azoteq,samp-cap-double",
		.reg_grp = IQS7222_REG_GRP_CHAN,
		.reg_offset = 0,
		.reg_shift = 3,
		.reg_width = 1,
	},
	{
		.name = "azoteq,vref-half",
		.reg_grp = IQS7222_REG_GRP_CHAN,
		.reg_offset = 0,
		.reg_shift = 2,
		.reg_width = 1,
	},
	{
		.name = "azoteq,proj-bias",
		.reg_grp = IQS7222_REG_GRP_CHAN,
		.reg_offset = 0,
		.reg_shift = 0,
		.reg_width = 2,
		.label = "projected bias current",
	},
	{
		.name = "azoteq,ati-target",
		.reg_grp = IQS7222_REG_GRP_CHAN,
		.reg_offset = 1,
		.reg_shift = 8,
		.reg_width = 8,
		.val_pitch = 8,
		.label = "ATI target",
	},
	{
		.name = "azoteq,ati-base",
		.reg_grp = IQS7222_REG_GRP_CHAN,
		.reg_offset = 1,
		.reg_shift = 3,
		.reg_width = 5,
		.val_pitch = 16,
		.label = "ATI base",
	},
	{
		.name = "azoteq,ati-mode",
		.reg_grp = IQS7222_REG_GRP_CHAN,
		.reg_offset = 1,
		.reg_shift = 0,
		.reg_width = 3,
		.val_max = 5,
		.label = "ATI mode",
	},
	{
		.name = "azoteq,ati-frac-div-fine",
		.reg_grp = IQS7222_REG_GRP_CHAN,
		.reg_offset = 2,
		.reg_shift = 9,
		.reg_width = 5,
		.label = "ATI fine fractional divider",
	},
	{
		.name = "azoteq,ati-frac-mult-coarse",
		.reg_grp = IQS7222_REG_GRP_CHAN,
		.reg_offset = 2,
		.reg_shift = 5,
		.reg_width = 4,
		.label = "ATI coarse fractional multiplier",
	},
	{
		.name = "azoteq,ati-frac-div-coarse",
		.reg_grp = IQS7222_REG_GRP_CHAN,
		.reg_offset = 2,
		.reg_shift = 0,
		.reg_width = 5,
		.label = "ATI coarse fractional divider",
	},
	{
		.name = "azoteq,ati-comp-div",
		.reg_grp = IQS7222_REG_GRP_CHAN,
		.reg_offset = 3,
		.reg_shift = 11,
		.reg_width = 5,
		.label = "ATI compensation divider",
	},
	{
		.name = "azoteq,ati-comp-select",
		.reg_grp = IQS7222_REG_GRP_CHAN,
		.reg_offset = 3,
		.reg_shift = 0,
		.reg_width = 10,
		.label = "ATI compensation selection",
	},
	{
		.name = "azoteq,debounce-exit",
		.reg_grp = IQS7222_REG_GRP_BTN,
		.reg_key = IQS7222_REG_KEY_DEBOUNCE,
		.reg_offset = 0,
		.reg_shift = 12,
		.reg_width = 4,
		.label = "debounce exit factor",
	},
	{
		.name = "azoteq,debounce-enter",
		.reg_grp = IQS7222_REG_GRP_BTN,
		.reg_key = IQS7222_REG_KEY_DEBOUNCE,
		.reg_offset = 0,
		.reg_shift = 8,
		.reg_width = 4,
		.label = "debounce entrance factor",
	},
	{
		.name = "azoteq,thresh",
		.reg_grp = IQS7222_REG_GRP_BTN,
		.reg_key = IQS7222_REG_KEY_PROX,
		.reg_offset = 0,
		.reg_shift = 0,
		.reg_width = 8,
		.val_max = 127,
		.label = "threshold",
	},
	{
		.name = "azoteq,thresh",
		.reg_grp = IQS7222_REG_GRP_BTN,
		.reg_key = IQS7222_REG_KEY_TOUCH,
		.reg_offset = 1,
		.reg_shift = 0,
		.reg_width = 8,
		.label = "threshold",
	},
	{
		.name = "azoteq,hyst",
		.reg_grp = IQS7222_REG_GRP_BTN,
		.reg_key = IQS7222_REG_KEY_TOUCH,
		.reg_offset = 1,
		.reg_shift = 8,
		.reg_width = 8,
		.label = "hysteresis",
	},
	{
		.name = "azoteq,lta-beta-lp",
		.reg_grp = IQS7222_REG_GRP_FILT,
		.reg_offset = 0,
		.reg_shift = 12,
		.reg_width = 4,
		.label = "low-power mode long-term average beta",
	},
	{
		.name = "azoteq,lta-beta-np",
		.reg_grp = IQS7222_REG_GRP_FILT,
		.reg_offset = 0,
		.reg_shift = 8,
		.reg_width = 4,
		.label = "normal-power mode long-term average beta",
	},
	{
		.name = "azoteq,counts-beta-lp",
		.reg_grp = IQS7222_REG_GRP_FILT,
		.reg_offset = 0,
		.reg_shift = 4,
		.reg_width = 4,
		.label = "low-power mode counts beta",
	},
	{
		.name = "azoteq,counts-beta-np",
		.reg_grp = IQS7222_REG_GRP_FILT,
		.reg_offset = 0,
		.reg_shift = 0,
		.reg_width = 4,
		.label = "normal-power mode counts beta",
	},
	{
		.name = "azoteq,lta-fast-beta-lp",
		.reg_grp = IQS7222_REG_GRP_FILT,
		.reg_offset = 1,
		.reg_shift = 4,
		.reg_width = 4,
		.label = "low-power mode long-term average fast beta",
	},
	{
		.name = "azoteq,lta-fast-beta-np",
		.reg_grp = IQS7222_REG_GRP_FILT,
		.reg_offset = 1,
		.reg_shift = 0,
		.reg_width = 4,
		.label = "normal-power mode long-term average fast beta",
	},
	{
		.name = "azoteq,lower-cal",
		.reg_grp = IQS7222_REG_GRP_SLDR,
		.reg_offset = 0,
		.reg_shift = 8,
		.reg_width = 8,
		.label = "lower calibration",
	},
	{
		.name = "azoteq,static-beta",
		.reg_grp = IQS7222_REG_GRP_SLDR,
		.reg_key = IQS7222_REG_KEY_NO_WHEEL,
		.reg_offset = 0,
		.reg_shift = 6,
		.reg_width = 1,
	},
	{
		.name = "azoteq,bottom-beta",
		.reg_grp = IQS7222_REG_GRP_SLDR,
		.reg_key = IQS7222_REG_KEY_NO_WHEEL,
		.reg_offset = 0,
		.reg_shift = 3,
		.reg_width = 3,
		.label = "bottom beta",
	},
	{
		.name = "azoteq,static-beta",
		.reg_grp = IQS7222_REG_GRP_SLDR,
		.reg_key = IQS7222_REG_KEY_WHEEL,
		.reg_offset = 0,
		.reg_shift = 7,
		.reg_width = 1,
	},
	{
		.name = "azoteq,bottom-beta",
		.reg_grp = IQS7222_REG_GRP_SLDR,
		.reg_key = IQS7222_REG_KEY_WHEEL,
		.reg_offset = 0,
		.reg_shift = 4,
		.reg_width = 3,
		.label = "bottom beta",
	},
	{
		.name = "azoteq,bottom-speed",
		.reg_grp = IQS7222_REG_GRP_SLDR,
		.reg_offset = 1,
		.reg_shift = 8,
		.reg_width = 8,
		.label = "bottom speed",
	},
	{
		.name = "azoteq,upper-cal",
		.reg_grp = IQS7222_REG_GRP_SLDR,
		.reg_offset = 1,
		.reg_shift = 0,
		.reg_width = 8,
		.label = "upper calibration",
	},
	{
		.name = "azoteq,gesture-max-ms",
		.reg_grp = IQS7222_REG_GRP_SLDR,
		.reg_key = IQS7222_REG_KEY_TAP,
		.reg_offset = 9,
		.reg_shift = 8,
		.reg_width = 8,
		.val_pitch = 4,
		.label = "maximum gesture time",
	},
	{
		.name = "azoteq,gesture-min-ms",
		.reg_grp = IQS7222_REG_GRP_SLDR,
		.reg_key = IQS7222_REG_KEY_TAP,
		.reg_offset = 9,
		.reg_shift = 3,
		.reg_width = 5,
		.val_pitch = 4,
		.label = "minimum gesture time",
	},
	{
		.name = "azoteq,gesture-dist",
		.reg_grp = IQS7222_REG_GRP_SLDR,
		.reg_key = IQS7222_REG_KEY_AXIAL,
		.reg_offset = 10,
		.reg_shift = 8,
		.reg_width = 8,
		.val_pitch = 16,
		.label = "gesture distance",
	},
	{
		.name = "azoteq,gesture-max-ms",
		.reg_grp = IQS7222_REG_GRP_SLDR,
		.reg_key = IQS7222_REG_KEY_AXIAL,
		.reg_offset = 10,
		.reg_shift = 0,
		.reg_width = 8,
		.val_pitch = 4,
		.label = "maximum gesture time",
	},
	{
		.name = "drive-open-drain",
		.reg_grp = IQS7222_REG_GRP_GPIO,
		.reg_offset = 0,
		.reg_shift = 1,
		.reg_width = 1,
	},
	{
		.name = "azoteq,timeout-ati-ms",
		.reg_grp = IQS7222_REG_GRP_SYS,
		.reg_offset = 1,
		.reg_shift = 0,
		.reg_width = 16,
		.val_pitch = 500,
		.label = "ATI error timeout",
	},
	{
		.name = "azoteq,rate-ati-ms",
		.reg_grp = IQS7222_REG_GRP_SYS,
		.reg_offset = 2,
		.reg_shift = 0,
		.reg_width = 16,
		.label = "ATI report rate",
	},
	{
		.name = "azoteq,timeout-np-ms",
		.reg_grp = IQS7222_REG_GRP_SYS,
		.reg_offset = 3,
		.reg_shift = 0,
		.reg_width = 16,
		.label = "normal-power mode timeout",
	},
	{
		.name = "azoteq,rate-np-ms",
		.reg_grp = IQS7222_REG_GRP_SYS,
		.reg_offset = 4,
		.reg_shift = 0,
		.reg_width = 16,
		.val_max = 3000,
		.label = "normal-power mode report rate",
	},
	{
		.name = "azoteq,timeout-lp-ms",
		.reg_grp = IQS7222_REG_GRP_SYS,
		.reg_offset = 5,
		.reg_shift = 0,
		.reg_width = 16,
		.label = "low-power mode timeout",
	},
	{
		.name = "azoteq,rate-lp-ms",
		.reg_grp = IQS7222_REG_GRP_SYS,
		.reg_offset = 6,
		.reg_shift = 0,
		.reg_width = 16,
		.val_max = 3000,
		.label = "low-power mode report rate",
	},
	{
		.name = "azoteq,timeout-ulp-ms",
		.reg_grp = IQS7222_REG_GRP_SYS,
		.reg_offset = 7,
		.reg_shift = 0,
		.reg_width = 16,
		.label = "ultra-low-power mode timeout",
	},
	{
		.name = "azoteq,rate-ulp-ms",
		.reg_grp = IQS7222_REG_GRP_SYS,
		.reg_offset = 8,
		.reg_shift = 0,
		.reg_width = 16,
		.val_max = 3000,
		.label = "ultra-low-power mode report rate",
	},
};

