[v2] Input: touchscreen - Add new Novatek NVT-ts driver

Add a new driver for the Novatek i2c touchscreen controller as found
on the Acer Iconia One 7 B1-750 tablet. Unfortunately the touchscreen
controller model-number is unknown. Even with the tablet opened up it
is impossible to read the model-number.

Android calls this a "NVT-ts" touchscreen, but that may apply to other
Novatek controller models too.

This appears to be the same controller as the one supported by
https://github.com/advx9600/android/blob/master/touchscreen/NVTtouch_Android4.0/NVTtouch.c
but unfortunately that does not give us a model-number either.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 MAINTAINERS                                |   6 +
 drivers/input/touchscreen/Kconfig          |  10 +
 drivers/input/touchscreen/Makefile         |   1 +
 drivers/input/touchscreen/novatek-nvt-ts.c | 289 +++++++++++++++++++++
 4 files changed, 306 insertions(+)
 create mode 100644 drivers/input/touchscreen/novatek-nvt-ts.c

On Sun, Mar 26, 2023 at 11:23:08PM +0200, Hans de Goede wrote:
> Add a new driver for the Novatek i2c touchscreen controller as found
> on the Acer Iconia One 7 B1-750 tablet. Unfortunately the touchscreen
> controller model-number is unknown. Even with the tablet opened up it
> is impossible to read the model-number.
> 
> Android calls this a "NVT-ts" touchscreen, but that may apply to other
> Novatek controller models too.
> 
> This appears to be the same controller as the one supported by
> https://github.com/advx9600/android/blob/master/touchscreen/NVTtouch_Android4.0/NVTtouch.c
> but unfortunately that does not give us a model-number either.
> 
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>

Reviewed-by: Jeff LaBundy <jeff@labundy.com>

> ---
>  MAINTAINERS                                |   6 +
>  drivers/input/touchscreen/Kconfig          |  10 +
>  drivers/input/touchscreen/Makefile         |   1 +
>  drivers/input/touchscreen/novatek-nvt-ts.c | 289 +++++++++++++++++++++
>  4 files changed, 306 insertions(+)
>  create mode 100644 drivers/input/touchscreen/novatek-nvt-ts.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 08b7178d645b..30b57a4afe9e 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -14788,6 +14788,12 @@ T:	git git://git.kernel.org/pub/scm/linux/kernel/git/wtarreau/nolibc.git
>  F:	tools/include/nolibc/
>  F:	tools/testing/selftests/nolibc/
>  
> +NOVATEK NVT-TS I2C TOUCHSCREEN DRIVER
> +M:	Hans de Goede <hdegoede@redhat.com>
> +L:	linux-input@vger.kernel.org
> +S:	Maintained
> +F:	drivers/input/touchscreen/novatek-nvt-ts.c
> +
>  NSDEPS
>  M:	Matthias Maennich <maennich@google.com>
>  S:	Maintained
> diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
> index 1a2049b336a6..1feecd7ed3cb 100644
> --- a/drivers/input/touchscreen/Kconfig
> +++ b/drivers/input/touchscreen/Kconfig
> @@ -654,6 +654,16 @@ config TOUCHSCREEN_MTOUCH
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called mtouch.
>  
> +config TOUCHSCREEN_NOVATEK_NVT_TS
> +	tristate "Novatek NVT-ts touchscreen support"
> +	depends on I2C
> +	help
> +	  Say Y here if you have a Novatek NVT-ts touchscreen.
> +	  If unsure, say N.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called novatek-nvt-ts.
