cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
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twl4030_keypad.c (11869B)


      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 * twl4030_keypad.c - driver for 8x8 keypad controller in twl4030 chips
      4 *
      5 * Copyright (C) 2007 Texas Instruments, Inc.
      6 * Copyright (C) 2008 Nokia Corporation
      7 *
      8 * Code re-written for 2430SDP by:
      9 * Syed Mohammed Khasim <x0khasim@ti.com>
     10 *
     11 * Initial Code:
     12 * Manjunatha G K <manjugk@ti.com>
     13 */
     14
     15#include <linux/kernel.h>
     16#include <linux/module.h>
     17#include <linux/interrupt.h>
     18#include <linux/input.h>
     19#include <linux/platform_device.h>
     20#include <linux/mfd/twl.h>
     21#include <linux/slab.h>
     22#include <linux/of.h>
     23
     24/*
     25 * The TWL4030 family chips include a keypad controller that supports
     26 * up to an 8x8 switch matrix.  The controller can issue system wakeup
     27 * events, since it uses only the always-on 32KiHz oscillator, and has
     28 * an internal state machine that decodes pressed keys, including
     29 * multi-key combinations.
     30 *
     31 * This driver lets boards define what keycodes they wish to report for
     32 * which scancodes, as part of the "struct twl4030_keypad_data" used in
     33 * the probe() routine.
     34 *
     35 * See the TPS65950 documentation; that's the general availability
     36 * version of the TWL5030 second generation part.
     37 */
     38#define TWL4030_MAX_ROWS	8	/* TWL4030 hard limit */
     39#define TWL4030_MAX_COLS	8
     40/*
     41 * Note that we add space for an extra column so that we can handle
     42 * row lines connected to the gnd (see twl4030_col_xlate()).
     43 */
     44#define TWL4030_ROW_SHIFT	4
     45#define TWL4030_KEYMAP_SIZE	(TWL4030_MAX_ROWS << TWL4030_ROW_SHIFT)
     46
     47struct twl4030_keypad {
     48	unsigned short	keymap[TWL4030_KEYMAP_SIZE];
     49	u16		kp_state[TWL4030_MAX_ROWS];
     50	bool		autorepeat;
     51	unsigned int	n_rows;
     52	unsigned int	n_cols;
     53	int		irq;
     54
     55	struct device *dbg_dev;
     56	struct input_dev *input;
     57};
     58
     59/*----------------------------------------------------------------------*/
     60
     61/* arbitrary prescaler value 0..7 */
     62#define PTV_PRESCALER			4
     63
     64/* Register Offsets */
     65#define KEYP_CTRL			0x00
     66#define KEYP_DEB			0x01
     67#define KEYP_LONG_KEY			0x02
     68#define KEYP_LK_PTV			0x03
     69#define KEYP_TIMEOUT_L			0x04
     70#define KEYP_TIMEOUT_H			0x05
     71#define KEYP_KBC			0x06
     72#define KEYP_KBR			0x07
     73#define KEYP_SMS			0x08
     74#define KEYP_FULL_CODE_7_0		0x09	/* row 0 column status */
     75#define KEYP_FULL_CODE_15_8		0x0a	/* ... row 1 ... */
     76#define KEYP_FULL_CODE_23_16		0x0b
     77#define KEYP_FULL_CODE_31_24		0x0c
     78#define KEYP_FULL_CODE_39_32		0x0d
     79#define KEYP_FULL_CODE_47_40		0x0e
     80#define KEYP_FULL_CODE_55_48		0x0f
     81#define KEYP_FULL_CODE_63_56		0x10
     82#define KEYP_ISR1			0x11
     83#define KEYP_IMR1			0x12
     84#define KEYP_ISR2			0x13
     85#define KEYP_IMR2			0x14
     86#define KEYP_SIR			0x15
     87#define KEYP_EDR			0x16	/* edge triggers */
     88#define KEYP_SIH_CTRL			0x17
     89
     90/* KEYP_CTRL_REG Fields */
     91#define KEYP_CTRL_SOFT_NRST		BIT(0)
     92#define KEYP_CTRL_SOFTMODEN		BIT(1)
     93#define KEYP_CTRL_LK_EN			BIT(2)
     94#define KEYP_CTRL_TOE_EN		BIT(3)
     95#define KEYP_CTRL_TOLE_EN		BIT(4)
     96#define KEYP_CTRL_RP_EN			BIT(5)
     97#define KEYP_CTRL_KBD_ON		BIT(6)
     98
     99/* KEYP_DEB, KEYP_LONG_KEY, KEYP_TIMEOUT_x*/
    100#define KEYP_PERIOD_US(t, prescale)	((t) / (31 << ((prescale) + 1)) - 1)
    101