struct iqs7222_private {
	const struct iqs7222_dev_desc *dev_desc;
	struct gpio_desc *reset_gpio;
	struct gpio_desc *irq_gpio;
	struct i2c_client *client;
	struct input_dev *keypad;
	unsigned int kp_type[IQS7222_MAX_CHAN][ARRAY_SIZE(iqs7222_kp_events)];
	unsigned int kp_code[IQS7222_MAX_CHAN][ARRAY_SIZE(iqs7222_kp_events)];
	unsigned int sl_code[IQS7222_MAX_SLDR][ARRAY_SIZE(iqs7222_sl_events)];
	unsigned int sl_axis[IQS7222_MAX_SLDR];
	u16 cycle_setup[IQS7222_MAX_CHAN / 2][IQS7222_MAX_COLS_CYCLE];
	u16 glbl_setup[IQS7222_MAX_COLS_GLBL];
	u16 btn_setup[IQS7222_MAX_CHAN][IQS7222_MAX_COLS_BTN];
	u16 chan_setup[IQS7222_MAX_CHAN][IQS7222_MAX_COLS_CHAN];
	u16 filt_setup[IQS7222_MAX_COLS_FILT];
	u16 sldr_setup[IQS7222_MAX_SLDR][IQS7222_MAX_COLS_SLDR];
	u16 gpio_setup[ARRAY_SIZE(iqs7222_gpio_links)][IQS7222_MAX_COLS_GPIO];
	u16 sys_setup[IQS7222_MAX_COLS_SYS];
};

static u16 *iqs7222_setup(struct iqs7222_private *iqs7222,
			  enum iqs7222_reg_grp_id reg_grp, int row)
{
	switch (reg_grp) {
	case IQS7222_REG_GRP_CYCLE:
		return iqs7222->cycle_setup[row];

	case IQS7222_REG_GRP_GLBL:
		return iqs7222->glbl_setup;

	case IQS7222_REG_GRP_BTN:
		return iqs7222->btn_setup[row];

	case IQS7222_REG_GRP_CHAN:
		return iqs7222->chan_setup[row];

	case IQS7222_REG_GRP_FILT:
		return iqs7222->filt_setup;

	case IQS7222_REG_GRP_SLDR:
		return iqs7222->sldr_setup[row];

	case IQS7222_REG_GRP_GPIO:
		return iqs7222->gpio_setup[row];

	case IQS7222_REG_GRP_SYS:
		return iqs7222->sys_setup;

	default:
		return NULL;
	}
}

static int iqs7222_irq_poll(struct iqs7222_private *iqs7222, u16 timeout_ms)
{
	ktime_t irq_timeout = ktime_add_ms(ktime_get(), timeout_ms);
	int ret;

	do {
		usleep_range(1000, 1100);

		ret = gpiod_get_value_cansleep(iqs7222->irq_gpio);
		if (ret < 0)
			return ret;
		else if (ret > 0)
			return 0;
	} while (ktime_compare(ktime_get(), irq_timeout) < 0);

	return -EBUSY;
}

static int iqs7222_hard_reset(struct iqs7222_private *iqs7222)
{
	struct i2c_client *client = iqs7222->client;
	int error;

	if (!iqs7222->reset_gpio)
		return 0;

	gpiod_set_value_cansleep(iqs7222->reset_gpio, 1);
	usleep_range(1000, 1100);

	gpiod_set_value_cansleep(iqs7222->reset_gpio, 0);

	error = iqs7222_irq_poll(iqs7222, IQS7222_RESET_TIMEOUT_MS);
	if (error)
		dev_err(&client->dev, "Failed to reset device: %d\n", error);

	return error;
}

static int iqs7222_force_comms(struct iqs7222_private *iqs7222)
{
	u8 msg_buf[] = { 0xFF, 0x00, };
	int ret;