> +
>  config TOUCHSCREEN_IMAGIS
>  	tristate "Imagis touchscreen support"
>  	depends on I2C
> diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
> index f2fd28cc34a6..159cd5136fdb 100644
> --- a/drivers/input/touchscreen/Makefile
> +++ b/drivers/input/touchscreen/Makefile
> @@ -67,6 +67,7 @@ obj-$(CONFIG_TOUCHSCREEN_MMS114)	+= mms114.o
>  obj-$(CONFIG_TOUCHSCREEN_MSG2638)	+= msg2638.o
>  obj-$(CONFIG_TOUCHSCREEN_MTOUCH)	+= mtouch.o
>  obj-$(CONFIG_TOUCHSCREEN_MK712)		+= mk712.o
> +obj-$(CONFIG_TOUCHSCREEN_NOVATEK_NVT_TS)	+= novatek-nvt-ts.o
>  obj-$(CONFIG_TOUCHSCREEN_HP600)		+= hp680_ts_input.o
>  obj-$(CONFIG_TOUCHSCREEN_HP7XX)		+= jornada720_ts.o
>  obj-$(CONFIG_TOUCHSCREEN_IPAQ_MICRO)	+= ipaq-micro-ts.o
> diff --git a/drivers/input/touchscreen/novatek-nvt-ts.c b/drivers/input/touchscreen/novatek-nvt-ts.c
> new file mode 100644
> index 000000000000..f959e7b14ad6
> --- /dev/null
> +++ b/drivers/input/touchscreen/novatek-nvt-ts.c
> @@ -0,0 +1,289 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Driver for Novatek i2c touchscreen controller as found on
> + * the Acer Iconia One 7 B1-750 tablet. The Touchscreen controller
> + * model-number is unknown. Android calls this a "NVT-ts" touchscreen,
> + * but that may apply to other Novatek controller models too.
> + *
> + * Copyright (c) 2023 Hans de Goede <hdegoede@redhat.com>
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/gpio/consumer.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>
> +
> +#include <asm/unaligned.h>
> +
> +#define NVT_TS_TOUCH_START		0x00
> +#define NVT_TS_TOUCH_SIZE		6
> +
> +#define NVT_TS_PARAMETERS_START		0x78
> +/* These are offsets from NVT_TS_PARAMETERS_START */
> +#define NVT_TS_PARAMS_WIDTH		0x04
> +#define NVT_TS_PARAMS_HEIGHT		0x06
> +#define NVT_TS_PARAMS_MAX_TOUCH		0x09
> +#define NVT_TS_PARAMS_MAX_BUTTONS	0x0a
> +#define NVT_TS_PARAMS_IRQ_TYPE		0x0b
> +#define NVT_TS_PARAMS_WAKE_TYPE		0x0c
> +#define NVT_TS_PARAMS_CHIP_ID		0x0e
> +#define NVT_TS_PARAMS_SIZE		0x0f
> +
> +#define NVT_TS_SUPPORTED_WAKE_TYPE	0x05
> +#define NVT_TS_SUPPORTED_CHIP_ID	0x05
> +
> +#define NVT_TS_MAX_TOUCHES		10
> +#define NVT_TS_MAX_SIZE			4096
> +
> +#define NVT_TS_TOUCH_INVALID		0xff
> +#define NVT_TS_TOUCH_SLOT_SHIFT		3
> +#define NVT_TS_TOUCH_TYPE_MASK		GENMASK(2, 0)
> +#define NVT_TS_TOUCH_NEW		1
> +#define NVT_TS_TOUCH_UPDATE		2
> +#define NVT_TS_TOUCH_RELEASE		3
> +
> +static const int nvt_ts_irq_type[4] = {
> +	IRQF_TRIGGER_RISING,
> +	IRQF_TRIGGER_FALLING,
> +	IRQF_TRIGGER_LOW,
> +	IRQF_TRIGGER_HIGH
> +};
> +
> +struct nvt_ts_data {
> +	struct i2c_client *client;
> +	struct input_dev *input;
> +	struct gpio_desc *reset_gpio;
> +	struct touchscreen_properties prop;
> +	int max_touches;
> +	u8 buf[NVT_TS_TOUCH_SIZE * NVT_TS_MAX_TOUCHES];
> +};
> +
> +static int nvt_ts_read_data(struct i2c_client *client, u8 reg, u8 *data, int count)
> +{
> +	struct i2c_msg msg[2] = {
> +		{
> +			.addr = client->addr,
> +			.len = 1,
> +			.buf = &reg,
> +		},
> +		{
> +			.addr = client->addr,
> +			.flags = I2C_M_RD,
> +			.len = count,
> +			.buf = data,
> +		}
> +	};
> +	int ret;
> +
