Date:   Tue, 12 Mar 2019 14:01:37 -0500
From:   Adam Ford <aford173@...il.com>
To:     linux-input@...r.kernel.org
Cc:     adam.ford@...icpd.com, Adam Ford <aford173@...il.com>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Henrik Rydberg <rydberg@...math.org>,
        linux-kernel@...r.kernel.org
Subject: [PATCH] Input: ili2117a - Add support for Ilitek ILI2117A based touchscreens

This driver supports the ILI2117A touch controller.  This is
different than the ILI210x and it uses different register and
algorithm so it's a separate driver rather than integrating with
the other.

Signed-off-by: Adam Ford <aford173@...il.com>

diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index 6c16aaeb4191..ff7cd369514e 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -416,6 +416,18 @@ config TOUCHSCREEN_ILI210X
 	  To compile this driver as a module, choose M here: the
 	  module will be called ili210x.
 
+config TOUCHSCREEN_ILI2117A
+	tristate "Ilitek ILI2117A Multi-Touch Controller"
+	depends on I2C
+	help
+	  Say Y here if you have a ILI2117A based touchscreen
+	  controller.
+
+	  If unsure, say N.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ili2117a.
+
 config TOUCHSCREEN_IPROC
 	tristate "IPROC touch panel driver support"
 	depends on ARCH_BCM_IPROC || COMPILE_TEST
diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
index fcc7605fba8d..0290d503bed1 100644
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -46,6 +46,7 @@ obj-$(CONFIG_TOUCHSCREEN_FUJITSU)	+= fujitsu_ts.o
 obj-$(CONFIG_TOUCHSCREEN_GOODIX)	+= goodix.o
 obj-$(CONFIG_TOUCHSCREEN_HIDEEP)	+= hideep.o
 obj-$(CONFIG_TOUCHSCREEN_ILI210X)	+= ili210x.o
+obj-$(CONFIG_TOUCHSCREEN_ILI2117A)      += ili2117a.o
 obj-$(CONFIG_TOUCHSCREEN_IMX6UL_TSC)	+= imx6ul_tsc.o
 obj-$(CONFIG_TOUCHSCREEN_INEXIO)	+= inexio.o
 obj-$(CONFIG_TOUCHSCREEN_IPROC)		+= bcm_iproc_tsc.o
diff --git a/drivers/input/touchscreen/ili2117a.c b/drivers/input/touchscreen/ili2117a.c
new file mode 100644
index 000000000000..c47874ee89f4
--- /dev/null
+++ b/drivers/input/touchscreen/ili2117a.c
@@ -0,0 +1,308 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+#include <linux/input.h>
+#include <linux/input/mt.h>
+#include <linux/delay.h>
+#include <linux/workqueue.h>
+
+#define MAX_TOUCHES		10
+#define DEFAULT_POLL_PERIOD	20
+#define MAX_X			((1 << 12) - 1)
+#define MAX_Y			((1 << 12) - 1)
+
+/* Touchscreen commands */
+#define TOUCH_INFO	0x00
+
+struct finger {
+	u8 xy;
+	u8 x;
+	u8 y;
+	u8 c_sum;
+} __packed;
+
+struct touchdata {
+	u8 packet_id;
+	struct finger finger[MAX_TOUCHES];
+	u8 key;
+	u8 checksum;
+} __packed;
+
+
+struct ili2117a {
+	struct i2c_client *client;
+	struct input_dev *input;
+	bool (*get_pendown_state)(void);
+	unsigned int poll_period;
+	struct delayed_work dwork;
+	int max_touch;
+};
+
+static int ili2117a_read_reg(struct i2c_client *client, u8 reg, void *buf,
+			    size_t len)
+{
+	struct i2c_msg msg[2] = {
+		{
+			.addr	= client->addr,
+			.flags	= 0,
+			.len	= 1,
+			.buf	= &reg,
+		},
+		{
+			.addr	= client->addr,