	/*
	 * The device cannot communicate until it asserts its interrupt (RDY)
	 * pin. Attempts to do so while RDY is deasserted return an ACK; how-
	 * ever all write data is ignored, and all read data returns 0xEE.
	 *
	 * Unsolicited communication must be preceded by a special force com-
	 * munication command, after which the device eventually asserts its
	 * RDY pin and agrees to communicate.
	 *
	 * Regardless of whether communication is forced or the result of an
	 * interrupt, the device automatically deasserts its RDY pin once it
	 * detects an I2C stop condition, or a timeout expires.
	 */
	ret = gpiod_get_value_cansleep(iqs7222->irq_gpio);
	if (ret < 0)
		return ret;
	else if (ret > 0)
		return 0;

	ret = i2c_master_send(iqs7222->client, msg_buf, sizeof(msg_buf));
	if (ret < (int)sizeof(msg_buf)) {
		if (ret >= 0)
			ret = -EIO;

		/*
		 * The datasheet states that the host must wait to retry any
		 * failed attempt to communicate over I2C.
		 */
		msleep(IQS7222_COMMS_RETRY_MS);
		return ret;
	}

	return iqs7222_irq_poll(iqs7222, IQS7222_COMMS_TIMEOUT_MS);
}

static int iqs7222_read_burst(struct iqs7222_private *iqs7222,
			      u16 reg, void *val, u16 num_val)
{
	u8 reg_buf[sizeof(__be16)];
	int ret, i;
	struct i2c_client *client = iqs7222->client;
	struct i2c_msg msg[] = {
		{
			.addr = client->addr,
			.flags = 0,
			.len = reg > U8_MAX ? sizeof(reg) : sizeof(u8),
			.buf = reg_buf,
		},
		{
			.addr = client->addr,
			.flags = I2C_M_RD,
			.len = num_val * sizeof(__le16),
			.buf = (u8 *)val,
		},
	};

	if (reg > U8_MAX)
		put_unaligned_be16(reg, reg_buf);
	else
		*reg_buf = (u8)reg;

	/*
	 * The following loop protects against an edge case in which the RDY
	 * pin is automatically deasserted just as the read is initiated. In
	 * that case, the read must be retried using forced communication.
	 */
	for (i = 0; i < IQS7222_NUM_RETRIES; i++) {
		ret = iqs7222_force_comms(iqs7222);
		if (ret < 0)
			continue;

		ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
		if (ret < (int)ARRAY_SIZE(msg)) {
			if (ret >= 0)
				ret = -EIO;

			msleep(IQS7222_COMMS_RETRY_MS);
			continue;
		}

		if (get_unaligned_le16(msg[1].buf) == IQS7222_COMMS_ERROR) {
			ret = -ENODATA;
			continue;
		}

		ret = 0;
		break;
	}

	/*
	 * The following delay ensures the device has deasserted the RDY pin
	 * following the I2C stop condition.
	 */
	usleep_range(50, 100);

	if (ret < 0)
		dev_err(&client->dev,
			"Failed to read from address 0x%04X: %d\n", reg, ret);

	return ret;
}

static int iqs7222_read_word(struct iqs7222_private *iqs7222, u16 reg, u16 *val)
{
	__le16 val_buf;
	int error;

	error = iqs7222_read_burst(iqs7222, reg, &val_buf, 1);
	if (error)
		return error;

	*val = le16_to_cpu(val_buf);

	return 0;
}

static int iqs7222_write_burst(struct iqs7222_private *iqs7222,
			       u16 reg, const void *val, u16 num_val)
{
	int reg_len = reg > U8_MAX ? sizeof(reg) : sizeof(u8);
	int val_len = num_val * sizeof(__le16);
	int msg_len = reg_len + val_len;
	int ret, i;
	struct i2c_client *client = iqs7222->client;
	u8 *msg_buf;

	msg_buf = kzalloc(msg_len, GFP_KERNEL);
	if (!msg_buf)
		return -ENOMEM;

	if (reg > U8_MAX)
		put_unaligned_be16(reg, msg_buf);
	else
		*msg_buf = (u8)reg;

	memcpy(msg_buf + reg_len, val, val_len);

	/*
	 * The following loop protects against an edge case in which the RDY
	 * pin is automatically asserted just before the force communication
	 * command is sent.
	 *
	 * In that case, the subsequent I2C stop condition tricks the device
	 * into preemptively deasserting the RDY pin and the command must be
	 * sent again.
	 */
	for (i = 0; i < IQS7222_NUM_RETRIES; i++) {
		ret = iqs7222_force_comms(iqs7222);
		if (ret < 0)
			continue;

		ret = i2c_master_send(client, msg_buf, msg_len);
		if (ret < msg_len) {
			if (ret >= 0)
				ret = -EIO;

			msleep(IQS7222_COMMS_RETRY_MS);
			continue;
		}

		ret = 0;
		break;
	}

	kfree(msg_buf);

	usleep_range(50, 100);

	if (ret < 0)
		dev_err(&client->dev,
			"Failed to write to address 0x%04X: %d\n", reg, ret);

	return ret;
}

static int iqs7222_write_word(struct iqs7222_private *iqs7222, u16 reg, u16 val)
{
	__le16 val_buf = cpu_to_le16(val);

	return iqs7222_write_burst(iqs7222, reg, &val_buf, 1);
}

static int iqs7222_ati_trigger(struct iqs7222_private *iqs7222)
{
	struct i2c_client *client = iqs7222->client;
	ktime_t ati_timeout;
	u16 sys_status = 0;
	u16 sys_setup = iqs7222->sys_setup[0] & ~IQS7222_SYS_SETUP_ACK_RESET;
	int error, i;

	for (i = 0; i < IQS7222_NUM_RETRIES; i++) {
		/*
		 * Trigger ATI from streaming and normal-power modes so that
		 * the RDY pin continues to be asserted during ATI.
		 */
		error = iqs7222_write_word(iqs7222, IQS7222_SYS_SETUP,
					   sys_setup |
					   IQS7222_SYS_SETUP_REDO_ATI);
		if (error)
			return error;

		ati_timeout = ktime_add_ms(ktime_get(), IQS7222_ATI_TIMEOUT_MS);

		do {
			error = iqs7222_irq_poll(iqs7222,
						 IQS7222_COMMS_TIMEOUT_MS);
			if (error)
				continue;

			error = iqs7222_read_word(iqs7222, IQS7222_SYS_STATUS,
						  &sys_status);
			if (error)
				return error;

			if (sys_status & IQS7222_SYS_STATUS_ATI_ACTIVE)
				continue;

			if (sys_status & IQS7222_SYS_STATUS_ATI_ERROR)
				break;

			/*
			 * Use stream-in-touch mode if either slider reports
			 * absolute position.
			 */
			sys_setup |= test_bit(EV_ABS, iqs7222->keypad->evbit)
				   ? IQS7222_SYS_SETUP_INTF_MODE_TOUCH
				   : IQS7222_SYS_SETUP_INTF_MODE_EVENT;
			sys_setup |= IQS7222_SYS_SETUP_PWR_MODE_AUTO;

			return iqs7222_write_word(iqs7222, IQS7222_SYS_SETUP,
						  sys_setup);
		} while (ktime_compare(ktime_get(), ati_timeout) < 0);

		dev_err(&client->dev,
			"ATI attempt %d of %d failed with status 0x%02X, %s\n",
			i + 1, IQS7222_NUM_RETRIES, (u8)sys_status,
			i < IQS7222_NUM_RETRIES ? "retrying..." : "stopping");
	}

	return -ETIMEDOUT;
}

static int iqs7222_dev_init(struct iqs7222_private *iqs7222, int dir)
{
	const struct iqs7222_dev_desc *dev_desc = iqs7222->dev_desc;
	int comms_offset = dev_desc->comms_offset;
	int error, i, j, k;