> +	ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
> +	if (ret != ARRAY_SIZE(msg)) {
> +		dev_err(&client->dev, "Error reading from 0x%02x: %d\n", reg, ret);
> +		return (ret < 0) ? ret : -EIO;
> +	}
> +
> +	return 0;
> +}
> +
> +static irqreturn_t nvt_ts_irq(int irq, void *dev_id)
> +{
> +	struct nvt_ts_data *data = dev_id;
> +	struct device *dev = &data->client->dev;
> +	int i, error, slot, x, y;
> +	bool active;
> +	u8 *touch;
> +
> +	error = nvt_ts_read_data(data->client, NVT_TS_TOUCH_START, data->buf,
> +				 data->max_touches * NVT_TS_TOUCH_SIZE);
> +	if (error)
> +		return IRQ_HANDLED;
> +
> +	for (i = 0; i < data->max_touches; i++) {
> +		touch = &data->buf[i * NVT_TS_TOUCH_SIZE];
> +
> +		if (touch[0] == NVT_TS_TOUCH_INVALID)
> +			continue;
> +
> +		slot = touch[0] >> NVT_TS_TOUCH_SLOT_SHIFT;
> +		if (slot < 1 || slot > data->max_touches) {
> +			dev_warn(dev, "slot %d out of range, ignoring\n", slot);
> +			continue;
> +		}
> +
> +		switch (touch[0] & NVT_TS_TOUCH_TYPE_MASK) {
> +		case NVT_TS_TOUCH_NEW:
> +		case NVT_TS_TOUCH_UPDATE:
> +			active = true;
> +			break;
> +		case NVT_TS_TOUCH_RELEASE:
> +			active = false;
> +			break;
> +		default:
> +			dev_warn(dev, "slot %d unknown state %d\n", slot, touch[0] & 7);
> +			continue;
> +		}
> +
> +		slot--;
> +		x = (touch[1] << 4) | (touch[3] >> 4);
> +		y = (touch[2] << 4) | (touch[3] & 0x0f);
> +
> +		input_mt_slot(data->input, slot);
> +		input_mt_report_slot_state(data->input, MT_TOOL_FINGER, active);
> +		touchscreen_report_pos(data->input, &data->prop, x, y, true);
> +	}
> +
> +	input_mt_sync_frame(data->input);
> +	input_sync(data->input);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int nvt_ts_start(struct input_dev *dev)
> +{
> +	struct nvt_ts_data *data = input_get_drvdata(dev);
> +
> +	enable_irq(data->client->irq);
> +	gpiod_set_value_cansleep(data->reset_gpio, 0);
> +
> +	return 0;
> +}
> +
> +static void nvt_ts_stop(struct input_dev *dev)
> +{
> +	struct nvt_ts_data *data = input_get_drvdata(dev);
> +
> +	disable_irq(data->client->irq);
> +	gpiod_set_value_cansleep(data->reset_gpio, 1);
> +}
> +
> +static int nvt_ts_suspend(struct device *dev)
> +{
> +	struct nvt_ts_data *data = i2c_get_clientdata(to_i2c_client(dev));
> +
> +	mutex_lock(&data->input->mutex);
> +	if (input_device_enabled(data->input))
> +		nvt_ts_stop(data->input);
> +	mutex_unlock(&data->input->mutex);
> +
> +	return 0;
> +}
> +
> +static int nvt_ts_resume(struct device *dev)
> +{
> +	struct nvt_ts_data *data = i2c_get_clientdata(to_i2c_client(dev));
> +
> +	mutex_lock(&data->input->mutex);
> +	if (input_device_enabled(data->input))
> +		nvt_ts_start(data->input);
> +	mutex_unlock(&data->input->mutex);
> +
> +	return 0;
> +}
> +
> +static DEFINE_SIMPLE_DEV_PM_OPS(nvt_ts_pm_ops, nvt_ts_suspend, nvt_ts_resume);
> +
> +static int nvt_ts_probe(struct i2c_client *client)
> +{
> +	struct device *dev = &client->dev;
> +	int error, width, height, irq_type;
> +	struct nvt_ts_data *data;
> +	struct input_dev *input;
> +
> +	if (!client->irq) {
> +		dev_err(dev, "Error no irq specified\n");
> +		return -EINVAL;