+			.flags	= I2C_M_RD,
+			.len	= len,
+			.buf	= buf,
+		}
+	};
+
+	if (i2c_transfer(client->adapter, msg, 2) != 2) {
+		dev_err(&client->dev, "i2c transfer failed\n");
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static bool ili2117a_report_events(struct input_dev *input,
+				  const struct touchdata *touchdata,
+				  int max_touch)
+{
+	int i;
+	bool touch;
+	bool pen_down = 0;
+	u16 x = 0xfff;
+	u16 y = 0xfff;
+	const struct finger *finger;
+
+	for (i = 0; i < max_touch; i++) {
+		touch = 0;
+		input_mt_slot(input, i);
+		finger = &touchdata->finger[i];
+
+		x = finger->x | (((finger->xy & 0xf0) >> 4) << 8);
+		y = finger->y | ((finger->xy & 0x0f) << 8);
+
+		/* This driver returns 0xfff if there is no touch */
+		if (x != 0xfff && y != 0xfff) {
+			touch = 1;
+			pen_down = 1;
+		}
+
+		input_mt_report_slot_state(input, MT_TOOL_FINGER, touch);
+
+		if (touch) {
+			input_report_abs(input, ABS_MT_POSITION_X, x);
+			input_report_abs(input, ABS_MT_POSITION_Y, y);
+		}
+	}
+
+	input_mt_report_pointer_emulation(input, false);
+	input_sync(input);
+	return pen_down;
+}
+
+static void ili2117a_work(struct work_struct *work)
+{
+	struct ili2117a *priv = container_of(work, struct ili2117a,
+					    dwork.work);
+	struct i2c_client *client = priv->client;
+	struct touchdata touchdata;
+	int error;
+	bool status;
+
+	error = ili2117a_read_reg(client, TOUCH_INFO,
+				  (uint8_t *) &touchdata, sizeof(touchdata));
+
+	if (error) {
+		dev_err(&client->dev,
+			"Unable to get touchdata, err = %d\n", error);
+		return;
+	}
+
+	status = ili2117a_report_events(priv->input, &touchdata,
+					priv->max_touch);
+
+	if (status) {
+		schedule_delayed_work(&priv->dwork,
+				      msecs_to_jiffies(priv->poll_period));
+	}
+}
+
+static irqreturn_t ili2117a_irq(int irq, void *irq_data)
+{
+	struct ili2117a *priv = irq_data;
+
+	schedule_delayed_work(&priv->dwork, 0);
+
+	return IRQ_HANDLED;
+}
+
+static struct attribute *ili2117a_attributes[] = {
+	NULL,
+};
+
+static const struct attribute_group ili2117a_attr_group = {
+	.attrs = ili2117a_attributes,
+};
+
+static int ili2117a_i2c_probe(struct i2c_client *client,
+				       const struct i2c_device_id *id)
+{
+	struct device *dev = &client->dev;
+	struct ili2117a *priv;
+	struct input_dev *input;
+	int error;
+	int poll_period;
+	int max_touch;
+
+	if (client->irq <= 0) {
+		dev_err(dev, "No IRQ!\n");
+		return -EINVAL;
+	}
+
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+	input = input_allocate_device();
+	if (!priv || !input) {
+		error = -ENOMEM;
+		goto err_free_mem;
+	}
+
+	priv->client = client;
+	priv->input = input;
+
+	error = device_property_read_u32(dev, "ili2117a,poll-period",
+					 &poll_period);
+	priv->poll_period = error ? DEFAULT_POLL_PERIOD : poll_period;
+
+	error = device_property_read_u32(dev, "ili2117a,max-touch",
+					 &max_touch);
+	if (max_touch > MAX_TOUCHES)
+		max_touch = MAX_TOUCHES;
+	priv->max_touch = error ? MAX_TOUCHES : max_touch;
+
+	INIT_DELAYED_WORK(&priv->dwork, ili2117a_work);
+
+	/* Setup input device */
