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

[Jaehoon Chung <jh80.chung@samsung.com>]

Hi Peng,

On 10/11/2016 03:37 PM, Peng Fan wrote:
> Hi Jaehoon,
> On Mon, Oct 10, 2016 at 01:19:41PM +0900, Jaehoon Chung wrote:
>> 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?
> 
> In the dts for my board, there is no vqmmc-supply. So I did not add this.
> Let me add it in V2 as the following.

Then just remain this as future work. :)
I think there is no use-case in uboot yet..

> 
> "
> ret = device_get_supply_regulator(mmc->dev, "vqmmc-supply",
> 				  &vqmmc_supply);
> if (ret) {
> 	debug("No vqmmc supply\n");
> 	return 0;
> }
> 
> ret = regulator_set_enable(vqmmc_supply, true);
> if (ret) {
> 	puts("Error enabling VQMMC supply\n");
> 	return ret;
> }
> "
> 
> 
>>
>>>
>>> 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@nxp.com>
>>> Cc: Jaehoon Chung <jh80.chung@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?
> 
> Sure. Fix in V2.
> 
>>
>>> +{
>>> +	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?
> 
> In U-Boot, not every board supports regulator now. Some boards may
> supports DM MMC, but DM REGULATOR not supported now. So I did not
> use error code here. Or use puts, but not debug?

Ok. Nothing. When you send patch v2, I will apply on u-boot-mmc, after checking.
Thanks!

Best Reagrds,
Jaehoon Chung

> 
> Any comments?
> 
> Regards,
> Peng.
> 
> 
>