> +	}
> +
> +	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
> +	if (!data)
> +		return -ENOMEM;
> +
> +	data->client = client;
> +	i2c_set_clientdata(client, data);
> +
> +	data->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
> +	if (IS_ERR(data->reset_gpio))
> +		return dev_err_probe(dev, PTR_ERR(data->reset_gpio), "requesting reset GPIO\n");
> +
> +	/* Wait for controller to come out of reset before params read */
> +	msleep(100);
> +	error = nvt_ts_read_data(data->client, NVT_TS_PARAMETERS_START, data->buf,
> +				 NVT_TS_PARAMS_SIZE);
> +	gpiod_set_value_cansleep(data->reset_gpio, 1); /* Put back in reset */
> +	if (error)
> +		return error;
> +
> +	width  = get_unaligned_be16(&data->buf[NVT_TS_PARAMS_WIDTH]);
> +	height = get_unaligned_be16(&data->buf[NVT_TS_PARAMS_HEIGHT]);
> +	data->max_touches = data->buf[NVT_TS_PARAMS_MAX_TOUCH];
> +	irq_type = data->buf[NVT_TS_PARAMS_IRQ_TYPE];
> +
> +	if (width > NVT_TS_MAX_SIZE || height >= NVT_TS_MAX_SIZE ||
> +	    data->max_touches > NVT_TS_MAX_TOUCHES ||
> +	    irq_type >= ARRAY_SIZE(nvt_ts_irq_type) ||
> +	    data->buf[NVT_TS_PARAMS_WAKE_TYPE] != NVT_TS_SUPPORTED_WAKE_TYPE ||
> +	    data->buf[NVT_TS_PARAMS_CHIP_ID] != NVT_TS_SUPPORTED_CHIP_ID) {
> +		dev_err(dev, "Unsupported touchscreen parameters: %*ph\n",
> +			NVT_TS_PARAMS_SIZE, data->buf);
> +		return -EIO;
> +	}
> +
> +	dev_dbg(dev, "Detected %dx%d touchscreen with %d max touches\n",
> +		width, height, data->max_touches);
> +
> +	if (data->buf[NVT_TS_PARAMS_MAX_BUTTONS])
> +		dev_warn(dev, "Touchscreen buttons are not supported\n");
> +
> +	input = devm_input_allocate_device(dev);
> +	if (!input)
> +		return -ENOMEM;
> +
> +	input->name = client->name;
> +	input->id.bustype = BUS_I2C;
> +	input->open = nvt_ts_start;
> +	input->close = nvt_ts_stop;
> +
> +	input_set_abs_params(input, ABS_MT_POSITION_X, 0, width - 1, 0, 0);
> +	input_set_abs_params(input, ABS_MT_POSITION_Y, 0, height - 1, 0, 0);
> +	touchscreen_parse_properties(input, true, &data->prop);
> +
> +	error = input_mt_init_slots(input, data->max_touches,
> +				    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
> +	if (error)
> +		return error;
> +
> +	data->input = input;
> +	input_set_drvdata(input, data);
> +
> +	error = devm_request_threaded_irq(dev, client->irq, NULL, nvt_ts_irq,
> +					  IRQF_ONESHOT | IRQF_NO_AUTOEN | nvt_ts_irq_type[irq_type],
> +					  client->name, data);
> +	if (error)
> +		return dev_err_probe(dev, error, "requesting irq\n");
> +
> +	return input_register_device(input);
> +}
> +
> +static const struct i2c_device_id nvt_ts_i2c_id[] = {
> +	{ "NVT-ts" },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(i2c, nvt_ts_i2c_id);
> +
> +static struct i2c_driver nvt_ts_driver = {
> +	.driver = {
> +		.name	= "novatek-nvt-ts",
> +		.pm	= pm_sleep_ptr(&nvt_ts_pm_ops),
> +	},
> +	.probe_new = nvt_ts_probe,
> +	.id_table = nvt_ts_i2c_id,
> +};
> +
> +module_i2c_driver(nvt_ts_driver);
> +
> +MODULE_DESCRIPTION("Novatek NVT-ts touchscreen driver");
> +MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
> +MODULE_LICENSE("GPL");
> -- 
> 2.39.1
>