+	input->name = "ili2117a Touchscreen";
+	input->id.bustype = BUS_I2C;
+	input->dev.parent = dev;
+
+	__set_bit(EV_SYN, input->evbit);
+	__set_bit(EV_KEY, input->evbit);
+	__set_bit(EV_ABS, input->evbit);
+	__set_bit(BTN_TOUCH, input->keybit);
+
+	/* Single touch */
+	input_set_abs_params(input, ABS_X, 0, MAX_X, 0, 0);
+	input_set_abs_params(input, ABS_Y, 0, MAX_Y, 0, 0);
+
+	/* Multi touch */
+	input_mt_init_slots(input, priv->max_touch, 0);
+	input_set_abs_params(input, ABS_MT_POSITION_X, 0, MAX_X, 0, 0);
+	input_set_abs_params(input, ABS_MT_POSITION_Y, 0, MAX_Y, 0, 0);
+
+	i2c_set_clientdata(client, priv);
+
+	error = devm_request_threaded_irq(dev, client->irq, NULL,
+					  ili2117a_irq,
+					  IRQF_TRIGGER_RISING | IRQF_ONESHOT,
+					  client->name, priv);
+
+	if (error) {
+		dev_err(dev, "Failed to request irq, err: %d\n", error);
+		goto err_free_mem;
+	}
+
+	error = sysfs_create_group(&dev->kobj, &ili2117a_attr_group);
+	if (error) {
+		dev_err(dev, "Unable to create sysfs attributes, err: %d\n",
+			error);
+		goto err_free_irq;
+	}
+
+	error = input_register_device(priv->input);
+	if (error) {
+		dev_err(dev, "Cannot register input device, err: %d\n", error);
+		goto err_remove_sysfs;
+	}
+
+	device_init_wakeup(dev, 1);
+	return 0;
+
+err_remove_sysfs:
+	sysfs_remove_group(&dev->kobj, &ili2117a_attr_group);
+err_free_irq:
+	free_irq(client->irq, priv);
+err_free_mem:
+	input_free_device(input);
+	kfree(priv);
+	return error;
+}
+
+static int ili2117a_i2c_remove(struct i2c_client *client)
+{
+	struct ili2117a *priv = i2c_get_clientdata(client);
+
+	sysfs_remove_group(&client->dev.kobj, &ili2117a_attr_group);
+	free_irq(priv->client->irq, priv);
+	cancel_delayed_work_sync(&priv->dwork);
+	input_unregister_device(priv->input);
+	kfree(priv);
+
+	return 0;
+}
+
+static int __maybe_unused ili2117a_i2c_suspend(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+
+	if (device_may_wakeup(&client->dev))
+		enable_irq_wake(client->irq);
+
+	return 0;
+}
+
+static int __maybe_unused ili2117a_i2c_resume(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+
+	if (device_may_wakeup(&client->dev))
+		disable_irq_wake(client->irq);
+
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(ili2117a_i2c_pm,
+			 ili2117a_i2c_suspend, ili2117a_i2c_resume);
+
+static const struct of_device_id ili_match_table[] = {
+	{ .compatible = "ilitek,ili2117a" },
+	{ },
+};
+
+static const struct i2c_device_id ili2117a_i2c_id[] = {
+	{ "ili2117a", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, ili2117a_i2c_id);
+
+static struct i2c_driver ili2117a_ts_driver = {
+	.driver = {
+		.name = "ili2117a_i2c",
+		.pm = &ili2117a_i2c_pm,
+		.of_match_table = of_match_ptr(ili_match_table),
+	},
+	.id_table = ili2117a_i2c_id,
+	.probe = ili2117a_i2c_probe,
+	.remove = ili2117a_i2c_remove,
+};
+
+module_i2c_driver(ili2117a_ts_driver);
+
+MODULE_AUTHOR("Adam Ford <adam.ford@...icpd.com>");
+MODULE_DESCRIPTION("ili2117a I2C Touchscreen Driver");
+MODULE_LICENSE("GPL");
-- 
2.17.1

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