Re: [PATCH v2] mmc: core: add mmc-card hardware reset enable support

From: Linus Walleij
Date: Tue Apr 11 2017 - 04:19:27 EST


On Tue, Apr 11, 2017 at 9:31 AM, Richard Leitner
<richard.leitner@xxxxxxxxxxx> wrote:

> Some eMMCs disable their hardware reset line (RST_N) by default. To enable
> it the host must set the corresponding bit in ECSD. An example for such
> a device is the Micron MTFCxGACAANA-4M.
>
> This patch adds a new mmc-card devicetree property to let the host enable
> this feature during card initialization.
>
> Signed-off-by: Richard Leitner <richard.leitner@xxxxxxxxxxx>

Do we know *WHY* these cards disable their hardware reset lines?

If it is just some random over-cautious panic thing we might consider
just force re-enableing it, maybe with a warning in the dmesg, so we can
always reset the card. No DT property needed.

Putting some people who work for eMMC vendors in the To: line so they
can say if they know about this.

Yours,
Linus Walleij