[v8,2/2] Input: add Imagis touchscreen driver

diff --git a/MAINTAINERS b/MAINTAINERS
index d7ea92ce1b1d..feab0c765d4b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9509,6 +9509,12 @@  M:	Stanislaw Gruszka <stf_xl@wp.pl>
 S:	Maintained
 F:	drivers/usb/atm/ueagle-atm.c
 
+IMAGIS TOUCHSCREEN DRIVER
+M:	Markuss Broks <markuss.broks@gmail.com>
+S:	Maintained
+F:	Documentation/devicetree/bindings/input/touchscreen/imagis,ist3038c.yaml
+F:	drivers/input/touchscreen/imagis.c
+
 IMGTEC ASCII LCD DRIVER
 M:	Paul Burton <paulburton@kernel.org>
 S:	Maintained
diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index 2f6adfb7b938..f1414f0ad7af 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -638,6 +638,16 @@  config TOUCHSCREEN_MTOUCH
 	  To compile this driver as a module, choose M here: the
 	  module will be called mtouch.
 
+config TOUCHSCREEN_IMAGIS
+	tristate "Imagis touchscreen support"
+	depends on I2C
+	help
+	  Say Y here if you have an Imagis IST30xxC touchscreen.
+	  If unsure, say N.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called imagis.
+
 config TOUCHSCREEN_IMX6UL_TSC
 	tristate "Freescale i.MX6UL touchscreen controller"
 	depends on ((OF && GPIOLIB) || COMPILE_TEST) && HAS_IOMEM
diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
index 39a8127cf6a5..557f84fd2075 100644
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -49,6 +49,7 @@  obj-$(CONFIG_TOUCHSCREEN_GOODIX)	+= goodix_ts.o
 obj-$(CONFIG_TOUCHSCREEN_HIDEEP)	+= hideep.o
 obj-$(CONFIG_TOUCHSCREEN_ILI210X)	+= ili210x.o
 obj-$(CONFIG_TOUCHSCREEN_ILITEK)	+= ilitek_ts_i2c.o
+obj-$(CONFIG_TOUCHSCREEN_IMAGIS)	+= imagis.o
 obj-$(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/imagis.c b/drivers/input/touchscreen/imagis.c
new file mode 100644
index 000000000000..ba26c35a338a
--- /dev/null
+++ b/drivers/input/touchscreen/imagis.c
@@ -0,0 +1,331 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/bits.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/input.h>
+#include <linux/input/mt.h>
+#include <linux/input/touchscreen.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/property.h>
+#include <linux/regulator/consumer.h>
+
+#define IST3038C_HIB_ACCESS		(0x800B << 16)
+#define IST3038C_DIRECT_ACCESS		BIT(31)
+#define IST3038C_REG_CHIPID		0x40001000
+#define IST3038C_REG_HIB_BASE		0x30000100
+#define IST3038C_REG_TOUCH_STATUS		(IST3038C_REG_HIB_BASE | IST3038C_HIB_ACCESS)
+#define IST3038C_REG_TOUCH_COORD		(IST3038C_REG_HIB_BASE | IST3038C_HIB_ACCESS | 0x8)
+#define IST3038C_REG_INTR_MESSAGE		(IST3038C_REG_HIB_BASE | IST3038C_HIB_ACCESS | 0x4)
+#define IST3038C_WHOAMI			0x38c
+#define IST3038C_CHIP_ON_DELAY_MS		60
+#define IST3038C_I2C_RETRY_COUNT		3
+#define IST3038C_MAX_SUPPORTED_FINGER_NUM		10
+#define IST3038C_X_MASK		GENMASK(23, 12)
+#define IST3038C_X_SHIFT		12
+#define IST3038C_Y_MASK		GENMASK(11, 0)
+#define IST3038C_AREA_MASK		GENMASK(27, 24)
+#define IST3038C_AREA_SHIFT		24
+#define IST3038C_FINGER_COUNT_MASK		GENMASK(15, 12)
+#define IST3038C_FINGER_COUNT_SHIFT		12
+#define IST3038C_FINGER_STATUS_MASK		GENMASK(9, 0)
+
+struct imagis_ts {
+	struct i2c_client *client;
+	struct input_dev *input_dev;
+	struct touchscreen_properties prop;
+	struct regulator_bulk_data supplies[2];
+};
+
+static int imagis_i2c_read_reg(struct imagis_ts *ts,
+			       unsigned int reg, unsigned int *buffer)
+{
+	__be32 ret_be;
+	__be32 reg_be = cpu_to_be32(reg);
+	struct i2c_msg msg[] = {
+		{
+			.addr = ts->client->addr,
+			.flags = 0,
+			.buf = (unsigned char *)&reg_be,
+			.len = sizeof(reg_be),
+		}, {
+			.addr = ts->client->addr,
+			.flags = I2C_M_RD,
