// SPDX-License-Identifier: GPL-2.0-only/* * Driver for MStar msg2638 touchscreens * * Copyright (c) 2021 Vincent Knecht <vincent.knecht@mailoo.org> * * Checksum and IRQ handler based on mstar_drv_common.c and * mstar_drv_mutual_fw_control.c * Copyright (c) 2006-2012 MStar Semiconductor, Inc. * * Driver structure based on zinitix.c by Michael Srba <Michael.Srba@seznam.cz> */ #include <linux/delay.h>#include <linux/gpio/consumer.h>#include <linux/i2c.h>#include <linux/input.h>#include <linux/input/mt.h>#include <linux/input/touchscreen.h>#include <linux/interrupt.h>#include <linux/kernel.h>#include <linux/mod_devicetable.h>#include <linux/module.h>#include <linux/regulator/consumer.h>#include <linux/slab.h> #define MODE_DATA_RAW			0x5A #define MAX_SUPPORTED_FINGER_NUM	5 #define CHIP_ON_DELAY_MS		15#define FIRMWARE_ON_DELAY_MS		50#define RESET_DELAY_MIN_US		10000#define RESET_DELAY_MAX_US		11000 struct packet {	u8	xy_hi; /* higher bits of x and y coordinates */	u8	x_low;	u8	y_low;	u8	pressure;}; struct touch_event {	u8	mode;	struct	packet pkt[MAX_SUPPORTED_FINGER_NUM];	u8	proximity;	u8	checksum;}; struct msg2638_ts_data {	struct i2c_client *client;	struct input_dev *input_dev;	struct touchscreen_properties prop;	struct regulator_bulk_data supplies[2];	struct gpio_desc *reset_gpiod;}; static u8 msg2638_checksum(u8 *data, u32 length){	s32 sum = 0;	u32 i; 	for (i = 0; i < length; i++)		sum += data[i]; 	return (u8)((-sum) & 0xFF);} static irqreturn_t msg2638_ts_irq_handler(int irq, void *msg2638_handler){	struct msg2638_ts_data *msg2638 = msg2638_handler;	struct i2c_client *client = msg2638->client;	struct input_dev *input = msg2638->input_dev;	struct touch_event touch_event;	u32 len = sizeof(touch_event);	struct i2c_msg msg[] = {		{			.addr	= client->addr,			.flags	= I2C_M_RD,			.len	= sizeof(touch_event),			.buf	= (u8 *)&touch_event,		},	};	struct packet *p;	u16 x, y;	int ret;	int i; 	ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));	if (ret != ARRAY_SIZE(msg)) {		dev_err(&client->dev,			"Failed I2C transfer in irq handler: %d\n",			ret < 0 ? ret : -EIO);		goto out;	} 	if (touch_event.mode != MODE_DATA_RAW)		goto out; 	if (msg2638_checksum((u8 *)&touch_event, len - 1) !=						touch_event.checksum) {		dev_err(&client->dev, "Failed checksum!\n");		goto out;	} 	for (i = 0; i < MAX_SUPPORTED_FINGER_NUM; i++) {		p = &touch_event.pkt[i]; 		/* Ignore non-pressed finger data */		if (p->xy_hi == 0xFF && p->x_low == 0xFF && p->y_low == 0xFF)			continue; 		x = (((p->xy_hi & 0xF0) << 4) | p->x_low);		y = (((p->xy_hi & 0x0F) << 8) | p->y_low); 		input_mt_slot(input, i);		input_mt_report_slot_state(input, MT_TOOL_FINGER, true);		touchscreen_report_pos(input, &msg2638->prop, x, y, true);	} 	input_mt_sync_frame(msg2638->input_dev);	input_sync(msg2638->input_dev); out:	return IRQ_HANDLED;} static void msg2638_reset(struct msg2638_ts_data *msg2638){	gpiod_set_value_cansleep(msg2638->reset_gpiod, 1);	usleep_range(RESET_DELAY_MIN_US, RESET_DELAY_MAX_US);	gpiod_set_value_cansleep(msg2638->reset_gpiod, 0);	msleep(FIRMWARE_ON_DELAY_MS);} static int msg2638_start(struct msg2638_ts_data *msg2638){	int error; 	error = regulator_bulk_enable(ARRAY_SIZE(msg2638->supplies),				      msg2638->supplies);	if (error) {		dev_err(&msg2638->client->dev,			"Failed to enable regulators: %d\n", error);		return error;	} 	msleep(CHIP_ON_DELAY_MS); 	msg2638_reset(msg2638); 	enable_irq(msg2638->client->irq); 	return 0;} static int msg2638_stop(struct msg2638_ts_data *msg2638){	int error; 	disable_irq(msg2638->client->irq); 	error = regulator_bulk_disable(ARRAY_SIZE(msg2638->supplies),				       msg2638->supplies);	if (error) {		dev_err(&msg2638->client->dev,			"Failed to disable regulators: %d\n", error);		return error;	} 	return 0;} static int msg2638_input_open(struct input_dev *dev){	struct msg2638_ts_data *msg2638 = input_get_drvdata(dev); 	return msg2638_start(msg2638);} static void msg2638_input_close(struct input_dev *dev){	struct msg2638_ts_data *msg2638 = input_get_drvdata(dev); 	msg2638_stop(msg2638);} static int msg2638_init_input_dev(struct msg2638_ts_data *msg2638){	struct device *dev = &msg2638->client->dev;	struct input_dev *input_dev;	int error; 	input_dev = devm_input_allocate_device(dev);	if (!input_dev) {		dev_err(dev, "Failed to allocate input device.