[PATCH v3 01/20] mmc: sdhci: Add helper functions for UHS modes

[Aswath Govindraju]

Hi Jaehoon,

On 26/01/21 3:48 am, Jaehoon Chung wrote:
> On 1/21/21 9:40 PM, Aswath Govindraju wrote:
>> From: Faiz Abbas <faiz_abbas at ti.com>
>>
>> Add a set_voltage() function which handles the switch from 3.3V to 1.8V
>> for SD card UHS modes.
>>
>> Signed-off-by: Faiz Abbas <faiz_abbas at ti.com>
>> Signed-off-by: Aswath Govindraju <a-govindraju at ti.com>
>> ---
>>  drivers/mmc/sdhci.c | 80 +++++++++++++++++++++++++++++++++++++++++++++
>>  include/sdhci.h     |  1 +
>>  2 files changed, 81 insertions(+)
>>
>> diff --git a/drivers/mmc/sdhci.c b/drivers/mmc/sdhci.c
>> index 06289343124e..e7e3e22d1a7e 100644
>> --- a/drivers/mmc/sdhci.c
>> +++ b/drivers/mmc/sdhci.c
>> @@ -20,6 +20,7 @@
>>  #include <linux/delay.h>
>>  #include <linux/dma-mapping.h>
>>  #include <phys2bus.h>
>> +#include <power/regulator.h>
>>  
>>  static void sdhci_reset(struct sdhci_host *host, u8 mask)
>>  {
>> @@ -509,6 +510,85 @@ void sdhci_set_uhs_timing(struct sdhci_host *host)
>>  	sdhci_writew(host, reg, SDHCI_HOST_CONTROL2);
>>  }
>>  
>> +#if CONFIG_IS_ENABLED(MMC_IO_VOLTAGE)
>> +static void sdhci_set_voltage(struct sdhci_host *host)
>> +{
>> +	struct mmc *mmc = (struct mmc *)host->mmc;
>> +	u32 ctrl;
>> +	int ret;
>> +
>> +	ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
>> +
>> +	switch (mmc->signal_voltage) {
>> +	case MMC_SIGNAL_VOLTAGE_330:
>> +#if CONFIG_IS_ENABLED(DM_REGULATOR)
>> +		if (mmc->vqmmc_supply) {
>> +			ret = regulator_set_enable(mmc->vqmmc_supply, false);
>> +			if (ret) {
>> +				pr_err("failed to disable vqmmc-supply: %d\n", ret);
>> +				return;
>> +			}
>> +
>> +			ret = regulator_set_value(mmc->vqmmc_supply, 3300000);
>> +			if (ret) {
>> +				pr_err("failed to set vqmmc-voltage to 3.3V: %d\n", ret);
>> +				return;
>> +			}
>> +
>> +			ret = regulator_set_enable(mmc->vqmmc_supply, true);
>> +			if (ret) {
>> +				pr_err("failed to enable vqmmc-supply: %d\n", ret);
>> +				return;
>> +			}
>> +		}
>> +#endif
>> +		mdelay(5);
> 
> Could you add just comment for mdelay(5)? Maybe it needs to be stable, right?
> 

I have added a comment in the respin(v4). Thank you for the comments and
reviews

Thanks,
Aswath

> 
>> +		if (IS_SD(mmc)) {
>> +			ctrl &= ~SDHCI_CTRL_VDD_180;
>> +			sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
>> +		}
>> +		break;
>> +	case MMC_SIGNAL_VOLTAGE_180:
>> +#if CONFIG_IS_ENABLED(DM_REGULATOR)
>> +		if (mmc->vqmmc_supply) {
>> +			regulator_set_enable(mmc->vqmmc_supply, false);
>> +			if (ret) {
>> +				pr_err("failed to disable vqmmc-supply: %d\n", ret);
>> +				return;
>> +			}
>> +
>> +			regulator_set_value(mmc->vqmmc_supply, 1800000);
>> +			if (ret) {
>> +				pr_err("failed to set vqmmc-voltage to 1.8V: %d\n", ret);
>> +				return;
>> +			}
>> +
>> +			regulator_set_enable(mmc->vqmmc_supply, true);
>> +			if (ret) {
>> +				pr_err("failed to enable vqmmc-supply: %d\n", ret);
>> +				return;
>> +			}
>> +		}
>> +#endif
>> +		if (IS_SD(mmc)) {
>> +			ctrl |= SDHCI_CTRL_VDD_180;
>> +			sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
>> +		}
>> +		break;
>> +	default:
>> +		/* No signal voltage switch required */
>> +		return;
>> +	}
>> +}
>> +#else
>> +static void sdhci_set_voltage(struct sdhci_host *host) { }
>> +#endif
>> +void sdhci_set_control_reg(struct sdhci_host *host)
>> +{
>> +	sdhci_set_voltage(host);
>> +	sdhci_set_uhs_timing(host);
>> +}
>> +
>>  #ifdef CONFIG_DM_MMC
>>  static int sdhci_set_ios(struct udevice *dev)
>>  {
>> diff --git a/include/sdhci.h b/include/sdhci.h
>> index 3e5a64981857..0f820c6d2669 100644
>> --- a/include/sdhci.h
>> +++ b/include/sdhci.h
>> @@ -491,6 +491,7 @@ void sdhci_set_uhs_timing(struct sdhci_host *host);
>>  /* Export the operations to drivers */
>>  int sdhci_probe(struct udevice *dev);
>>  int sdhci_set_clock(struct mmc *mmc, unsigned int clock);
>> +void sdhci_set_control_reg(struct sdhci_host *host);
>>  extern const struct dm_mmc_ops sdhci_ops;
>>  #else
>>  #endif
>>
>