Input: add driver for the Goodix touchpanel

Add a driver for the Goodix touchscreen panel found in Onda v975w tablets.
The driver is based off the Android driver gt9xx.c found in some Android
code dumps, but now bears no resemblance to the original driver.

The driver was tested on the aforementioned tablet.
Signed-off-by: Bastien Nocera <hadess@hadess.net>
Tested-by: Bastien Nocera <hadess@hadess.net>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

MAINTAINERS

@@ -4062,6 +4062,12 @@ L:	linux-media@vger.kernel.org
 S:	Maintained
 F:	drivers/media/usb/go7007/
 
+GOODIX TOUCHSCREEN
+M:	Bastien Nocera <hadess@hadess.net>
+L:	linux-input@vger.kernel.org
+S:	Maintained
+F:	drivers/input/touchscreen/goodix.c
+
 GPIO SUBSYSTEM
 M:	Linus Walleij <linus.walleij@linaro.org>
 M:	Alexandre Courbot <gnurou@gmail.com>

drivers/input/touchscreen/Kconfig

@@ -295,6 +295,19 @@ config TOUCHSCREEN_FUJITSU
 	  To compile this driver as a module, choose M here: the
 	  module will be called fujitsu-ts.
 
+config TOUCHSCREEN_GOODIX
+	tristate "Goodix I2C touchscreen"
+	depends on I2C && ACPI
+	help
+	  Say Y here if you have the Goodix touchscreen (such as one
+	  installed in Onda v975w tablets) connected to your
+	  system.
+
+	  If unsure, say N.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called goodix.
+
 config TOUCHSCREEN_ILI210X
 	tristate "Ilitek ILI210X based touchscreen"
 	depends on I2C

drivers/input/touchscreen/Makefile

@@ -34,6 +34,7 @@ obj-$(CONFIG_TOUCHSCREEN_EETI)		+= eeti_ts.o
 obj-$(CONFIG_TOUCHSCREEN_ELO)		+= elo.o
 obj-$(CONFIG_TOUCHSCREEN_EGALAX)	+= egalax_ts.o
 obj-$(CONFIG_TOUCHSCREEN_FUJITSU)	+= fujitsu_ts.o
+obj-$(CONFIG_TOUCHSCREEN_GOODIX)	+= goodix.o
 obj-$(CONFIG_TOUCHSCREEN_ILI210X)	+= ili210x.o
 obj-$(CONFIG_TOUCHSCREEN_INEXIO)	+= inexio.o
 obj-$(CONFIG_TOUCHSCREEN_INTEL_MID)	+= intel-mid-touch.o

