Re: [linux-sunxi] Re: [PATCH] mmc: sunxi: fix unusuable eMMC on some H6 boards by disabling DDR
From: Chen-Yu Tsai
Date: Wed Aug 28 2019 - 09:47:00 EST
On Wed, Aug 28, 2019 at 9:43 PM Maxime Ripard <mripard@xxxxxxxxxx> wrote:
> On Wed, Aug 28, 2019 at 09:29:32PM +0800, Chen-Yu Tsai wrote:
> > On Wed, Aug 28, 2019 at 8:52 PM Linus Walleij <linus.walleij@xxxxxxxxxx> wrote:
> > >
> > > On Sun, Aug 25, 2019 at 5:06 PM Alejandro GonzÃlez
> > > <alejandro.gonzalez.correo@xxxxxxxxx> wrote:
> > >
> > > > Jernej Skrabec compared the BSP driver with this
> > > > driver, and found that the BSP driver configures pinctrl to operate at
> > > > 1.8 V when entering DDR mode (although 3.3 V operation is supported), while
> > > > the mainline kernel lacks any mechanism to switch voltages dynamically.
> > AFAIK The Pine H64 does not have the ability to switch I/O voltages. It is
> > fixed to either 1.8V (the default based on the schematics) or 3.3V.
> Should that be handled at the board level then maybe?
Yeah. You'd specify which one using vqmmc-supply in the mmc node and
in the pinctrl node.