	/*
	 * Take advantage of the stop-bit disable function, if available, to
	 * save the trouble of having to reopen a communication window after
	 * each burst read or write.
	 */
	if (comms_offset) {
		u16 comms_setup;

		error = iqs7222_read_word(iqs7222,
					  IQS7222_SYS_SETUP + comms_offset,
					  &comms_setup);
		if (error)
			return error;

		error = iqs7222_write_word(iqs7222,
					   IQS7222_SYS_SETUP + comms_offset,
					   comms_setup | IQS7222_COMMS_HOLD);
		if (error)
			return error;
	}

	for (i = 0; i < IQS7222_NUM_REG_GRPS; i++) {
		int num_row = dev_desc->reg_grps[i].num_row;
		int num_col = dev_desc->reg_grps[i].num_col;
		u16 reg = dev_desc->reg_grps[i].base;
		__le16 *val_buf;
		u16 *val;

		if (!num_col)
			continue;

		val = iqs7222_setup(iqs7222, i, 0);
		if (!val)
			continue;

		val_buf = kcalloc(num_col, sizeof(__le16), GFP_KERNEL);
		if (!val_buf)
			return -ENOMEM;

		for (j = 0; j < num_row; j++) {
			switch (dir) {
			case READ:
				error = iqs7222_read_burst(iqs7222, reg,
							   val_buf, num_col);
				for (k = 0; k < num_col; k++)
					val[k] = le16_to_cpu(val_buf[k]);
				break;

			case WRITE:
				for (k = 0; k < num_col; k++)
					val_buf[k] = cpu_to_le16(val[k]);
				error = iqs7222_write_burst(iqs7222, reg,
							    val_buf, num_col);
				break;

			default:
				error = -EINVAL;
			}

			if (error)
				break;

			reg += IQS7222_REG_OFFSET;
			val += iqs7222_max_cols[i];
		}

		kfree(val_buf);

		if (error)
			return error;
	}

	if (comms_offset) {
		u16 comms_setup;

		error = iqs7222_read_word(iqs7222,
					  IQS7222_SYS_SETUP + comms_offset,
					  &comms_setup);
		if (error)
			return error;

		error = iqs7222_write_word(iqs7222,
					   IQS7222_SYS_SETUP + comms_offset,
					   comms_setup & ~IQS7222_COMMS_HOLD);
		if (error)
			return error;
	}

	if (dir == READ)
		return 0;

	return iqs7222_ati_trigger(iqs7222);
}

static int iqs7222_dev_info(struct iqs7222_private *iqs7222)
{
	struct i2c_client *client = iqs7222->client;
	bool prod_num_valid = false;
	__le16 dev_id[3];
	int error, i;

	error = iqs7222_read_burst(iqs7222, IQS7222_PROD_NUM, dev_id,
				   ARRAY_SIZE(dev_id));
	if (error)
		return error;

	for (i = 0; i < ARRAY_SIZE(iqs7222_devs); i++) {
		if (le16_to_cpu(dev_id[0]) != iqs7222_devs[i].prod_num)
			continue;

		prod_num_valid = true;

		if (le16_to_cpu(dev_id[1]) < iqs7222_devs[i].fw_major)
			continue;

		if (le16_to_cpu(dev_id[2]) < iqs7222_devs[i].fw_minor)
			continue;

		iqs7222->dev_desc = &iqs7222_devs[i];
		return 0;
	}

	if (prod_num_valid)
		dev_err(&client->dev, "Unsupported firmware revision: %u.%u\n",
			le16_to_cpu(dev_id[1]), le16_to_cpu(dev_id[2]));
	else
		dev_err(&client->dev, "Unrecognized product number: %u\n",
			le16_to_cpu(dev_id[0]));

	return -EINVAL;
}

static int iqs7222_gpio_select(struct iqs7222_private *iqs7222,
			       struct fwnode_handle *child_node,
			       int child_enable, u16 child_link)
{
	const struct iqs7222_dev_desc *dev_desc = iqs7222->dev_desc;
	struct i2c_client *client = iqs7222->client;
	int num_gpio = dev_desc->reg_grps[IQS7222_REG_GRP_GPIO].num_row;
	int error, count, i;
	unsigned int gpio_sel[ARRAY_SIZE(iqs7222_gpio_links)];

	if (!num_gpio)
		return 0;

	if (!fwnode_property_present(child_node, "azoteq,gpio-select"))
		return 0;

	count = fwnode_property_count_u32(child_node, "azoteq,gpio-select");
	if (count > num_gpio) {
		dev_err(&client->dev, "Invalid number of %s GPIOs\n",
			fwnode_get_name(child_node));
		return -EINVAL;
	} else if (count < 0) {
		dev_err(&client->dev, "Failed to count %s GPIOs: %d\n",
			fwnode_get_name(child_node), count);
		return count;
	}

	error = fwnode_property_read_u32_array(child_node,
					       "azoteq,gpio-select",
					       gpio_sel, count);
	if (error) {
		dev_err(&client->dev, "Failed to read %s GPIOs: %d\n",
			fwnode_get_name(child_node), error);
		return error;
	}

	for (i = 0; i < count; i++) {
		u16 *gpio_setup;

		if (gpio_sel[i] >= num_gpio) {
			dev_err(&client->dev, "Invalid %s GPIO: %u\n",
				fwnode_get_name(child_node), gpio_sel[i]);
			return -EINVAL;
		}

		gpio_setup = iqs7222->gpio_setup[gpio_sel[i]];

		if (gpio_setup[2] && child_link != gpio_setup[2]) {
			dev_err(&client->dev,
				"Conflicting GPIO %u event types\n",
				gpio_sel[i]);
			return -EINVAL;
		}

		gpio_setup[0] |= IQS7222_GPIO_SETUP_0_GPIO_EN;
		gpio_setup[1] |= child_enable;
		gpio_setup[2] = child_link;
	}

	return 0;
}

static int iqs7222_parse_props(struct iqs7222_private *iqs7222,
			       struct fwnode_handle **child_node,
			       int child_index,
			       enum iqs7222_reg_grp_id reg_grp,
			       enum iqs7222_reg_key_id reg_key)
{
	u16 *setup = iqs7222_setup(iqs7222, reg_grp, child_index);
	struct i2c_client *client = iqs7222->client;
	struct fwnode_handle *reg_grp_node;
	char reg_grp_name[16];
	int i;

	switch (reg_grp) {
	case IQS7222_REG_GRP_CYCLE:
	case IQS7222_REG_GRP_CHAN:
	case IQS7222_REG_GRP_SLDR:
	case IQS7222_REG_GRP_GPIO:
	case IQS7222_REG_GRP_BTN:
		/*
		 * These groups derive a child node and return it to the caller
		 * for additional group-specific processing. In some cases, the
		 * child node may have already been derived.
		 */
		reg_grp_node = *child_node;
		if (reg_grp_node)
			break;

		snprintf(reg_grp_name, sizeof(reg_grp_name), "%s-%d",
			 iqs7222_reg_grp_names[reg_grp], child_index);

		reg_grp_node = device_get_named_child_node(&client->dev,
							   reg_grp_name);
		if (!reg_grp_node)
			return 0;

