[U-Boot] [PATCH] mmc: introduce mmc_power_init

[Jaehoon Chung]

Hi Peng,

On 10/08/2016 07:07 PM, Peng Fan wrote:
> In device tree, there is vmmc-supply property for SD/MMC.
> Introduce mmc_power_init function to handle vmmc-supply.

As i know, vqmmc-supply should be optional. Do you have a plan to add this?

> 
> mmc_power_init will first invoke board_mmc_power_init to
> avoid break boards which already implement board_mmc_power_init.
> 
> If DM_MMC and DM_REGULATOR is defined, the regulator
> will be enabled to power up the device.
> 
> Signed-off-by: Peng Fan <peng.fan at nxp.com>
> Cc: Jaehoon Chung <jh80.chung at samsung.com>
> ---
> 
> The RFC patset thread: http://lists.denx.de/pipermail/u-boot/2016-April/251019.html
> V1: Use a generic way to handle vmmc supply, but not let vendor driver
>     to handle it.
> 
>  drivers/mmc/mmc.c | 30 +++++++++++++++++++++++++++++-
>  1 file changed, 29 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
> index 0312da9..c361098 100644
> --- a/drivers/mmc/mmc.c
> +++ b/drivers/mmc/mmc.c
> @@ -15,6 +15,7 @@
>  #include <errno.h>
>  #include <mmc.h>
>  #include <part.h>
> +#include <power/regulator.h>
>  #include <malloc.h>
>  #include <memalign.h>
>  #include <linux/list.h>
> @@ -1582,6 +1583,31 @@ __weak void board_mmc_power_init(void)
>  {
>  }
>  
> +int mmc_power_init(struct mmc *mmc)

Can be static?

> +{
> +	board_mmc_power_init();
> +
> +#if defined(CONFIG_DM_MMC) && defined(CONFIG_DM_REGULATOR) && \
> +	!defined(CONFIG_SPL_BUILD)
> +	struct udevice *vmmc_supply;
> +	int ret;
> +
> +	ret = device_get_supply_regulator(mmc->dev, "vmmc-supply",
> +					  &vmmc_supply);
> +	if (ret) {
> +		debug("No vmmc supply\n");
> +		return 0;

"return 0" is Right? Doesn't need to return error?

> +	}
> +
> +	ret = regulator_set_enable(vmmc_supply, true);
> +	if (ret) {
> +		puts("Error enabling VMMC supply\n");
> +		return ret;
> +	}
> +#endif
> +	return 0;
> +}
> +
>  int mmc_start_init(struct mmc *mmc)
>  {
>  	bool no_card;
> @@ -1606,7 +1632,9 @@ int mmc_start_init(struct mmc *mmc)
>  #ifdef CONFIG_FSL_ESDHC_ADAPTER_IDENT
>  	mmc_adapter_card_type_ident();
>  #endif
> -	board_mmc_power_init();
> +	err = mmc_power_init(mmc);
> +	if (err)
> +		return err;
>  
>  #ifdef CONFIG_DM_MMC_OPS
>  	/* The device has already been probed ready for use */
>