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

[Antony Pavlov <antonynpavlov@gmail.com>]

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?

> so you need to provide working inline instead
>> +
>> +static inline void gpio_free_array(const struct gpio *array, size_t num)
>> +{
>> +     /* GPIO can never have been requested */
>> +     WARN_ON(1);
>> +}
>>  #else
>>  int gpio_request(unsigned gpio, const char *label);
>>  void gpio_free(unsigned gpio);
>> +int gpio_request_one(unsigned gpio, unsigned long flags, const char *label);
>> +int gpio_request_array(const struct gpio *array, size_t num);
>> +void gpio_free_array(const struct gpio *array, size_t num);
>>  #endif
>>
>>  struct gpio_chip;
>> --
>> 1.7.10.4
>>
>>
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-- 
Best regards,
  Antony Pavlov

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