    102/* KEYP_LK_PTV_REG Fields */
    103#define KEYP_LK_PTV_PTV_SHIFT		5
    104
    105/* KEYP_{IMR,ISR,SIR} Fields */
    106#define KEYP_IMR1_MIS			BIT(3)
    107#define KEYP_IMR1_TO			BIT(2)
    108#define KEYP_IMR1_LK			BIT(1)
    109#define KEYP_IMR1_KP			BIT(0)
    110
    111/* KEYP_EDR Fields */
    112#define KEYP_EDR_KP_FALLING		0x01
    113#define KEYP_EDR_KP_RISING		0x02
    114#define KEYP_EDR_KP_BOTH		0x03
    115#define KEYP_EDR_LK_FALLING		0x04
    116#define KEYP_EDR_LK_RISING		0x08
    117#define KEYP_EDR_TO_FALLING		0x10
    118#define KEYP_EDR_TO_RISING		0x20
    119#define KEYP_EDR_MIS_FALLING		0x40
    120#define KEYP_EDR_MIS_RISING		0x80
    121
    122
    123/*----------------------------------------------------------------------*/
    124
    125static int twl4030_kpread(struct twl4030_keypad *kp,
    126		u8 *data, u32 reg, u8 num_bytes)
    127{
    128	int ret = twl_i2c_read(TWL4030_MODULE_KEYPAD, data, reg, num_bytes);
    129
    130	if (ret < 0)
    131		dev_warn(kp->dbg_dev,
    132			"Couldn't read TWL4030: %X - ret %d[%x]\n",
    133			 reg, ret, ret);
    134
    135	return ret;
    136}
    137
    138static int twl4030_kpwrite_u8(struct twl4030_keypad *kp, u8 data, u32 reg)
    139{
    140	int ret = twl_i2c_write_u8(TWL4030_MODULE_KEYPAD, data, reg);
    141
    142	if (ret < 0)
    143		dev_warn(kp->dbg_dev,
    144			"Could not write TWL4030: %X - ret %d[%x]\n",
    145			 reg, ret, ret);
    146
    147	return ret;
    148}
    149
    150static inline u16 twl4030_col_xlate(struct twl4030_keypad *kp, u8 col)
    151{
    152	/*
    153	 * If all bits in a row are active for all columns then
    154	 * we have that row line connected to gnd. Mark this
    155	 * key on as if it was on matrix position n_cols (i.e.
    156	 * one higher than the size of the matrix).
    157	 */
    158	if (col == 0xFF)
    159		return 1 << kp->n_cols;
    160	else
    161		return col & ((1 << kp->n_cols) - 1);
    162}
    163
    164static int twl4030_read_kp_matrix_state(struct twl4030_keypad *kp, u16 *state)
    165{
    166	u8 new_state[TWL4030_MAX_ROWS];
    167	int row;
    168	int ret = twl4030_kpread(kp, new_state,
    169				 KEYP_FULL_CODE_7_0, kp->n_rows);
    170	if (ret >= 0)
    171		for (row = 0; row < kp->n_rows; row++)
    172			state[row] = twl4030_col_xlate(kp, new_state[row]);
    173
    174	return ret;
    175}
    176
    177static bool twl4030_is_in_ghost_state(struct twl4030_keypad *kp, u16 *key_state)
    178{
    179	int i;
    180	u16 check = 0;
    181
    182	for (i = 0; i < kp->n_rows; i++) {
    183		u16 col = key_state[i];
    184
    185		if ((col & check) && hweight16(col) > 1)
    186			return true;
    187
    188		check |= col;
    189	}
    190
    191	return false;
    192}
    193
    194static void twl4030_kp_scan(struct twl4030_keypad *kp, bool release_all)
    195{
    196	struct input_dev *input = kp->input;
    197	u16 new_state[TWL4030_MAX_ROWS];
    198	int col, row;
    199
    200	if (release_all) {
    201		memset(new_state, 0, sizeof(new_state));
    202	} else {
    203		/* check for any changes */
    204		int ret = twl4030_read_kp_matrix_state(kp, new_state);
    205
    206		if (ret < 0)	/* panic ... */
    207			return;
    208
    209		if (twl4030_is_in_ghost_state(kp, new_state))
    210			return;
    211	}
    212
    213	/* check for changes and print those */
    214	for (row = 0; row < kp->n_rows; row++) {
    215		int changed = new_state[row] ^ kp->kp_state[row];
    216
    217		if (!changed)
    218			continue;
    219
    220		/* Extra column handles "all gnd" rows */
    221		for (col = 0; col < kp->n_cols + 1; col++) {
    222			int code;
    223
    224			if (!(changed & (1 << col)))
    225				continue;
    226
    227			dev_dbg(kp->dbg_dev, "key [%d:%d] %s\n", row, col,
    228				(new_state[row] & (1 << col)) ?