		*child_node = reg_grp_node;
		break;

	case IQS7222_REG_GRP_GLBL:
	case IQS7222_REG_GRP_FILT:
	case IQS7222_REG_GRP_SYS:
		/*
		 * These groups are not organized beneath a child node, nor are
		 * they subject to any additional processing by the caller.
		 */
		reg_grp_node = dev_fwnode(&client->dev);
		break;

	default:
		return -EINVAL;
	}

	for (i = 0; i < ARRAY_SIZE(iqs7222_props); i++) {
		const char *name = iqs7222_props[i].name;
		int reg_offset = iqs7222_props[i].reg_offset;
		int reg_shift = iqs7222_props[i].reg_shift;
		int reg_width = iqs7222_props[i].reg_width;
		int val_pitch = iqs7222_props[i].val_pitch ? : 1;
		int val_min = iqs7222_props[i].val_min;
		int val_max = iqs7222_props[i].val_max;
		bool invert = iqs7222_props[i].invert;
		const char *label = iqs7222_props[i].label ? : name;
		unsigned int val;
		int error;

		if (iqs7222_props[i].reg_grp != reg_grp ||
		    iqs7222_props[i].reg_key != reg_key)
			continue;

		/*
		 * Boolean register fields are one bit wide; they are forcibly
		 * reset to provide a means to undo changes by a bootloader if
		 * necessary.
		 *
		 * Scalar fields, on the other hand, are left untouched unless
		 * their corresponding properties are present.
		 */
		if (reg_width == 1) {
			if (invert)
				setup[reg_offset] |= BIT(reg_shift);
			else
				setup[reg_offset] &= ~BIT(reg_shift);
		}

		if (!fwnode_property_present(reg_grp_node, name))
			continue;

		if (reg_width == 1) {
			if (invert)
				setup[reg_offset] &= ~BIT(reg_shift);
			else
				setup[reg_offset] |= BIT(reg_shift);

			continue;
		}

		error = fwnode_property_read_u32(reg_grp_node, name, &val);
		if (error) {
			dev_err(&client->dev, "Failed to read %s %s: %d\n",
				fwnode_get_name(reg_grp_node), label, error);
			return error;
		}

		if (!val_max)
			val_max = GENMASK(reg_width - 1, 0) * val_pitch;

		if (val < val_min || val > val_max) {
			dev_err(&client->dev, "Invalid %s %s: %u\n",
				fwnode_get_name(reg_grp_node), label, val);
			return -EINVAL;
		}

		setup[reg_offset] &= ~GENMASK(reg_shift + reg_width - 1,
					      reg_shift);
		setup[reg_offset] |= (val / val_pitch << reg_shift);
	}

	return 0;
}

static int iqs7222_parse_cycle(struct iqs7222_private *iqs7222, int cycle_index)
{
	u16 *cycle_setup = iqs7222->cycle_setup[cycle_index];
	struct i2c_client *client = iqs7222->client;
	struct fwnode_handle *cycle_node = NULL;
	unsigned int pins[9];
	int error, count, i;

	/*
	 * Each channel shares a cycle with one other channel; the mapping of
	 * channels to cycles is fixed. Properties defined for a cycle impact
	 * both channels tied to the cycle.
	 */
	error = iqs7222_parse_props(iqs7222, &cycle_node, cycle_index,
				    IQS7222_REG_GRP_CYCLE,
				    IQS7222_REG_KEY_NONE);
	if (error)
		return error;

	if (!cycle_node)
		return 0;

	/*
	 * Unlike channels which are restricted to a select range of CRx pins
	 * based on channel number, any cycle can claim any of the device's 9
	 * CTx pins (CTx0-8).
	 */
	if (!fwnode_property_present(cycle_node, "azoteq,tx-enable"))
		return 0;

	count = fwnode_property_count_u32(cycle_node, "azoteq,tx-enable");
	if (count < 0) {
		dev_err(&client->dev, "Failed to count %s CTx pins: %d\n",
			fwnode_get_name(cycle_node), count);
		return count;
	} else if (count > ARRAY_SIZE(pins)) {
		dev_err(&client->dev, "Invalid number of %s CTx pins\n",
			fwnode_get_name(cycle_node));
		return -EINVAL;
	}

	error = fwnode_property_read_u32_array(cycle_node, "azoteq,tx-enable",
					       pins, count);
	if (error) {
		dev_err(&client->dev, "Failed to read %s CTx pins: %d\n",
			fwnode_get_name(cycle_node), error);
		return error;
	}

	cycle_setup[1] &= ~GENMASK(7 + ARRAY_SIZE(pins) - 1, 7);

	for (i = 0; i < count; i++) {
		if (pins[i] > 8) {
			dev_err(&client->dev, "Invalid %s CTx pin: %u\n",
				fwnode_get_name(cycle_node), pins[i]);
			return -EINVAL;
		}

		cycle_setup[1] |= BIT(pins[i] + 7);
	}

	return 0;
}

static int iqs7222_parse_chan(struct iqs7222_private *iqs7222, int chan_index)
{
	const struct iqs7222_dev_desc *dev_desc = iqs7222->dev_desc;
	struct i2c_client *client = iqs7222->client;
	struct fwnode_handle *chan_node = NULL;
	int num_chan = dev_desc->reg_grps[IQS7222_REG_GRP_CHAN].num_row;
	int ext_chan = rounddown(num_chan, 10);
	int error, i;
	u16 *chan_setup = iqs7222->chan_setup[chan_index];
	u16 *sys_setup = iqs7222->sys_setup;
	unsigned int val;

	error = iqs7222_parse_props(iqs7222, &chan_node, chan_index,
				    IQS7222_REG_GRP_CHAN,
				    IQS7222_REG_KEY_NONE);
	if (error)
		return error;

	if (!chan_node)
		return 0;

	if (dev_desc->allow_offset) {
		sys_setup[dev_desc->allow_offset] |= BIT(chan_index);
		if (fwnode_property_present(chan_node, "azoteq,ulp-allow"))
			sys_setup[dev_desc->allow_offset] &= ~BIT(chan_index);
	}

	chan_setup[0] |= IQS7222_CHAN_SETUP_0_CHAN_EN;

	/*
	 * The reference channel function allows for differential measurements
	 * and is only available in the case of IQS7222A or IQS7222C.
	 */
	if (dev_desc->reg_grps[IQS7222_REG_GRP_CHAN].num_col > 4 &&
	    fwnode_property_present(chan_node, "azoteq,ref-select")) {
		u16 *ref_setup;

		error = fwnode_property_read_u32(chan_node, "azoteq,ref-select",
						 &val);
		if (error) {
			dev_err(&client->dev,
				"Failed to read %s reference channel: %d\n",
				fwnode_get_name(chan_node), error);
			return error;
		}

		if (val >= ext_chan) {
			dev_err(&client->dev,
				"Invalid %s reference channel: %u\n",
				fwnode_get_name(chan_node), val);
			return -EINVAL;
		}

		ref_setup = iqs7222->chan_setup[val];

		/*
		 * Configure the current channel as a follower of the selected
		 * reference channel.
		 */
		chan_setup[0] |= IQS7222_CHAN_SETUP_0_REF_MODE_FOLLOW;
		chan_setup[4] = val * 42 + 1048;

		if (!fwnode_property_read_u32(chan_node, "azoteq,ref-weight",
					      &val)) {
			if (val > U16_MAX) {
				dev_err(&client->dev,
					"Invalid %s reference weight: %u\n",
					fwnode_get_name(chan_node), val);
				return -EINVAL;
			}

			chan_setup[5] = val;
		}

		/*
		 * Configure the selected channel as a reference channel which
		 * serves the current channel.
		 */
		ref_setup[0] |= IQS7222_CHAN_SETUP_0_REF_MODE_REF;
		ref_setup[5] |= BIT(chan_index);

		ref_setup[4] = dev_desc->touch_link;
		if (fwnode_property_present(chan_node, "azoteq,use-prox"))
			ref_setup[4] -= 2;
	}

	if (fwnode_property_present(chan_node, "azoteq,rx-enable")) {
		/*
		 * Each channel can claim up to 4 CRx pins. The first half of
		 * the channels can use CRx0-3, while the second half can use
		 * CRx4-7.
		 */
		unsigned int pins[4];
		int count;

