Re: [PATCH v2 1/2] Input: tsc2007 - convert to GPIO descriptors

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

On Mon, Mar 08, 2021 at 11:55:07PM +0200, Andy Shevchenko wrote:
> This converts the driver to use GPIO descriptors.
> 
> Note that it now uses logical polarity and thus nagation has been dropped.
> 
> Signed-off-by: Andy Shevchenko <andy.shevchenko@gmail.com>
> ---
> v2: dropped negation (Dmitry)
>  drivers/input/touchscreen/tsc2007.h      |  4 +++-
>  drivers/input/touchscreen/tsc2007_core.c | 17 ++++++++---------
>  2 files changed, 11 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/input/touchscreen/tsc2007.h b/drivers/input/touchscreen/tsc2007.h
> index 91c60bf6dcaf..69b08dd6c8df 100644
> --- a/drivers/input/touchscreen/tsc2007.h
> +++ b/drivers/input/touchscreen/tsc2007.h
> @@ -19,6 +19,8 @@
>  #ifndef _TSC2007_H
>  #define _TSC2007_H
>  
> +struct gpio_desc;
> +
>  #define TSC2007_MEASURE_TEMP0		(0x0 << 4)
>  #define TSC2007_MEASURE_AUX		(0x2 << 4)
>  #define TSC2007_MEASURE_TEMP1		(0x4 << 4)
> @@ -69,7 +71,7 @@ struct tsc2007 {
>  	int			fuzzy;
>  	int			fuzzz;
>  
> -	unsigned int		gpio;
> +	struct gpio_desc	*gpiod;
>  	int			irq;
>  
>  	wait_queue_head_t	wait;
> diff --git a/drivers/input/touchscreen/tsc2007_core.c b/drivers/input/touchscreen/tsc2007_core.c
> index 3b80abfc1eca..eecd10effb56 100644
> --- a/drivers/input/touchscreen/tsc2007_core.c
> +++ b/drivers/input/touchscreen/tsc2007_core.c
> @@ -19,11 +19,11 @@
>  
>  #include <linux/module.h>
>  #include <linux/slab.h>
> +#include <linux/gpio/consumer.h>
>  #include <linux/input.h>
>  #include <linux/interrupt.h>
>  #include <linux/i2c.h>
>  #include <linux/of_device.h>
> -#include <linux/of_gpio.h>
>  #include <linux/platform_data/tsc2007.h>
>  #include "tsc2007.h"
>  
> @@ -226,11 +226,12 @@ static int tsc2007_get_pendown_state_gpio(struct device *dev)
>  	struct i2c_client *client = to_i2c_client(dev);
>  	struct tsc2007 *ts = i2c_get_clientdata(client);
>  
> -	return !gpio_get_value(ts->gpio);
> +	return gpiod_get_value(ts->gpiod);
>  }
>  
>  static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts)
>  {
> +	struct device *dev = &client->dev;
>  	struct device_node *np = client->dev.of_node;
>  	u32 val32;
>  	u64 val64;
> @@ -266,13 +267,11 @@ static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts)
>  		return -EINVAL;
>  	}
>  
> -	ts->gpio = of_get_gpio(np, 0);
> -	if (gpio_is_valid(ts->gpio))
> -		ts->get_pendown_state = tsc2007_get_pendown_state_gpio;
> -	else
> -		dev_warn(&client->dev,
> -			 "GPIO not specified in DT (of_get_gpio returned %d)\n",
> -			 ts->gpio);
> +	ts->gpiod = devm_gpiod_get_optional(dev, NULL, GPIOD_IN);
> +	if (IS_ERR(ts->gpiod))
> +		return PTR_ERR(ts->gpiod);
> +
> +	ts->get_pendown_state = tsc2007_get_pendown_state_gpio;

OK, I know what my concern was here. You are now assigning
ts->get_pendown_state unconditionally, and with ts->gpiod being NULL it
will always return false, whereas the old code would skip setting
ts->get_pendown_state when GPIO is not available, and the driver would
assume that on interrupt the pen is actually down.

Thanks.

-- 
Dmitry