Input: add support for ChipOne icn8505 based touchscreens

The ChipOne icn8505 is an i2c capacitive touchscreen controller typically
used in cheap x86 tablets, this commit adds a driver for it.

Note the icn8505 is somewhat similar to the icn8318 and I started with
modifying that driver to support both, but in the end the differences were
too large and I decided to write a new driver instead.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

MAINTAINERS

@@ -3441,6 +3441,12 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/input/touchscreen/chipone_icn8318.txt
 F:	drivers/input/touchscreen/chipone_icn8318.c
 
+CHIPONE ICN8505 I2C TOUCHSCREEN DRIVER
+M:	Hans de Goede <hdegoede@redhat.com>
+L:	linux-input@vger.kernel.org
+S:	Maintained
+F:	drivers/input/touchscreen/chipone_icn8505.c
+
 CHROME HARDWARE PLATFORM SUPPORT
 M:	Benson Leung <bleung@chromium.org>
 M:	Olof Johansson <olof@lixom.net>

drivers/input/touchscreen/Kconfig

@@ -164,6 +164,17 @@ config TOUCHSCREEN_CHIPONE_ICN8318
 	  To compile this driver as a module, choose M here: the
 	  module will be called chipone_icn8318.
 
+config TOUCHSCREEN_CHIPONE_ICN8505
+	tristate "chipone icn8505 touchscreen controller"
+	depends on I2C && ACPI
+	help
+	  Say Y here if you have a ChipOne icn8505 based I2C touchscreen.
+
+	  If unsure, say N.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called chipone_icn8505.
+
 config TOUCHSCREEN_CY8CTMG110
 	tristate "cy8ctmg110 touchscreen"
 	depends on I2C

drivers/input/touchscreen/Makefile

@@ -19,6 +19,7 @@ obj-$(CONFIG_TOUCHSCREEN_ATMEL_MXT)	+= atmel_mxt_ts.o
 obj-$(CONFIG_TOUCHSCREEN_AUO_PIXCIR)	+= auo-pixcir-ts.o
 obj-$(CONFIG_TOUCHSCREEN_BU21013)	+= bu21013_ts.o
 obj-$(CONFIG_TOUCHSCREEN_CHIPONE_ICN8318)	+= chipone_icn8318.o
+obj-$(CONFIG_TOUCHSCREEN_CHIPONE_ICN8505)	+= chipone_icn8505.o
 obj-$(CONFIG_TOUCHSCREEN_CY8CTMG110)	+= cy8ctmg110_ts.o
 obj-$(CONFIG_TOUCHSCREEN_CYTTSP_CORE)	+= cyttsp_core.o
 obj-$(CONFIG_TOUCHSCREEN_CYTTSP_I2C)	+= cyttsp_i2c.o cyttsp_i2c_common.o

