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

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Message-ID: <2c322fe1-6a86-43c9-11f3-387b917836ed@codeaurora.org>
Date:   Mon, 13 Jul 2020 21:26:08 +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


On 7/11/2020 5:49 AM, Matthias Kaehlcke wrote:
> Hi,
>
> On Fri, Jul 10, 2020 at 04:28:36PM +0530, Veerabhadrarao Badiganti wrote:
>> 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.
> Did you test system suspend too? At least in the Chrome OS kernel tree system
> suspend is not supported yet in the main branch, you'd need a pile of 30+
> extra patches to get it to work. This is expected to change soon though :)
Yes. I have verified with system  suspend-resume scenario.
Sorry forgot to mention this point explicitly in last response.

I believe all the needed patches were present on qcom internal tree.
Suspend-resume is working fine on sc7180 qcom chrome tree.

>> Let me know if you are observing this issue constantly on multiple boards, I
>> will share you
>> a debug patch to check it further.
> I currently have only one board with the SD card slot populated, I might
> get another one next week.
>
> The toggling occurs only when no SD card is inserted.