+			.buf = (unsigned char *)&ret_be,
+			.len = sizeof(ret_be),
+		},
+	};
+	int ret, error;
+	int retry = IST3038C_I2C_RETRY_COUNT;
+
+	/* Retry in case the controller fails to respond */
+	do {
+		ret = i2c_transfer(ts->client->adapter, msg, ARRAY_SIZE(msg));
+		if (ret == ARRAY_SIZE(msg)) {
+			*buffer = be32_to_cpu(ret_be);
+			return 0;
+		}
+
+		error = ret < 0 ? ret : -EIO;
+		dev_err(&ts->client->dev,
+			"%s - i2c_transfer failed: %d (%d)\n",
+			__func__, error, ret);
+	} while (--retry);
+
+	return error;
+}
+
+static irqreturn_t imagis_interrupt(int irq, void *dev_id)
+{
+	struct imagis_ts *ts = dev_id;
+	unsigned int finger_status, intr_message;
+	int error, i, finger_count, finger_pressed;
+
+	error = imagis_i2c_read_reg(ts, IST3038C_REG_INTR_MESSAGE, &intr_message);
+	if (error) {
+		dev_err(&ts->client->dev, "failed to read the interrupt message\n");
+		return IRQ_HANDLED;
+	}
+
+	finger_count = (intr_message & IST3038C_FINGER_COUNT_MASK) >> IST3038C_FINGER_COUNT_SHIFT;
+	finger_pressed = intr_message & IST3038C_FINGER_STATUS_MASK;
+	if (finger_count > IST3038C_MAX_SUPPORTED_FINGER_NUM) {
+		dev_err(&ts->client->dev, "finger count is more than maximum supported\n");
+		return IRQ_HANDLED;
+	}
+
+	for (i = 0; i < finger_count; i++) {
+		error = imagis_i2c_read_reg(ts, IST3038C_REG_TOUCH_COORD + (i * 4), &finger_status);
+		if (error) {
+			dev_err(&ts->client->dev, "failed to read coordinates for finger %d\n", i);
+			return IRQ_HANDLED;
+		}
+		input_mt_slot(ts->input_dev, i);
+		input_mt_report_slot_state(ts->input_dev, MT_TOOL_FINGER,
+					   finger_pressed & BIT(i));
+		touchscreen_report_pos(ts->input_dev, &ts->prop,
+				       (finger_status & IST3038C_X_MASK) >> IST3038C_X_SHIFT,
+				       finger_status & IST3038C_Y_MASK, 1);
+		input_report_abs(ts->input_dev, ABS_MT_TOUCH_MAJOR,
+				 (finger_status & IST3038C_AREA_MASK) >> IST3038C_AREA_SHIFT);
+	}
+	input_mt_sync_frame(ts->input_dev);
+	input_sync(ts->input_dev);
+
+	return IRQ_HANDLED;
+}
+
+static void imagis_power_off(void *_ts)
+{
+	struct imagis_ts *ts = _ts;
+
+	return regulator_bulk_disable(ARRAY_SIZE(ts->supplies), ts->supplies);
+}
+
+static int imagis_power_on(struct imagis_ts *ts)
+{
+	int error;
+
+	error = regulator_bulk_enable(ARRAY_SIZE(ts->supplies), ts->supplies);
+	msleep(IST3038C_CHIP_ON_DELAY_MS);
+
+	return error;
+}
+
+static int imagis_start(struct imagis_ts *ts)
+{
+	int error;
+
+	error = imagis_power_on(ts);
+	if (error)
+		return error;
+
+	msleep(IST3038C_CHIP_ON_DELAY_MS);
+
+	enable_irq(ts->client->irq);
+	return error;
+}
+
+static int imagis_stop(struct imagis_ts *ts)
+{
+	disable_irq(ts->client->irq);
+
+	imagis_power_off(ts);
+
+	return 0;
+}
+
+static int imagis_input_open(struct input_dev *dev)
+{
+	struct imagis_ts *ts = input_get_drvdata(dev);
+
+	return imagis_start(ts);
+}
+
+static void imagis_input_close(struct input_dev *dev)
+{
+	struct imagis_ts *ts = input_get_drvdata(dev);
+
+	imagis_stop(ts);
+}
+
+static int imagis_init_input_dev(struct imagis_ts *ts)
+{
+	struct input_dev *input_dev;
+	int error;
+
+	input_dev = devm_input_allocate_device(&ts->client->dev);
+	if (!input_dev)
+		return -ENOMEM;
+
+	ts->input_dev = input_dev;
+
+	input_dev->name = "Imagis capacitive touchscreen";
+	input_dev->phys = "input/ts";
+	input_dev->id.bustype = BUS_I2C;
+	input_dev->open = imagis_input_open;
+	input_dev->close = imagis_input_close;
+
+	input_set_drvdata(input_dev, ts);
+
+	input_set_capability(input_dev, EV_ABS, ABS_MT_POSITION_X);
+	input_set_capability(input_dev, EV_ABS, ABS_MT_POSITION_Y);
+	input_set_abs_params(input_dev, ABS_MT_TOUCH_MAJOR, 0, 255, 0, 0);
