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Message-ID: <d828948f-2cd4-9bc1-688d-5de6bd7b58bc@intel.com>
Date:   Thu, 5 Jan 2023 23:27:08 +0200
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From:   Adrian Hunter <adrian.hunter@intel.com>
Subject: Re: [PATCH V6 11/24] mmc: sdhci-uhs2: add set_power() to support vdd2
To:     Victor Shih <victorshihgli@gmail.com>, ulf.hansson@linaro.org
Cc:     linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org,
        benchuanggli@gmail.com, HL.Liu@genesyslogic.com.tw,
        Greg.tu@genesyslogic.com.tw, takahiro.akashi@linaro.org,
        dlunev@chromium.org, Victor Shih <victor.shih@genesyslogic.com.tw>,
        Ben Chuang <ben.chuang@genesyslogic.com.tw>
References: <20221213090047.3805-1-victor.shih@genesyslogic.com.tw>
 <20221213090047.3805-12-victor.shih@genesyslogic.com.tw>
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In-Reply-To: <20221213090047.3805-12-victor.shih@genesyslogic.com.tw>
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On 13/12/22 11:00, Victor Shih wrote:
> This is a UHS-II version of sdhci's set_power operation.
> VDD2, as well as VDD, is handled here.
> 
> Signed-off-by: Ben Chuang <ben.chuang@genesyslogic.com.tw>
> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> Signed-off-by: Victor Shih <victor.shih@genesyslogic.com.tw>
> ---
>  drivers/mmc/host/sdhci-uhs2.c | 46 +++++++++++++++++++++++++
>  drivers/mmc/host/sdhci.c      | 63 +++++++++++++++++++----------------
>  drivers/mmc/host/sdhci.h      |  1 +
>  3 files changed, 82 insertions(+), 28 deletions(-)
> 
> diff --git a/drivers/mmc/host/sdhci-uhs2.c b/drivers/mmc/host/sdhci-uhs2.c
> index ae862e1eadab..780491781613 100644
> --- a/drivers/mmc/host/sdhci-uhs2.c
> +++ b/drivers/mmc/host/sdhci-uhs2.c
> @@ -57,6 +57,13 @@ EXPORT_SYMBOL_GPL(sdhci_uhs2_dump_regs);
>   *                                                                           *
>  \*****************************************************************************/
>  
> +static inline int mmc_opt_regulator_set_ocr(struct mmc_host *mmc,
> +					    struct regulator *supply,
> +					    unsigned short vdd_bit)
> +{
> +	return IS_ERR_OR_NULL(supply) ? 0 : mmc_regulator_set_ocr(mmc, supply, vdd_bit);
> +}
> +
>  bool sdhci_uhs2_mode(struct sdhci_host *host)
>  {
>  	return host->mmc->flags & MMC_UHS2_SUPPORT;
> @@ -95,6 +102,45 @@ void sdhci_uhs2_reset(struct sdhci_host *host, u16 mask)
>  }
>  EXPORT_SYMBOL_GPL(sdhci_uhs2_reset);
>  
> +static void sdhci_uhs2_set_power(struct sdhci_host *host, unsigned char mode,
> +			  unsigned short vdd)
> +{
> +	struct mmc_host *mmc = host->mmc;
> +	u8 pwr;
> +
> +	if (mode != MMC_POWER_OFF) {
> +		pwr = sdhci_get_vdd_value(vdd);
> +		if (!pwr)
> +			WARN(1, "%s: Invalid vdd %#x\n",
> +			     mmc_hostname(host->mmc), vdd);
> +		pwr |= SDHCI_VDD2_POWER_180;
> +	}
> +
> +	if (host->pwr == pwr)
> +		return;
> +	host->pwr = pwr;
> +
> +	if (pwr == 0) {
> +		sdhci_writeb(host, 0, SDHCI_POWER_CONTROL);
> +
> +		mmc_opt_regulator_set_ocr(mmc, mmc->supply.vmmc, 0);
> +		mmc_opt_regulator_set_ocr(mmc, mmc->supply.vmmc2, 0);
> +	} else {
> +		mmc_opt_regulator_set_ocr(mmc, mmc->supply.vmmc, vdd);
> +		/* support 1.8v only for now */
> +		mmc_opt_regulator_set_ocr(mmc, mmc->supply.vmmc2, fls(MMC_VDD2_165_195) - 1);
> +
		/* Clear the power reg before setting a new value */
		sdhci_writeb(host, 0, SDHCI_POWER_CONTROL);

