[PATCH v3] drm/bridge: analogix_dp: use devm_phy_optional_get() for the DP PHY

[PATCH v3] drm/bridge: analogix_dp: use devm_phy_optional_get() for the DP PHY

[Jun Yan]

The DP PHY is optional: the Rockchip RK3399 eDP controller (used as the
internal eDP port) has no separate PHY device and relies on its built-in
PHY, which is programmed directly through the GRF registers, so its DT
node carries no "phys"/"phy-names" property.

Requesting the PHY with devm_phy_get() therefore returns -ENODEV (or
-ENOSYS when CONFIG_GENERIC_PHY is disabled) and the driver logs a
misleading "no DP phy configured" error at probe time before falling back
to a NULL phy.

Use devm_phy_optional_get() instead, which returns NULL when the PHY is
absent and otherwise behaves identically, and drop the manual -ENODEV/
-ENOSYS handling. This also removes the spurious error message.

Signed-off-by: Jun Yan <jerrysteve1101@gmail.com>
Reviewed-by: Damon Ding <damon.ding@rock-chips.com>
---
Changes in v3:
  - Add missing changelog entries and reference links
  - Link to v2: https://lore.kernel.org/dri-devel/20261013134659.335829-1-jerrysteve1101@gmail.com/

Changes in v2:
  - Added comments to explain the changes made.
  - Link to v1: https://lore.kernel.org/dri-devel/20260924020417.868588-1-jerrysteve1101@gmail.com/

 .../drm/bridge/analogix/analogix_dp_core.c    | 22 ++++++-------------
 1 file changed, 7 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index 6df6963740d2..637b1bff0f6c 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -1426,21 +1426,13 @@ analogix_dp_probe(struct device *dev, struct analogix_dp_plat_data *plat_data)
 	if (ret)
 		return ERR_PTR(ret);
 
-	dp->phy = devm_phy_get(dp->dev, "dp");
-	if (IS_ERR(dp->phy)) {
-		dev_err(dp->dev, "no DP phy configured\n");
-		ret = PTR_ERR(dp->phy);
-		if (ret) {
-			/*
-			 * phy itself is not enabled, so we can move forward
-			 * assigning NULL to phy pointer.
-			 */
-			if (ret == -ENOSYS || ret == -ENODEV)
-				dp->phy = NULL;
-			else
-				return ERR_PTR(ret);
-		}
-	}
+	/*
+	 * RK3288/RK3399 use Analogix DP controller built-in PHY,
+	 * no extra PHY configuration is required.
+	 */
+	dp->phy = devm_phy_optional_get(dp->dev, "dp");
+	if (IS_ERR(dp->phy))
+		return ERR_CAST(dp->phy);
 
 	dp->clock = devm_clk_get(&pdev->dev, "dp");
 	if (IS_ERR(dp->clock)) {
-- 
2.56.0

Re: [PATCH v3] drm/bridge: analogix_dp: use devm_phy_optional_get() for the DP PHY

[Luca Ceresoli]

