diff mbox series

[2/4] drm: ti-sn65dsi86: Check bridge connection failure

Message ID 20240619102219.138927-3-jacopo.mondi@ideasonboard.com (mailing list archive)
State New, archived
Headers show
Series drm: rcar-du: Add support for R8A779H0 | expand

Commit Message

Jacopo Mondi June 19, 2024, 10:22 a.m. UTC 
From: Phong Hoang <phong.hoang.wz@renesas.com>

Add a check to the register access function when attaching a bridge
device.

Signed-off-by: Phong Hoang <phong.hoang.wz@renesas.com>
Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
---
 drivers/gpu/drm/bridge/ti-sn65dsi86.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

Comments

Laurent Pinchart June 19, 2024, 7:32 p.m. UTC | #1 
Hi Jacopo,

Thank you for the patch.

On Wed, Jun 19, 2024 at 12:22:16PM +0200, Jacopo Mondi wrote:
> From: Phong Hoang <phong.hoang.wz@renesas.com>
> 
> Add a check to the register access function when attaching a bridge
> device.
> 
> Signed-off-by: Phong Hoang <phong.hoang.wz@renesas.com>
> Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>

Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

> ---
>  drivers/gpu/drm/bridge/ti-sn65dsi86.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> index 84698a0b27a8..b7df53577987 100644
> --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> @@ -696,6 +696,7 @@ static struct ti_sn65dsi86 *bridge_to_ti_sn65dsi86(struct drm_bridge *bridge)
>  
>  static int ti_sn_attach_host(struct auxiliary_device *adev, struct ti_sn65dsi86 *pdata)
>  {
> +	int ret;
>  	int val;
>  	struct mipi_dsi_host *host;
>  	struct mipi_dsi_device *dsi;
> @@ -720,8 +721,11 @@ static int ti_sn_attach_host(struct auxiliary_device *adev, struct ti_sn65dsi86
>  
>  	/* check if continuous dsi clock is required or not */
>  	pm_runtime_get_sync(dev);
> -	regmap_read(pdata->regmap, SN_DPPLL_SRC_REG, &val);
> +	ret = regmap_read(pdata->regmap, SN_DPPLL_SRC_REG, &val);
>  	pm_runtime_put_autosuspend(dev);
> +	if (ret)
> +		return ret;
> +
>  	if (!(val & DPPLL_CLK_SRC_DSICLK))
>  		dsi->mode_flags |= MIPI_DSI_CLOCK_NON_CONTINUOUS;
>
Tomi Valkeinen June 20, 2024, 6:43 a.m. UTC | #2 
On 19/06/2024 22:32, Laurent Pinchart wrote:
> Hi Jacopo,
> 
> Thank you for the patch.
> 
> On Wed, Jun 19, 2024 at 12:22:16PM +0200, Jacopo Mondi wrote:
>> From: Phong Hoang <phong.hoang.wz@renesas.com>
>>
>> Add a check to the register access function when attaching a bridge
>> device.

I think the desc is missing the "why". I'm guessing it's the first 
register access to the IC, and thus verifies that it is accessible.

  Tomi

>>
>> Signed-off-by: Phong Hoang <phong.hoang.wz@renesas.com>
>> Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
> 
> Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> 
>> ---
>>   drivers/gpu/drm/bridge/ti-sn65dsi86.c | 6 +++++-
>>   1 file changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
>> index 84698a0b27a8..b7df53577987 100644
>> --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
>> +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
>> @@ -696,6 +696,7 @@ static struct ti_sn65dsi86 *bridge_to_ti_sn65dsi86(struct drm_bridge *bridge)
>>   
>>   static int ti_sn_attach_host(struct auxiliary_device *adev, struct ti_sn65dsi86 *pdata)
>>   {
>> +	int ret;
>>   	int val;
>>   	struct mipi_dsi_host *host;
>>   	struct mipi_dsi_device *dsi;
>> @@ -720,8 +721,11 @@ static int ti_sn_attach_host(struct auxiliary_device *adev, struct ti_sn65dsi86
>>   
>>   	/* check if continuous dsi clock is required or not */
>>   	pm_runtime_get_sync(dev);
>> -	regmap_read(pdata->regmap, SN_DPPLL_SRC_REG, &val);
>> +	ret = regmap_read(pdata->regmap, SN_DPPLL_SRC_REG, &val);
>>   	pm_runtime_put_autosuspend(dev);
>> +	if (ret)
>> +		return ret;
>> +
>>   	if (!(val & DPPLL_CLK_SRC_DSICLK))
>>   		dsi->mode_flags |= MIPI_DSI_CLOCK_NON_CONTINUOUS;
>>   
>
Laurent Pinchart June 20, 2024, 10:42 a.m. UTC | #3 
On Thu, Jun 20, 2024 at 09:43:05AM +0300, Tomi Valkeinen wrote:
> On 19/06/2024 22:32, Laurent Pinchart wrote:
> > Hi Jacopo,
> > 
> > Thank you for the patch.
> > 
> > On Wed, Jun 19, 2024 at 12:22:16PM +0200, Jacopo Mondi wrote:
> >> From: Phong Hoang <phong.hoang.wz@renesas.com>
> >>
> >> Add a check to the register access function when attaching a bridge
> >> device.
> 
> I think the desc is missing the "why". I'm guessing it's the first 
> register access to the IC, and thus verifies that it is accessible.

Isn't it a good idea in general to always check if I2C reads succeeded ?