		count = fwnode_property_count_u32(chan_node,
						  "azoteq,rx-enable");
		if (count < 0) {
			dev_err(&client->dev,
				"Failed to count %s CRx pins: %d\n",
				fwnode_get_name(chan_node), count);
			return count;
		} else if (count > ARRAY_SIZE(pins)) {
			dev_err(&client->dev,
				"Invalid number of %s CRx pins\n",
				fwnode_get_name(chan_node));
			return -EINVAL;
		}

		error = fwnode_property_read_u32_array(chan_node,
						       "azoteq,rx-enable",
						       pins, count);
		if (error) {
			dev_err(&client->dev,
				"Failed to read %s CRx pins: %d\n",
				fwnode_get_name(chan_node), error);
			return error;
		}

		chan_setup[0] &= ~GENMASK(4 + ARRAY_SIZE(pins) - 1, 4);

		for (i = 0; i < count; i++) {
			int min_crx = chan_index < ext_chan / 2 ? 0 : 4;

			if (pins[i] < min_crx || pins[i] > min_crx + 3) {
				dev_err(&client->dev,
					"Invalid %s CRx pin: %u\n",
					fwnode_get_name(chan_node), pins[i]);
				return -EINVAL;
			}

			chan_setup[0] |= BIT(pins[i] + 4 - min_crx);
		}
	}

	for (i = 0; i < ARRAY_SIZE(iqs7222_kp_events); i++) {
		const char *event_name = iqs7222_kp_events[i].name;
		u16 event_enable = iqs7222_kp_events[i].enable;
		struct fwnode_handle *event_node;

		event_node = fwnode_get_named_child_node(chan_node, event_name);
		if (!event_node)
			continue;

		error = iqs7222_parse_props(iqs7222, &event_node, chan_index,
					    IQS7222_REG_GRP_BTN,
					    iqs7222_kp_events[i].reg_key);
		if (error)
			return error;

		error = iqs7222_gpio_select(iqs7222, event_node,
					    BIT(chan_index),
					    dev_desc->touch_link - (i ? 0 : 2));
		if (error)
			return error;

		if (!fwnode_property_read_u32(event_node,
					      "azoteq,timeout-press-ms",
					      &val)) {
			/*
			 * The IQS7222B employs a global pair of press timeout
			 * registers as opposed to channel-specific registers.
			 */
			u16 *setup = dev_desc->reg_grps
				     [IQS7222_REG_GRP_BTN].num_col > 2 ?
				     &iqs7222->btn_setup[chan_index][2] :
				     &sys_setup[9];

			if (val > U8_MAX * 500) {
				dev_err(&client->dev,
					"Invalid %s press timeout: %u\n",
					fwnode_get_name(chan_node), val);
				return -EINVAL;
			}

			*setup &= ~(U8_MAX << i * 8);
			*setup |= (val / 500 << i * 8);
		}

		error = fwnode_property_read_u32(event_node, "linux,code",
						 &val);
		if (error) {
			dev_err(&client->dev, "Failed to read %s code: %d\n",
				fwnode_get_name(chan_node), error);
			return error;
		}

		iqs7222->kp_code[chan_index][i] = val;
		iqs7222->kp_type[chan_index][i] = EV_KEY;

		if (fwnode_property_present(event_node, "linux,input-type")) {
			error = fwnode_property_read_u32(event_node,
							 "linux,input-type",
							 &val);
			if (error) {
				dev_err(&client->dev,
					"Failed to read %s input type: %d\n",
					fwnode_get_name(chan_node), error);
				return error;
			}

			if (val != EV_KEY && val != EV_SW) {
				dev_err(&client->dev,
					"Invalid %s input type: %u\n",
					fwnode_get_name(chan_node), val);
				return -EINVAL;
			}

			iqs7222->kp_type[chan_index][i] = val;
		}

		/*
		 * Reference channels can opt out of event reporting by using
		 * KEY_RESERVED in place of a true key or switch code.
		 */
		if (iqs7222->kp_type[chan_index][i] == EV_KEY &&
		    iqs7222->kp_code[chan_index][i] == KEY_RESERVED)
			continue;

		input_set_capability(iqs7222->keypad,
				     iqs7222->kp_type[chan_index][i],
				     iqs7222->kp_code[chan_index][i]);

		if (!dev_desc->event_offset)
			continue;

		sys_setup[dev_desc->event_offset] |= event_enable;
	}

	/*
	 * The following call handles a special pair of properties that apply
	 * to a channel node, but reside within the button (event) group.
	 */
	return iqs7222_parse_props(iqs7222, &chan_node, chan_index,
				   IQS7222_REG_GRP_BTN,
				   IQS7222_REG_KEY_DEBOUNCE);
}

static int iqs7222_parse_sldr(struct iqs7222_private *iqs7222, int sldr_index)
{
	const struct iqs7222_dev_desc *dev_desc = iqs7222->dev_desc;
	struct i2c_client *client = iqs7222->client;
	struct fwnode_handle *sldr_node = NULL;
	int num_chan = dev_desc->reg_grps[IQS7222_REG_GRP_CHAN].num_row;
	int ext_chan = rounddown(num_chan, 10);
	int count, error, reg_offset, i;
	u16 *sldr_setup = iqs7222->sldr_setup[sldr_index];
	u16 *sys_setup = iqs7222->sys_setup;
	unsigned int chan_sel[4], val;

	error = iqs7222_parse_props(iqs7222, &sldr_node, sldr_index,
				    IQS7222_REG_GRP_SLDR,
				    IQS7222_REG_KEY_NONE);
	if (error)
		return error;

	if (!sldr_node)
		return 0;

	/*
	 * Each slider can be spread across 3 to 4 channels. It is possible to
	 * select only 2 channels, but doing so prevents the slider from using
	 * the specified resolution.
	 */
	count = fwnode_property_count_u32(sldr_node, "azoteq,channel-select");
	if (count < 0) {
		dev_err(&client->dev, "Failed to count %s channels: %d\n",
			fwnode_get_name(sldr_node), count);
		return count;
	} else if (count < 3 || count > ARRAY_SIZE(chan_sel)) {
		dev_err(&client->dev, "Invalid number of %s channels\n",
			fwnode_get_name(sldr_node));
		return -EINVAL;
	}

	error = fwnode_property_read_u32_array(sldr_node,
					       "azoteq,channel-select",
					       chan_sel, count);
	if (error) {
		dev_err(&client->dev, "Failed to read %s channels: %d\n",
			fwnode_get_name(sldr_node), error);
		return error;
	}

	/*
	 * Resolution and top speed, if small enough, are packed into a single
	 * register. Otherwise, each occupies its own register and the rest of
	 * the slider-related register addresses are offset by one.
	 */
	reg_offset = dev_desc->sldr_res < U16_MAX ? 0 : 1;

	sldr_setup[0] |= count;
	sldr_setup[3 + reg_offset] &= ~IQS7222_SLDR_SETUP_3_CHAN_SEL_MASK;

	for (i = 0; i < ARRAY_SIZE(chan_sel); i++) {
		sldr_setup[5 + reg_offset + i] = 0;
		if (i >= count)
			continue;

		if (chan_sel[i] >= ext_chan) {
			dev_err(&client->dev, "Invalid %s channel: %u\n",
				fwnode_get_name(sldr_node), chan_sel[i]);
			return -EINVAL;
		}

