Re: [PATCH v5 12/20] drm/rockchip: analogix_dp: Add support to get panel from the DP AUX bus

From: Damon Ding <damon.ding@rock-chips.com>
To: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: robh@kernel.org, conor+dt@kernel.org, algea.cao@rock-chips.com,
	rfoss@kernel.org, heiko@sntech.de, devicetree@vger.kernel.org,
	linux-phy@lists.infradead.org, linux-kernel@vger.kernel.org,
	sebastian.reichel@collabora.com, dri-devel@lists.freedesktop.org,
	hjc@rock-chips.com, kever.yang@rock-chips.com,
	linux-rockchip@lists.infradead.org, vkoul@kernel.org,
	andy.yan@rock-chips.com, krzk+dt@kernel.org,
	linux-arm-kernel@lists.infradead.org, l.stach@pengutronix.de
Subject: Re: [PATCH v5 12/20] drm/rockchip: analogix_dp: Add support to get panel from the DP AUX bus
Date: Wed, 22 Jan 2025 16:17:03 +0800	[thread overview]
Message-ID: <330041c4-aaee-4b41-8ccd-e2807415c709@rock-chips.com> (raw)
In-Reply-To: <d7zpv6qt52mhny54dejw4yqlp2k2c437op7qmepqe27pufplqk@64xvohrz7h2q>

Hi Dmitry,

On 2025/1/9 20:48, Dmitry Baryshkov wrote:
> On Thu, Jan 09, 2025 at 11:27:17AM +0800, Damon Ding wrote:
>> Move drm_of_find_panel_or_bridge() a little later and combine it with
>> component_add() into a new function rockchip_dp_link_panel(). The function
>> will serve as done_probing() callback of devm_of_dp_aux_populate_bus(),
>> aiding to support for obtaining the eDP panel via the DP AUX bus.
>>
>> If failed to get the panel from the DP AUX bus, it will then try the other
>> way to get panel information through the platform bus.
>>
>> In addition, use dev_err() instead of drm_err() in rockchip_dp_poweron()
>> , which will be called before rockchip_dp_bind().
>>
>> Signed-off-by: Damon Ding <damon.ding@rock-chips.com>
>>
>> ---
>>
>> Changes in v4:
>> - Use done_probing() to call drm_of_find_panel_or_bridge() and
>>    component_add() when getting panel from the DP AUX bus
>>
>> Changes in v5:
>> - Use the functions exported by the Analogix side to get the pointers of
>>    struct analogix_dp_plat_data and struct drm_dp_aux.
>> - Use dev_err() instead of drm_err() in rockchip_dp_poweron().
>>
>> ---
>>   .../gpu/drm/rockchip/analogix_dp-rockchip.c   | 41 ++++++++++++++-----
>>   1 file changed, 30 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c b/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
>> index 0957d3c5d31d..3ae01b870f49 100644
>> --- a/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
>> +++ b/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
>> @@ -124,13 +124,13 @@ static int rockchip_dp_poweron(struct analogix_dp_plat_data *plat_data)
>>   
>>   	ret = clk_prepare_enable(dp->pclk);
>>   	if (ret < 0) {
>> -		drm_err(dp->drm_dev, "failed to enable pclk %d\n", ret);
>> +		dev_err(dp->dev, "failed to enable pclk %d\n", ret);
> 
> 
> why?
> 

The &rockchip_dp_device.drm_dev will be assigned in rockchip_dp_bind(), 
which is called after probing process. The PM operations have been 
advanced to the probing for the AUX transmission, so the dev_err() may 
be better than drm_err().

>>   		return ret;
>>   	}
>>   
>>   	ret = rockchip_dp_pre_init(dp);
>>   	if (ret < 0) {
>> -		drm_err(dp->drm_dev, "failed to dp pre init %d\n", ret);
>> +		dev_err(dp->dev, "failed to dp pre init %d\n", ret);
>>   		clk_disable_unprepare(dp->pclk);
>>   		return ret;
>>   	}
> 

Best regards
Damon

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