2024-05-22 10:04:12

by John Keeping

Subject: [PATCH] Input: ili210x - fix ili251x_read_touch_data() return value

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 <[email protected]>
---
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;
+ 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

2024-05-22 19:33:29

by Dmitry Torokhov

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 <[email protected]>
> ---
> 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

2024-05-22 20:25:44

by Markus Elfring

Subject: Re: [PATCH] Input: ili210x - fix ili251x_read_touch_data() return value

…
> This fixes touch reporting when there are more than 6 active touches.

Does such information indicate a need for the tag “Fixes”?


…
> +++ 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) {
…

I suggest to define the variable “ret” in the shown if branch.

Regards,
Markus