Hi,

We have at least few cases where hardware engineers decided to use one
powerdown/shutdown/reset GPIO line for multiple devices:

1. WSA884x (this and previous patch):
https://lore.kernel.org/all/b7aeda24-d638-45b7-8e30-80d287f498f8@sirena.org.uk/
2. https://lore.kernel.org/all/20231027033104.1348921-1-chris.packham@alliedtelesis.co.nz/
3. https://lore.kernel.org/lkml/20191030120440.3699-1-peter.ujfalusi@ti.com/
4. https://lore.kernel.org/all/20211018234923.1769028-1-sean.anderson@seco.com/
5. https://social.treehouse.systems/@marcan/111268780311634160

I try to solve my case, hopefuly Chris' (2), partially Sean's (4) and maybe
Hectors (5), using Rob's suggestion:

https://lore.kernel.org/all/YXi5CUCEi7YmNxXM@robh.at.kernel.org/

Best regards,
Krzysztof

Cc: Chris Packham <chris.packham@alliedtelesis.co.nz>
Cc: Bartosz Golaszewski <brgl@bgdev.pl>
Cc: Sean Anderson <sean.anderson@seco.com>

Krzysztof Kozlowski (4):
  reset: instantiate reset GPIO controller for shared reset-gpios
  reset: add GPIO-based reset controller
  ASoC: dt-bindings: qcom,wsa8840: Add reset-gpios for shared line
  ASoC: codecs: wsa884x: Allow sharing reset GPIO

 .../bindings/sound/qcom,wsa8840.yaml          |   9 +-
 MAINTAINERS                                   |   5 +
 drivers/reset/Kconfig                         |   9 ++
 drivers/reset/Makefile                        |   1 +
 drivers/reset/core.c                          |  70 ++++++++++--
 drivers/reset/reset-gpio.c                    | 105 ++++++++++++++++++
 include/linux/reset-controller.h              |   2 +
 sound/soc/codecs/wsa884x.c                    |  52 +++++++--
 8 files changed, 231 insertions(+), 22 deletions(-)
 create mode 100644 drivers/reset/reset-gpio.c

-- 
2.34.1

On Fri, Dec 22, 2023 at 04:01:29PM +0100, Krzysztof Kozlowski wrote:

> I try to solve my case, hopefuly Chris' (2), partially Sean's (4) and maybe
> Hectors (5), using Rob's suggestion:

Hector's case wasn't an actual reset, it was a runtime power control, so
I'm not sure it'll fit there but otherwise this looks OK from an ASoC
point of view.

On 22/12/2023 16:01, Krzysztof Kozlowski wrote:
> Hi,
> 
> We have at least few cases where hardware engineers decided to use one
> powerdown/shutdown/reset GPIO line for multiple devices:
> 

Bartosz,
Please kindly provide feedback whether my way of using "struct
gpio_desc" to compare cookies is acceptable.

Best regards,
Krzysztof