drivers/input/touchscreen/chipone_icn8505.c

+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Driver for ChipOne icn8505 i2c touchscreen controller
+ *
+ * Copyright (c) 2015-2018 Red Hat Inc.
+ *
+ * Red Hat authors:
+ * Hans de Goede <hdegoede@redhat.com>
+ */
+
+#include <asm/unaligned.h>
+#include <linux/acpi.h>
+#include <linux/crc32.h>
+#include <linux/delay.h>
+#include <linux/firmware.h>
+#include <linux/interrupt.h>
+#include <linux/i2c.h>
+#include <linux/input.h>
+#include <linux/input/mt.h>
+#include <linux/input/touchscreen.h>
+#include <linux/module.h>
+
+/* Normal operation mode defines */
+#define ICN8505_REG_ADDR_WIDTH		16
+
+#define ICN8505_REG_POWER		0x0004
+#define ICN8505_REG_TOUCHDATA		0x1000
+#define ICN8505_REG_CONFIGDATA		0x8000
+
+/* ICN8505_REG_POWER commands */
+#define ICN8505_POWER_ACTIVE		0x00
+#define ICN8505_POWER_MONITOR		0x01
+#define ICN8505_POWER_HIBERNATE		0x02
+/*
+ * The Android driver uses these to turn on/off the charger filter, but the
+ * filter is way too aggressive making e.g. onscreen keyboards unusable.
+ */
+#define ICN8505_POWER_ENA_CHARGER_MODE	0x55
+#define ICN8505_POWER_DIS_CHARGER_MODE	0x66
+
+#define ICN8505_MAX_TOUCHES		10
+
+/* Programming mode defines */
+#define ICN8505_PROG_I2C_ADDR		0x30
+#define ICN8505_PROG_REG_ADDR_WIDTH	24
+
+#define MAX_FW_UPLOAD_TRIES		3
+
+struct icn8505_touch {
+	u8 slot;
+	u8 x[2];
+	u8 y[2];
+	u8 pressure;	/* Seems more like finger width then pressure really */
+	u8 event;
+/* The difference between 2 and 3 is unclear */
+#define ICN8505_EVENT_NO_DATA	1 /* No finger seen yet since wakeup */
+#define ICN8505_EVENT_UPDATE1	2 /* New or updated coordinates */
+#define ICN8505_EVENT_UPDATE2	3 /* New or updated coordinates */
+#define ICN8505_EVENT_END	4 /* Finger lifted */
+} __packed;
+
+struct icn8505_touch_data {
+	u8 softbutton;
+	u8 touch_count;
+	struct icn8505_touch touches[ICN8505_MAX_TOUCHES];
+} __packed;
+
+struct icn8505_data {
+	struct i2c_client *client;
+	struct input_dev *input;
+	struct gpio_desc *wake_gpio;
+	struct touchscreen_properties prop;
+	char firmware_name[32];
+};
+
+static int icn8505_read_xfer(struct i2c_client *client, u16 i2c_addr,
+			     int reg_addr, int reg_addr_width,
+			     void *data, int len, bool silent)
+{
+	u8 buf[3];
+	int i, ret;
+	struct i2c_msg msg[2] = {
+		{
+			.addr = i2c_addr,
+			.buf = buf,
+			.len = reg_addr_width / 8,
+		},
+		{
+			.addr = i2c_addr,
+			.flags = I2C_M_RD,
+			.buf = data,
+			.len = len,
+		}
+	};
+
+	for (i = 0; i < (reg_addr_width / 8); i++)
+		buf[i] = (reg_addr >> (reg_addr_width - (i + 1) * 8)) & 0xff;
+
+	ret = i2c_transfer(client->adapter, msg, 2);
+	if (ret != ARRAY_SIZE(msg)) {
+		if (ret >= 0)
+			ret = -EIO;
+		if (!silent)
+			dev_err(&client->dev,
+				"Error reading addr %#x reg %#x: %d\n",
+				i2c_addr, reg_addr, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int icn8505_write_xfer(struct i2c_client *client, u16 i2c_addr,
+			      int reg_addr, int reg_addr_width,
+			      const void *data, int len, bool silent)
+{
+	u8 buf[3 + 32]; /* 3 bytes for 24 bit reg-addr + 32 bytes max len */
+	int i, ret;
+	struct i2c_msg msg = {
+		.addr = i2c_addr,
+		.buf = buf,
+		.len = reg_addr_width / 8 + len,
+	};
+
+	if (WARN_ON(len > 32))
+		return -EINVAL;
+
+	for (i = 0; i < (reg_addr_width / 8); i++)
+		buf[i] = (reg_addr >> (reg_addr_width - (i + 1) * 8)) & 0xff;
+
+	memcpy(buf + reg_addr_width / 8, data, len);