drivers/input/touchscreen/goodix.c

+/*
+ *  Driver for Goodix Touchscreens
+ *
+ *  Copyright (c) 2014 Red Hat Inc.
+ *
+ *  This code is based on gt9xx.c authored by andrew@goodix.com:
+ *
+ *  2010 - 2012 Goodix Technology.
+ */
+
+/*
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; version 2 of the License.
+ */
+
+#include <linux/kernel.h>
+#include <linux/i2c.h>
+#include <linux/input.h>
+#include <linux/input/mt.h>
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+#include <asm/unaligned.h>
+
+struct goodix_ts_data {
+	struct i2c_client *client;
+	struct input_dev *input_dev;
+	int abs_x_max;
+	int abs_y_max;
+	unsigned int max_touch_num;
+	unsigned int int_trigger_type;
+};
+
+#define GOODIX_MAX_HEIGHT		4096
+#define GOODIX_MAX_WIDTH		4096
+#define GOODIX_INT_TRIGGER		1
+#define GOODIX_CONTACT_SIZE		8
+#define GOODIX_MAX_CONTACTS		10
+
+#define GOODIX_CONFIG_MAX_LENGTH	240
+
+/* Register defines */
+#define GOODIX_READ_COOR_ADDR		0x814E
+#define GOODIX_REG_CONFIG_DATA		0x8047
+#define GOODIX_REG_VERSION		0x8140
+
+#define RESOLUTION_LOC		1
+#define TRIGGER_LOC		6
+
+static const unsigned long goodix_irq_flags[] = {
+	IRQ_TYPE_EDGE_RISING,
+	IRQ_TYPE_EDGE_FALLING,
+	IRQ_TYPE_LEVEL_LOW,
+	IRQ_TYPE_LEVEL_HIGH,
+};
+
+/**
+ * goodix_i2c_read - read data from a register of the i2c slave device.
+ *
+ * @client: i2c device.
+ * @reg: the register to read from.
+ * @buf: raw write data buffer.
+ * @len: length of the buffer to write
+ */
+static int goodix_i2c_read(struct i2c_client *client,
+				u16 reg, u8 *buf, int len)
+{
+	struct i2c_msg msgs[2];
+	u16 wbuf = cpu_to_be16(reg);
+	int ret;
+
+	msgs[0].flags = 0;
+	msgs[0].addr  = client->addr;
+	msgs[0].len   = 2;
+	msgs[0].buf   = (u8 *) &wbuf;
+
+	msgs[1].flags = I2C_M_RD;
+	msgs[1].addr  = client->addr;
+	msgs[1].len   = len;
+	msgs[1].buf   = buf;
+
+	ret = i2c_transfer(client->adapter, msgs, 2);
+	return ret < 0 ? ret : (ret != ARRAY_SIZE(msgs) ? -EIO : 0);
+}
+
+static int goodix_ts_read_input_report(struct goodix_ts_data *ts, u8 *data)
+{
+	int touch_num;
+	int error;
+
+	error = goodix_i2c_read(ts->client, GOODIX_READ_COOR_ADDR, data,
+				GOODIX_CONTACT_SIZE + 1);
+	if (error) {
+		dev_err(&ts->client->dev, "I2C transfer error: %d\n", error);
+		return error;
+	}
+
+	touch_num = data[0] & 0x0f;
+	if (touch_num > GOODIX_MAX_CONTACTS)
+		return -EPROTO;
+
+	if (touch_num > 1) {
+		data += 1 + GOODIX_CONTACT_SIZE;
+		error = goodix_i2c_read(ts->client,
+					GOODIX_READ_COOR_ADDR +
+						1 + GOODIX_CONTACT_SIZE,
+					data,
+					GOODIX_CONTACT_SIZE * (touch_num - 1));
+		if (error)
+			return error;
+	}
+
+	return touch_num;
+}
+
+static void goodix_ts_report_touch(struct goodix_ts_data *ts, u8 *coor_data)
+{
+	int id = coor_data[0] & 0x0F;
+	int input_x = get_unaligned_le16(&coor_data[1]);
+	int input_y = get_unaligned_le16(&coor_data[3]);
+	int input_w = get_unaligned_le16(&coor_data[5]);
+
+	input_mt_slot(ts->input_dev, id);
+	input_mt_report_slot_state(ts->input_dev, MT_TOOL_FINGER, true);
+	input_report_abs(ts->input_dev, ABS_MT_POSITION_X, input_x);
+	input_report_abs(ts->input_dev, ABS_MT_POSITION_Y, input_y);
+	input_report_abs(ts->input_dev, ABS_MT_TOUCH_MAJOR, input_w);
+	input_report_abs(ts->input_dev, ABS_MT_WIDTH_MAJOR, input_w);
+}
+
+/**
