Re: [PATCH 2/3] gpio: Add a driver for the Raspberry Pi's firmware GPIO calls.

From: Stephen Warren
Date: Mon Sep 26 2016 - 12:46:53 EST

On 09/23/2016 07:15 AM, Eric Anholt wrote:
Linus Walleij <linus.walleij@xxxxxxxxxx> writes:

On Mon, Sep 19, 2016 at 6:13 PM, Eric Anholt <eric@xxxxxxxxxx> wrote:

This driver will be used for accessing the FXL6408 GPIO exander on the
Pi3. We can't drive it directly from Linux because the firmware is
continuously polling one of the expander's lines to do its
undervoltage detection.

Signed-off-by: Eric Anholt <eric@xxxxxxxxxx>

+ tristate "Raspberry Pi firmware-based GPIO access"
+ help
+ Turns on support for using the Raspberry Pi firmware to
+ control GPIO pins. Used for access to the FXL6408 GPIO
+ expander on the Pi 3.

Maybe it should be named GPIO_RPI_FXL6408 ?

(No strong opinion.)

See DT binding comment -- I think since this driver has no dependency on
being to the 6408 on the pi3, we shouldn't needlessly bind it to the
FXL6408. (the help comment was just context for why you would want the
driver today).

I'd suggest including "FW" or "FIRMWARE" in the Kconfig option too; the Raspberry Pi has multiple GPIO drivers; one accessing the BCM283x HW directly and the other going through the FW. It'd be good if each Kconfig name was pretty explicit re: which one it represented.