+
+	ret = i2c_transfer(client->adapter, &msg, 1);
+	if (ret != 1) {
+		if (ret >= 0)
+			ret = -EIO;
+		if (!silent)
+			dev_err(&client->dev,
+				"Error writing addr %#x reg %#x: %d\n",
+				i2c_addr, reg_addr, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int icn8505_read_data(struct icn8505_data *icn8505, int reg,
+			     void *buf, int len)
+{
+	return icn8505_read_xfer(icn8505->client, icn8505->client->addr, reg,
+				 ICN8505_REG_ADDR_WIDTH, buf, len, false);
+}
+
+static int icn8505_read_reg_silent(struct icn8505_data *icn8505, int reg)
+{
+	u8 buf;
+	int error;
+
+	error = icn8505_read_xfer(icn8505->client, icn8505->client->addr, reg,
+				  ICN8505_REG_ADDR_WIDTH, &buf, 1, true);
+	if (error)
+		return error;
+
+	return buf;
+}
+
+static int icn8505_write_reg(struct icn8505_data *icn8505, int reg, u8 val)
+{
+	return icn8505_write_xfer(icn8505->client, icn8505->client->addr, reg,
+				  ICN8505_REG_ADDR_WIDTH, &val, 1, false);
+}
+
+static int icn8505_read_prog_data(struct icn8505_data *icn8505, int reg,
+				  void *buf, int len)
+{
+	return icn8505_read_xfer(icn8505->client, ICN8505_PROG_I2C_ADDR, reg,
+				 ICN8505_PROG_REG_ADDR_WIDTH, buf, len, false);
+}
+
+static int icn8505_write_prog_data(struct icn8505_data *icn8505, int reg,
+				   const void *buf, int len)
+{
+	return icn8505_write_xfer(icn8505->client, ICN8505_PROG_I2C_ADDR, reg,
+				  ICN8505_PROG_REG_ADDR_WIDTH, buf, len, false);
+}
+
+static int icn8505_write_prog_reg(struct icn8505_data *icn8505, int reg, u8 val)
+{
+	return icn8505_write_xfer(icn8505->client, ICN8505_PROG_I2C_ADDR, reg,
+				  ICN8505_PROG_REG_ADDR_WIDTH, &val, 1, false);
+}
+
+/*
+ * Note this function uses a number of magic register addresses and values,
+ * there are deliberately no defines for these because the algorithm is taken
+ * from the icn85xx Android driver and I do not want to make up possibly wrong
+ * names for the addresses and/or values.
+ */
+static int icn8505_try_fw_upload(struct icn8505_data *icn8505,
+				 const struct firmware *fw)
+{
+	struct device *dev = &icn8505->client->dev;
+	size_t offset, count;
+	int error;
+	u8 buf[4];
+	u32 crc;
+
+	/* Put the controller in programming mode */
+	error = icn8505_write_prog_reg(icn8505, 0xcc3355, 0x5a);
+	if (error)
+		return error;
+
+	usleep_range(2000, 5000);
+
+	error = icn8505_write_prog_reg(icn8505, 0x040400, 0x01);
+	if (error)
+		return error;
+
+	usleep_range(2000, 5000);
+
+	error = icn8505_read_prog_data(icn8505, 0x040002, buf, 1);
+	if (error)
+		return error;
+
+	if (buf[0] != 0x85) {
+		dev_err(dev, "Failed to enter programming mode\n");
+		return -ENODEV;
+	}
+
+	usleep_range(1000, 5000);
+
+	/* Enable CRC mode */
+	error = icn8505_write_prog_reg(icn8505, 0x40028, 1);
+	if (error)
+		return error;
+
+	/* Send the firmware to SRAM */
+	for (offset = 0; offset < fw->size; offset += count) {
+		count = min_t(size_t, fw->size - offset, 32);
+		error = icn8505_write_prog_data(icn8505, offset,
+					      fw->data + offset, count);
+		if (error)
+			return error;
+	}
+
+	/* Disable CRC mode */
+	error = icn8505_write_prog_reg(icn8505, 0x40028, 0);
+	if (error)
+		return error;
+
+	/* Get and check length and CRC */
+	error = icn8505_read_prog_data(icn8505, 0x40034, buf, 2);
+	if (error)
+		return error;
+
+	if (get_unaligned_le16(buf) != fw->size) {
+		dev_warn(dev, "Length mismatch after uploading fw\n");
+		return -EIO;