+ * goodix_process_events - Process incoming events
+ *
+ * @ts: our goodix_ts_data pointer
+ *
+ * Called when the IRQ is triggered. Read the current device state, and push
+ * the input events to the user space.
+ */
+static void goodix_process_events(struct goodix_ts_data *ts)
+{
+	u8  point_data[1 + GOODIX_CONTACT_SIZE * GOODIX_MAX_CONTACTS];
+	int touch_num;
+	int i;
+
+	touch_num = goodix_ts_read_input_report(ts, point_data);
+	if (touch_num < 0)
+		return;
+
+	for (i = 0; i < touch_num; i++)
+		goodix_ts_report_touch(ts,
+				&point_data[1 + GOODIX_CONTACT_SIZE * i]);
+
+	input_mt_sync_frame(ts->input_dev);
+	input_sync(ts->input_dev);
+}
+
+/**
+ * goodix_ts_irq_handler - The IRQ handler
+ *
+ * @irq: interrupt number.
+ * @dev_id: private data pointer.
+ */
+static irqreturn_t goodix_ts_irq_handler(int irq, void *dev_id)
+{
+	static const u8 end_cmd[] = {
+		GOODIX_READ_COOR_ADDR >> 8,
+		GOODIX_READ_COOR_ADDR & 0xff,
+		0
+	};
+	struct goodix_ts_data *ts = dev_id;
+
+	goodix_process_events(ts);
+
+	if (i2c_master_send(ts->client, end_cmd, sizeof(end_cmd)) < 0)
+		dev_err(&ts->client->dev, "I2C write end_cmd error\n");
+
+	return IRQ_HANDLED;
+}
+
+/**
+ * goodix_read_config - Read the embedded configuration of the panel
+ *
+ * @ts: our goodix_ts_data pointer
+ *
+ * Must be called during probe
+ */
+static void goodix_read_config(struct goodix_ts_data *ts)
+{
+	u8 config[GOODIX_CONFIG_MAX_LENGTH];
+	int error;
+
+	error = goodix_i2c_read(ts->client, GOODIX_REG_CONFIG_DATA,
+			      config,
+			   GOODIX_CONFIG_MAX_LENGTH);
+	if (error) {
+		dev_warn(&ts->client->dev,
+			 "Error reading config (%d), using defaults\n",
+			 error);
+		ts->abs_x_max = GOODIX_MAX_WIDTH;
+		ts->abs_y_max = GOODIX_MAX_HEIGHT;
+		ts->int_trigger_type = GOODIX_INT_TRIGGER;
+		return;
+	}
+
+	ts->abs_x_max = get_unaligned_le16(&config[RESOLUTION_LOC]);
+	ts->abs_y_max = get_unaligned_le16(&config[RESOLUTION_LOC + 2]);
+	ts->int_trigger_type = (config[TRIGGER_LOC]) & 0x03;
+	if (!ts->abs_x_max || !ts->abs_y_max) {
+		dev_err(&ts->client->dev,
+			"Invalid config, using defaults\n");
+		ts->abs_x_max = GOODIX_MAX_WIDTH;
+		ts->abs_y_max = GOODIX_MAX_HEIGHT;
+	}
+}
+
+
+/**
+ * goodix_read_version - Read goodix touchscreen version
+ *
+ * @client: the i2c client
+ * @version: output buffer containing the version on success
+ */
+static int goodix_read_version(struct i2c_client *client, u16 *version)
+{
+	int error;
+	u8 buf[6];
+
+	error = goodix_i2c_read(client, GOODIX_REG_VERSION, buf, sizeof(buf));
+	if (error) {
+		dev_err(&client->dev, "read version failed: %d\n", error);
+		return error;
+	}
+
+	if (version)
+		*version = get_unaligned_le16(&buf[4]);
+
+	dev_info(&client->dev, "IC VERSION: %6ph\n", buf);
+
+	return 0;
+}
+
+/**
+ * goodix_i2c_test - I2C test function to check if the device answers.
+ *
+ * @client: the i2c client
+ */
+static int goodix_i2c_test(struct i2c_client *client)
+{
+	int retry = 0;
+	int error;
+	u8 test;
+
+	while (retry++ < 2) {
+		error = goodix_i2c_read(client, GOODIX_REG_CONFIG_DATA,
+					&test, 1);
+		if (!error)
+			return 0;
+
+		dev_err(&client->dev, "i2c test failed attempt %d: %d\n",
+			retry, error);
+		msleep(20);
+	}
+
+	return error;
+}
+
+/**
+ * goodix_request_input_dev - Allocate, populate and register the input device