Hello,

On Tue Nov 10, 2026 at 3:37 AM CET, Jun Yan wrote:
> The DP PHY is optional: the Rockchip RK3399 eDP controller (used as the
> internal eDP port) has no separate PHY device and relies on its built-in
> PHY, which is programmed directly through the GRF registers, so its DT
> node carries no "phys"/"phy-names" property.
>
> Requesting the PHY with devm_phy_get() therefore returns -ENODEV (or
> -ENOSYS when CONFIG_GENERIC_PHY is disabled) and the driver logs a
> misleading "no DP phy configured" error at probe time before falling back
> to a NULL phy.
>
> Use devm_phy_optional_get() instead, which returns NULL when the PHY is
> absent and otherwise behaves identically, and drop the manual -ENODEV/
> -ENOSYS handling. This also removes the spurious error message.
>
> Signed-off-by: Jun Yan <jerrysteve1101@gmail.com>
> Reviewed-by: Damon Ding <damon.ding@rock-chips.com>
> ---
> Changes in v3:
>   - Add missing changelog entries and reference links
>   - Link to v2: https://lore.kernel.org/dri-devel/20261013134659.335829-1-jerrysteve1101@gmail.com/
>
> Changes in v2:
>   - Added comments to explain the changes made.
>   - Link to v1: https://lore.kernel.org/dri-devel/20260924020417.868588-1-jerrysteve1101@gmail.com/
>
>  .../drm/bridge/analogix/analogix_dp_core.c    | 22 ++++++-------------
>  1 file changed, 7 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> index 6df6963740d2..637b1bff0f6c 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> @@ -1426,21 +1426,13 @@ analogix_dp_probe(struct device *dev, struct analogix_dp_plat_data *plat_data)
>  	if (ret)
>  		return ERR_PTR(ret);
>
> -	dp->phy = devm_phy_get(dp->dev, "dp");
> -	if (IS_ERR(dp->phy)) {
> -		dev_err(dp->dev, "no DP phy configured\n");
> -		ret = PTR_ERR(dp->phy);
> -		if (ret) {
> -			/*
> -			 * phy itself is not enabled, so we can move forward
> -			 * assigning NULL to phy pointer.
> -			 */
> -			if (ret == -ENOSYS || ret == -ENODEV)
> -				dp->phy = NULL;
> -			else
> -				return ERR_PTR(ret);
> -		}
> -	}
> +	/*
> +	 * RK3288/RK3399 use Analogix DP controller built-in PHY,
> +	 * no extra PHY configuration is required.
> +	 */
> +	dp->phy = devm_phy_optional_get(dp->dev, "dp");
> +	if (IS_ERR(dp->phy))
> +		return ERR_CAST(dp->phy);

The original code ignbores -ENOSYS, devm_phy_optional_get() does not. So,
either -ENOSYS was just impossible, or this patch potentially changes the
behaviour.

Can you elaborate on that?

Luca

--
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

Re: [PATCH v3] drm/bridge: analogix_dp: use devm_phy_optional_get() for the DP PHY

[Damon Ding]

On 11/12/2026 11:39 PM, Luca Ceresoli wrote:
> Hello,
> 
> On Tue Nov 10, 2026 at 3:37 AM CET, Jun Yan wrote:
>> The DP PHY is optional: the Rockchip RK3399 eDP controller (used as the
>> internal eDP port) has no separate PHY device and relies on its built-in
>> PHY, which is programmed directly through the GRF registers, so its DT
>> node carries no "phys"/"phy-names" property.
>>
>> Requesting the PHY with devm_phy_get() therefore returns -ENODEV (or
>> -ENOSYS when CONFIG_GENERIC_PHY is disabled) and the driver logs a
>> misleading "no DP phy configured" error at probe time before falling back
>> to a NULL phy.
>>
>> Use devm_phy_optional_get() instead, which returns NULL when the PHY is
>> absent and otherwise behaves identically, and drop the manual -ENODEV/
>> -ENOSYS handling. This also removes the spurious error message.
>>
>> Signed-off-by: Jun Yan <jerrysteve1101@gmail.com>
>> Reviewed-by: Damon Ding <damon.ding@rock-chips.com>
>> ---
>> Changes in v3:
>>    - Add missing changelog entries and reference links
>>    - Link to v2: https://lore.kernel.org/dri-devel/20261013134659.335829-1-jerrysteve1101@gmail.com/
>>
>> Changes in v2:
>>    - Added comments to explain the changes made.
>>    - Link to v1: https://lore.kernel.org/dri-devel/20260924020417.868588-1-jerrysteve1101@gmail.com/
>>
>>   .../drm/bridge/analogix/analogix_dp_core.c    | 22 ++++++-------------
>>   1 file changed, 7 insertions(+), 15 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
>> index 6df6963740d2..637b1bff0f6c 100644
>> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
>> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
>> @@ -1426,21 +1426,13 @@ analogix_dp_probe(struct device *dev, struct analogix_dp_plat_data *plat_data)
>>   	if (ret)
>>   		return ERR_PTR(ret);
>>
>> -	dp->phy = devm_phy_get(dp->dev, "dp");
>> -	if (IS_ERR(dp->phy)) {
>> -		dev_err(dp->dev, "no DP phy configured\n");
>> -		ret = PTR_ERR(dp->phy);
>> -		if (ret) {
>> -			/*
>> -			 * phy itself is not enabled, so we can move forward
>> -			 * assigning NULL to phy pointer.
>> -			 */
>> -			if (ret == -ENOSYS || ret == -ENODEV)
>> -				dp->phy = NULL;
>> -			else
>> -				return ERR_PTR(ret);
>> -		}
>> -	}
>> +	/*
>> +	 * RK3288/RK3399 use Analogix DP controller built-in PHY,
>> +	 * no extra PHY configuration is required.
>> +	 */
>> +	dp->phy = devm_phy_optional_get(dp->dev, "dp");
>> +	if (IS_ERR(dp->phy))
>> +		return ERR_CAST(dp->phy);
> 
> The original code ignbores -ENOSYS, devm_phy_optional_get() does not. So,
> either -ENOSYS was just impossible, or this patch potentially changes the
> behaviour.
> 
> Can you elaborate on that?
> 
> 

