Input: add driver for Zeitec ZET6223

This is a basic driver for the Zeitec ZET6223 I2C touchscreen
controllers. The driver does not support firmware loading, which is not
required for all tablets which contain this chip.

Signed-off-by: Jelle van der Waa <[e-mail]>
Acked-by: Rob Herring <[e-mail]>
Signed-off-by: Dmitry Torokhov <[e-mail]>

Documentation/devicetree/bindings/input/touchscreen/zet6223.txt

···
+Zeitec ZET6223 I2C touchscreen controller
+
+Required properties:
+- compatible		  : "zeitec,zet6223"
+- reg			  : I2C slave address of the chip (0x76)
+- interrupt-parent	  : a phandle pointing to the interrupt controller
+			    serving the interrupt for this chip
+- interrupts		  : interrupt specification for the zet6223 interrupt
+
+Optional properties:
+
+- vio-supply		  : Specification for VIO supply (1.8V or 3.3V,
+			    depending on system interface needs).
+- vcc-supply		  : Specification for 3.3V VCC supply.
+- touchscreen-size-x	  : See touchscreen.txt
+- touchscreen-size-y	  : See touchscreen.txt
+- touchscreen-inverted-x  : See touchscreen.txt
+- touchscreen-inverted-y  : See touchscreen.txt
+- touchscreen-swapped-x-y : See touchscreen.txt
+
+Example:
+
+i2c@00000000 {
+
+	zet6223: touchscreen@76 {
+		compatible = "zeitec,zet6223";
+		reg = <0x76>;
+		interrupt-parent = <&pio>;
+		interrupts = <6 11 IRQ_TYPE_EDGE_FALLING>
+	};
+
+};

Documentation/devicetree/bindings/vendor-prefixes.txt

···
 xillybus	Xillybus Ltd.
 xlnx	Xilinx
 zarlink	Zarlink Semiconductor
+zeitec	ZEITEC Semiconductor Co., LTD.
 zii	Zodiac Inflight Innovations
 zte	ZTE Corp.
 zyxel	ZyXEL Communications Corp.

drivers/input/touchscreen/Kconfig

···
 	  To compile this driver as a module, choose M here: the
 	  module will be called tps6507x_ts.
 
+config TOUCHSCREEN_ZET6223
+	tristate "Zeitec ZET6223 touchscreen driver"
+	depends on I2C
+	help
+	  Say Y here if you have a touchscreen using Zeitec ZET6223
+
+	  If unsure, say N.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called zet6223.
+
 config TOUCHSCREEN_ZFORCE
 	tristate "Neonode zForce infrared touchscreens"
 	depends on I2C

drivers/input/touchscreen/Makefile

···
 obj-$(CONFIG_TOUCHSCREEN_W90X900)	+= w90p910_ts.o
 obj-$(CONFIG_TOUCHSCREEN_SX8654)	+= sx8654.o
 obj-$(CONFIG_TOUCHSCREEN_TPS6507X)	+= tps6507x-ts.o
+obj-$(CONFIG_TOUCHSCREEN_ZET6223)	+= zet6223.o
 obj-$(CONFIG_TOUCHSCREEN_ZFORCE)	+= zforce_ts.o
 obj-$(CONFIG_TOUCHSCREEN_COLIBRI_VF50)	+= colibri-vf50-ts.o
 obj-$(CONFIG_TOUCHSCREEN_ROHM_BU21023)	+= rohm_bu21023.o