+
+	touchscreen_parse_properties(input_dev, true, &ts->prop);
+	if (!ts->prop.max_x || !ts->prop.max_y) {
+		dev_err(&ts->client->dev,
+			"Touchscreen-size-x and/or touchscreen-size-y not set in dts\n");
+		return -EINVAL;
+	}
+
+	error = input_mt_init_slots(input_dev, IST3038C_MAX_SUPPORTED_FINGER_NUM,
+				    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
+	if (error) {
+		dev_err(&ts->client->dev,
+			"Failed to initialize MT slots: %d", error);
+		return error;
+	}
+
+	error = input_register_device(input_dev);
+	if (error)
+		dev_err(&ts->client->dev,
+			"Failed to register input device: %d", error);
+
+	return error;
+}
+
+static int imagis_init_regulators(struct imagis_ts *ts)
+{
+	struct i2c_client *client = ts->client;
+
+	ts->supplies[0].supply = "vdd";
+	ts->supplies[1].supply = "vddio";
+	return devm_regulator_bulk_get(&client->dev,
+				       ARRAY_SIZE(ts->supplies),
+				       ts->supplies);
+
+}
+
+static int imagis_probe(struct i2c_client *i2c)
+{
+	struct device *dev = &i2c->dev;
+	struct imagis_ts *ts;
+	int chip_id, error;
+
+	ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
+	if (!ts)
+		return -ENOMEM;
+
+	ts->client = i2c;
+
+	error = imagis_init_regulators(ts);
+	if (error)
+		return dev_err_probe(dev, error, "regulator init error: %d\n", error);
+
+	error = devm_add_action_or_reset(dev, imagis_power_off, ts);
+	if (error)
+		return dev_err_probe(dev, error, "failed to install poweroff action: %d\n", error);
+
+	error = imagis_power_on(ts);
+	if (error)
+		return dev_err_probe(dev, error, "failed to enable regulators: %d\n", error);
+
+	error = imagis_i2c_read_reg(ts, IST3038C_REG_CHIPID | IST3038C_DIRECT_ACCESS, &chip_id);
+	if (error)
+		return dev_err_probe(dev, error, "chip ID read failure: %d\n", error);
+
+	if (chip_id != IST3038C_WHOAMI)
+		return dev_err_probe(dev, -EINVAL, "unknown chip ID: 0x%x\n", chip_id);
+
+	error = devm_request_threaded_irq(dev, i2c->irq,
+					  NULL, imagis_interrupt,
+					  IRQF_ONESHOT | IRQF_NO_AUTOEN,
+					  "imagis-touchscreen", ts);
+	if (error)
+		return dev_err_probe(dev, error, "IRQ allocation failure: %d\n", error);
+
+	error = imagis_init_input_dev(ts);
+	if (error)
+		return dev_err_probe(dev, error, "input subsystem init error: %d\n", error);
+
+	return 0;
+}
+
+static int __maybe_unused imagis_suspend(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct imagis_ts *ts = i2c_get_clientdata(client);
+	int error = 0;
+
+	mutex_lock(&ts->input_dev->mutex);
+
+	if (input_device_enabled(ts->input_dev))
+		error = imagis_stop(ts);
+
+	mutex_unlock(&ts->input_dev->mutex);
+
+	return error;
+}
+
+static int __maybe_unused imagis_resume(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct imagis_ts *ts = i2c_get_clientdata(client);
+	int error = 0;
+
+	mutex_lock(&ts->input_dev->mutex);
+
+	if (input_device_enabled(ts->input_dev))
+		error = imagis_start(ts);
+
+	mutex_unlock(&ts->input_dev->mutex);
+
+	return error;
+}
+
+static SIMPLE_DEV_PM_OPS(imagis_pm_ops, imagis_suspend, imagis_resume);
+
+#ifdef CONFIG_OF
+static const struct of_device_id imagis_of_match[] = {
+	{ .compatible = "imagis,ist3038c", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, imagis_of_match);
+#endif
+
+static struct i2c_driver imagis_ts_driver = {
+	.driver = {
+		.name = "imagis-touchscreen",
+		.pm = &imagis_pm_ops,
+		.of_match_table = of_match_ptr(imagis_of_match),
+	},
+	.probe_new = imagis_probe,
+};
+
+module_i2c_driver(imagis_ts_driver);
+
+MODULE_DESCRIPTION("Imagis IST3038C Touchscreen Driver");
+MODULE_AUTHOR("Markuss Broks <markuss.broks@gmail.com>");
+MODULE_LICENSE("GPL");