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

[Veerabhadrarao Badiganti <vbadigan@codeaurora.org>]

On 7/13/2020 9:26 PM, Veerabhadrarao Badiganti wrote:
>
> 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@codeaurora.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.
>
Thanks Matthias. I cloud reproduce the issue on device without SDcard.

Without SDcard inserted, cd-gpio (SD card detect GPIO) is getting read 
as active HIGH
(as if card is inserted) during system-resume, resulting SDcard probe/scan.

After that its triggering interrupt again when pinctrl config is applied 
during SDcard
power-up sequence (as part of probe/scan) which is again triggering 
sdcard scan.

I will have to change SDcard cd-gpio sleep config to fix this issue like 
below:

diff --git a/arch/arm64/boot/dts/qcom/sc7180.dtsi 
b/arch/arm64/boot/dts/qcom/sc7180.dtsi
index e2230f47a17d..9266d514e163 100644
--- a/arch/arm64/boot/dts/qcom/sc7180.dtsi
+++ b/arch/arm64/boot/dts/qcom/sc7180.dtsi
@@ -2447,7 +2447,7 @@

                                 pinconf-sd-cd {
                                         pins = "gpio69";
-                                       bias-disable;
+                                       bias-pull-up;
                                         drive-strength = <2>;

I will check more on why its getting read as active HIGH during resume.


>>> 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.

Thanks

Veera