		/*
		 * The following fields indicate which channels participate in
		 * the slider, as well as each channel's relative placement.
		 */
		sldr_setup[3 + reg_offset] |= BIT(chan_sel[i]);
		sldr_setup[5 + reg_offset + i] = chan_sel[i] * 42 + 1080;
	}

	sldr_setup[4 + reg_offset] = dev_desc->touch_link;
	if (fwnode_property_present(sldr_node, "azoteq,use-prox"))
		sldr_setup[4 + reg_offset] -= 2;

	if (!fwnode_property_read_u32(sldr_node, "azoteq,slider-size", &val)) {
		if (!val || val > dev_desc->sldr_res) {
			dev_err(&client->dev, "Invalid %s size: %u\n",
				fwnode_get_name(sldr_node), val);
			return -EINVAL;
		}

		if (reg_offset) {
			sldr_setup[3] = val;
		} else {
			sldr_setup[2] &= ~IQS7222_SLDR_SETUP_2_RES_MASK;
			sldr_setup[2] |= (val / 16 <<
					  IQS7222_SLDR_SETUP_2_RES_SHIFT);
		}
	}

	if (!fwnode_property_read_u32(sldr_node, "azoteq,top-speed", &val)) {
		if (val > (reg_offset ? U16_MAX : U8_MAX * 4)) {
			dev_err(&client->dev, "Invalid %s top speed: %u\n",
				fwnode_get_name(sldr_node), val);
			return -EINVAL;
		}

		if (reg_offset) {
			sldr_setup[2] = val;
		} else {
			sldr_setup[2] &= ~IQS7222_SLDR_SETUP_2_TOP_SPEED_MASK;
			sldr_setup[2] |= (val / 4);
		}
	}

	if (!fwnode_property_read_u32(sldr_node, "linux,axis", &val)) {
		u16 sldr_max = sldr_setup[3] - 1;

		if (!reg_offset) {
			sldr_max = sldr_setup[2];

			sldr_max &= IQS7222_SLDR_SETUP_2_RES_MASK;
			sldr_max >>= IQS7222_SLDR_SETUP_2_RES_SHIFT;

			sldr_max = sldr_max * 16 - 1;
		}

		input_set_abs_params(iqs7222->keypad, val, 0, sldr_max, 0, 0);
		iqs7222->sl_axis[sldr_index] = val;
	}

	if (dev_desc->wheel_enable) {
		sldr_setup[0] &= ~dev_desc->wheel_enable;
		if (iqs7222->sl_axis[sldr_index] == ABS_WHEEL)
			sldr_setup[0] |= dev_desc->wheel_enable;
	}

	for (i = 0; i < ARRAY_SIZE(iqs7222_sl_events); i++) {
		const char *event_name = iqs7222_sl_events[i].name;
		struct fwnode_handle *event_node;

		/*
		 * The absence of a register offset means the remaining fields
		 * in the group represent gesture settings.
		 */
		if (iqs7222_sl_events[i].enable && !reg_offset)
			sldr_setup[9] &= ~iqs7222_sl_events[i].enable;

		event_node = fwnode_get_named_child_node(sldr_node, event_name);
		if (!event_node)
			continue;

		error = iqs7222_parse_props(iqs7222, &event_node, sldr_index,
					    IQS7222_REG_GRP_SLDR,
					    reg_offset ?
					    IQS7222_REG_KEY_RESERVED :
					    iqs7222_sl_events[i].reg_key);
		if (error)
			return error;

		error = fwnode_property_read_u32(event_node, "linux,code",
						 &val);
		if (error) {
			dev_err(&client->dev, "Failed to read %s code: %d\n",
				fwnode_get_name(sldr_node), error);
			return error;
		}

		iqs7222->sl_code[sldr_index][i] = val;
		input_set_capability(iqs7222->keypad, EV_KEY, val);

		/*
		 * The press/release event is determined based on whether the
		 * coordinate field reports 0xFFFF and has no explicit enable
		 * control.
		 */
		if (!iqs7222_sl_events[i].enable || reg_offset)
			continue;

		sldr_setup[9] |= iqs7222_sl_events[i].enable;

		error = iqs7222_gpio_select(iqs7222, event_node,
					    iqs7222_sl_events[i].enable,
					    1568 + sldr_index * 30);
		if (error)
			return error;

		if (!dev_desc->event_offset)
			continue;

		sys_setup[dev_desc->event_offset] |= BIT(10 + sldr_index);
	}

	/*
	 * The following call handles a special pair of properties that shift
	 * to make room for a wheel enable control in the case of IQS7222C.
	 */
	return iqs7222_parse_props(iqs7222, &sldr_node, sldr_index,
				   IQS7222_REG_GRP_SLDR,
				   dev_desc->wheel_enable ?
				   IQS7222_REG_KEY_WHEEL :
				   IQS7222_REG_KEY_NO_WHEEL);
}

static int iqs7222_parse_all(struct iqs7222_private *iqs7222)
{
	const struct iqs7222_dev_desc *dev_desc = iqs7222->dev_desc;
	const struct iqs7222_reg_grp_desc *reg_grps = dev_desc->reg_grps;
	u16 *sys_setup = iqs7222->sys_setup;
	int error, i;

	if (dev_desc->event_offset)
		sys_setup[dev_desc->event_offset] = IQS7222_EVENT_MASK_ATI;

	for (i = 0; i < reg_grps[IQS7222_REG_GRP_CYCLE].num_row; i++) {
		error = iqs7222_parse_cycle(iqs7222, i);
		if (error)
			return error;
	}

	error = iqs7222_parse_props(iqs7222, NULL, 0, IQS7222_REG_GRP_GLBL,
				    IQS7222_REG_KEY_NONE);
	if (error)
		return error;

	for (i = 0; i < reg_grps[IQS7222_REG_GRP_GPIO].num_row; i++) {
		struct fwnode_handle *gpio_node = NULL;
		u16 *gpio_setup = iqs7222->gpio_setup[i];
		int j;

		gpio_setup[0] &= ~IQS7222_GPIO_SETUP_0_GPIO_EN;
		gpio_setup[1] = 0;
		gpio_setup[2] = 0;

		error = iqs7222_parse_props(iqs7222, &gpio_node, i,
					    IQS7222_REG_GRP_GPIO,
					    IQS7222_REG_KEY_NONE);
		if (error)
			return error;

		if (reg_grps[IQS7222_REG_GRP_GPIO].num_row == 1)
			continue;

		/*
		 * The IQS7222C exposes multiple GPIO and must be informed
		 * as to which GPIO this group represents.
		 */
		for (j = 0; j < ARRAY_SIZE(iqs7222_gpio_links); j++)
			gpio_setup[0] &= ~BIT(iqs7222_gpio_links[j]);

		gpio_setup[0] |= BIT(iqs7222_gpio_links[i]);
	}

	for (i = 0; i < reg_grps[IQS7222_REG_GRP_CHAN].num_row; i++) {
		u16 *chan_setup = iqs7222->chan_setup[i];

		chan_setup[0] &= ~IQS7222_CHAN_SETUP_0_REF_MODE_MASK;
		chan_setup[0] &= ~IQS7222_CHAN_SETUP_0_CHAN_EN;

		chan_setup[5] = 0;
	}

	for (i = 0; i < reg_grps[IQS7222_REG_GRP_CHAN].num_row; i++) {
		error = iqs7222_parse_chan(iqs7222, i);
		if (error)
			return error;
	}

	error = iqs7222_parse_props(iqs7222, NULL, 0, IQS7222_REG_GRP_FILT,
				    IQS7222_REG_KEY_NONE);
	if (error)
		return error;

	for (i = 0; i < reg_grps[IQS7222_REG_GRP_SLDR].num_row; i++) {
		u16 *sldr_setup = iqs7222->sldr_setup[i];

		sldr_setup[0] &= ~IQS7222_SLDR_SETUP_0_CHAN_CNT_MASK;

		error = iqs7222_parse_sldr(iqs7222, i);
		if (error)
			return error;
	}

	sys_setup[0] &= ~IQS7222_SYS_SETUP_INTF_MODE_MASK;
	sys_setup[0] &= ~IQS7222_SYS_SETUP_PWR_MODE_MASK;

