linux-kernel - Re: [PATCH] Input: ili210x - fix ili251x_read_touch

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Date: Wed, 22 May 2024 12:28:45 -0700
From: Dmitry Torokhov <dmitry.torokhov@...il.com>
To: John Keeping <jkeeping@...usicbrands.com>
Cc: linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Input: ili210x - fix ili251x_read_touch_data() return
 value

On Wed, May 22, 2024 at 11:03:41AM +0100, John Keeping wrote:
> The caller of this function treats all non-zero values as an error, so
> the return value of i2c_master_recv() cannot be returned directly.
> Follow the same pattern as ili211x_read_touch_data() to return zero when
> the correct number of bytes is read and a negative error code otherwise.
> 
> This fixes touch reporting when there are more than 6 active touches.
> 
> Signed-off-by: John Keeping <jkeeping@...usicbrands.com>
> ---
>  drivers/input/touchscreen/ili210x.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/input/touchscreen/ili210x.c b/drivers/input/touchscreen/ili210x.c
> index 31ffdc2a93f35..8846c6d10fc0d 100644
> --- a/drivers/input/touchscreen/ili210x.c
> +++ b/drivers/input/touchscreen/ili210x.c
> @@ -255,14 +255,15 @@ static int ili251x_read_reg(struct i2c_client *client,
>  static int ili251x_read_touch_data(struct i2c_client *client, u8 *data)
>  {
>  	int error;
> +	int ret;
>  
>  	error = ili251x_read_reg_common(client, REG_TOUCHDATA,
>  					data, ILI251X_DATA_SIZE1, 0);
>  	if (!error && data[0] == 2) {
> -		error = i2c_master_recv(client, data + ILI251X_DATA_SIZE1,
> -					ILI251X_DATA_SIZE2);
> -		if (error >= 0 && error != ILI251X_DATA_SIZE2)
> -			error = -EIO;

Thanks for noticing this. Can we say

		if (error >= 0)
			error = error != ILI251X_DATA_SIZE2 ? -EIO : 0;

> +		ret = i2c_master_recv(client, data + ILI251X_DATA_SIZE1,
> +				      ILI251X_DATA_SIZE2);
> +		if (ret != ILI251X_DATA_SIZE2)
> +			error = ret < 0 ? ret : -EIO;
>  	}
>  
>  	return error;
> -- 
> 2.45.1
> 

Thanks.

-- 
Dmitry