Re: [PATCH v8 6/8] i2c: of-prober: Add GPIO support to simple helpers

[Andy Shevchenko]

On Tue, Oct 08, 2024 at 03:34:25PM +0800, Chen-Yu Tsai wrote:
> Add GPIO support to the simple helpers for the I2C OF component prober.
> Components that the prober intends to probe likely require their
> regulator supplies be enabled, and GPIOs be toggled to enable them or
> bring them out of reset before they will respond to probe attempts.
> Regulator supplies were handled in the previous patch.
> 
> The assumption is that the same class of components to be probed are
> always connected in the same fashion with the same regulator supply
> and GPIO. The names may vary due to binding differences, but the
> physical layout does not change.
> 
> This supports at most one GPIO pin. The user must specify the GPIO name,
> the polarity, and the amount of time to wait after the GPIO is toggled.
> Devices with more than one GPIO pin likely require specific power
> sequencing beyond what generic code can easily support.

...

> +static int i2c_of_probe_simple_get_gpiod(struct device *dev, struct device_node *node,
> +					 struct i2c_of_probe_simple_ctx *ctx)
> +{
> +	struct fwnode_handle *fwnode = of_fwnode_handle(node);
> +	struct gpio_desc *gpiod;
> +	const char *con_id;
> +
> +	/* NULL signals no GPIO needed */
> +	if (!ctx->opts->gpio_name)
> +		return 0;
> +
> +	/* An empty string signals an unnamed GPIO */
> +	if (!ctx->opts->gpio_name[0])
> +		con_id = NULL;
> +	else
> +		con_id = ctx->opts->gpio_name;

Can it use positive conditional?

	if (ctx->opts->gpio_name[0])
		con_id = ctx->opts->gpio_name;
	else
		con_id = NULL;

> +	gpiod = fwnode_gpiod_get_index(fwnode, con_id, 0, GPIOD_ASIS, "i2c-of-prober");
> +	if (IS_ERR(gpiod))
> +		return PTR_ERR(gpiod);
> +
> +	ctx->gpiod = gpiod;
> +
> +	return 0;
> +}

...

> +static void i2c_of_probe_simple_disable_gpio(struct device *dev, struct i2c_of_probe_simple_ctx *ctx)
> +{
> +	if (!ctx->gpiod)
> +		return;

Do you need this check for the future patches?

> +	/* Ignore error if GPIO is not in output direction */
> +	gpiod_set_value(ctx->gpiod, !ctx->opts->gpio_assert_to_enable);
> +}

...

>  struct regulator;
> +struct gpio_desc;

Ordered?

-- 
With Best Regards,
Andy Shevchenko