drivers/input/touchscreen/zet6223.c

···
+/*
+ * Copyright (C) 2016, Jelle van der Waa <[e-mail]>
+ *
+ * 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; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * 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/delay.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/module.h>
+#include <linux/regulator/consumer.h>
+#include <asm/unaligned.h>
+
+#define ZET6223_MAX_FINGERS		16
+#define ZET6223_MAX_PKT_SIZE		(3 + 4 * ZET6223_MAX_FINGERS)
+
+#define ZET6223_CMD_INFO		0xB2
+#define ZET6223_CMD_INFO_LENGTH		17
+#define ZET6223_VALID_PACKET		0x3c
+
+#define ZET6223_POWER_ON_DELAY_MSEC	30
+
+struct zet6223_ts {
+	struct i2c_client *client;
+	struct input_dev *input;
+	struct regulator *vcc;
+	struct regulator *vio;
+	struct touchscreen_properties prop;
+	struct regulator_bulk_data supplies[2];
+	u16 max_x;
+	u16 max_y;
+	u8 fingernum;
+};
+
+static int zet6223_start(struct input_dev *dev)
+{
+	struct zet6223_ts *ts = input_get_drvdata(dev);
+
+	enable_irq(ts->client->irq);
+
+	return 0;
+}
+
+static void zet6223_stop(struct input_dev *dev)
+{
+	struct zet6223_ts *ts = input_get_drvdata(dev);
+
+	disable_irq(ts->client->irq);
+}
+
+static irqreturn_t zet6223_irq(int irq, void *dev_id)
+{
+	struct zet6223_ts *ts = dev_id;
+	u16 finger_bits;
+
+	/*
+	 * First 3 bytes are an identifier, two bytes of finger data.
+	 * X, Y data per finger is 4 bytes.
+	 */
+	u8 bufsize = 3 + 4 * ts->fingernum;
+	u8 buf[ZET6223_MAX_PKT_SIZE];
+	int i;
+	int ret;
+	int error;
+
+	ret = i2c_master_recv(ts->client, buf, bufsize);
+	if (ret != bufsize) {
+		error = ret < 0 ? ret : -EIO;
+		dev_err_ratelimited(&ts->client->dev,
+				    "Error reading input data: %d\n", error);
+		return IRQ_HANDLED;
+	}
+
+	if (buf[0] != ZET6223_VALID_PACKET)
+		return IRQ_HANDLED;
+
+	finger_bits = get_unaligned_be16(buf + 1);
+	for (i = 0; i < ts->fingernum; i++) {
+		if (!(finger_bits & BIT(15 - i)))
+			continue;
+
+		input_mt_slot(ts->input, i);
+		input_mt_report_slot_state(ts->input, MT_TOOL_FINGER, true);
+		input_event(ts->input, EV_ABS, ABS_MT_POSITION_X,
+				((buf[i + 3] >> 4) << 8) + buf[i + 4]);
+		input_event(ts->input, EV_ABS, ABS_MT_POSITION_Y,
+				((buf[i + 3] & 0xF) << 8) + buf[i + 5]);
+	}
+
+	input_mt_sync_frame(ts->input);
+	input_sync(ts->input);
+
+	return IRQ_HANDLED;
+}
+
+static void zet6223_power_off(void *_ts)
+{
+	struct zet6223_ts *ts = _ts;
+
+	regulator_bulk_disable(ARRAY_SIZE(ts->supplies), ts->supplies);
+}
+
+static int zet6223_power_on(struct zet6223_ts *ts)
+{
+	struct device *dev = &ts->client->dev;
+	int error;
+
+	ts->supplies[0].supply = "vio";
+	ts->supplies[1].supply = "vcc";
+
+	error = devm_regulator_bulk_get(dev, ARRAY_SIZE(ts->supplies),
+					ts->supplies);
+	if (error)
+		return error;
+
+	error = regulator_bulk_enable(ARRAY_SIZE(ts->supplies), ts->supplies);
+	if (error)
+		return error;
+
+	msleep(ZET6223_POWER_ON_DELAY_MSEC);
+
+	error = devm_add_action_or_reset(dev, zet6223_power_off, ts);
+	if (error) {
+		dev_err(dev, "failed to install poweroff action: %d\n", error);
