Handle the error returned by reset_control_deassert() in the probe
function to prevent continuing probe when reset deassertion fails.

Previously, reset_control_deassert() was called without checking its
return value, which could lead to probe continuing even when the
device reset wasn't properly deasserted.

The fix checks the return value and returns an error with dev_err_probe()
if reset deassertion fails, providing better error handling and
diagnostics.

Signed-off-by: Artem Shimko <a.shimko.dev@gmail.com>
---
Hello maintainers and reviewers,

This patch adds proper error handling for reset_control_deassert() in the 
DesignWare I2C platform driver probe function.

Currently, if reset deassertion fails, the driver continues probing which
could lead to operating a device that is still held in reset. This patch
ensures we properly check the return value and fail the probe with a
meaningful error message if reset deassertion fails.

The change is safe because:
1. reset_control_deassert() handles NULL pointers (for optional resets) 
   by returning 0 (success)
2. For non-NULL reset controls, we now properly validate the operation
3. dev_err_probe() provides appropriate error context for diagnostics

Thank you for your consideration.

Best regards,
Artem Shimko

 drivers/i2c/busses/i2c-designware-platdrv.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index a35e4c64a1d4..4c57c79d4ce5 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -240,7 +240,9 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)
 	if (IS_ERR(dev->rst))
 		return PTR_ERR(dev->rst);
 
-	reset_control_deassert(dev->rst);
+	ret = reset_control_deassert(dev->rst);
+	if (ret)
+		return dev_err_probe(&pdev->dev, ret, "Failed to deassert reset\n");
 
 	ret = i2c_dw_fw_parse_and_configure(dev);
 	if (ret)
-- 
2.43.0

Hi Artem,

On Do, 2025-10-09 at 10:44 +0300, Artem Shimko wrote:
> Handle the error returned by reset_control_deassert() in the probe
> function to prevent continuing probe when reset deassertion fails.
> 
> Previously, reset_control_deassert() was called without checking its
> return value, which could lead to probe continuing even when the
> device reset wasn't properly deasserted.
> 
> The fix checks the return value and returns an error with dev_err_probe()
> if reset deassertion fails, providing better error handling and
> diagnostics.
> 
> Signed-off-by: Artem Shimko <a.shimko.dev@gmail.com>
> ---
> Hello maintainers and reviewers,
> 
> This patch adds proper error handling for reset_control_deassert() in the 
> DesignWare I2C platform driver probe function.
> 
> Currently, if reset deassertion fails, the driver continues probing which
> could lead to operating a device that is still held in reset. This patch
> ensures we properly check the return value and fail the probe with a
> meaningful error message if reset deassertion fails.
> 
> The change is safe because:
> 1. reset_control_deassert() handles NULL pointers (for optional resets) 
>    by returning 0 (success)
> 2. For non-NULL reset controls, we now properly validate the operation
> 3. dev_err_probe() provides appropriate error context for diagnostics
> 
> Thank you for your consideration.
> 
> Best regards,
> Artem Shimko
> 
>  drivers/i2c/busses/i2c-designware-platdrv.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
> index a35e4c64a1d4..4c57c79d4ce5 100644
> --- a/drivers/i2c/busses/i2c-designware-platdrv.c
> +++ b/drivers/i2c/busses/i2c-designware-platdrv.c
> @@ -240,7 +240,9 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)
>  	if (IS_ERR(dev->rst))
>  		return PTR_ERR(dev->rst);
>  
> -	reset_control_deassert(dev->rst);
> +	ret = reset_control_deassert(dev->rst);
> +	if (ret)
> +		return dev_err_probe(&pdev->dev, ret, "Failed to deassert reset\n");

There is a local variable "struct device *device = &pdev->dev", better
use that for consistency.

regards
Philipp

Handle the error returned by reset_control_deassert() in the probe
function to prevent continuing probe when reset deassertion fails.

Previously, reset_control_deassert() was called without checking its
return value, which could lead to probe continuing even when the
device reset wasn't properly deasserted.

The fix checks the return value and returns an error with dev_err_probe()
if reset deassertion fails, providing better error handling and
diagnostics.

Signed-off-by: Artem Shimko <a.shimko.dev@gmail.com>
---
Hi Philipp,

Oh, sorry, sure.

Could you please have a look at the v2.

Thank you

Best regards,
Artem Shimko

ChangeLog:
  v1:
    * https://lore.kernel.org/all/20251009074443.2010699-1-a.shimko.dev@gmail.com/
  v2:
    * change pdev->dev to local device dev

 drivers/i2c/busses/i2c-designware-platdrv.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index a35e4c64a1d4..c89af7cbdfac 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -240,7 +240,9 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)
 	if (IS_ERR(dev->rst))
 		return PTR_ERR(dev->rst);
 
-	reset_control_deassert(dev->rst);
+	ret = reset_control_deassert(dev->rst);
+	if (ret)
+		return dev_err_probe(device, ret, "Failed to deassert reset\n");
 
 	ret = i2c_dw_fw_parse_and_configure(dev);
 	if (ret)
-- 
2.43.0

On Do, 2025-10-09 at 11:37 +0300, Artem Shimko wrote:
> Handle the error returned by reset_control_deassert() in the probe
> function to prevent continuing probe when reset deassertion fails.
> 
> Previously, reset_control_deassert() was called without checking its
> return value, which could lead to probe continuing even when the
> device reset wasn't properly deasserted.
> 
> The fix checks the return value and returns an error with dev_err_probe()
> if reset deassertion fails, providing better error handling and
> diagnostics.
> 
> Signed-off-by: Artem Shimko <a.shimko.dev@gmail.com>

Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>

regards
Philipp

On Thu, Oct 9, 2025 at 12:39 PM Philipp Zabel <p.zabel@pengutronix.de> wrote:
>
> On Do, 2025-10-09 at 11:37 +0300, Artem Shimko wrote:
> > Handle the error returned by reset_control_deassert() in the probe
> > function to prevent continuing probe when reset deassertion fails.
> >
> > Previously, reset_control_deassert() was called without checking its
> > return value, which could lead to probe continuing even when the
> > device reset wasn't properly deasserted.
> >
> > The fix checks the return value and returns an error with dev_err_probe()
> > if reset deassertion fails, providing better error handling and
> > diagnostics.
> >
> > Signed-off-by: Artem Shimko <a.shimko.dev@gmail.com>
>
> Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>

Hi Philipp,

Should I do something to bring the changes to linux-next?

--
Best regards,
Artem

Hi,

On Thu, Oct 09, 2025 at 11:37:03AM +0300, Artem Shimko wrote:
> Handle the error returned by reset_control_deassert() in the probe
> function to prevent continuing probe when reset deassertion fails.
> 
> Previously, reset_control_deassert() was called without checking its
> return value, which could lead to probe continuing even when the
> device reset wasn't properly deasserted.
> 
> The fix checks the return value and returns an error with dev_err_probe()
> if reset deassertion fails, providing better error handling and
> diagnostics.
> 
> Signed-off-by: Artem Shimko <a.shimko.dev@gmail.com>

Looks good to me,

Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>