[RFC] gpiolib: import gpio_request_array() from linux 3.7

[Sascha Hauer]

On Mon, Feb 04, 2013 at 01:22:39AM +0400, Antony Pavlov wrote:
> On 4 February 2013 01:13, Jean-Christophe PLAGNIOL-VILLARD
> <plagnioj at jcrosoft.com> wrote:
> > On 23:16 Sun 03 Feb     , Antony Pavlov wrote:
> >> Also import related functions gpio_request_one() and
> >> gpio_free_array().
> >>
> >> Signed-off-by: Antony Pavlov <antonynpavlov at gmail.com>
> >> ---
> >>  drivers/gpio/gpio.c |   66 +++++++++++++++++++++++++++++++++++++++++++++++++++
> >>  include/gpio.h      |   43 +++++++++++++++++++++++++++++++++
> >>  2 files changed, 109 insertions(+)
> >>
> >> diff --git a/drivers/gpio/gpio.c b/drivers/gpio/gpio.c
> >> index d37f5a0..631168d 100644
> >> --- a/drivers/gpio/gpio.c
> >> +++ b/drivers/gpio/gpio.c
> >> @@ -65,6 +65,72 @@ void gpio_free(unsigned gpio)
> >>       free(gi->label);
> >>  }
> >>
> >> +/**
> >> + * gpio_request_one - request a single GPIO with initial configuration
> >> + * @gpio:    the GPIO number
> >> + * @flags:   GPIO configuration as specified by GPIOF_*
> >> + * @label:   a literal description string of this GPIO
> >> + */
> >> +int gpio_request_one(unsigned gpio, unsigned long flags, const char *label)
> >> +{
> >> +     int err;
> >> +
> >> +     err = gpio_request(gpio, label);
> >> +     if (err)
> >> +             return err;
> >> +
> >> +     if (flags & GPIOF_DIR_IN)
> >> +             err = gpio_direction_input(gpio);
> >> +     else
> >> +             err = gpio_direction_output(gpio,
> >> +                             (flags & GPIOF_INIT_HIGH) ? 1 : 0);
> >> +
> >> +     if (err)
> >> +             goto free_gpio;
> >> +
> >> +     return 0;
> >> +
> >> +free_gpio:
> >> +     gpio_free(gpio);
> >> +     return err;
> >> +}
> >> +EXPORT_SYMBOL(gpio_request_one);
> >> +
> >> +/**
> >> + * gpio_request_array - request multiple GPIOs in a single call
> >> + * @array:   array of the 'struct gpio'
> >> + * @num:     how many GPIOs in the array
> >> + */
> >> +int gpio_request_array(const struct gpio *array, size_t num)
> >> +{
> >> +     int i, err;
> >> +
> >> +     for (i = 0; i < num; i++, array++) {
> >> +             err = gpio_request_one(array->gpio, array->flags, array->label);
> >> +             if (err)
> >> +                     goto err_free;
> >> +     }
> >> +     return 0;
> >> +
> >> +err_free:
> >> +     while (i--)
> >> +             gpio_free((--array)->gpio);
> >> +     return err;
> >> +}
> >> +EXPORT_SYMBOL(gpio_request_array);
> >> +
> >> +/**
> >> + * gpio_free_array - release multiple GPIOs in a single call
> >> + * @array:   array of the 'struct gpio'
> >> + * @num:     how many GPIOs in the array
> >> + */
> >> +void gpio_free_array(const struct gpio *array, size_t num)
> >> +{
> >> +     while (num--)
> >> +             gpio_free((array++)->gpio);
> >> +}
> >> +EXPORT_SYMBOL(gpio_free_array);
> >> +
> >>  void gpio_set_value(unsigned gpio, int value)
> >>  {
> >>       struct gpio_info *gi = &gpio_desc[gpio];
> >> diff --git a/include/gpio.h b/include/gpio.h
> >> index eedb980..37c151d 100644
> >> --- a/include/gpio.h
> >> +++ b/include/gpio.h
> >> @@ -3,6 +3,29 @@
> >>
> >>  #include <asm/gpio.h>
> >>
> >> +/* make these flag values available regardless of GPIO kconfig options */
> >> +#define GPIOF_DIR_OUT        (0 << 0)
> >> +#define GPIOF_DIR_IN (1 << 0)
> >> +
> >> +#define GPIOF_INIT_LOW       (0 << 1)
> >> +#define GPIOF_INIT_HIGH      (1 << 1)
> >> +
> >> +#define GPIOF_IN             (GPIOF_DIR_IN)
> >> +#define GPIOF_OUT_INIT_LOW   (GPIOF_DIR_OUT | GPIOF_INIT_LOW)
> >> +#define GPIOF_OUT_INIT_HIGH  (GPIOF_DIR_OUT | GPIOF_INIT_HIGH)
> >> +
> >> +/**
> >> + * struct gpio - a structure describing a GPIO with configuration
> >> + * @gpio:    the GPIO number
> >> + * @flags:   GPIO configuration as specified by GPIOF_*
> >> + * @label:   a literal description string of this GPIO
> >> + */
> >> +struct gpio {
> >> +     unsigned        gpio;
> >> +     unsigned long   flags;
> >> +     const char      *label;
> >> +};
> >> +
> >>  #ifndef CONFIG_GPIOLIB
> >>  static inline int gpio_request(unsigned gpio, const char *label)
> >>  {
> >> @@ -12,9 +35,29 @@ static inline int gpio_request(unsigned gpio, const char *label)
> >>  static inline void gpio_free(unsigned gpio)
> >>  {
> >>  }
> >> +
> >> +static inline int gpio_request_one(unsigned gpio,
> >> +                                     unsigned long flags, const char *label)
> >> +{
> >> +     return 0;
> >> +}
> >> +
> >> +static inline int gpio_request_array(const struct gpio *array, size_t num)
> >> +{
> >> +     return 0;
> >> +}
> > you can not do this
> >
> > as if we start to use this in generic driver where gpio_direction_input/output
> > work
> >
> > we will endup with no configuration
> 
> But now in include/gpio.h we have this:
> 
> static inline int gpio_request(unsigned gpio, const char *label)
> {
>     return 0;
> }
> 
> Can you explain the difference?

gpio_request is not implemented without gpiolib, still you have to
configure the direction and value.

Sascha

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