cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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ar1021_i2c.c (4416B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * Microchip AR1020 and AR1021 driver for I2C
      4 *
      5 * Author: Christian Gmeiner <christian.gmeiner@gmail.com>
      6 */
      7
      8#include <linux/bitops.h>
      9#include <linux/module.h>
     10#include <linux/input.h>
     11#include <linux/of.h>
     12#include <linux/i2c.h>
     13#include <linux/irq.h>
     14#include <linux/interrupt.h>
     15
     16#define AR1021_TOUCH_PKG_SIZE	5
     17
     18#define AR1021_MAX_X	4095
     19#define AR1021_MAX_Y	4095
     20
     21#define AR1021_CMD	0x55
     22
     23#define AR1021_CMD_ENABLE_TOUCH		0x12
     24
     25struct ar1021_i2c {
     26	struct i2c_client *client;
     27	struct input_dev *input;
     28	u8 data[AR1021_TOUCH_PKG_SIZE];
     29};
     30
     31static irqreturn_t ar1021_i2c_irq(int irq, void *dev_id)
     32{
     33	struct ar1021_i2c *ar1021 = dev_id;
     34	struct input_dev *input = ar1021->input;
     35	u8 *data = ar1021->data;
     36	unsigned int x, y, button;
     37	int retval;
     38
     39	retval = i2c_master_recv(ar1021->client,
     40				 ar1021->data, sizeof(ar1021->data));
     41	if (retval != sizeof(ar1021->data))
     42		goto out;
     43
     44	/* sync bit set ? */
     45	if (!(data[0] & BIT(7)))
     46		goto out;
     47
     48	button = data[0] & BIT(0);
     49	x = ((data[2] & 0x1f) << 7) | (data[1] & 0x7f);
     50	y = ((data[4] & 0x1f) << 7) | (data[3] & 0x7f);
     51
     52	input_report_abs(input, ABS_X, x);
     53	input_report_abs(input, ABS_Y, y);
     54	input_report_key(input, BTN_TOUCH, button);
     55	input_sync(input);
     56
     57out:
     58	return IRQ_HANDLED;
     59}
     60
     61static int ar1021_i2c_open(struct input_dev *dev)
     62{
     63	static const u8 cmd_enable_touch[] = {
     64		AR1021_CMD,
     65		0x01, /* number of bytes after this */
     66		AR1021_CMD_ENABLE_TOUCH
     67	};
     68	struct ar1021_i2c *ar1021 = input_get_drvdata(dev);
     69	struct i2c_client *client = ar1021->client;
     70	int error;
     71
     72	error = i2c_master_send(ar1021->client, cmd_enable_touch,
     73				sizeof(cmd_enable_touch));
     74	if (error < 0)
     75		return error;
     76
     77	enable_irq(client->irq);
     78
     79	return 0;
     80}
     81
     82static void ar1021_i2c_close(struct input_dev *dev)
     83{
     84	struct ar1021_i2c *ar1021 = input_get_drvdata(dev);
     85	struct i2c_client *client = ar1021->client;
     86
     87	disable_irq(client->irq);
     88}
     89
     90static int ar1021_i2c_probe(struct i2c_client *client,
     91			    const struct i2c_device_id *id)
     92{
     93	struct ar1021_i2c *ar1021;
     94	struct input_dev *input;
     95	int error;
     96
     97	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
     98		dev_err(&client->dev, "i2c_check_functionality error\n");
     99		return -ENXIO;
    100	}
    101
    102	ar1021 = devm_kzalloc(&client->dev, sizeof(*ar1021), GFP_KERNEL);
    103	if (!ar1021)
    104		return -ENOMEM;
    105
    106	input = devm_input_allocate_device(&client->dev);
    107	if (!input)
    108		return -ENOMEM;
    109
    110	ar1021->client = client;
    111	ar1021->input = input;
    112
    113	input->name = "ar1021 I2C Touchscreen";
    114	input->id.bustype = BUS_I2C;
    115	input->dev.parent = &client->dev;
    116	input->open = ar1021_i2c_open;
    117	input->close = ar1021_i2c_close;
    118
    119	__set_bit(INPUT_PROP_DIRECT, input->propbit);
    120	input_set_capability(input, EV_KEY, BTN_TOUCH);
    121	input_set_abs_params(input, ABS_X, 0, AR1021_MAX_X, 0, 0);
    122	input_set_abs_params(input, ABS_Y, 0, AR1021_MAX_Y, 0, 0);
    123
    124	input_set_drvdata(input, ar1021);
    125
    126	error = devm_request_threaded_irq(&client->dev, client->irq,
    127					  NULL, ar1021_i2c_irq,
    128					  IRQF_ONESHOT | IRQF_NO_AUTOEN,
    129					  "ar1021_i2c", ar1021);
    130	if (error) {
    131		dev_err(&client->dev,
    132			"Failed to enable IRQ, error: %d\n", error);
    133		return error;
    134	}
    135
    136	error = input_register_device(ar1021->input);
    137	if (error) {
    138		dev_err(&client->dev,
    139			"Failed to register input device, error: %d\n", error);
    140		return error;
    141	}
    142
    143	return 0;
    144}
    145
    146static int __maybe_unused ar1021_i2c_suspend(struct device *dev)
    147{
    148	struct i2c_client *client = to_i2c_client(dev);
    149
    150	disable_irq(client->irq);
    151
    152	return 0;
    153}
    154
    155static int __maybe_unused ar1021_i2c_resume(struct device *dev)
    156{
    157	struct i2c_client *client = to_i2c_client(dev);
    158
    159	enable_irq(client->irq);
    160
    161	return 0;
    162}
    163
    164static SIMPLE_DEV_PM_OPS(ar1021_i2c_pm, ar1021_i2c_suspend, ar1021_i2c_resume);
    165
    166static const struct i2c_device_id ar1021_i2c_id[] = {
    167	{ "ar1021", 0 },
    168	{ },
    169};
    170MODULE_DEVICE_TABLE(i2c, ar1021_i2c_id);
    171
    172static const struct of_device_id ar1021_i2c_of_match[] = {
    173	{ .compatible = "microchip,ar1021-i2c", },
    174	{ }
    175};
    176MODULE_DEVICE_TABLE(of, ar1021_i2c_of_match);
    177
    178static struct i2c_driver ar1021_i2c_driver = {
    179	.driver	= {
    180		.name	= "ar1021_i2c",
    181		.pm	= &ar1021_i2c_pm,
    182		.of_match_table = ar1021_i2c_of_match,
    183	},
    184
    185	.probe		= ar1021_i2c_probe,
    186	.id_table	= ar1021_i2c_id,
    187};
    188module_i2c_driver(ar1021_i2c_driver);
    189
    190MODULE_AUTHOR("Christian Gmeiner <christian.gmeiner@gmail.com>");
    191MODULE_DESCRIPTION("Microchip AR1020 and AR1021 I2C Driver");
    192MODULE_LICENSE("GPL");