Re: [PATCH] gpiolib: fix gpio-hog functionality

[Marco Felsch <m.felsch@pengutronix.de>]

On 23-06-01, Sascha Hauer wrote:
> On Thu, Jun 01, 2023 at 04:25:06PM +0200, Marco Felsch wrote:
> > This reverts commit 3641d381e63321016e3bf09504852a6b2a2f879b.
> > 
> > Since the of_xlate support the gpio-hog support is broken because the
> > 'gpio' property used to specify the gpio-hog pin does not contain any
> > phandle. Due to the fact that of_xlate was never implemented the easiest
> > way to fix the gpio-hog functionality is to revert the commit.
> 
> 3641d381e63321016e3bf09504852a6b2a2f879b was introduced for sunxi. As
> Jules is currently working on sunxi support this is likely needed soon,
> so what's the second easiest way?

There is no sunxi driver within the kernel which make use of of_xlate.

Regards,
  Marco

> 
> Sascha
> 
> > 
> > Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
> > ---
> >  drivers/gpio/gpiolib.c | 58 ++++++++++++++++++++----------------------
> >  drivers/of/of_gpio.c   |  5 ++--
> >  include/gpio.h         |  4 +--
> >  3 files changed, 30 insertions(+), 37 deletions(-)
> > 
> > diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> > index 6ec63b1119..b4a3a4e550 100644
> > --- a/drivers/gpio/gpiolib.c
> > +++ b/drivers/gpio/gpiolib.c
> > @@ -444,27 +444,44 @@ static int of_hog_gpio(struct device_node *np, struct gpio_chip *chip,
> >  		       unsigned int idx)
> >  {
> >  	struct device_node *chip_np = chip->dev->of_node;
> > -	struct of_phandle_args gpiospec;
> >  	unsigned long flags = 0;
> > -	u32 gpio_flags;
> > +	u32 gpio_cells, gpio_num, gpio_flags;
> >  	int ret, gpio;
> >  	const char *name = NULL;
> >  
> > -	ret = of_parse_phandle_with_args(chip_np, "gpios", "#gpio-cells", idx,
> > -					&gpiospec);
> > +	ret = of_property_read_u32(chip_np, "#gpio-cells", &gpio_cells);
> >  	if (ret)
> >  		return ret;
> >  
> > -	gpio = gpio_of_xlate(chip->dev, &gpiospec, &gpio_flags);
> > +	/*
> > +	 * Support for GPIOs that don't have #gpio-cells set to 2 is
> > +	 * not implemented
> > +	 */
> > +	if (WARN_ON(gpio_cells != 2))
> > +		return -ENOTSUPP;
> > +
> > +	ret = of_property_read_u32_index(np, "gpios", idx * gpio_cells,
> > +					 &gpio_num);
> > +	if (ret)
> > +		return ret;
> > +
> > +	ret = of_property_read_u32_index(np, "gpios", idx * gpio_cells + 1,
> > +					 &gpio_flags);
> > +	if (ret)
> > +		return ret;
> > +
> > +	if (gpio_flags & OF_GPIO_ACTIVE_LOW)
> > +		flags |= GPIOF_ACTIVE_LOW;
> > +
> > +	gpio = gpio_get_num(chip->dev, gpio_num);
> >  	if (gpio == -EPROBE_DEFER)
> >  		return gpio;
> > +
> >  	if (gpio < 0) {
> > -		dev_err(chip->dev, "unable to get gpio: %d\n", gpio);
> > +		dev_err(chip->dev, "unable to get gpio %u\n", gpio_num);
> >  		return gpio;
> >  	}
> >  
> > -	if (gpio_flags & OF_GPIO_ACTIVE_LOW)
> > -		flags |= GPIOF_ACTIVE_LOW;
> >  
> >  	/*
> >  	 * Note that, in order to be compatible with Linux, the code
> > @@ -625,23 +642,6 @@ void gpiochip_remove(struct gpio_chip *chip)
> >  	list_del(&chip->list);
> >  }
> >  
> > -static int of_gpio_simple_xlate(struct gpio_chip *chip,
> > -				const struct of_phandle_args *gpiospec,
