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Date:   Thu, 24 Jan 2019 00:48:12 -0800
From:   Dmitry Torokhov <dmitry.torokhov@gmail.com>
To:     Martin Kepplinger <martink@posteo.de>
Cc:     devicetree@vger.kernel.org, linux-input@vger.kernel.org,
        robh+dt@kernel.org, mark.rutland@arm.com,
        chinyeow.sim.xt@renesas.com, linux-kernel@vger.kernel.org,
        Martin Kepplinger <martin.kepplinger@ginzinger.com>
Subject: Re: [PATCH 2/2] Input: st1232 - add support for st1633
Message-ID: <20190124084812.GC139904@dtor-ws>
References: <20190123072651.31791-1-martink@posteo.de>
 <20190123072651.31791-2-martink@posteo.de>
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Hi Martin,

On Wed, Jan 23, 2019 at 08:26:51AM +0100, Martin Kepplinger wrote:
> From: Martin Kepplinger <martin.kepplinger@ginzinger.com>
> 
> Add support for the Sitronix ST1633 touchscreen controller to the st1232
> driver.
> 
> Signed-off-by: Martin Kepplinger <martin.kepplinger@ginzinger.com>
> ---
>  drivers/input/touchscreen/Kconfig  |   6 +-
>  drivers/input/touchscreen/st1232.c | 130 +++++++++++++++++++++--------
>  2 files changed, 98 insertions(+), 38 deletions(-)
> 
> diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
> index 068dbbc610fc..7c597a49c265 100644
> --- a/drivers/input/touchscreen/Kconfig
> +++ b/drivers/input/touchscreen/Kconfig
> @@ -1168,11 +1168,11 @@ config TOUCHSCREEN_SIS_I2C
>  	  module will be called sis_i2c.
>  
>  config TOUCHSCREEN_ST1232
> -	tristate "Sitronix ST1232 touchscreen controllers"
> +	tristate "Sitronix ST1232 or ST1633 touchscreen controllers"
>  	depends on I2C
>  	help
> -	  Say Y here if you want to support Sitronix ST1232
> -	  touchscreen controller.
> +	  Say Y here if you want to support the Sitronix ST1232
> +	  or ST1633 touchscreen controller.
>  
>  	  If unsure, say N.
>  
> diff --git a/drivers/input/touchscreen/st1232.c b/drivers/input/touchscreen/st1232.c
> index 11ff32c68025..dc0288f37fda 100644
> --- a/drivers/input/touchscreen/st1232.c
> +++ b/drivers/input/touchscreen/st1232.c
> @@ -18,18 +18,21 @@
>  #include <linux/module.h>
>  #include <linux/of.h>
>  #include <linux/of_gpio.h>
> +#include <linux/of_device.h>
>  #include <linux/pm_qos.h>
>  #include <linux/slab.h>
>  #include <linux/types.h>
>  
>  #define ST1232_TS_NAME	"st1232-ts"
> +#define ST1633_TS_NAME	"st1633-ts"
> +
> +enum {
> +	st1232,
> +	st1633,
> +};
>  
>  #define MIN_X		0x00
>  #define MIN_Y		0x00
> -#define MAX_X		0x31f	/* (800 - 1) */
> -#define MAX_Y		0x1df	/* (480 - 1) */
> -#define MAX_AREA	0xff
> -#define MAX_FINGERS	2
>  
>  struct st1232_ts_finger {
>  	u16 x;
> @@ -38,12 +41,24 @@ struct st1232_ts_finger {
>  	bool is_valid;
>  };
>  
> +struct st_chip_info {
> +	u8	id;

It should be the enum, not u8, but I do not think you need id here at
all. You only check id when you decide whether to report
ABS_MT_TOUCH_MAJOR, I think having a boolean to indicate that fact would
be more in line with the spirit of this patch.

> +	u16	max_x;
> +	u16	max_y;
> +	u16	max_area;
> +	u16	max_fingers;
> +	u8	start_reg;
> +};
> +
>  struct st1232_ts_data {
>  	struct i2c_client *client;
>  	struct input_dev *input_dev;
> -	struct st1232_ts_finger finger[MAX_FINGERS];
>  	struct dev_pm_qos_request low_latency_req;
>  	int reset_gpio;
> +	const struct st_chip_info *chip_info;
> +	int read_buf_len;
> +	u8 *read_buf;
> +	struct st1232_ts_finger *finger;
>  };
>  
>  static int st1232_ts_read_data(struct st1232_ts_data *ts)
> @@ -52,40 +67,35 @@ static int st1232_ts_read_data(struct st1232_ts_data *ts)
>  	struct i2c_client *client = ts->client;
>  	struct i2c_msg msg[2];
>  	int error;
> -	u8 start_reg;
> -	u8 buf[10];
> +	int i, y;
> +	u8 start_reg = ts->chip_info->start_reg;
> +	u8 *buf = ts->read_buf;
>  
> -	/* read touchscreen data from ST1232 */
> +	/* read touchscreen data */
>  	msg[0].addr = client->addr;
>  	msg[0].flags = 0;
>  	msg[0].len = 1;
>  	msg[0].buf = &start_reg;
> -	start_reg = 0x10;
>  
>  	msg[1].addr = ts->client->addr;
>  	msg[1].flags = I2C_M_RD;
> -	msg[1].len = sizeof(buf);
> +	msg[1].len = ts->read_buf_len;
>  	msg[1].buf = buf;
>  
>  	error = i2c_transfer(client->adapter, msg, 2);
>  	if (error < 0)
>  		return error;
>  
> -	/* get "valid" bits */
> -	finger[0].is_valid = buf[2] >> 7;
> -	finger[1].is_valid = buf[5] >> 7;
> +	for (i = 0, y = 0; i < ts->chip_info->max_fingers; i++, y += 3) {
> +		finger[i].is_valid = buf[i + y] >> 7;
> +		if (finger[i].is_valid) {
> +			finger[i].x = ((buf[i + y] & 0x0070) << 4) | buf[i + 1];
> +			finger[i].y = ((buf[i + y] & 0x0007) << 8) | buf[i + 2];
>  
> -	/* get xy coordinate */
> -	if (finger[0].is_valid) {
> -		finger[0].x = ((buf[2] & 0x0070) << 4) | buf[3];
> -		finger[0].y = ((buf[2] & 0x0007) << 8) | buf[4];
> -		finger[0].t = buf[8];
> -	}
> -
> -	if (finger[1].is_valid) {
> -		finger[1].x = ((buf[5] & 0x0070) << 4) | buf[6];
> -		finger[1].y = ((buf[5] & 0x0007) << 8) | buf[7];
> -		finger[1].t = buf[9];
> +			/* st1232 includes a z-axis / touch strength */
> +			if (ts->chip_info->id == st1232)
> +				finger[i].t = buf[i + 6];
> +		}
>  	}
>  
>  	return 0;
> @@ -104,11 +114,14 @@ static irqreturn_t st1232_ts_irq_handler(int irq, void *dev_id)
>  		goto end;
>  
>  	/* multi touch protocol */
> -	for (i = 0; i < MAX_FINGERS; i++) {
> +	for (i = 0; i < ts->chip_info->max_fingers; i++) {
>  		if (!finger[i].is_valid)
>  			continue;
>  
> -		input_report_abs(input_dev, ABS_MT_TOUCH_MAJOR, finger[i].t);
> +		if (ts->chip_info->id == st1232)
> +			input_report_abs(input_dev, ABS_MT_TOUCH_MAJOR,
> +					 finger[i].t);
> +
>  		input_report_abs(input_dev, ABS_MT_POSITION_X, finger[i].x);
>  		input_report_abs(input_dev, ABS_MT_POSITION_Y, finger[i].y);
>  		input_mt_sync(input_dev);
> @@ -142,12 +155,46 @@ static void st1232_ts_power(struct st1232_ts_data *ts, bool poweron)
>  		gpio_direction_output(ts->reset_gpio, poweron);
>  }
>  
> +static const struct st_chip_info st_chip_info_table[] = {

Instead of array just define 2 separate structures.

> +	[st1232] = {
> +		.id = st1232,
> +		.max_x = 0x31f, /* 800 - 1 */
> +		.max_y = 0x1df, /* 480 -1 */
> +		.max_area = 0xff,
> +		.max_fingers = 2,
> +		.start_reg = 0x12,
> +	},
> +	[st1633] = {
> +		.id = st1633,
> +		.max_x = 0x13f, /* 320 - 1 */
> +		.max_y = 0x1df, /* 480 -1 */
> +		.max_area = 0x00,
> +		.max_fingers = 5,
> +		.start_reg = 0x12,
> +	},
> +};
> +
> +static const struct of_device_id st1232_ts_dt_ids[] = {
> +	{ .compatible = "sitronix,st1232", .data = &st_chip_info_table[st1232] },
> +	{ .compatible = "sitronix,st1633", .data = &st_chip_info_table[st1633] },
> +	{ }
> +};

No need to move the table here, you can use device_get_match_data() that
does not require supplying table. This will also transparently handle
non-OF case (but you need to add data to i2c ids as well).