    229				"press" : "release");
    230
    231			code = MATRIX_SCAN_CODE(row, col, TWL4030_ROW_SHIFT);
    232			input_event(input, EV_MSC, MSC_SCAN, code);
    233			input_report_key(input, kp->keymap[code],
    234					 new_state[row] & (1 << col));
    235		}
    236		kp->kp_state[row] = new_state[row];
    237	}
    238	input_sync(input);
    239}
    240
    241/*
    242 * Keypad interrupt handler
    243 */
    244static irqreturn_t do_kp_irq(int irq, void *_kp)
    245{
    246	struct twl4030_keypad *kp = _kp;
    247	u8 reg;
    248	int ret;
    249
    250	/* Read & Clear TWL4030 pending interrupt */
    251	ret = twl4030_kpread(kp, &reg, KEYP_ISR1, 1);
    252
    253	/*
    254	 * Release all keys if I2C has gone bad or
    255	 * the KEYP has gone to idle state.
    256	 */
    257	if (ret >= 0 && (reg & KEYP_IMR1_KP))
    258		twl4030_kp_scan(kp, false);
    259	else
    260		twl4030_kp_scan(kp, true);
    261
    262	return IRQ_HANDLED;
    263}
    264
    265static int twl4030_kp_program(struct twl4030_keypad *kp)
    266{
    267	u8 reg;
    268	int i;
    269
    270	/* Enable controller, with hardware decoding but not autorepeat */
    271	reg = KEYP_CTRL_SOFT_NRST | KEYP_CTRL_SOFTMODEN
    272		| KEYP_CTRL_TOE_EN | KEYP_CTRL_KBD_ON;
    273	if (twl4030_kpwrite_u8(kp, reg, KEYP_CTRL) < 0)
    274		return -EIO;
    275
    276	/*
    277	 * NOTE: we could use sih_setup() here to package keypad
    278	 * event sources as four different IRQs ... but we don't.
    279	 */
    280
    281	/* Enable TO rising and KP rising and falling edge detection */
    282	reg = KEYP_EDR_KP_BOTH | KEYP_EDR_TO_RISING;
    283	if (twl4030_kpwrite_u8(kp, reg, KEYP_EDR) < 0)
    284		return -EIO;
    285
    286	/* Set PTV prescaler Field */
    287	reg = (PTV_PRESCALER << KEYP_LK_PTV_PTV_SHIFT);
    288	if (twl4030_kpwrite_u8(kp, reg, KEYP_LK_PTV) < 0)
    289		return -EIO;
    290
    291	/* Set key debounce time to 20 ms */
    292	i = KEYP_PERIOD_US(20000, PTV_PRESCALER);
    293	if (twl4030_kpwrite_u8(kp, i, KEYP_DEB) < 0)
    294		return -EIO;
    295
    296	/* Set timeout period to 200 ms */
    297	i = KEYP_PERIOD_US(200000, PTV_PRESCALER);
    298	if (twl4030_kpwrite_u8(kp, (i & 0xFF), KEYP_TIMEOUT_L) < 0)
    299		return -EIO;
    300
    301	if (twl4030_kpwrite_u8(kp, (i >> 8), KEYP_TIMEOUT_H) < 0)
    302		return -EIO;
    303
    304	/*
    305	 * Enable Clear-on-Read; disable remembering events that fire
    306	 * after the IRQ but before our handler acks (reads) them.