> > -				u32 *flags)
> > -{
> > -	/*
> > -	 * Support for GPIOs that don't have #gpio-cells set to 2 is
> > -	 * not implemented
> > -	 */
> > -	if (WARN_ON(gpiospec->args_count != 2))
> > -		return -ENOTSUPP;
> > -
> > -	if (flags)
> > -		*flags = gpiospec->args[1];
> > -
> > -	return chip->base + gpiospec->args[0];
> > -}
> > -
> >  struct gpio_chip *gpio_get_chip_by_dev(struct device *dev)
> >  {
> >  	struct gpio_chip *chip;
> > @@ -654,8 +654,7 @@ struct gpio_chip *gpio_get_chip_by_dev(struct device *dev)
> >  	return NULL;
> >  }
> >  
> > -int gpio_of_xlate(struct device *dev, struct of_phandle_args *gpiospec,
> > -		  int *flags)
> > +int gpio_get_num(struct device *dev, int gpio)
> >  {
> >  	struct gpio_chip *chip;
> >  
> > @@ -666,10 +665,7 @@ int gpio_of_xlate(struct device *dev, struct of_phandle_args *gpiospec,
> >  	if (!chip)
> >  		return -EPROBE_DEFER;
> >  
> > -	if (chip->ops->of_xlate)
> > -		return chip->ops->of_xlate(chip, gpiospec, flags);
> > -	else
> > -		return of_gpio_simple_xlate(chip, gpiospec, flags);
> > +	return chip->base + gpio;
> >  }
> >  
> >  struct gpio_chip *gpio_get_chip(int gpio)
> > diff --git a/drivers/of/of_gpio.c b/drivers/of/of_gpio.c
> > index b662563742..5da80e2493 100644
> > --- a/drivers/of/of_gpio.c
> > +++ b/drivers/of/of_gpio.c
> > @@ -62,7 +62,6 @@ int of_get_named_gpio_flags(struct device_node *np, const char *propname,
> >  {
> >  	struct of_phandle_args out_args;
> >  	struct device *dev;
> > -	int of_flags;
> >  	int ret;
> >  
> >  	ret = of_parse_phandle_with_args(np, propname, "#gpio-cells",
> > @@ -80,7 +79,7 @@ int of_get_named_gpio_flags(struct device_node *np, const char *propname,
> >  		return -EPROBE_DEFER;
> >  	}
> >  
> > -	ret = gpio_of_xlate(dev, &out_args, &of_flags);
> > +	ret = gpio_get_num(dev, out_args.args[0]);
> >  	if (ret == -EPROBE_DEFER)
> >  		return ret;
> >  	if (ret < 0) {
> > @@ -90,7 +89,7 @@ int of_get_named_gpio_flags(struct device_node *np, const char *propname,
> >  	}
> >  
> >  	if (flags) {
> > -		*flags = of_flags;
> > +		*flags = out_args.args[1];
> >  		of_gpio_flags_quirks(np, propname, flags, index);
> >  	}
> >  
> > diff --git a/include/gpio.h b/include/gpio.h
> > index 10ac7fd7c4..5f2c16584c 100644
> > --- a/include/gpio.h
> > +++ b/include/gpio.h
> > @@ -177,7 +177,6 @@ struct gpio_ops {
> >  	int (*get_direction)(struct gpio_chip *chip, unsigned offset);
> >  	int (*get)(struct gpio_chip *chip, unsigned offset);
> >  	void (*set)(struct gpio_chip *chip, unsigned offset, int value);
> > -	int (*of_xlate)(struct gpio_chip *chip, const struct of_phandle_args *gpiospec, u32 *flags);
> >  };
> >  
> >  struct gpio_chip {
> > @@ -194,8 +193,7 @@ struct gpio_chip {
> >  int gpiochip_add(struct gpio_chip *chip);
> >  void gpiochip_remove(struct gpio_chip *chip);
> >  
> > -int gpio_of_xlate(struct device *dev, struct of_phandle_args *gpiospec,
> > -		  int *flags);
> > +int gpio_get_num(struct device *dev, int gpio);
> >  struct gpio_chip *gpio_get_chip(int gpio);
> >  
> >  #endif /* __GPIO_H */
> > -- 
> > 2.39.2
> > 
> > 
> > 
> 
> -- 
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