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

From: Veerabhadrarao Badiganti
Date: Tue Jul 14 2020 - 10:12:22 EST


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@xxxxxxxxxxxxxx>
---
ÂÂ drivers/mmc/host/sdhci-msm.c | 17 +++++++++++++++++
ÂÂ 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 @@
ÂÂ #include <linux/iopoll.h>
ÂÂ #include <linux/regulator/consumer.h>
ÂÂ #include <linux/interconnect.h>
+#include <linux/pinctrl/consumer.h>
ÂÂ #include "sdhci-pltfm.h"
ÂÂ #include "cqhci.h"
@@ -1352,6 +1353,19 @@ static void sdhci_msm_set_uhs_signaling(struct sdhci_host *host,
ÂÂÂÂÂÂÂÂÂÂ sdhci_msm_hs400(host, &mmc->ios);
ÂÂ }
+static int sdhci_msm_set_pincfg(struct sdhci_msm_host *msm_host, bool level)
+{
+ÂÂÂ struct platform_device *pdev = msm_host->pdev;
+ÂÂÂ int ret;
+
+ÂÂÂ if (level)
+ÂÂÂÂÂÂÂ ret = pinctrl_pm_select_default_state(&pdev->dev);
+ÂÂÂ else
+ÂÂÂÂÂÂÂ ret = pinctrl_pm_select_sleep_state(&pdev->dev);
+
+ÂÂÂ return ret;
+}
+
ÂÂ static int sdhci_msm_set_vmmc(struct mmc_host *mmc)
ÂÂ {
ÂÂÂÂÂÂ if (IS_ERR(mmc->supply.vmmc))
@@ -1596,6 +1610,9 @@ static void sdhci_msm_handle_pwr_irq(struct sdhci_host *host, int irq)
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂ ret = sdhci_msm_set_vqmmc(msm_host, mmc,
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ pwr_state & REQ_BUS_ON);
ÂÂÂÂÂÂÂÂÂÂ if (!ret)
+ÂÂÂÂÂÂÂÂÂÂÂ ret = sdhci_msm_set_pincfg(msm_host,
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ pwr_state & REQ_BUS_ON);
+ÂÂÂÂÂÂÂ if (!ret)
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂ irq_ack |= CORE_PWRCTL_BUS_SUCCESS;
ÂÂÂÂÂÂÂÂÂÂ else
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂ 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 @@

ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ pinconf-sd-cd {
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ pins = "gpio69";
-ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ bias-disable;
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ bias-pull-up;
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ 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