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

[Antony Pavlov <antonynpavlov@gmail.com>]

On 4 February 2013 12:37, Sascha Hauer <s.hauer@pengutronix.de> wrote:
> On Mon, Feb 04, 2013 at 01:22:39AM +0400, Antony Pavlov wrote:
>> On 4 February 2013 01:13, Jean-Christophe PLAGNIOL-VILLARD
>> <plagnioj@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@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.

Can we use this functions only if gpiolib is enabled?
Can we skip the function's definiton in the non-gpio situation?


-- 
Best regards,
  Antony Pavlov

_______________________________________________
barebox mailing list
barebox@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/barebox