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Message-ID: <ec78bd64-b1f2-48c1-b1ab-b7e2f0b9e24d@linaro.org>
Date: Thu, 6 Jun 2024 15:29:52 +0200
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From: Neil Armstrong <neil.armstrong@linaro.org>
Reply-To: neil.armstrong@linaro.org
Subject: Re: [PATCH v2 2/7] phy: qcom: qmp-combo: store DP phy power state
To: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Vinod Koul <vkoul@kernel.org>, Kishon Vijay Abraham I
 <kishon@kernel.org>, Rob Herring <robh@kernel.org>,
 Krzysztof Kozlowski <krzk+dt@kernel.org>, Conor Dooley
 <conor+dt@kernel.org>, Bjorn Andersson <andersson@kernel.org>,
 Konrad Dybcio <konrad.dybcio@linaro.org>,
 Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
 linux-arm-msm@vger.kernel.org, linux-phy@lists.infradead.org,
 devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20240527-topic-sm8x50-upstream-phy-combo-typec-mux-v2-0-a03e68d7b8fc@linaro.org>
 <20240527-topic-sm8x50-upstream-phy-combo-typec-mux-v2-2-a03e68d7b8fc@linaro.org>
 <du4345tswno5pfeiux5ks5eo37bbydilvdzw3firnsps2ejgn5@avnoqzxbmzj7>
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On 27/05/2024 10:59, Dmitry Baryshkov wrote:
> On Mon, May 27, 2024 at 10:42:34AM +0200, Neil Armstrong wrote:
>> Switching the PHY Mode requires the DisplayPort PHY to be powered off,
>> keep track of the DisplayPort phy power state.
> 
> How is this different from dp_init_count?

dp_init_count tracks the DP PHY init, while dp_powered_on tracks
the DP PHY beeing powered on by the DRM DP driver, those are
not the same state at all.

While testing, I figured that de-initializing the DP PHY while
is was powered-on by the DRM DP, caused the system to freeze and crash.

SO I've added this to track this state and try to de-init the DP phy
if still in use.

Neil

> 
>>
>> Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
>> ---
>>   drivers/phy/qualcomm/phy-qcom-qmp-combo.c | 5 +++++
>>   1 file changed, 5 insertions(+)
>>
>> diff --git a/drivers/phy/qualcomm/phy-qcom-qmp-combo.c b/drivers/phy/qualcomm/phy-qcom-qmp-combo.c
>> index 7f999e8a433d..183cd9cd1884 100644
>> --- a/drivers/phy/qualcomm/phy-qcom-qmp-combo.c
>> +++ b/drivers/phy/qualcomm/phy-qcom-qmp-combo.c
>> @@ -1512,6 +1512,7 @@ struct qmp_combo {
>>   	unsigned int dp_aux_cfg;
>>   	struct phy_configure_opts_dp dp_opts;
>>   	unsigned int dp_init_count;
>> +	bool dp_powered_on;
>>   
>>   	struct clk_fixed_rate pipe_clk_fixed;
>>   	struct clk_hw dp_link_hw;
>> @@ -2685,6 +2686,8 @@ static int qmp_combo_dp_power_on(struct phy *phy)
>>   	/* Configure link rate, swing, etc. */
>>   	cfg->configure_dp_phy(qmp);
>>   
>> +	qmp->dp_powered_on = true;
>> +
>>   	mutex_unlock(&qmp->phy_mutex);
>>   
>>   	return 0;
>> @@ -2699,6 +2702,8 @@ static int qmp_combo_dp_power_off(struct phy *phy)
>>   	/* Assert DP PHY power down */
>>   	writel(DP_PHY_PD_CTL_PSR_PWRDN, qmp->dp_dp_phy + QSERDES_DP_PHY_PD_CTL);
>>   
>> +	qmp->dp_powered_on = false;
>> +
>>   	mutex_unlock(&qmp->phy_mutex);
>>   
>>   	return 0;
>>
>> -- 
>> 2.34.1
>>
>