Re: [RESEND PATCH] gpio: pcf857x: restore the initial line state of all pcf lines

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Fri, May 27, 2016 at 8:35 AM, Kishon Vijay Abraham I <kishon@xxxxxx> wrote:

> The reset values for all the PCF lines are high and hence on
> shutdown we should drive all the lines high in order to
> bring it to the reset state.
>
> This is actually required since PCF doesn't have a reset
> line and even after warm reset (by invoking "reboot" in
> prompt) the PCF lines maintains it's previous programmed
> state. This becomes a problem if the boards are designed to
> work with the default initial state.
>
> DRA7XX_evm uses PCF8575 and one of the PCF output lines
> feeds to MMC/SD VDD and this line should be driven high in order
> for the MMC/SD to be detected.  This line is modelled as
> regulator and the hsmmc driver takes care of enabling and
> disabling it. In the case of 'reboot', during shutdown path
> as part of it's cleanup process the hsmmc driver disables
> this regulator. This makes MMC *boot* not functional.
>
> Fix it by driving all the pcf lines high.
>
> Signed-off-by: Kishon Vijay Abraham I <kishon@xxxxxx>
> Signed-off-by: Sekhar Nori <nsekhar@xxxxxx>

Patch applied.

Yours,
Linus Walleij
--
To unsubscribe from this list: send the line "unsubscribe linux-gpio" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Index of Archives]     [Linux SPI]     [Linux Kernel]     [Linux ARM (vger)]     [Linux ARM MSM]     [Linux Omap]     [Linux Arm]     [Linux Tegra]     [Fedora ARM]     [Linux for Samsung SOC]     [eCos]     [Linux Fastboot]     [Gcc Help]     [Git]     [DCCP]     [IETF Announce]     [Security]     [Linux MIPS]     [Yosemite Campsites]

  Powered by Linux