linux-kernel - Re: [PATCH v3] mmc: sdhci-msm: Correctly set the load for the regulator

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Message-ID: <Z4C8i2daxeH0lOCf@cse-cd02-lnx.ap.qualcomm.com>
Date: Fri, 10 Jan 2025 14:22:03 +0800
From: Yuanjie Yang <quic_yuanjiey@...cinc.com>
To: Adrian Hunter <adrian.hunter@...el.com>
CC: <dmitry.baryshkov@...aro.org>, <ulf.hansson@...aro.org>,
        <linux-arm-msm@...r.kernel.org>, <linux-mmc@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <andersson@...nel.org>,
        <quic_tingweiz@...cinc.com>, <quic_zhgao@...cinc.com>,
        <quic_yuanjiey@...cinc.com>
Subject: Re: [PATCH v3] mmc: sdhci-msm: Correctly set the load for the
 regulator

On Thu, Jan 09, 2025 at 10:00:49AM +0200, Adrian Hunter wrote:
> On 26/12/24 05:18, Yuanjie Yang wrote:
> > Qualcomm regulator supports two power supply modes: HPM and LPM.
> > Currently, the sdhci-msm.c driver does not set the load to adjust
> > the current for eMMC and SD. If the regulator dont't set correct
> > load in LPM state, it will lead to the inability to properly
> > initialize eMMC and SD.
> > 
> > Set the correct regulator current for eMMC and SD to ensure that the
> > device can work normally even when the regulator is in LPM.
> > 
> > Signed-off-by: Yuanjie Yang <quic_yuanjiey@...cinc.com>
> > ---
> > Changes in v3:
> > - Optimize the code logic and separate code for regulator vmmc and vqmmc
> > - Rebase on tag: next-20241217
> > - Link to v2: https://lore.kernel.org/all/20241127095029.3918290-1-quic_yuanjiey@quicinc.com/
> > 
> > Changes in v2:
> > - Add enum msm_reg_type to optimize the code
> > - Delete redundant emmc type judgment
> > - Link to v1: https://lore.kernel.org/linux-arm-msm/20241122075048.2006894-1-quic_yuanjiey@quicinc.com/
> > 
> > ---
> >  drivers/mmc/host/sdhci-msm.c | 64 ++++++++++++++++++++++++++++++++++--
> >  1 file changed, 62 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
> > index e00208535bd1..22811964ba61 100644
> > --- a/drivers/mmc/host/sdhci-msm.c
> > +++ b/drivers/mmc/host/sdhci-msm.c
> > @@ -134,9 +134,18 @@
> >  /* Timeout value to avoid infinite waiting for pwr_irq */
> >  #define MSM_PWR_IRQ_TIMEOUT_MS 5000
> >  
> > +/* Max load for eMMC Vdd supply */
> > +#define MMC_VMMC_MAX_LOAD_UA	570000
> > +
> >  /* Max load for eMMC Vdd-io supply */
> >  #define MMC_VQMMC_MAX_LOAD_UA	325000
> >  
> > +/* Max load for SD Vdd supply */
> > +#define SD_VMMC_MAX_LOAD_UA	800000
> > +
> > +/* Max load for SD Vdd-io supply */
> > +#define SD_VQMMC_MAX_LOAD_UA	22000
> > +
> >  #define msm_host_readl(msm_host, host, offset) \
> >  	msm_host->var_ops->msm_readl_relaxed(host, offset)
> >  
> > @@ -1403,11 +1412,59 @@ static int sdhci_msm_set_pincfg(struct sdhci_msm_host *msm_host, bool level)
> >  	return ret;
> >  }
> >  
> > -static int sdhci_msm_set_vmmc(struct mmc_host *mmc)
> > +static void msm_config_vmmc_regulator(struct mmc_host *mmc, bool hpm)
> > +{
> > +	int load;
> > +
> > +	if (!mmc->card) {
> > +		regulator_set_mode(mmc->supply.vmmc,
> > +				   hpm ? REGULATOR_MODE_NORMAL : REGULATOR_MODE_IDLE);
> 
> Why use regulator_set_mode() in this case but use regulator_set_load()
> otherwise?
> 
> Previous patches used the maximum 'max(MMC_VMMC_MAX_LOAD_UA, SD_VMMC_MAX_LOAD_UA)'
> for the '!mmc->card' bus-on case, so why not:
> 
> static void msm_config_vmmc_regulator(struct mmc_host *mmc, bool hpm)
> {
> 	int load;
> 
> 	if (!hpm)
> 		load = 0;
> 	else if (!mmc->card)
> 		load = max(MMC_VMMC_MAX_LOAD_UA, SD_VMMC_MAX_LOAD_UA);
> 	else if (mmc_card_mmc(mmc->card))
> 		load = MMC_VMMC_MAX_LOAD_UA;
> 	else if (mmc_card_sd(mmc->card))
> 		load =  SD_VMMC_MAX_LOAD_UA;
> 	else
> 		return;
> 
> 	regulator_set_load(mmc->supply.vmmc, load);
> }
Thanks, my purpose for using regulator_set_mode() in this case is just
to simplify the code logic.
And I readlize that using regulator_set_mode() here might cause side
effect.

