Subject: [PATCH 1/2] pinctrl: qcom: disable GPIO groups with no pins

From: [email-masked] (Stephen Boyd)
Date: Fri, 14 Jul 2017 10:11:48 -0700

On 07/13, Timur Tabi wrote:
> diff --git a/drivers/pinctrl/qcom/pinctrl-msm.c b/drivers/pinctrl/qcom/pinctrl-msm.c
> index 273badd..e915db4 100644
> --- a/drivers/pinctrl/qcom/pinctrl-msm.c
> +++ b/drivers/pinctrl/qcom/pinctrl-msm.c
> @@ -165,7 +165,22 @@ static int msm_pinmux_set_mux(struct pinctrl_dev *pctldev,
>  	return 0;
>  }
>  
> +/*
> + * Request a GPIO. If the number of pins for this GPIO group is zero,
> + * then assume that the GPIO is unavailable.
> + */
> +static int msm_request(struct pinctrl_dev *pctldev, unsigned int offset)

These names are awful. Reminds me of the serial driver that has
functions like msm_reset(). But when in Rome this is how it goes
I suppose.

> +{
> +	struct msm_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctldev);
> +	const struct msm_pingroup *g;
> +
> +	g = &pctrl->soc->groups[offset];
> +
> +	return g->npins ? 0 : -ENODEV;
> +}
> +
>  static const struct pinmux_ops msm_pinmux_ops = {
> +	.request		= msm_request,
>  	.get_functions_count	= msm_get_functions_count,
>  	.get_function_name	= msm_get_function_name,
>  	.get_function_groups	= msm_get_function_groups,
> @@ -430,6 +445,14 @@ static int msm_gpio_get_direction(struct gpio_chip *chip, unsigned int offset)
>  
>  	g = &pctrl->soc->groups[offset];
>  
> +	/*
> +	 * If the GPIO is unavailable, just return error.  This is necessary
> +	 * because the GPIO layer tries to initialize the direction of all
> +	 * the GPIOs, even the ones that are unavailable.
> +	 */
> +	if (!g->npins)
> +		return -ENODEV;
> +

gpiochips also have a request() hook. Can we use that before
initializing direction to make sure the GPIO is accessible?

>  	val = readl(pctrl->regs + g->ctl_reg);
>  
>  	/* 0 = output, 1 = input */
> @@ -503,7 +531,7 @@ static void msm_gpio_dbg_show_one(struct seq_file *s,
>  
>  	seq_printf(s, " %-8s: %-3s %d", g->name, is_out ? "out" : "in", func);
>  	seq_printf(s, " %dmA", msm_regval_to_drive(drive));
> -	seq_printf(s, " %s", pulls[pull]);
> +	seq_printf(s, " %s\n", pulls[pull]);
>  }
>  
>  static void msm_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
> @@ -511,10 +539,8 @@ static void msm_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
>  	unsigned gpio = chip->base;
>  	unsigned i;
>  
> -	for (i = 0; i < chip->ngpio; i++, gpio++) {
> +	for (i = 0; i < chip->ngpio; i++, gpio++)
>  		msm_gpio_dbg_show_one(s, NULL, chip, i, gpio);
> -		seq_puts(s, "\n");
> -	}
>  }

Were these two hunks necessary? Looks like noise.

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