+	}
+
+	error = icn8505_read_prog_data(icn8505, 0x4002c, buf, 4);
+	if (error)
+		return error;
+
+	crc = crc32_be(0, fw->data, fw->size);
+	if (get_unaligned_le32(buf) != crc) {
+		dev_warn(dev, "CRC mismatch after uploading fw\n");
+		return -EIO;
+	}
+
+	/* Boot controller from SRAM */
+	error = icn8505_write_prog_reg(icn8505, 0x40400, 0x03);
+	if (error)
+		return error;
+
+	usleep_range(2000, 5000);
+	return 0;
+}
+
+static int icn8505_upload_fw(struct icn8505_data *icn8505)
+{
+	struct device *dev = &icn8505->client->dev;
+	const struct firmware *fw;
+	int i, error;
+
+	/*
+	 * Always load the firmware, even if we don't need it at boot, we
+	 * we may need it at resume. Having loaded it once will make the
+	 * firmware class code cache it at suspend/resume.
+	 */
+	error = request_firmware(&fw, icn8505->firmware_name, dev);
+	if (error) {
+		dev_err(dev, "Firmware request error %d\n", error);
+		return error;
+	}
+
+	/* Check if the controller is not already up and running */
+	if (icn8505_read_reg_silent(icn8505, 0x000a) == 0x85)
+		goto success;
+
+	for (i = 1; i <= MAX_FW_UPLOAD_TRIES; i++) {
+		error = icn8505_try_fw_upload(icn8505, fw);
+		if (!error)
+			goto success;
+
+		dev_err(dev, "Failed to upload firmware: %d (attempt %d/%d)\n",
+			error, i, MAX_FW_UPLOAD_TRIES);
+		usleep_range(2000, 5000);
+	}
+
+success:
+	release_firmware(fw);
+	return error;
+}
+
+static bool icn8505_touch_active(u8 event)
+{
+	return event == ICN8505_EVENT_UPDATE1 ||
+	       event == ICN8505_EVENT_UPDATE2;
+}
+
+static irqreturn_t icn8505_irq(int irq, void *dev_id)
+{
+	struct icn8505_data *icn8505 = dev_id;
+	struct device *dev = &icn8505->client->dev;
+	struct icn8505_touch_data touch_data;
+	int i, error;
+
+	error = icn8505_read_data(icn8505, ICN8505_REG_TOUCHDATA,
+				  &touch_data, sizeof(touch_data));
+	if (error) {
+		dev_err(dev, "Error reading touch data: %d\n", error);
+		return IRQ_HANDLED;
+	}
+
+	if (touch_data.touch_count > ICN8505_MAX_TOUCHES) {
+		dev_warn(dev, "Too many touches %d > %d\n",
+			 touch_data.touch_count, ICN8505_MAX_TOUCHES);
+		touch_data.touch_count = ICN8505_MAX_TOUCHES;
+	}
+
+	for (i = 0; i < touch_data.touch_count; i++) {
+		struct icn8505_touch *touch = &touch_data.touches[i];
+		bool act = icn8505_touch_active(touch->event);
+
+		input_mt_slot(icn8505->input, touch->slot);
+		input_mt_report_slot_state(icn8505->input, MT_TOOL_FINGER, act);
+		if (!act)
+			continue;
+
+		touchscreen_report_pos(icn8505->input, &icn8505->prop,
+				       get_unaligned_le16(touch->x),
+				       get_unaligned_le16(touch->y),
+				       true);
+	}
+
+	input_mt_sync_frame(icn8505->input);
+	input_report_key(icn8505->input, KEY_LEFTMETA,
+			 touch_data.softbutton == 1);
+	input_sync(icn8505->input);
+
+	return IRQ_HANDLED;
+}
+
+static int icn8505_probe_acpi(struct icn8505_data *icn8505, struct device *dev)
+{
+	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+	const char *subsys = "unknown";
+	struct acpi_device *adev;
+	union acpi_object *obj;
+	acpi_status status;
+
+	adev = ACPI_COMPANION(dev);
+	if (!adev)
+		return -ENODEV;
+
+	status = acpi_evaluate_object(adev->handle, "_SUB", NULL, &buffer);
+	if (ACPI_SUCCESS(status)) {
+		obj = buffer.pointer;
+		if (obj->type == ACPI_TYPE_STRING)
+			subsys = obj->string.pointer;
+		else
+			dev_warn(dev, "Warning ACPI _SUB did not return a string\n");
+	} else {
+		dev_warn(dev, "Warning ACPI _SUB failed: %#x\n", status);
