linux-kernel - Re: [PATCH] pinctrl: st: stop abusing of_get_named

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Message-ID: <88c9109d-2c97-ac21-91dc-4025dd27b552@foss.st.com>
Date:   Thu, 29 Sep 2022 10:49:29 +0200
From:   Patrice CHOTARD <patrice.chotard@...s.st.com>
To:     Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Linus Walleij <linus.walleij@...aro.org>
CC:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-gpio@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] pinctrl: st: stop abusing of_get_named_gpio()

Hi Dmitry

On 9/28/22 22:20, Dmitry Torokhov wrote:
> Pin descriptions for this chip only look like standard GPIO device tree
> descriptions, while in fact they contain additional data (in excess of
> number of cells specified in description of gpio controllers). They also
> refer to only pins/gpios belonging to the driver and not to arbitrary
> gpio in the system.
> 
> Because we want to stop exporting OF-specific handlers from gpiolib-of,
> let's parse the pin reference ourself instead of trying to call
> of_get_named_gpio().
> 
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@...il.com>
> ---
> 
> Just compiled, not tested on real hardware.
> 
>  drivers/pinctrl/pinctrl-st.c | 34 ++++++++++++++++++++++++++++++----
>  1 file changed, 30 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/pinctrl/pinctrl-st.c b/drivers/pinctrl/pinctrl-st.c
> index 0fea71fd9a00..cf7f9cbe6044 100644
> --- a/drivers/pinctrl/pinctrl-st.c
> +++ b/drivers/pinctrl/pinctrl-st.c
> @@ -12,7 +12,6 @@
>  #include <linux/io.h>
>  #include <linux/of.h>
>  #include <linux/of_irq.h>
> -#include <linux/of_gpio.h> /* of_get_named_gpio() */
>  #include <linux/of_address.h>
>  #include <linux/gpio/driver.h>
>  #include <linux/regmap.h>
> @@ -1162,6 +1161,31 @@ static void st_parse_syscfgs(struct st_pinctrl *info, int bank,
>  	return;
>  }
>  
> +static int st_pctl_dt_calculate_pin(struct st_pinctrl *info,
> +				    phandle bank, unsigned int offset)
> +{
> +	struct device_node *np;
> +	struct gpio_chip *chip;
> +	int retval = -EINVAL;
> +	int i;
> +
> +	np = of_find_node_by_phandle(bank);
> +	if (!np)
> +		return -EINVAL;
> +
> +	for (i = 0; i < info->nbanks; i++) {
> +		chip = &info->banks[i].gpio_chip;
> +		if (chip->of_node == np) {
> +			if (offset < chip->ngpio)
> +				retval = chip->base + offset;
> +			break;
> +		}
> +	}
> +
> +	of_node_put(np);
> +	return retval;
> +}
> +
>  /*
>   * Each pin is represented in of the below forms.
>   * <bank offset mux direction rt_type rt_delay rt_clk>
> @@ -1175,6 +1199,8 @@ static int st_pctl_dt_parse_groups(struct device_node *np,
>  	struct device *dev = info->dev;
>  	struct st_pinconf *conf;
>  	struct device_node *pins;
> +	phandle bank;
> +	unsigned int offset;
>  	int i = 0, npins = 0, nr_props, ret = 0;
>  
>  	pins = of_get_child_by_name(np, "st,pins");
> @@ -1214,9 +1240,9 @@ static int st_pctl_dt_parse_groups(struct device_node *np,
>  		conf = &grp->pin_conf[i];
>  
>  		/* bank & offset */
> -		be32_to_cpup(list++);
> -		be32_to_cpup(list++);
> -		conf->pin = of_get_named_gpio(pins, pp->name, 0);
> +		bank = be32_to_cpup(list++);
> +		offset = be32_to_cpup(list++);
> +		conf->pin = st_pctl_dt_calculate_pin(info, bank, offset);
>  		conf->name = pp->name;
>  		grp->pins[i] = conf->pin;
>  		/* mux */

I tested it on stih410-b2260 board

Tested-by: Patrice Chotard <patrice.chotard@...s.st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@...s.st.com>

Thanks
Patrice