Input: add driver for SiS 9200 family I2C touchscreen controllers

* SiS I2C Multiple Touch Controller

Required properties:

- compatible: must be "sis,9200-ts"

- reg: i2c slave address

- interrupt-parent: the phandle for the interrupt controller

  (see interrupt binding [0])

- interrupts: touch controller interrupt (see interrupt

  binding [0])

Optional properties:

- pinctrl-names: should be "default" (see pinctrl binding [1]).

- pinctrl-0: a phandle pointing to the pin settings for the

  device (see pinctrl binding [1]).

- attn-gpios: the gpio pin used as attention line

- reset-gpios: the gpio pin used to reset the controller

- wakeup-source: touchscreen can be used as a wakeup source

[0]: Documentation/devicetree/bindings/interrupt-controller/interrupts.txt

[1]: Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt

Example:

	sis9255@5c  {

		compatible = "sis,9200-ts";

		reg = <0x5c>;

		pinctrl-names = "default";

		pinctrl-0 = <&pinctrl_sis>;

		interrupt-parent = <&gpio3>;

		interrupts = <19 IRQ_TYPE_EDGE_FALLING>;

		irq-gpios = <&gpio3 19 GPIO_ACTIVE_LOW>;

		reset-gpios = <&gpio2 30 GPIO_ACTIVE_LOW>;

	};

sii	Seiko Instruments, Inc.

silergy	Silergy Corp.

sirf	SiRF Technology, Inc.

sis	Silicon Integrated Systems Corp.

sitronix	Sitronix Technology Corporation

skyworks	Skyworks Solutions, Inc.

smsc	Standard Microsystems Corporation

	  To compile this driver as a module, choose M here: the

	  module will be called silead.

config TOUCHSCREEN_SIS_I2C

	tristate "SiS 9200 family I2C touchscreen"

	depends on I2C

	depends on GPIOLIB || COMPILE_TEST

	help

	  This enables support for SiS 9200 family over I2C based touchscreens.

	  If unsure, say N.

	  To compile this driver as a module, choose M here: the

	  module will be called sis_i2c.

config TOUCHSCREEN_ST1232

	tristate "Sitronix ST1232 touchscreen controllers"

	depends on I2C

obj-$(CONFIG_TOUCHSCREEN_RM_TS)		+= raydium_i2c_ts.o

obj-$(CONFIG_TOUCHSCREEN_S3C2410)	+= s3c2410_ts.o

obj-$(CONFIG_TOUCHSCREEN_SILEAD)	+= silead.o

obj-$(CONFIG_TOUCHSCREEN_SIS_I2C)	+= sis_i2c.o

obj-$(CONFIG_TOUCHSCREEN_ST1232)	+= st1232.o

obj-$(CONFIG_TOUCHSCREEN_STMPE)		+= stmpe-ts.o

obj-$(CONFIG_TOUCHSCREEN_SUN4I)		+= sun4i-ts.o

/*

 * Touch Screen driver for SiS 9200 family I2C Touch panels

 *

 * Copyright (C) 2015 SiS, Inc.

 * Copyright (C) 2016 Nextfour Group

 *

 * This software is licensed under the terms of the GNU General Public

 * License version 2, as published by the Free Software Foundation, and

 * may be copied, distributed, and modified under those terms.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 */

#include <linux/crc-itu-t.h>

#include <linux/delay.h>

#include <linux/i2c.h>

#include <linux/input.h>

#include <linux/input/mt.h>

#include <linux/interrupt.h>

#include <linux/gpio/consumer.h>

#include <linux/module.h>

#include <linux/slab.h>

#include <asm/unaligned.h>

#define SIS_I2C_NAME		"sis_i2c_ts"

/*

 * The I2C packet format:

 * le16		byte count

 * u8		Report ID

 * <contact data - variable length>

 * u8		Number of contacts

 * le16		Scan Time (optional)

 * le16		CRC

 *

 * One touch point information consists of 6+ bytes, the order is:

 * u8		contact state

 * u8		finger id

 * le16		x axis

 * le16		y axis

 * u8		contact width (optional)

 * u8		contact height (optional)

 * u8		pressure (optional)

 *

 * Maximum amount of data transmitted in one shot is 64 bytes, if controller

 * needs to report more contacts than fit in one packet it will send true

 * number of contacts in first packet and 0 as number of contacts in second

 * packet.