Thanks for your code suggestion, I will use your suggestion to modify
this part of code in next version.

> > +		return;
> > +	}
> > +
> > +	if (!mmc_card_mmc(mmc->card) &&
> > +	    !mmc_card_sd(mmc->card))
> > +		return;
> > +
> > +	if (mmc_card_mmc(mmc->card))
> > +		load = MMC_VMMC_MAX_LOAD_UA;
> > +	else if (mmc_card_sd(mmc->card))
> > +		load =  SD_VMMC_MAX_LOAD_UA;
> > +	load = hpm ? load : 0;
> > +
> > +	regulator_set_load(mmc->supply.vmmc, load);
> > +
> > +	return;
> 
> 'return' at the end of a function returning 'void' is not needed.
OK, I will delete return in next version.

> > +}
> > +
> > +static void msm_config_vqmmc_regulator(struct mmc_host *mmc, bool hpm)
> > +{
> > +	int load;
> > +
> > +	if (!mmc->card) {
> > +		regulator_set_mode(mmc->supply.vqmmc,
> > +				   hpm ? REGULATOR_MODE_NORMAL : REGULATOR_MODE_IDLE);
> > +		return;
> > +	}
> > +
> > +	if (!mmc_card_sd(mmc->card))
> > +		return;
> > +
> > +	load =  hpm ? SD_VQMMC_MAX_LOAD_UA : 0;
> > +
> > +	regulator_set_load(mmc->supply.vqmmc, load);
> > +
> > +	return;
> 
> 'return' at the end of a function returning 'void' is not needed.
OK , I will delete return in next version.

> > +}
> > +
> > +static int sdhci_msm_set_vmmc(struct sdhci_msm_host *msm_host,
> > +			      struct mmc_host *mmc, bool hpm)
> >  {
> >  	if (IS_ERR(mmc->supply.vmmc))
> >  		return 0;
> >  
> > +	msm_config_vmmc_regulator(mmc, hpm);
> > +
> >  	return mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, mmc->ios.vdd);
> >  }
> >  
> > @@ -1420,6 +1477,8 @@ static int msm_toggle_vqmmc(struct sdhci_msm_host *msm_host,
> >  	if (msm_host->vqmmc_enabled == level)
> >  		return 0;
> >  
> > +	msm_config_vqmmc_regulator(mmc, level);
> > +
> >  	if (level) {
> >  		/* Set the IO voltage regulator to default voltage level */
> >  		if (msm_host->caps_0 & CORE_3_0V_SUPPORT)
> > @@ -1642,7 +1701,8 @@ static void sdhci_msm_handle_pwr_irq(struct sdhci_host *host, int irq)
> >  	}
> >  
> >  	if (pwr_state) {
> > -		ret = sdhci_msm_set_vmmc(mmc);
> > +		ret = sdhci_msm_set_vmmc(msm_host, mmc,
> > +					 pwr_state & REQ_BUS_ON);
> >  		if (!ret)
> >  			ret = sdhci_msm_set_vqmmc(msm_host, mmc,
> >  					pwr_state & REQ_BUS_ON);
> 

Thanks,
Yuanjie