+ *
+ * @ts: our goodix_ts_data pointer
+ *
+ * Must be called during probe
+ */
+static int goodix_request_input_dev(struct goodix_ts_data *ts)
+{
+	int error;
+
+	ts->input_dev = devm_input_allocate_device(&ts->client->dev);
+	if (!ts->input_dev) {
+		dev_err(&ts->client->dev, "Failed to allocate input device.");
+		return -ENOMEM;
+	}
+
+	ts->input_dev->evbit[0] = BIT_MASK(EV_SYN) |
+				  BIT_MASK(EV_KEY) |
+				  BIT_MASK(EV_ABS);
+
+	input_set_abs_params(ts->input_dev, ABS_MT_POSITION_X, 0,
+				ts->abs_x_max, 0, 0);
+	input_set_abs_params(ts->input_dev, ABS_MT_POSITION_Y, 0,
+				ts->abs_y_max, 0, 0);
+	input_set_abs_params(ts->input_dev, ABS_MT_WIDTH_MAJOR, 0, 255, 0, 0);
+	input_set_abs_params(ts->input_dev, ABS_MT_TOUCH_MAJOR, 0, 255, 0, 0);
+
+	input_mt_init_slots(ts->input_dev, GOODIX_MAX_CONTACTS,
+			    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
+
+	ts->input_dev->name = "Goodix Capacitive TouchScreen";
+	ts->input_dev->phys = "input/ts";
+	ts->input_dev->id.bustype = BUS_I2C;
+	ts->input_dev->id.vendor = 0x0416;
+	ts->input_dev->id.product = 0x1001;
+	ts->input_dev->id.version = 10427;
+
+	error = input_register_device(ts->input_dev);
+	if (error) {
+		dev_err(&ts->client->dev,
+			"Failed to register input device: %d", error);
+		return error;
+	}
+
+	return 0;
+}
+
+static int goodix_ts_probe(struct i2c_client *client,
+			   const struct i2c_device_id *id)
+{
+	struct goodix_ts_data *ts;
+	unsigned long irq_flags;
+	int error;
+	u16 version_info;
+
+	dev_dbg(&client->dev, "I2C Address: 0x%02x\n", client->addr);
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
+		dev_err(&client->dev, "I2C check functionality failed.\n");
+		return -ENXIO;
+	}
+
+	ts = devm_kzalloc(&client->dev, sizeof(*ts), GFP_KERNEL);
+	if (!ts)
+		return -ENOMEM;
+
+	ts->client = client;
+	i2c_set_clientdata(client, ts);
+
+	error = goodix_i2c_test(client);
+	if (error) {
+		dev_err(&client->dev, "I2C communication failure: %d\n", error);
+		return error;
+	}
+
+	error = goodix_read_version(client, &version_info);
+	if (error) {
+		dev_err(&client->dev, "Read version failed.\n");
+		return error;
+	}
+
+	goodix_read_config(ts);
+
+	error = goodix_request_input_dev(ts);
+	if (error)
+		return error;
+
+	irq_flags = goodix_irq_flags[ts->int_trigger_type] | IRQF_ONESHOT;
+	error = devm_request_threaded_irq(&ts->client->dev, client->irq,
+					  NULL, goodix_ts_irq_handler,
+					  irq_flags, client->name, ts);
+	if (error) {
+		dev_err(&client->dev, "request IRQ failed: %d\n", error);
+		return error;
+	}
+
+	return 0;
+}
+
+static const struct i2c_device_id goodix_ts_id[] = {
+	{ "GDIX1001:00", 0 },
+	{ }
+};
+
+static const struct acpi_device_id goodix_acpi_match[] = {
+	{ "GDIX1001", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, goodix_acpi_match);
+
+static struct i2c_driver goodix_ts_driver = {
+	.probe = goodix_ts_probe,
+	.id_table = goodix_ts_id,
+	.driver = {
+		.name = "Goodix-TS",
+		.owner = THIS_MODULE,
+		.acpi_match_table = goodix_acpi_match,
+	},
+};
+module_i2c_driver(goodix_ts_driver);
+
+MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");
+MODULE_AUTHOR("Bastien Nocera <hadess@hadess.net>");
+MODULE_DESCRIPTION("Goodix touchscreen driver");
+MODULE_LICENSE("GPL v2");