\n");		return -ENOMEM;	} 	input_set_drvdata(input_dev, msg2638);	msg2638->input_dev = input_dev; 	input_dev->name = "MStar TouchScreen";	input_dev->phys = "input/ts";	input_dev->id.bustype = BUS_I2C;	input_dev->open = msg2638_input_open;	input_dev->close = msg2638_input_close; 	input_set_capability(input_dev, EV_ABS, ABS_MT_POSITION_X);	input_set_capability(input_dev, EV_ABS, ABS_MT_POSITION_Y); 	touchscreen_parse_properties(input_dev, true, &msg2638->prop);	if (!msg2638->prop.max_x || !msg2638->prop.max_y) {		dev_err(dev, "touchscreen-size-x and/or touchscreen-size-y not set in properties\n");		return -EINVAL;	} 	error = input_mt_init_slots(input_dev, MAX_SUPPORTED_FINGER_NUM,				    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);	if (error) {		dev_err(dev, "Failed to initialize MT slots: %d\n", error);		return error;	} 	error = input_register_device(input_dev);	if (error) {		dev_err(dev, "Failed to register input device: %d\n", error);		return error;	} 	return 0;} static int msg2638_ts_probe(struct i2c_client *client){	struct device *dev = &client->dev;	struct msg2638_ts_data *msg2638;	int error; 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {		dev_err(dev, "Failed to assert adapter's support for plain I2C.\n");		return -ENXIO;	} 	msg2638 = devm_kzalloc(dev, sizeof(*msg2638), GFP_KERNEL);	if (!msg2638)		return -ENOMEM; 	msg2638->client = client;	i2c_set_clientdata(client, msg2638); 	msg2638->supplies[0].supply = "vdd";	msg2638->supplies[1].supply = "vddio";	error = devm_regulator_bulk_get(dev, ARRAY_SIZE(msg2638->supplies),					msg2638->supplies);	if (error) {		dev_err(dev, "Failed to get regulators: %d\n", error);		return error;	} 	msg2638->reset_gpiod = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);	if (IS_ERR(msg2638->reset_gpiod)) {		error = PTR_ERR(msg2638->reset_gpiod);		dev_err(dev, "Failed to request reset GPIO: %d\n", error);		return error;	} 	error = msg2638_init_input_dev(msg2638);	if (error) {		dev_err(dev, "Failed to initialize input device: %d\n", error);		return error;	} 	error = devm_request_threaded_irq(dev, client->irq,					  NULL, msg2638_ts_irq_handler,					  IRQF_ONESHOT | IRQF_NO_AUTOEN,					  client->name, msg2638);	if (error) {		dev_err(dev, "Failed to request IRQ: %d\n", error);		return error;	} 	return 0;} static int __maybe_unused msg2638_suspend(struct device *dev){	struct i2c_client *client = to_i2c_client(dev);	struct msg2638_ts_data *msg2638 = i2c_get_clientdata(client); 	mutex_lock(&msg2638->input_dev->mutex); 	if (input_device_enabled(msg2638->input_dev))		msg2638_stop(msg2638); 	mutex_unlock(&msg2638->input_dev->mutex); 	return 0;} static int __maybe_unused msg2638_resume(struct device *dev){	struct i2c_client *client = to_i2c_client(dev);	struct msg2638_ts_data *msg2638 = i2c_get_clientdata(client);	int ret = 0; 	mutex_lock(&msg2638->input_dev->mutex); 	if (input_device_enabled(msg2638->input_dev))		ret = msg2638_start(msg2638); 	mutex_unlock(&msg2638->input_dev->mutex); 	return ret;} static SIMPLE_DEV_PM_OPS(msg2638_pm_ops, msg2638_suspend, msg2638_resume); static const struct of_device_id msg2638_of_match[] = {	{ .compatible = "mstar,msg2638" },	{ }};MODULE_DEVICE_TABLE(of, msg2638_of_match); static struct i2c_driver msg2638_ts_driver = {	.probe_new = msg2638_ts_probe,	.driver = {		.name = "MStar-TS",		.pm = &msg2638_pm_ops,		.of_match_table = msg2638_of_match,	},};module_i2c_driver(msg2638_ts_driver); MODULE_AUTHOR("Vincent Knecht <vincent.knecht@mailoo.org>");MODULE_DESCRIPTION("MStar MSG2638 touchscreen driver");MODULE_LICENSE("GPL v2");