> >>
> >> Signed-off-by: Phong Hoang <phong.hoang.wz@renesas.com>
> >> Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
> > 
> > Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> > 
> >> ---
> >>   drivers/gpu/drm/bridge/ti-sn65dsi86.c | 6 +++++-
> >>   1 file changed, 5 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> >> index 84698a0b27a8..b7df53577987 100644
> >> --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> >> +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> >> @@ -696,6 +696,7 @@ static struct ti_sn65dsi86 *bridge_to_ti_sn65dsi86(struct drm_bridge *bridge)
> >>   
> >>   static int ti_sn_attach_host(struct auxiliary_device *adev, struct ti_sn65dsi86 *pdata)
> >>   {
> >> +	int ret;
> >>   	int val;
> >>   	struct mipi_dsi_host *host;
> >>   	struct mipi_dsi_device *dsi;
> >> @@ -720,8 +721,11 @@ static int ti_sn_attach_host(struct auxiliary_device *adev, struct ti_sn65dsi86
> >>   
> >>   	/* check if continuous dsi clock is required or not */
> >>   	pm_runtime_get_sync(dev);
> >> -	regmap_read(pdata->regmap, SN_DPPLL_SRC_REG, &val);
> >> +	ret = regmap_read(pdata->regmap, SN_DPPLL_SRC_REG, &val);
> >>   	pm_runtime_put_autosuspend(dev);
> >> +	if (ret)
> >> +		return ret;
> >> +
> >>   	if (!(val & DPPLL_CLK_SRC_DSICLK))
> >>   		dsi->mode_flags |= MIPI_DSI_CLOCK_NON_CONTINUOUS;
> >>
Tomi Valkeinen June 20, 2024, 11 a.m. UTC | #4 
On 20/06/2024 13:42, Laurent Pinchart wrote:
> On Thu, Jun 20, 2024 at 09:43:05AM +0300, Tomi Valkeinen wrote:
>> On 19/06/2024 22:32, Laurent Pinchart wrote:
>>> Hi Jacopo,
>>>
>>> Thank you for the patch.
>>>
>>> On Wed, Jun 19, 2024 at 12:22:16PM +0200, Jacopo Mondi wrote:
>>>> From: Phong Hoang <phong.hoang.wz@renesas.com>
>>>>
>>>> Add a check to the register access function when attaching a bridge
>>>> device.
>>
>> I think the desc is missing the "why". I'm guessing it's the first
>> register access to the IC, and thus verifies that it is accessible.
> 
> Isn't it a good idea in general to always check if I2C reads succeeded ?

It is. But if there are tens of other i2c accesses for which the return 
value is ignored, the question remains: why this single one was 
specifically fixed?

  Tomi

> 
>>>>
>>>> Signed-off-by: Phong Hoang <phong.hoang.wz@renesas.com>
>>>> Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
>>>
>>> Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
>>>
>>>> ---
>>>>    drivers/gpu/drm/bridge/ti-sn65dsi86.c | 6 +++++-
>>>>    1 file changed, 5 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
>>>> index 84698a0b27a8..b7df53577987 100644
>>>> --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
>>>> +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
>>>> @@ -696,6 +696,7 @@ static struct ti_sn65dsi86 *bridge_to_ti_sn65dsi86(struct drm_bridge *bridge)
>>>>    
>>>>    static int ti_sn_attach_host(struct auxiliary_device *adev, struct ti_sn65dsi86 *pdata)
>>>>    {
>>>> +	int ret;
>>>>    	int val;
>>>>    	struct mipi_dsi_host *host;
>>>>    	struct mipi_dsi_device *dsi;
>>>> @@ -720,8 +721,11 @@ static int ti_sn_attach_host(struct auxiliary_device *adev, struct ti_sn65dsi86
>>>>    
>>>>    	/* check if continuous dsi clock is required or not */
>>>>    	pm_runtime_get_sync(dev);
>>>> -	regmap_read(pdata->regmap, SN_DPPLL_SRC_REG, &val);
>>>> +	ret = regmap_read(pdata->regmap, SN_DPPLL_SRC_REG, &val);
>>>>    	pm_runtime_put_autosuspend(dev);
>>>> +	if (ret)
>>>> +		return ret;
>>>> +
>>>>    	if (!(val & DPPLL_CLK_SRC_DSICLK))
>>>>    		dsi->mode_flags |= MIPI_DSI_CLOCK_NON_CONTINUOUS;
>>>>    
>
diff mbox series

Patch

diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
index 84698a0b27a8..b7df53577987 100644
--- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
+++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
@@ -696,6 +696,7 @@  static struct ti_sn65dsi86 *bridge_to_ti_sn65dsi86(struct drm_bridge *bridge)
 
 static int ti_sn_attach_host(struct auxiliary_device *adev, struct ti_sn65dsi86 *pdata)
 {
+	int ret;
 	int val;
 	struct mipi_dsi_host *host;
 	struct mipi_dsi_device *dsi;
@@ -720,8 +721,11 @@  static int ti_sn_attach_host(struct auxiliary_device *adev, struct ti_sn65dsi86
 
 	/* check if continuous dsi clock is required or not */
 	pm_runtime_get_sync(dev);
-	regmap_read(pdata->regmap, SN_DPPLL_SRC_REG, &val);
+	ret = regmap_read(pdata->regmap, SN_DPPLL_SRC_REG, &val);
 	pm_runtime_put_autosuspend(dev);
+	if (ret)
+		return ret;
+
 	if (!(val & DPPLL_CLK_SRC_DSICLK))
 		dsi->mode_flags |= MIPI_DSI_CLOCK_NON_CONTINUOUS;