	sys_setup[0] |= IQS7222_SYS_SETUP_ACK_RESET;

	return iqs7222_parse_props(iqs7222, NULL, 0, IQS7222_REG_GRP_SYS,
				   IQS7222_REG_KEY_NONE);
}

static int iqs7222_report(struct iqs7222_private *iqs7222)
{
	const struct iqs7222_dev_desc *dev_desc = iqs7222->dev_desc;
	struct i2c_client *client = iqs7222->client;
	int num_chan = dev_desc->reg_grps[IQS7222_REG_GRP_CHAN].num_row;
	int num_stat = dev_desc->reg_grps[IQS7222_REG_GRP_STAT].num_col;
	int error, i, j;
	__le16 status[IQS7222_MAX_COLS_STAT];

	error = iqs7222_read_burst(iqs7222, IQS7222_SYS_STATUS, status,
				   num_stat);
	if (error)
		return error;

	if (le16_to_cpu(status[0]) & IQS7222_SYS_STATUS_RESET) {
		dev_err(&client->dev, "Unexpected device reset\n");
		return iqs7222_dev_init(iqs7222, WRITE);
	}

	if (le16_to_cpu(status[0]) & IQS7222_SYS_STATUS_ATI_ERROR) {
		dev_err(&client->dev, "Unexpected ATI error\n");
		return iqs7222_ati_trigger(iqs7222);
	}

	if (le16_to_cpu(status[0]) & IQS7222_SYS_STATUS_ATI_ACTIVE)
		return 0;

	for (i = 0; i < num_chan; i++) {
		u16 *chan_setup = iqs7222->chan_setup[i];

		if (!(chan_setup[0] & IQS7222_CHAN_SETUP_0_CHAN_EN))
			continue;

		for (j = 0; j < ARRAY_SIZE(iqs7222_kp_events); j++) {
			/*
			 * Proximity state begins at offset 2 and spills into
			 * offset 3 for devices with more than 16 channels.
			 *
			 * Touch state begins at the first offset immediately
			 * following proximity state.
			 */
			int k = 2 + j * (num_chan > 16 ? 2 : 1);
			u16 state = le16_to_cpu(status[k + i / 16]);

			input_event(iqs7222->keypad,
				    iqs7222->kp_type[i][j],
				    iqs7222->kp_code[i][j],
				    !!(state & BIT(i % 16)));
		}
	}

	for (i = 0; i < dev_desc->reg_grps[IQS7222_REG_GRP_SLDR].num_row; i++) {
		u16 *sldr_setup = iqs7222->sldr_setup[i];
		u16 sldr_pos = le16_to_cpu(status[4 + i]);
		u16 state = le16_to_cpu(status[6 + i]);

		if (!(sldr_setup[0] & IQS7222_SLDR_SETUP_0_CHAN_CNT_MASK))
			continue;

		if (sldr_pos < dev_desc->sldr_res)
			input_report_abs(iqs7222->keypad, iqs7222->sl_axis[i],
					 sldr_pos);

		for (j = 0; j < ARRAY_SIZE(iqs7222_sl_events); j++) {
			u16 mask = iqs7222_sl_events[j].mask;
			u16 val = iqs7222_sl_events[j].val;

			if (!iqs7222_sl_events[j].enable) {
				input_report_key(iqs7222->keypad,
						 iqs7222->sl_code[i][j],
						 sldr_pos < dev_desc->sldr_res);
				continue;
			}

			/*
			 * The remaining offsets represent gesture state, and
			 * are discarded in the case of IQS7222C because only
			 * absolute position is reported.
			 */
			if (num_stat < IQS7222_MAX_COLS_STAT)
				continue;

			input_report_key(iqs7222->keypad,
					 iqs7222->sl_code[i][j],
					 (state & mask) == val);
		}
	}

	input_sync(iqs7222->keypad);

	return 0;
}

static irqreturn_t iqs7222_irq(int irq, void *context)
{
	struct iqs7222_private *iqs7222 = context;

	return iqs7222_report(iqs7222) ? IRQ_NONE : IRQ_HANDLED;
}

static int iqs7222_probe(struct i2c_client *client)
{
	struct iqs7222_private *iqs7222;
	unsigned long irq_flags;
	int error, irq;

	iqs7222 = devm_kzalloc(&client->dev, sizeof(*iqs7222), GFP_KERNEL);
	if (!iqs7222)
		return -ENOMEM;

	i2c_set_clientdata(client, iqs7222);
	iqs7222->client = client;

	iqs7222->keypad = devm_input_allocate_device(&client->dev);
	if (!iqs7222->keypad)
		return -ENOMEM;

	iqs7222->keypad->name = client->name;
	iqs7222->keypad->id.bustype = BUS_I2C;

	/*
	 * The RDY pin behaves as an interrupt, but must also be polled ahead
	 * of unsolicited I2C communication. As such, it is first opened as a
	 * GPIO and then passed to gpiod_to_irq() to register the interrupt.
	 */
	iqs7222->irq_gpio = devm_gpiod_get(&client->dev, "irq", GPIOD_IN);
	if (IS_ERR(iqs7222->irq_gpio)) {
		error = PTR_ERR(iqs7222->irq_gpio);
		dev_err(&client->dev, "Failed to request IRQ GPIO: %d\n",
			error);
		return error;
	}

	iqs7222->reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
						      GPIOD_OUT_HIGH);
	if (IS_ERR(iqs7222->reset_gpio)) {
		error = PTR_ERR(iqs7222->reset_gpio);
		dev_err(&client->dev, "Failed to request reset GPIO: %d\n",
			error);
		return error;
	}

	error = iqs7222_hard_reset(iqs7222);
	if (error)
		return error;

	error = iqs7222_dev_info(iqs7222);
	if (error)
		return error;

	error = iqs7222_dev_init(iqs7222, READ);
	if (error)
		return error;

	error = iqs7222_parse_all(iqs7222);
	if (error)
		return error;

	error = iqs7222_dev_init(iqs7222, WRITE);
	if (error)
		return error;

	error = iqs7222_report(iqs7222);
	if (error)
		return error;

	error = input_register_device(iqs7222->keypad);
	if (error) {
		dev_err(&client->dev, "Failed to register device: %d\n", error);
		return error;
	}

	irq = gpiod_to_irq(iqs7222->irq_gpio);
	if (irq < 0)
		return irq;

	irq_flags = gpiod_is_active_low(iqs7222->irq_gpio) ? IRQF_TRIGGER_LOW
							   : IRQF_TRIGGER_HIGH;
	irq_flags |= IRQF_ONESHOT;

	error = devm_request_threaded_irq(&client->dev, irq, NULL, iqs7222_irq,
					  irq_flags, client->name, iqs7222);
	if (error)
		dev_err(&client->dev, "Failed to request IRQ: %d\n", error);

	return error;
}

static const struct of_device_id iqs7222_of_match[] = {
	{ .compatible = "azoteq,iqs7222a" },
	{ .compatible = "azoteq,iqs7222b" },
	{ .compatible = "azoteq,iqs7222c" },
	{ }
};
MODULE_DEVICE_TABLE(of, iqs7222_of_match);

static struct i2c_driver iqs7222_i2c_driver = {
	.driver = {
		.name = "iqs7222",
		.of_match_table = iqs7222_of_match,
	},
	.probe_new = iqs7222_probe,
};
module_i2c_driver(iqs7222_i2c_driver);

MODULE_AUTHOR("Jeff LaBundy <jeff@labundy.com>");
MODULE_DESCRIPTION("Azoteq IQS7222A/B/C Capacitive Touch Controller");
MODULE_LICENSE("GPL");