> +MODULE_DEVICE_TABLE(of, st1232_ts_dt_ids);
> +
>  static int st1232_ts_probe(struct i2c_client *client,
>  			   const struct i2c_device_id *id)
>  {
>  	struct st1232_ts_data *ts;
> +	struct st1232_ts_finger *finger;
>  	struct input_dev *input_dev;
>  	int error;
> +	const struct of_device_id *match;
> +
> +	match = of_match_device(st1232_ts_dt_ids, &client->dev);
> +	if (!match) {
> +		dev_err(&client->dev, "unknown device model\n");
> +		return -ENODEV;
> +	}
>  
>  	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
>  		dev_err(&client->dev, "need I2C_FUNC_I2C\n");
> @@ -163,6 +210,19 @@ static int st1232_ts_probe(struct i2c_client *client,
>  	if (!ts)
>  		return -ENOMEM;
>  
> +	ts->chip_info = match->data;
> +	ts->finger = devm_kzalloc(&client->dev,
> +				  sizeof(*finger) * ts->chip_info->max_fingers,
> +				  GFP_KERNEL);
> +	if (!ts->finger)
> +		return -ENOMEM;
> +
> +	/* allocate a buffer according to the number of registers to read */
> +	ts->read_buf_len = ts->chip_info->max_fingers * 4;
> +	ts->read_buf = devm_kzalloc(&client->dev, ts->read_buf_len, GFP_KERNEL);
> +	if (!ts->read_buf)
> +		return -ENOMEM;
> +
>  	input_dev = devm_input_allocate_device(&client->dev);
>  	if (!input_dev)
>  		return -ENOMEM;
> @@ -192,9 +252,14 @@ static int st1232_ts_probe(struct i2c_client *client,
>  	__set_bit(EV_KEY, input_dev->evbit);
>  	__set_bit(EV_ABS, input_dev->evbit);
>  
> -	input_set_abs_params(input_dev, ABS_MT_TOUCH_MAJOR, 0, MAX_AREA, 0, 0);
> -	input_set_abs_params(input_dev, ABS_MT_POSITION_X, MIN_X, MAX_X, 0, 0);
> -	input_set_abs_params(input_dev, ABS_MT_POSITION_Y, MIN_Y, MAX_Y, 0, 0);
> +	if (ts->chip_info->id == st1232)
> +		input_set_abs_params(input_dev, ABS_MT_TOUCH_MAJOR, 0,
> +				     ts->chip_info->max_area, 0, 0);
> +
> +	input_set_abs_params(input_dev, ABS_MT_POSITION_X,
> +			     MIN_X, ts->chip_info->max_x, 0, 0);
> +	input_set_abs_params(input_dev, ABS_MT_POSITION_Y,
> +			     MIN_Y, ts->chip_info->max_y, 0, 0);
>  
>  	error = devm_request_threaded_irq(&client->dev, client->irq,
>  					  NULL, st1232_ts_irq_handler,
> @@ -262,16 +327,11 @@ static SIMPLE_DEV_PM_OPS(st1232_ts_pm_ops,
>  
>  static const struct i2c_device_id st1232_ts_id[] = {
>  	{ ST1232_TS_NAME, 0 },
> +	{ ST1633_TS_NAME, 0 },
>  	{ }
>  };
>  MODULE_DEVICE_TABLE(i2c, st1232_ts_id);
>  
> -static const struct of_device_id st1232_ts_dt_ids[] = {
> -	{ .compatible = "sitronix,st1232", },
> -	{ }
> -};
> -MODULE_DEVICE_TABLE(of, st1232_ts_dt_ids);
> -
>  static struct i2c_driver st1232_ts_driver = {
>  	.probe		= st1232_ts_probe,
>  	.remove		= st1232_ts_remove,
> -- 
> 2.20.1
> 

Thanks.

-- 
Dmitry