> +		/* vdd first */
> +		pwr |= SDHCI_POWER_ON;
> +		sdhci_writeb(host, pwr & 0xf, SDHCI_POWER_CONTROL);
> +		mdelay(5);
> +
> +		pwr |= SDHCI_VDD2_POWER_ON;
> +		sdhci_writeb(host, pwr, SDHCI_POWER_CONTROL);
> +		mdelay(5);
> +	}
> +}
> +
>  /*****************************************************************************\
>   *                                                                           *
>   * Driver init/exit                                                          *
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 9b66b9a32c72..99633a3ef549 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -23,7 +23,7 @@
>  #include <linux/regulator/consumer.h>
>  #include <linux/pm_runtime.h>
>  #include <linux/of.h>
> -
> +#include <linux/bug.h>
>  #include <linux/leds.h>
>  
>  #include <linux/mmc/mmc.h>
> @@ -2061,41 +2061,48 @@ static void sdhci_set_power_reg(struct sdhci_host *host, unsigned char mode,
>  		sdhci_writeb(host, 0, SDHCI_POWER_CONTROL);
>  }
>  
> +unsigned short sdhci_get_vdd_value(unsigned short vdd)
> +{
> +	u8 pwr;

It is simpler without pwr

> +
> +	switch (1 << vdd) {
> +	case MMC_VDD_165_195:
> +	/*
> +	 * Without a regulator, SDHCI does not support 2.0v
> +	 * so we only get here if the driver deliberately
> +	 * added the 2.0v range to ocr_avail. Map it to 1.8v
> +	 * for the purpose of turning on the power.
> +	 */
> +	case MMC_VDD_20_21:
> +		pwr = SDHCI_POWER_180;
> +		break;

		return SDHCI_POWER_180;

> +	case MMC_VDD_29_30:
> +	case MMC_VDD_30_31:
> +		pwr = SDHCI_POWER_300;
> +		break;
		
		return SDHCI_POWER_300;

> +	case MMC_VDD_32_33:
> +	case MMC_VDD_33_34:

Missing:

	/*
	 * 3.4 ~ 3.6V are valid only for those platforms where it's
	 * known that the voltage range is supported by hardware.
	 */
	case MMC_VDD_34_35:
	case MMC_VDD_35_36:


> +		pwr = SDHCI_POWER_330;
> +		break;

		return SDHCI_POWER_330;

> +	default:
> +		pwr = 0;
> +		break;

		return 0;

> +	}
> +
> +	return pwr;

Not needed. Control never reaches it anymore.

> +}
> +EXPORT_SYMBOL_GPL(sdhci_get_vdd_value);
> +
>  void sdhci_set_power_noreg(struct sdhci_host *host, unsigned char mode,
>  			   unsigned short vdd)
>  {
>  	u8 pwr = 0;
>  
>  	if (mode != MMC_POWER_OFF) {
> -		switch (1 << vdd) {
> -		case MMC_VDD_165_195:
> -		/*
> -		 * Without a regulator, SDHCI does not support 2.0v
> -		 * so we only get here if the driver deliberately
> -		 * added the 2.0v range to ocr_avail. Map it to 1.8v
> -		 * for the purpose of turning on the power.
> -		 */
> -		case MMC_VDD_20_21:
> -			pwr = SDHCI_POWER_180;
> -			break;
> -		case MMC_VDD_29_30:
> -		case MMC_VDD_30_31:
> -			pwr = SDHCI_POWER_300;
> -			break;
> -		case MMC_VDD_32_33:
> -		case MMC_VDD_33_34:
> -		/*
> -		 * 3.4 ~ 3.6V are valid only for those platforms where it's
> -		 * known that the voltage range is supported by hardware.
> -		 */
> -		case MMC_VDD_34_35:
> -		case MMC_VDD_35_36:
> -			pwr = SDHCI_POWER_330;
> -			break;
> -		default:
> +		pwr = sdhci_get_vdd_value(vdd);
> +		if (!pwr) {
>  			WARN(1, "%s: Invalid vdd %#x\n",
>  			     mmc_hostname(host->mmc), vdd);
> -			break;
>  		}
>  	}
>  
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index f41c19c76994..df7fa0c0ebf8 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -840,6 +840,7 @@ void sdhci_set_power(struct sdhci_host *host, unsigned char mode,
>  void sdhci_set_power_and_bus_voltage(struct sdhci_host *host,
>  				     unsigned char mode,
>  				     unsigned short vdd);
> +unsigned short sdhci_get_vdd_value(unsigned short vdd);
>  void sdhci_set_power_noreg(struct sdhci_host *host, unsigned char mode,
>  			   unsigned short vdd);
>  int sdhci_get_cd_nogpio(struct mmc_host *mmc);