 */

#define SIS_MAX_PACKET_SIZE		64

#define SIS_PKT_LEN_OFFSET		0

#define SIS_PKT_REPORT_OFFSET		2 /* Report ID/type */

#define SIS_PKT_CONTACT_OFFSET		3 /* First contact */

#define SIS_SCAN_TIME_LEN		2

/* Supported report types */

#define SIS_ALL_IN_ONE_PACKAGE		0x10

#define SIS_PKT_IS_TOUCH(x)		(((x) & 0x0f) == 0x01)

#define SIS_PKT_IS_HIDI2C(x)		(((x) & 0x0f) == 0x06)

/* Contact properties within report */

#define SIS_PKT_HAS_AREA(x)		((x) & BIT(4))

#define SIS_PKT_HAS_PRESSURE(x)		((x) & BIT(5))

#define SIS_PKT_HAS_SCANTIME(x)		((x) & BIT(6))

/* Contact size */

#define SIS_BASE_LEN_PER_CONTACT	6

#define SIS_AREA_LEN_PER_CONTACT	2

#define SIS_PRESSURE_LEN_PER_CONTACT	1

/* Offsets within contact data */

#define SIS_CONTACT_STATUS_OFFSET	0

#define SIS_CONTACT_ID_OFFSET		1 /* Contact ID */

#define SIS_CONTACT_X_OFFSET		2

#define SIS_CONTACT_Y_OFFSET		4

#define SIS_CONTACT_WIDTH_OFFSET	6

#define SIS_CONTACT_HEIGHT_OFFSET	7

#define SIS_CONTACT_PRESSURE_OFFSET(id)	(SIS_PKT_HAS_AREA(id) ? 8 : 6)

/* Individual contact state */

#define SIS_STATUS_UP			0x0

#define SIS_STATUS_DOWN			0x3

/* Touchscreen parameters */

#define SIS_MAX_FINGERS			10

#define SIS_MAX_X			4095

#define SIS_MAX_Y			4095

#define SIS_MAX_PRESSURE		255

/* Resolution diagonal */

#define SIS_AREA_LENGTH_LONGER		5792

/*((SIS_MAX_X^2) + (SIS_MAX_Y^2))^0.5*/

#define SIS_AREA_LENGTH_SHORT		5792

#define SIS_AREA_UNIT			(5792 / 32)

struct sis_ts_data {

	struct i2c_client *client;

	struct input_dev *input;

	struct gpio_desc *attn_gpio;

	struct gpio_desc *reset_gpio;

	u8 packet[SIS_MAX_PACKET_SIZE];

};

static int sis_read_packet(struct i2c_client *client, u8 *buf,

			   unsigned int *num_contacts,

			   unsigned int *contact_size)

{

	int count_idx;

	int ret;

	u16 len;

	u16 crc, pkg_crc;

	u8 report_id;

	ret = i2c_master_recv(client, buf, SIS_MAX_PACKET_SIZE);

	if (ret <= 0)

		return -EIO;

	len = get_unaligned_le16(&buf[SIS_PKT_LEN_OFFSET]);

	if (len > SIS_MAX_PACKET_SIZE) {

		dev_err(&client->dev,

			"%s: invalid packet length (%d vs %d)\n",

			__func__, len, SIS_MAX_PACKET_SIZE);

		return -E2BIG;

	}

	if (len < 10)

		return -EINVAL;

	report_id = buf[SIS_PKT_REPORT_OFFSET];

	count_idx  = len - 1;

	*contact_size = SIS_BASE_LEN_PER_CONTACT;

	if (report_id != SIS_ALL_IN_ONE_PACKAGE) {

		if (SIS_PKT_IS_TOUCH(report_id)) {

			/*

			 * Calculate CRC ignoring packet length

			 * in the beginning and CRC transmitted

			 * at the end of the packet.