You are right, this is really a valid concern.

If CONFIG_GENERIC_PHY is disabled, the old code could still proceed and 
keep the driver probing, while the new version would return an error 
directly.

It should be better to keep the -ENOSYS handling to preserve the 
original behavior.

Best regards,
Damon

Re: [PATCH v3] drm/bridge: analogix_dp: use devm_phy_optional_get() for the DP PHY

[Jun Yan]

Hi Damon,

> You are right, this is really a valid concern.
>
> If CONFIG_GENERIC_PHY is disabled, the old code could still proceed and
> keep the driver probing, while the new version would return an error
> directly.

-ENOSYS can only come from the !CONFIG_GENERIC_PHY stubs in
include/linux/phy/phy.h; the real implementation in drivers/phy/phy-core.c
never returns it. And the stub for the optional variant returns NULL, not
-ENOSYS:

    static inline struct phy *devm_phy_optional_get(struct device *dev,
                                                    const char *string)
    {
            return NULL;
    }

So with CONFIG_GENERIC_PHY disabled the PHY is still treated as absent
(NULL), exactly as the old -ENOSYS branch did. With CONFIG_GENERIC_PHY
enabled, -ENOSYS cannot occur, devm_phy_optional_get() turns -ENODEV into
NULL, and any other error is still propagated - same as the open-coded
check.

> It should be better to keep the -ENOSYS handling to preserve the
> original behavior.

Overall the behaviour is unchanged in both configurations, so no separate
handling is needed.

Best regards,
Jun Yan

Re: [PATCH v3] drm/bridge: analogix_dp: use devm_phy_optional_get() for the DP PHY

[Luca Ceresoli]

Hello,

On Fri Nov 13, 2026 at 2:12 PM CET, Jun Yan wrote:
> Hi Damon,
>
>> You are right, this is really a valid concern.
>>
>> If CONFIG_GENERIC_PHY is disabled, the old code could still proceed and
>> keep the driver probing, while the new version would return an error
>> directly.
>
> -ENOSYS can only come from the !CONFIG_GENERIC_PHY stubs in
> include/linux/phy/phy.h; the real implementation in drivers/phy/phy-core.c
> never returns it. And the stub for the optional variant returns NULL, not
> -ENOSYS:
>
>     static inline struct phy *devm_phy_optional_get(struct device *dev,
>                                                     const char *string)
>     {
>             return NULL;
>     }
>
> So with CONFIG_GENERIC_PHY disabled the PHY is still treated as absent
> (NULL), exactly as the old -ENOSYS branch did. With CONFIG_GENERIC_PHY
> enabled, -ENOSYS cannot occur, devm_phy_optional_get() turns -ENODEV into
> NULL, and any other error is still propagated - same as the open-coded
> check.
>
>> It should be better to keep the -ENOSYS handling to preserve the
>> original behavior.
>
> Overall the behaviour is unchanged in both configurations, so no separate
> handling is needed.

Thanks for the analysis! Cna you send a v4 with that explained in the
commit message, possibly in a more concise way, maybe with bullets for the
various CONFIG_GENERIC_PHY on/off cases or so, for readability?

Reading it now, this v3 commit message kind of said the same things. but it
misled both me and Damon, so it's worth a clear explanation.

Thanks!

Luca

--
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com