Re: [PATCH v4 09/16] gpio: support ROHM BD71815 GPOs

Hello Linus,

On Thu, 2021-03-25 at 10:35 +0100, Linus Walleij wrote:

On Wed, Mar 24, 2021 at 8:29 AM Matti Vaittinen
[off-list ref] wrote:

quoted

Support GPO(s) found from ROHM BD71815 power management IC. The IC
has two
GPO pins but only one is properly documented in data-sheet. The
driver
exposes by default only the documented GPO. The second GPO is
connected to
E5 pin and is marked as GND in data-sheet. Control for this
undocumented
pin can be enabled using a special DT property.

This driver is derived from work by Peter Yang <
yanglsh@embest-tech.com>
although not so much of original is left.

Signed-off-by: Matti Vaittinen <redacted>
---
Changes since v3:
  - No changes

This looks OK to me:
Acked-by: Linus Walleij <redacted>

It could potentially (like the other Rohm GPIO MFD PMIC drivers)
make some use of the gpio regmap library, but we have some
pending changes for that so look into it after the next merge
window.

I.e. for your TODO: look at the GPIO_REGMAP helper.

I just took a quick peek at gpio_regmap and it looks pretty good to me!

Any particular reason why gpio_regmap is not just part of gpio_chip? I
guess providing the 'gpio_regmap_direction_*()', 'gpio_regmap_get()',
'gpio_regmap_set()' as exported helpers and leaving calling the
(devm_)gpiochip_add_data() to IC driver would have allowed more
flexibility. Drivers could then use the gpio_regamap features which fit
the IC (by providing pointers to helper functions in gpio_chip) - and
handle potential oddball-features by using pointers to some customized
functions in gpio_chip.

Anyways, definitely worth getting familiar with! Thanks for the pointer
:]

Best Regards,
	Matti Vaittinen