Re: [RFC] mmc: core: add the capability for broken voltage

[Adrian Hunter <adrian.hunter@intel.com>]

On 16/01/12 10:49, Jaehoon Chung wrote:
> This patch is added the MMC_CAP2_BROKEN_VOLTAGE.
> 
> if the voltage didn't satisfy between min_uV and max_uV,

Why is the fixed voltage not in the acceptable range for the card?
Doesn't that risk breaking the card?

> try to change the voltage in core.c.
> When change the voltage, maybe use the regulator_set_voltage().
> 
> In regulator_set_voltage(), check the below condition.
> 
> 	/* sanity check */
> 	if (!rdev->desc->ops->set_voltage &&
> 	    !rdev->desc->ops->set_voltage_sel) {
> 		ret = -EINVAL;
> 		goto out;
> 	}
> 
> If Some-board should use the fixed-regulator, always return -EINVAL.
> Then, eMMC didn't initialize always.
> 
> So if use the fixed-regulator or etc, we need to add the MMC_CAP2_BROKEN_VOLTAGE.
> 
> Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
> ---
>  drivers/mmc/core/core.c  |    4 ++++
>  include/linux/mmc/host.h |    1 +
>  2 files changed, 5 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index bec0bf2..6848789 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -1121,6 +1121,10 @@ int mmc_regulator_set_ocr(struct mmc_host *mmc,
>  		 * might not allow this operation
>  		 */
>  		voltage = regulator_get_voltage(supply);
> +
> +		if (mmc->caps2 & MMC_CAP2_BROKEN_VOLTAGE)
> +			min_uV = max_uV = voltage;
> +
>  		if (voltage < 0)
>  			result = voltage;
>  		else if (voltage < min_uV || voltage > max_uV)
> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
> index dd13e05..5659aee 100644
> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -257,6 +257,7 @@ struct mmc_host {
>  #define MMC_CAP2_HS200_1_2V_SDR	(1 << 6)        /* can support */
>  #define MMC_CAP2_HS200		(MMC_CAP2_HS200_1_8V_SDR | \
>  				 MMC_CAP2_HS200_1_2V_SDR)
> +#define MMC_CAP2_BROKEN_VOLTAGE	(1 << 7)	/* Use the broken voltage */
>  
>  	mmc_pm_flag_t		pm_caps;	/* supported pm features */
>  	unsigned int        power_notify_type;
> --
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