			 */

			crc = crc_itu_t(0, buf + 2, len - 2 - 2);

			pkg_crc = get_unaligned_le16(&buf[len - 2]);

			if (crc != pkg_crc) {

				dev_err(&client->dev,

					"%s: CRC Error (%d vs %d)\n",

					__func__, crc, pkg_crc);

				return -EINVAL;

			}

			count_idx -= 2;

		} else if (!SIS_PKT_IS_HIDI2C(report_id)) {

			dev_err(&client->dev,

				"%s: invalid packet ID %#02x\n",

				__func__, report_id);

			return -EINVAL;

		}

		if (SIS_PKT_HAS_SCANTIME(report_id))

			count_idx -= SIS_SCAN_TIME_LEN;

		if (SIS_PKT_HAS_AREA(report_id))

			*contact_size += SIS_AREA_LEN_PER_CONTACT;

		if (SIS_PKT_HAS_PRESSURE(report_id))

			*contact_size += SIS_PRESSURE_LEN_PER_CONTACT;

	}

	*num_contacts = buf[count_idx];

	return 0;

}

static int sis_ts_report_contact(struct sis_ts_data *ts, const u8 *data, u8 id)

{

	struct input_dev *input = ts->input;

	int slot;

	u8 status = data[SIS_CONTACT_STATUS_OFFSET];

	u8 pressure;

	u8 height, width;

	u16 x, y;

	if (status != SIS_STATUS_DOWN && status != SIS_STATUS_UP) {

		dev_err(&ts->client->dev, "Unexpected touch status: %#02x\n",

			data[SIS_CONTACT_STATUS_OFFSET]);

		return -EINVAL;

	}

	slot = input_mt_get_slot_by_key(input, data[SIS_CONTACT_ID_OFFSET]);

	if (slot < 0)

		return -ENOENT;

	input_mt_slot(input, slot);

	input_mt_report_slot_state(input, MT_TOOL_FINGER,

				   status == SIS_STATUS_DOWN);

	if (status == SIS_STATUS_DOWN) {

		pressure = height = width = 1;

		if (id != SIS_ALL_IN_ONE_PACKAGE) {

			if (SIS_PKT_HAS_AREA(id)) {

				width = data[SIS_CONTACT_WIDTH_OFFSET];

				height = data[SIS_CONTACT_HEIGHT_OFFSET];

			}

			if (SIS_PKT_HAS_PRESSURE(id))

				pressure =

					data[SIS_CONTACT_PRESSURE_OFFSET(id)];

		}

		x = get_unaligned_le16(&data[SIS_CONTACT_X_OFFSET]);

		y = get_unaligned_le16(&data[SIS_CONTACT_Y_OFFSET]);

		input_report_abs(input, ABS_MT_TOUCH_MAJOR,

				 width * SIS_AREA_UNIT);

		input_report_abs(input, ABS_MT_TOUCH_MINOR,

				 height * SIS_AREA_UNIT);

		input_report_abs(input, ABS_MT_PRESSURE, pressure);

		input_report_abs(input, ABS_MT_POSITION_X, x);

		input_report_abs(input, ABS_MT_POSITION_Y, y);

	}

	return 0;

}

static void sis_ts_handle_packet(struct sis_ts_data *ts)

{

	const u8 *contact;

	unsigned int num_to_report = 0;

	unsigned int num_contacts;

	unsigned int num_reported;

	unsigned int contact_size;

	int error;

	u8 report_id;

	do {

		error = sis_read_packet(ts->client, ts->packet,

					&num_contacts, &contact_size);

		if (error)

			break;

		if (num_to_report == 0) {

			num_to_report = num_contacts;

		} else if (num_contacts != 0) {

			dev_err(&ts->client->dev,

				"%s: nonzero (%d) point count in tail packet\n",

				__func__, num_contacts);

			break;

		}

		report_id = ts->packet[SIS_PKT_REPORT_OFFSET];

		contact = &ts->packet[SIS_PKT_CONTACT_OFFSET];

		num_reported = 0;

		while (num_to_report > 0) {

			error = sis_ts_report_contact(ts, contact, report_id);

			if (error)

				break;

			contact += contact_size;

			num_to_report--;

			num_reported++;

			if (report_id != SIS_ALL_IN_ONE_PACKAGE &&

			    num_reported >= 5) {

				/*

				 * The remainder of contacts is sent

				 * in the 2nd packet.

