linux-kernel - Re: [PATCH 02/22] gpio: Add ChromeOS EC GPIO driver

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Date: Tue, 13 Feb 2024 18:57:22 +0100
From: Linus Walleij <linus.walleij@...aro.org>
To: Stephen Boyd <swboyd@...omium.org>
Cc: chrome-platform@...ts.linux.dev, linux-kernel@...r.kernel.org, 
	patches@...ts.linux.dev, linux-arm-kernel@...ts.infradead.org, 
	devicetree@...r.kernel.org, linux-arm-msm@...r.kernel.org, 
	Douglas Anderson <dianders@...omium.org>, Pin-yen Lin <treapking@...omium.org>, 
	Bartosz Golaszewski <brgl@...ev.pl>, Benson Leung <bleung@...omium.org>, Guenter Roeck <groeck@...omium.org>, 
	linux-gpio@...r.kernel.org
Subject: Re: [PATCH 02/22] gpio: Add ChromeOS EC GPIO driver

Hi Stephen,

thanks for your patch!

Overall it looks good I have a few nitpicks

On Sat, Feb 10, 2024 at 8:09 AM Stephen Boyd <swboyd@...omium.org> wrote:

> The ChromeOS embedded controller (EC) supports setting the state of
> GPIOs when the system is unlocked, and getting the state of GPIOs in all
> cases. The GPIOs are on the EC itself, so the EC acts similar to a GPIO
> expander. Add a driver to get and set the GPIOs on the EC through the
> host command interface.
>
> Cc: Linus Walleij <linus.walleij@...aro.org>
> Cc: Bartosz Golaszewski <brgl@...ev.pl>
> Cc: Benson Leung <bleung@...omium.org>
> Cc: Guenter Roeck <groeck@...omium.org>
> Cc: <linux-gpio@...r.kernel.org>
> Cc: <chrome-platform@...ts.linux.dev>
> Cc: Pin-yen Lin <treapking@...omium.org>
> Signed-off-by: Stephen Boyd <swboyd@...omium.org>
(...)

> +config GPIO_CROS_EC
> +       tristate "ChromeOS EC GPIO support"
> +       depends on CROS_EC
> +       help
> +         GPIO driver for exposing GPIOs on the ChromeOS Embedded
> +         Controller.
> +
> +         This driver can also be built as a module. If so, the module
> +         will be called gpio-cros-ec.

Classified as "MFD Expander" but I honestly don't know anything better.

> +#include <linux/bitops.h>
> +#include <linux/errno.h>
> +#include <linux/gpio/driver.h>
> +#include <linux/init.h>

Do you need init.h?
I guess maybe... I thought module would be enough for this.

> +static int cros_ec_gpio_request(struct gpio_chip *chip, unsigned gpio_pin)
> +{
> +       if (gpio_pin < chip->ngpio)
> +               return 0;
> +
> +       return -EINVAL;
> +}

If this check is needed, it should be in gpiolib I think?

> +#ifdef CONFIG_OF

This ifdef should not be needed these days.

> +static const struct of_device_id cros_ec_gpio_of_match[] = {
> +       { .compatible = "google,cros-ec-gpio" },
> +       {}
> +};
> +MODULE_DEVICE_TABLE(of, cros_ec_gpio_of_match);
> +#endif
> +
> +static struct platform_driver cros_ec_gpio_driver = {
> +       .probe = cros_ec_gpio_probe,
> +       .driver = {
> +               .name = "cros-ec-gpio",
> +               .of_match_table = of_match_ptr(cros_ec_gpio_of_match),

Nor the of_match_ptr() business.

With these fixed/addressed:
Reviewed-by: Linus Walleij <linus.walleij@...aro.org>

Yours,
Linus Walleij