+		return error;
+	}
+
+	return 0;
+}
+
+static int zet6223_query_device(struct zet6223_ts *ts)
+{
+	u8 buf[ZET6223_CMD_INFO_LENGTH];
+	u8 cmd = ZET6223_CMD_INFO;
+	int ret;
+	int error;
+
+	ret = i2c_master_send(ts->client, &cmd, sizeof(cmd));
+	if (ret != sizeof(cmd)) {
+		error = ret < 0 ? ret : -EIO;
+		dev_err(&ts->client->dev,
+			"touchpanel info cmd failed: %d\n", error);
+		return error;
+	}
+
+	ret = i2c_master_recv(ts->client, buf, sizeof(buf));
+	if (ret != sizeof(buf)) {
+		error = ret < 0 ? ret : -EIO;
+		dev_err(&ts->client->dev,
+			"failed to retrieve touchpanel info: %d\n", error);
+		return error;
+	}
+
+	ts->fingernum = buf[15] & 0x7F;
+	if (ts->fingernum > ZET6223_MAX_FINGERS) {
+		dev_warn(&ts->client->dev,
+			 "touchpanel reports %d fingers, limiting to %d\n",
+			 ts->fingernum, ZET6223_MAX_FINGERS);
+		ts->fingernum = ZET6223_MAX_FINGERS;
+	}
+
+	ts->max_x = get_unaligned_le16(&buf[8]);
+	ts->max_y = get_unaligned_le16(&buf[10]);
+
+	return 0;
+}
+
+static int zet6223_probe(struct i2c_client *client,
+			 const struct i2c_device_id *id)
+{
+	struct device *dev = &client->dev;
+	struct zet6223_ts *ts;
+	struct input_dev *input;
+	int error;
+
+	if (!client->irq) {
+		dev_err(dev, "no irq specified\n");
+		return -EINVAL;
+	}
+
+	ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
+	if (!ts)
+		return -ENOMEM;
+
+	ts->client = client;
+
+	error = zet6223_power_on(ts);
+	if (error)
+		return error;
+
+	error = zet6223_query_device(ts);
+	if (error)
+		return error;
+
+	ts->input = input = devm_input_allocate_device(dev);
+	if (!input)
+		return -ENOMEM;
+
+	input_set_drvdata(input, ts);
+
+	input->name = client->name;
+	input->id.bustype = BUS_I2C;
+	input->open = zet6223_start;
+	input->close = zet6223_stop;
+
+	input_set_abs_params(input, ABS_MT_POSITION_X, 0, ts->max_x, 0, 0);
+	input_set_abs_params(input, ABS_MT_POSITION_Y, 0, ts->max_y, 0, 0);
+
+	touchscreen_parse_properties(input, true, &ts->prop);
+
+	error = input_mt_init_slots(input, ts->fingernum,
+				    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
+	if (error)
+		return error;
+
+	error = devm_request_threaded_irq(dev, client->irq, NULL, zet6223_irq,
+					  IRQF_ONESHOT, client->name, ts);
+	if (error) {
+		dev_err(dev, "failed to request irq %d: %d\n",
+			client->irq, error);
+		return error;
+	}
+
+	zet6223_stop(input);
+
+	error = input_register_device(input);
+	if (error)
+		return error;
+
+	return 0;
+}
+
+static const struct of_device_id zet6223_of_match[] = {
+	{ .compatible = "zeitec,zet6223" },
+	{ }
+};
+
+static const struct i2c_device_id zet6223_id[] = {
+	{ "zet6223", 0},
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, zet6223_id);
+
+static struct i2c_driver zet6223_driver = {
+	.driver = {
+		.name = "zet6223",
+		.of_match_table = zet6223_of_match,
+	},
+	.probe = zet6223_probe,
+	.id_table = zet6223_id
+};
+module_i2c_driver(zet6223_driver);
+
+MODULE_AUTHOR("Jelle van der Waa <[e-mail]>");
+MODULE_DESCRIPTION("ZEITEC zet622x I2C touchscreen driver");
+MODULE_LICENSE("GPL");