* [PATCH v1] touchscreen/88pm860x-ts: check the pm860x_set_bits return value
@ 2022-09-21 20:37 Li Zhong
2022-09-21 22:47 ` Dmitry Torokhov
0 siblings, 1 reply; 2+ messages in thread
From: Li Zhong @ 2022-09-21 20:37 UTC (permalink / raw)
To: linux-input; +Cc: dmitry.torokhov, Li Zhong
pm860x_touch_close() got the return value of pm860x_set_bits() but
didn't check it. However, pm860x_set_bits() could fail when writing the
reg map fails. Since pm860x_touch_close() cannot return an error value,
we retry the bit setting in the error handling.
Signed-off-by: Li Zhong <floridsleeves@gmail.com>
---
drivers/input/touchscreen/88pm860x-ts.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/input/touchscreen/88pm860x-ts.c b/drivers/input/touchscreen/88pm860x-ts.c
index 81a3ea4b9a3d..043520d1ff26 100644
--- a/drivers/input/touchscreen/88pm860x-ts.c
+++ b/drivers/input/touchscreen/88pm860x-ts.c
@@ -106,10 +106,13 @@ static void pm860x_touch_close(struct input_dev *dev)
{
struct pm860x_touch *touch = input_get_drvdata(dev);
int data;
+ int ret;
data = MEAS_PD_EN | MEAS_TSIX_EN | MEAS_TSIY_EN
| MEAS_TSIZ1_EN | MEAS_TSIZ2_EN;
- pm860x_set_bits(touch->i2c, MEAS_EN3, data, 0);
+ ret = pm860x_set_bits(touch->i2c, MEAS_EN3, data, 0);
+ if (ret < 0)
+ pm860x_set_bits(touch->i2c, MEAS_EN3, data, 0);
}
#ifdef CONFIG_OF
--
2.25.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v1] touchscreen/88pm860x-ts: check the pm860x_set_bits return value
2022-09-21 20:37 [PATCH v1] touchscreen/88pm860x-ts: check the pm860x_set_bits return value Li Zhong
@ 2022-09-21 22:47 ` Dmitry Torokhov
0 siblings, 0 replies; 2+ messages in thread
From: Dmitry Torokhov @ 2022-09-21 22:47 UTC (permalink / raw)
To: Li Zhong; +Cc: linux-input
Hi,
On Wed, Sep 21, 2022 at 01:37:06PM -0700, Li Zhong wrote:
> pm860x_touch_close() got the return value of pm860x_set_bits() but
> didn't check it. However, pm860x_set_bits() could fail when writing the
> reg map fails.
Under what conditions would the write fail?
> Since pm860x_touch_close() cannot return an error value,
> we retry the bit setting in the error handling.
What guarantees that the repeated write will not fail again? What is the
failure mode if write does not succeed?
>
> Signed-off-by: Li Zhong <floridsleeves@gmail.com>
> ---
> drivers/input/touchscreen/88pm860x-ts.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/input/touchscreen/88pm860x-ts.c b/drivers/input/touchscreen/88pm860x-ts.c
> index 81a3ea4b9a3d..043520d1ff26 100644
> --- a/drivers/input/touchscreen/88pm860x-ts.c
> +++ b/drivers/input/touchscreen/88pm860x-ts.c
> @@ -106,10 +106,13 @@ static void pm860x_touch_close(struct input_dev *dev)
> {
> struct pm860x_touch *touch = input_get_drvdata(dev);
> int data;
> + int ret;
>
> data = MEAS_PD_EN | MEAS_TSIX_EN | MEAS_TSIY_EN
> | MEAS_TSIZ1_EN | MEAS_TSIZ2_EN;
> - pm860x_set_bits(touch->i2c, MEAS_EN3, data, 0);
> + ret = pm860x_set_bits(touch->i2c, MEAS_EN3, data, 0);
> + if (ret < 0)
> + pm860x_set_bits(touch->i2c, MEAS_EN3, data, 0);
> }
>
> #ifdef CONFIG_OF
> --
> 2.25.1
>
Thanks.
--
Dmitry
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