    307	 */
    308	reg = TWL4030_SIH_CTRL_COR_MASK | TWL4030_SIH_CTRL_PENDDIS_MASK;
    309	if (twl4030_kpwrite_u8(kp, reg, KEYP_SIH_CTRL) < 0)
    310		return -EIO;
    311
    312	/* initialize key state; irqs update it from here on */
    313	if (twl4030_read_kp_matrix_state(kp, kp->kp_state) < 0)
    314		return -EIO;
    315
    316	return 0;
    317}
    318
    319/*
    320 * Registers keypad device with input subsystem
    321 * and configures TWL4030 keypad registers
    322 */
    323static int twl4030_kp_probe(struct platform_device *pdev)
    324{
    325	struct twl4030_keypad_data *pdata = dev_get_platdata(&pdev->dev);
    326	const struct matrix_keymap_data *keymap_data = NULL;
    327	struct twl4030_keypad *kp;
    328	struct input_dev *input;
    329	u8 reg;
    330	int error;
    331
    332	kp = devm_kzalloc(&pdev->dev, sizeof(*kp), GFP_KERNEL);
    333	if (!kp)
    334		return -ENOMEM;
    335
    336	input = devm_input_allocate_device(&pdev->dev);
    337	if (!input)
    338		return -ENOMEM;
    339
    340	/* get the debug device */
    341	kp->dbg_dev		= &pdev->dev;
    342	kp->input		= input;
    343
    344	/* setup input device */
    345	input->name		= "TWL4030 Keypad";
    346	input->phys		= "twl4030_keypad/input0";
    347
    348	input->id.bustype	= BUS_HOST;
    349	input->id.vendor	= 0x0001;
    350	input->id.product	= 0x0001;
    351	input->id.version	= 0x0003;
    352
    353	if (pdata) {
    354		if (!pdata->rows || !pdata->cols || !pdata->keymap_data) {
    355			dev_err(&pdev->dev, "Missing platform_data\n");
    356			return -EINVAL;
    357		}
    358
    359		kp->n_rows = pdata->rows;
    360		kp->n_cols = pdata->cols;
    361		kp->autorepeat = pdata->rep;
    362		keymap_data = pdata->keymap_data;
    363	} else {
    364		error = matrix_keypad_parse_properties(&pdev->dev, &kp->n_rows,
    365						       &kp->n_cols);
    366		if (error)
    367			return error;
    368
    369		kp->autorepeat = true;
    370	}
    371
    372	if (kp->n_rows > TWL4030_MAX_ROWS || kp->n_cols > TWL4030_MAX_COLS) {
    373		dev_err(&pdev->dev,
    374			"Invalid rows/cols amount specified in platform/devicetree data\n");
    375		return -EINVAL;
    376	}
    377
    378	kp->irq = platform_get_irq(pdev, 0);
    379	if (kp->irq < 0)
    380		return kp->irq;
    381
    382	error = matrix_keypad_build_keymap(keymap_data, NULL,
    383					   TWL4030_MAX_ROWS,
    384					   1 << TWL4030_ROW_SHIFT,
    385					   kp->keymap, input);
    386	if (error) {
    387		dev_err(kp->dbg_dev, "Failed to build keymap\n");
    388		return error;
    389	}
    390
    391	input_set_capability(input, EV_MSC, MSC_SCAN);
    392	/* Enable auto repeat feature of Linux input subsystem */
    393	if (kp->autorepeat)
    394		__set_bit(EV_REP, input->evbit);
    395
    396	error = input_register_device(input);
    397	if (error) {
    398		dev_err(kp->dbg_dev,
    399			"Unable to register twl4030 keypad device\n");
    400		return error;
    401	}
    402
    403	error = twl4030_kp_program(kp);
    404	if (error)
    405		return error;
    406
    407	/*
    408	 * This ISR will always execute in kernel thread context because of
    409	 * the need to access the TWL4030 over the I2C bus.
    410	 *
    411	 * NOTE:  we assume this host is wired to TWL4040 INT1, not INT2 ...
    412	 */
    413	error = devm_request_threaded_irq(&pdev->dev, kp->irq, NULL, do_kp_irq,
    414					  0, pdev->name, kp);
    415	if (error) {
    416		dev_info(kp->dbg_dev, "request_irq failed for irq no=%d: %d\n",
    417			kp->irq, error);
    418		return error;
    419	}
    420
    421	/* Enable KP and TO interrupts now. */
    422	reg = (u8) ~(KEYP_IMR1_KP | KEYP_IMR1_TO);
    423	if (twl4030_kpwrite_u8(kp, reg, KEYP_IMR1)) {
    424		/* mask all events - we don't care about the result */
    425		(void) twl4030_kpwrite_u8(kp, 0xff, KEYP_IMR1);
    426		return -EIO;
    427	}
    428
    429	return 0;
    430}
    431
    432#ifdef CONFIG_OF
    433static const struct of_device_id twl4030_keypad_dt_match_table[] = {
    434	{ .compatible = "ti,twl4030-keypad" },
    435	{},
    436};
    437MODULE_DEVICE_TABLE(of, twl4030_keypad_dt_match_table);
    438#endif
    439
    440/*
    441 * NOTE: twl4030 are multi-function devices connected via I2C.
    442 * So this device is a child of an I2C parent, thus it needs to
    443 * support unplug/replug (which most platform devices don't).
    444 */
    445
    446static struct platform_driver twl4030_kp_driver = {
    447	.probe		= twl4030_kp_probe,
    448	.driver		= {
    449		.name	= "twl4030_keypad",
    450		.of_match_table = of_match_ptr(twl4030_keypad_dt_match_table),
    451	},
    452};
    453module_platform_driver(twl4030_kp_driver);
    454
    455MODULE_AUTHOR("Texas Instruments");
    456MODULE_DESCRIPTION("TWL4030 Keypad Driver");
    457MODULE_LICENSE("GPL");
    458MODULE_ALIAS("platform:twl4030_keypad");