Re: [PATCH v2] Input: ili210x - Probe even if no resolution information

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

Hi Marek,

On Fri, Feb 17, 2023 at 03:52:00AM +0100, Marek Vasut wrote:
> Probe the touch controller driver even if resolution information is not
> available. This can happen e.g. in case the touch controller suffered a
> failed firmware update and is stuck in bootloader mode.
> 
> Signed-off-by: Marek Vasut <marex@denx.de>
> ---
> Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> Cc: Joe Hung <joe_hung@ilitek.com>
> Cc: Luca Hsu <luca_hsu@ilitek.com>
> ---
> V2: Add dev_warn() in case resolution is invalid
> ---
>  drivers/input/touchscreen/ili210x.c | 28 +++++++++++++++++++---------
>  1 file changed, 19 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/input/touchscreen/ili210x.c b/drivers/input/touchscreen/ili210x.c
> index 4897fafa4204d..d64b6d77d2e08 100644
> --- a/drivers/input/touchscreen/ili210x.c
> +++ b/drivers/input/touchscreen/ili210x.c
> @@ -370,22 +370,33 @@ static int ili251x_firmware_update_resolution(struct device *dev)
>  
>  	/* The firmware update blob might have changed the resolution. */
>  	error = priv->chip->read_reg(client, REG_PANEL_INFO, &rs, sizeof(rs));
> -	if (error)
> -		return error;
> +	if (!error) {
> +		resx = le16_to_cpup((__le16 *)rs);
> +		resy = le16_to_cpup((__le16 *)(rs + 2));
>  
> -	resx = le16_to_cpup((__le16 *)rs);
> -	resy = le16_to_cpup((__le16 *)(rs + 2));
> +		/* The value reported by the firmware is invalid. */
> +		if (!resx || resx == 0xffff || !resy || resy == 0xffff)
> +			error = -EINVAL;
> +	}
>  
> -	/* The value reported by the firmware is invalid. */
> -	if (!resx || resx == 0xffff || !resy || resy == 0xffff)
> -		return -EINVAL;
> +	/*
> +	 * In case of error, the firmware might be stuck in bootloader mode,
> +	 * e.g. after a failed firmware update. Set maximum resolution, but
> +	 * do not fail to probe, so the user can re-trigger the firmware
> +	 * update and recover the touch controller.
> +	 */
> +	if (error) {
> +		dev_warn(dev, "Invalid resolution reported by controller.\n");
> +		resx = 16384;
> +		resy = 16384;
> +	}
>  
>  	input_abs_set_max(priv->input, ABS_X, resx - 1);
>  	input_abs_set_max(priv->input, ABS_Y, resy - 1);
>  	input_abs_set_max(priv->input, ABS_MT_POSITION_X, resx - 1);
>  	input_abs_set_max(priv->input, ABS_MT_POSITION_Y, resy - 1);
>  
> -	return 0;
> +	return error;

I think this will make ili251x_firmware_update_cached_state() continue
failing when it reports invalid coordinates. Was this intended?

>  }
>  
>  static ssize_t ili251x_firmware_update_firmware_version(struct device *dev)
> @@ -980,7 +991,6 @@ static int ili210x_i2c_probe(struct i2c_client *client)
>  	if (error) {
>  		dev_err(dev, "Unable to cache firmware information, err: %d\n",
>  			error);
> -		return error;
>  	}
>  	touchscreen_parse_properties(input, true, &priv->prop);
>  
> -- 
> 2.39.1
> 

Thanks.

-- 
Dmitry