linux-kernel - [RFC PATCH 0/6] leds: Fix pca955x GPIO pin mappings

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Message-Id: <20210723075858.376378-1-andrew@aj.id.au>
Date:   Fri, 23 Jul 2021 17:28:52 +0930
From:   Andrew Jeffery <andrew@...id.au>
To:     linux-leds@...r.kernel.org, linux-gpio@...r.kernel.org
Cc:     clg@...d.org, robh+dt@...nel.org, joel@....id.au, pavel@....cz,
        linus.walleij@...aro.org, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-aspeed@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: [RFC PATCH 0/6] leds: Fix pca955x GPIO pin mappings

Hello,

This series does a bunch of crimes, so it's an RFC. I'm cross-posting to the
pinctrl/GPIO and LEDs lists because the PCA955x devices impact all of them. What
needs fixing is the leds-pca955x driver's failure to map the GPIO numberspace to
the pin numberspace of the PCA955x devices. The series solves that by
implementing pinctrl and pinmux in the leds-pca955x driver.

Things I'm unsure about:

1. Patch 1: The pinctrl_gpio_as_pin() API feels a bit dirty, not sure what
   others thoughts are on that (Linus?).

2. Patch 2: I've added a new callback to hook the entirety of the pinctrl map
   parsing rather than supplying a subnode-specific callback. This was necessary
   to handle the PCA955x devicetree binding in a backwards compatible way.

3. Patch 4: The PCA955x devices don't actually have any pinmux hardware, but the
   properties of the pinctrl/pinmux subsystems in the kernel map nicely onto the
   problem we have. But it's quite a bit of code...

4. Patch 6: I also lost a bunch of time to overlooking the get_group_pins()
   callback for pinctrl, and it seems odd to me that it isn't required.

Please review!

Andrew

Andrew Jeffery (6):
  pinctrl: Add pinctrl_gpio_as_pin()
  pinctrl: Add hook for device-specific map parsing
  leds: pca955x: Relocate chipdef-related descriptors
  leds: pca955x: Use pinctrl to map GPIOs to pins
  ARM: dts: rainier: Add presence-detect and fault indictor GPIO
    expander
  pinctrl: Check get_group_pins callback on init

 arch/arm/boot/dts/aspeed-bmc-ibm-rainier.dts |  76 +++
 drivers/leds/leds-pca955x.c                  | 554 +++++++++++++++----
 drivers/pinctrl/core.c                       |  28 +-
 include/linux/pinctrl/pinctrl.h              |   4 +
 4 files changed, 566 insertions(+), 96 deletions(-)

-- 
2.30.2