[U-Boot] [PATCH v1] mmc: sdhci: SDHCI controllers also need power

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Fri, 2017-04-07 at 19:05 +0900, Jaehoon Chung wrote:
> Hi Andy,
> 
> On 04/06/2017 07:58 PM, Andy Shevchenko wrote:
> > On Thu, Apr 6, 2017 at 1:50 PM, Jaehoon Chung <jh80.chung@samsung.co
> > m> wrote:
> > > On 04/06/2017 06:46 PM, Andy Shevchenko wrote:
> > > > On Thu, 2017-04-06 at 18:24 +0900, Jaehoon Chung wrote:
> > > > > On 04/06/2017 05:51 PM, Andy Shevchenko wrote:
> > > > > > On Thu, Apr 6, 2017 at 6:44 AM, Simon Glass <sjg@chromium.or
> > > > > > g>
> > > > > > wrote:
> > > > > > > On 1 April 2017 at 07:11, Andy Shevchenko
> > > > > > > <andriy.shevchenko@linux.intel.com> wrote:
> > > > > how about mmc_power_init() is called in mmc_probe()?
> > > > 
> > > > Yes, that's what I'm referring to. But the driver is pure SDHCI,
> > > > it
> > > > doesn't call mmc_probe() IIRC.
> > > 
> > > After converting to DM, it might have the dependent to probing
> > > sequence.
> > > I'm not sure that u-boot has the priority for probing. maybe
> > > not...
> > > 
> > > hmm..need to consider this patch..but i will think about more
> > > generic solution..
> > 
> > It would be nice to have a generic solution indeed.
> 
> Just thinking about below..?
> 
> vcc_sd: sdmmc-regulator {
> 	...
> 	regulator-boot-on;
> or
> 	regulator-always-on;
> 	...
> 	
> };
> 
> It should be always enabled..

Sorry, but no. It's not a regulator.

If you would like to know details, the 2 bits in PMU registers basically
represent clock gate and reset signal per IP which PMU controls.

P.S. Hardware might have a common regulator per power island which is
automatically latches the power down if all devices on the island are on
D3hot. But it's not controlled by software.

So, please consider my initial approach.

This patch holds Edison enabling...

-- 
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy