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

[Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>]

On 10:29 Tue 05 Feb     , Sascha Hauer wrote:
> On Tue, Feb 05, 2013 at 10:10:18AM +0400, Antony Pavlov wrote:
> > 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?
> 
> Sounds fine. We should get rid of the !gpiolib drivers anyway, maybe
> this adds some motivation.

until every driver are swith to gpiolib NACK as if we switch any generic
driver to this as leds, gpio-keys, i2c-gpio etc... we break board support
siliently

Best Regards,
J.
> 
> Sascha
> 
> -- 
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