				 */

				break;

			}

		}

	} while (num_to_report > 0);

	input_mt_sync_frame(ts->input);

	input_sync(ts->input);

}

static irqreturn_t sis_ts_irq_handler(int irq, void *dev_id)

{

	struct sis_ts_data *ts = dev_id;

	do {

		sis_ts_handle_packet(ts);

	} while (ts->attn_gpio && gpiod_get_value_cansleep(ts->attn_gpio));

	return IRQ_HANDLED;

}

static void sis_ts_reset(struct sis_ts_data *ts)

{

	if (ts->reset_gpio) {

		/* Get out of reset */

		usleep_range(1000, 2000);

		gpiod_set_value(ts->reset_gpio, 1);

		usleep_range(1000, 2000);

		gpiod_set_value(ts->reset_gpio, 0);

		msleep(100);

	}

}

static int sis_ts_probe(struct i2c_client *client,

			const struct i2c_device_id *id)

{

	struct sis_ts_data *ts;

	struct input_dev *input;

	int error;

	ts = devm_kzalloc(&client->dev, sizeof(*ts), GFP_KERNEL);

	if (!ts)

		return -ENOMEM;

	ts->client = client;

	i2c_set_clientdata(client, ts);

	ts->attn_gpio = devm_gpiod_get_optional(&client->dev,

						"attn", GPIOD_IN);

	if (IS_ERR(ts->attn_gpio)) {

		error = PTR_ERR(ts->attn_gpio);

		if (error != -EPROBE_DEFER)

			dev_err(&client->dev,

				"Failed to get attention GPIO: %d\n", error);

		return error;

	}

	ts->reset_gpio = devm_gpiod_get_optional(&client->dev,

						 "reset", GPIOD_OUT_LOW);

	if (IS_ERR(ts->reset_gpio)) {

		error = PTR_ERR(ts->reset_gpio);

		if (error != -EPROBE_DEFER)

			dev_err(&client->dev,

				"Failed to get reset GPIO: %d\n", error);

		return error;

	}

	sis_ts_reset(ts);

	ts->input = input = devm_input_allocate_device(&client->dev);

	if (!input) {

		dev_err(&client->dev, "Failed to allocate input device\n");

		return -ENOMEM;

	}

	input->name = "SiS Touchscreen";

	input->id.bustype = BUS_I2C;

	input_set_abs_params(input, ABS_MT_POSITION_X, 0, SIS_MAX_X, 0, 0);

	input_set_abs_params(input, ABS_MT_POSITION_Y, 0, SIS_MAX_Y, 0, 0);

	input_set_abs_params(input, ABS_MT_PRESSURE, 0, SIS_MAX_PRESSURE, 0, 0);

	input_set_abs_params(input, ABS_MT_TOUCH_MAJOR,

			     0, SIS_AREA_LENGTH_LONGER, 0, 0);

	input_set_abs_params(input, ABS_MT_TOUCH_MINOR,

			     0, SIS_AREA_LENGTH_SHORT, 0, 0);

	error = input_mt_init_slots(input, SIS_MAX_FINGERS, INPUT_MT_DIRECT);

	if (error) {

		dev_err(&client->dev,

			"Failed to initialize MT slots: %d\n", error);

		return error;

	}

	error = devm_request_threaded_irq(&client->dev, client->irq,

					  NULL, sis_ts_irq_handler,

					  IRQF_ONESHOT,

					  client->name, ts);

	if (error) {

		dev_err(&client->dev, "Failed to request IRQ: %d\n", error);

		return error;

	}

	error = input_register_device(ts->input);

	if (error) {

		dev_err(&client->dev,

			"Failed to register input device: %d\n", error);

		return error;

	}

	return 0;

}

#ifdef CONFIG_OF

static const struct of_device_id sis_ts_dt_ids[] = {

	{ .compatible = "sis,9200-ts" },

	{ /* sentinel */ }

};

MODULE_DEVICE_TABLE(of, sis_ts_dt_ids);

#endif

static const struct i2c_device_id sis_ts_id[] = {

	{ SIS_I2C_NAME,	0 },

	{ "9200-ts",	0 },

	{ /* sentinel */  }

};

MODULE_DEVICE_TABLE(i2c, sis_ts_id);

static struct i2c_driver sis_ts_driver = {

	.driver = {

		.name	= SIS_I2C_NAME,

		.of_match_table = of_match_ptr(sis_ts_dt_ids),

	},

	.probe		= sis_ts_probe,

	.id_table	= sis_ts_id,

};

module_i2c_driver(sis_ts_driver);

MODULE_DESCRIPTION("SiS 9200 Family Touchscreen Driver");

MODULE_LICENSE("GPL v2");

MODULE_AUTHOR("Mika Penttilä <mika.penttila@nextfour.com>");