+		buffer.pointer = NULL;
+	}
+
+	snprintf(icn8505->firmware_name, sizeof(icn8505->firmware_name),
+		 "chipone/icn8505-%s.fw", subsys);
+
+	kfree(buffer.pointer);
+	return 0;
+}
+
+static int icn8505_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct icn8505_data *icn8505;
+	struct input_dev *input;
+	__le16 resolution[2];
+	int error;
+
+	if (!client->irq) {
+		dev_err(dev, "No irq specified\n");
+		return -EINVAL;
+	}
+
+	icn8505 = devm_kzalloc(dev, sizeof(*icn8505), GFP_KERNEL);
+	if (!icn8505)
+		return -ENOMEM;
+
+	input = devm_input_allocate_device(dev);
+	if (!input)
+		return -ENOMEM;
+
+	input->name = client->name;
+	input->id.bustype = BUS_I2C;
+
+	input_set_capability(input, EV_ABS, ABS_MT_POSITION_X);
+	input_set_capability(input, EV_ABS, ABS_MT_POSITION_Y);
+	input_set_capability(input, EV_KEY, KEY_LEFTMETA);
+
+	icn8505->client = client;
+	icn8505->input = input;
+	input_set_drvdata(input, icn8505);
+
+	error = icn8505_probe_acpi(icn8505, dev);
+	if (error)
+		return error;
+
+	error = icn8505_upload_fw(icn8505);
+	if (error)
+		return error;
+
+	error = icn8505_read_data(icn8505, ICN8505_REG_CONFIGDATA,
+				resolution, sizeof(resolution));
+	if (error) {
+		dev_err(dev, "Error reading resolution: %d\n", error);
+		return error;
+	}
+
+	input_set_abs_params(input, ABS_MT_POSITION_X, 0,
+			     le16_to_cpu(resolution[0]) - 1, 0, 0);
+	input_set_abs_params(input, ABS_MT_POSITION_Y, 0,
+			     le16_to_cpu(resolution[1]) - 1, 0, 0);
+
+	touchscreen_parse_properties(input, true, &icn8505->prop);
+	if (!input_abs_get_max(input, ABS_MT_POSITION_X) ||
+	    !input_abs_get_max(input, ABS_MT_POSITION_Y)) {
+		dev_err(dev, "Error touchscreen-size-x and/or -y missing\n");
+		return -EINVAL;
+	}
+
+	error = input_mt_init_slots(input, ICN8505_MAX_TOUCHES,
+				  INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
+	if (error)
+		return error;
+
+	error = devm_request_threaded_irq(dev, client->irq, NULL, icn8505_irq,
+					IRQF_ONESHOT, client->name, icn8505);
+	if (error) {
+		dev_err(dev, "Error requesting irq: %d\n", error);
+		return error;
+	}
+
+	error = input_register_device(input);
+	if (error)
+		return error;
+
+	i2c_set_clientdata(client, icn8505);
+	return 0;
+}
+
+static int __maybe_unused icn8505_suspend(struct device *dev)
+{
+	struct icn8505_data *icn8505 = i2c_get_clientdata(to_i2c_client(dev));
+
+	disable_irq(icn8505->client->irq);
+
+	icn8505_write_reg(icn8505, ICN8505_REG_POWER, ICN8505_POWER_HIBERNATE);
+
+	return 0;
+}
+
+static int __maybe_unused icn8505_resume(struct device *dev)
+{
+	struct icn8505_data *icn8505 = i2c_get_clientdata(to_i2c_client(dev));
+	int error;
+
+	error = icn8505_upload_fw(icn8505);
+	if (error)
+		return error;
+
+	enable_irq(icn8505->client->irq);
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(icn8505_pm_ops, icn8505_suspend, icn8505_resume);
+
+static const struct acpi_device_id icn8505_acpi_match[] = {
+	{ "CHPN0001" },
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, icn8505_acpi_match);
+
+static struct i2c_driver icn8505_driver = {
+	.driver = {
+		.name	= "chipone_icn8505",
+		.pm	= &icn8505_pm_ops,
+		.acpi_match_table = icn8505_acpi_match,
+	},
+	.probe_new = icn8505_probe,
+};
+
+module_i2c_driver(icn8505_driver);
+
+MODULE_DESCRIPTION("ChipOne icn8505 I2C Touchscreen Driver");
+MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
+MODULE_LICENSE("GPL");