[0/3] Add support for Goodix GT917S touch controller

This patchset introduces support for Goodix GT917S touch controller.

The major difference with other touch controllers from Goodix is that
the ID string is no longer number-only (it contains a 'S'), so an
additional patch is introduced for migrating the ID to a string.

Icenowy Zheng (3):
  dt-bindings: input: touchscreen: add compatible string for Goodix
    GT917S
  Input: goodix - use string-based chip ID
  Input: goodix - Add support for Goodix GT917S

 .../bindings/input/touchscreen/goodix.txt     |  1 +
 drivers/input/touchscreen/goodix.c            | 41 +++++++++----------
 2 files changed, 21 insertions(+), 21 deletions(-)

On Sat, Jan 11, 2020 at 12:26:07AM +0800, Icenowy Zheng wrote:
> For Goodix GT917S chip, the chip ID string is "917S", which contains not
> only numbers now.
> 
> Use string-based chip ID in the driver to support this chip and further
> chips with alphanumber ID.
> 
> Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
> ---
>  drivers/input/touchscreen/goodix.c | 39 ++++++++++++++----------------
>  1 file changed, 18 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/input/touchscreen/goodix.c b/drivers/input/touchscreen/goodix.c
> index 0403102e807e..bfd067d7145e 100644
> --- a/drivers/input/touchscreen/goodix.c
> +++ b/drivers/input/touchscreen/goodix.c
> @@ -48,7 +48,7 @@ struct goodix_ts_data {
>  	struct regulator *vddio;
>  	struct gpio_desc *gpiod_int;
>  	struct gpio_desc *gpiod_rst;
> -	u16 id;
> +	char id[5];
>  	u16 version;
>  	const char *cfg_name;
>  	struct completion firmware_loading_complete;
> @@ -235,28 +235,25 @@ static int goodix_i2c_write_u8(struct i2c_client *client, u16 reg, u8 value)
>  	return goodix_i2c_write(client, reg, &value, sizeof(value));
>  }
>  
> -static const struct goodix_chip_data *goodix_get_chip_data(u16 id)
> +static const struct goodix_chip_data *goodix_get_chip_data(const char *id)
>  {
> -	switch (id) {
> -	case 1151:
> -	case 5663:
> -	case 5688:
> +	if (!strcmp(id, "1151") ||
> +	    !strcmp(id, "5663") ||
> +	    !strcmp(id, "5688"))
>  		return &gt1x_chip_data;
>  
> -	case 911:
> -	case 9271:
> -	case 9110:
> -	case 927:
> -	case 928:
> +	if (!strcmp(id, "911") ||
> +	    !strcmp(id, "9271") ||
> +	    !strcmp(id, "9110") ||
> +	    !strcmp(id, "927") ||
> +	    !strcmp(id, "928"))
>  		return &gt911_chip_data;
>  
> -	case 912:
> -	case 967:
> +	if (!strcmp(id, "912") ||
> +	    !strcmp(id, "967"))
>  		return &gt967_chip_data;
>  
> -	default:
> -		return &gt9x_chip_data;
> -	}
> +	return &gt9x_chip_data;

I wonder if with strings it would not be simpler to have a id -> pointer
mapping table and loop over it.

Thanks.