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

[Bjorn Andersson <bjorn.andersson@linaro.org>]

On Thu 13 Jul 14:52 PDT 2017, Timur Tabi wrote:

> To support sparse GPIO maps, pinctrl-msm client drivers can specify
> that a given GPIO has a pin count of zero.  These GPIOs will be
> considered "hidden".  Any attempt to claim the GPIO will fail, and they
> will not be listed in debugfs.
> 
> However, when the driver probes, it calls gpiochip_add_data() which
> wants to initialize the direction of all the GPIOs, even the ones that
> are unavailable.  Therefore, msm_gpio_get_direction() checks to make
> sure the pin is available.
> 
> Signed-off-by: Timur Tabi <timur@codeaurora.org>

We would have to drop the "const" on the groups arrays of the other
platform in order to use this, but I don't have a better suggestion at
this time.

Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Regards,
Bjorn

> ---
>  drivers/pinctrl/qcom/pinctrl-msm.c | 34 ++++++++++++++++++++++++++++++----
>  1 file changed, 30 insertions(+), 4 deletions(-)
> 
> 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)
> +{
> +	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;
> +
>  	val = readl(pctrl->regs + g->ctl_reg);
>  
>  	/* 0 = output, 1 = input */
> @@ -494,6 +517,11 @@ static void msm_gpio_dbg_show_one(struct seq_file *s,
>  	};
>  
>  	g = &pctrl->soc->groups[offset];
> +
> +	/* If the GPIO group has no pins, then don't show it. */
> +	if (!g->npins)
> +		return;
> +
>  	ctl_reg = readl(pctrl->regs + g->ctl_reg);
>  
>  	is_out = !!(ctl_reg & BIT(g->oe_bit));
> @@ -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");
> -	}
>  }
>  
>  #else
> -- 
> Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm
> Technologies, Inc.  Qualcomm Technologies, Inc. is a member of the
> Code Aurora Forum, a Linux Foundation Collaborative Project.
>