linux-kernel - Re: [PATCH V1] mmc: sdhci-msm: Set IO pins in low power state during suspend

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Date:   Fri, 10 Jul 2020 16:28:36 +0530
From:   Veerabhadrarao Badiganti <vbadigan@...eaurora.org>
To:     Matthias Kaehlcke <mka@...omium.org>
Cc:     adrian.hunter@...el.com, ulf.hansson@...aro.org,
        bjorn.andersson@...aro.org, linux-mmc@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        Andy Gross <agross@...nel.org>
Subject: Re: [PATCH V1] mmc: sdhci-msm: Set IO pins in low power state during
 suspend

Hi Mathias,

On 7/10/2020 6:22 AM, Matthias Kaehlcke wrote:
> Hi,
>
> On Wed, Jul 08, 2020 at 06:41:20PM +0530, Veerabhadrarao Badiganti wrote:
>> Configure SDHC IO pins with low power configuration when the driver
>> is in suspend state.
>>
>> Signed-off-by: Veerabhadrarao Badiganti <vbadigan@...eaurora.org>
>> ---
>>   drivers/mmc/host/sdhci-msm.c | 17 +++++++++++++++++
>>   1 file changed, 17 insertions(+)
>>
>> diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
>> index 392d41d57a6e..efd2bae1430c 100644
>> --- a/drivers/mmc/host/sdhci-msm.c
>> +++ b/drivers/mmc/host/sdhci-msm.c
>> @@ -15,6 +15,7 @@
>>   #include <linux/iopoll.h>
>>   #include <linux/regulator/consumer.h>
>>   #include <linux/interconnect.h>
>> +#include <linux/pinctrl/consumer.h>
>>   
>>   #include "sdhci-pltfm.h"
>>   #include "cqhci.h"
>> @@ -1352,6 +1353,19 @@ static void sdhci_msm_set_uhs_signaling(struct sdhci_host *host,
>>   		sdhci_msm_hs400(host, &mmc->ios);
>>   }
>>   
>> +static int sdhci_msm_set_pincfg(struct sdhci_msm_host *msm_host, bool level)
>> +{
>> +	struct platform_device *pdev = msm_host->pdev;
>> +	int ret;
>> +
>> +	if (level)
>> +		ret = pinctrl_pm_select_default_state(&pdev->dev);
>> +	else
>> +		ret = pinctrl_pm_select_sleep_state(&pdev->dev);
>> +
>> +	return ret;
>> +}
>> +
>>   static int sdhci_msm_set_vmmc(struct mmc_host *mmc)
>>   {
>>   	if (IS_ERR(mmc->supply.vmmc))
>> @@ -1596,6 +1610,9 @@ static void sdhci_msm_handle_pwr_irq(struct sdhci_host *host, int irq)
>>   			ret = sdhci_msm_set_vqmmc(msm_host, mmc,
>>   					pwr_state & REQ_BUS_ON);
>>   		if (!ret)
>> +			ret = sdhci_msm_set_pincfg(msm_host,
>> +					pwr_state & REQ_BUS_ON);
>> +		if (!ret)
>>   			irq_ack |= CORE_PWRCTL_BUS_SUCCESS;
>>   		else
>>   			irq_ack |= CORE_PWRCTL_BUS_FAIL;
> I happened to have a debug patch in my tree which logs when regulators
> are enabled/disabled, with this patch I see the SD card regulator
> toggling constantly after returning from the first system suspend.
>
> I added more logs:
>
> [ 1156.085819] DBG: sdhci_msm_set_pincfg: level = 0 (ret: 0)
> [ 1156.248936] DBG: sdhci_msm_set_pincfg: level = 1 (ret: 0)
> [ 1156.301989] DBG: sdhci_msm_set_pincfg: level = 0 (ret: 0)
> [ 1156.462383] DBG: sdhci_msm_set_pincfg: level = 1 (ret: 0)
> [ 1156.525988] DBG: sdhci_msm_set_pincfg: level = 0 (ret: 0)
> [ 1156.670372] DBG: sdhci_msm_set_pincfg: level = 1 (ret: 0)
> [ 1156.717935] DBG: sdhci_msm_set_pincfg: level = 0 (ret: 0)
> [ 1156.878122] DBG: sdhci_msm_set_pincfg: level = 1 (ret: 0)
> [ 1156.928134] DBG: sdhci_msm_set_pincfg: level = 0 (ret: 0)
>
> This is on an SC7180 platform. It doesn't run an upstream kernel though,
> but v5.4 with plenty of upstream patches.
I have verified this on couple of sc7180 targets (on Chrome platform 
with Chrome kernel).
But didn't see any issue. Its working as expected.

Let me know if you are observing this issue constantly on multiple 
boards, I will share you
a debug patch to check it further.

Thanks
Veera