Re: [PATCH] gpio: add gpio_add_lookup_tables() to add several tables at once

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Tue, 2017-07-25 at 13:58 -0700, Dmitry Torokhov wrote:
> When converting legacy board to use gpiod API() there migt be several
> lookup tables in board file, let's provide a way to register them all
> at
> once.

Looking into the code which is using several GPIO look up tables I
noticed that the pattern often something like


gpiod_add_lookup_table(x_tbl);
platform_device_register(x_dev);

...

gpiod_add_lookup_table(y_tbl);
platform_device_register(y_dev);

which looks also logical.

So, I have no strong opinion here, though it would be nice to have an
example where it makes sense.

> 
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> ---
>  drivers/gpio/gpiolib.c       | 18 ++++++++++++++++++
>  include/linux/gpio/machine.h |  2 ++
>  2 files changed, 20 insertions(+)
> 
> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> index a42a1eea5714..f8f4f8b61db8 100644
> --- a/drivers/gpio/gpiolib.c
> +++ b/drivers/gpio/gpiolib.c
> @@ -3010,6 +3010,24 @@ void gpiod_add_lookup_table(struct
> gpiod_lookup_table *table)
>  	mutex_unlock(&gpio_lookup_lock);
>  }
>  
> +/**
> + * gpiod_add_lookup_tables() - register GPIO device consumers
> + * @tables: list of table of consumers to register
> + * @n: number of tables in the list
> + */
> +void gpiod_add_lookup_tables(struct gpiod_lookup_table **tables,
> +			     unsigned int n)
> +{
> +	unsigned int i;
> +
> +	mutex_lock(&gpio_lookup_lock);
> +
> +	for (i = 0; i < n; i++)
> +		list_add_tail(&tables[i]->list, &gpio_lookup_list);
> +
> +	mutex_unlock(&gpio_lookup_lock);
> +}
> +
>  /**
>   * gpiod_remove_lookup_table() - unregister GPIO device consumers
>   * @table: table of consumers to unregister
> diff --git a/include/linux/gpio/machine.h
> b/include/linux/gpio/machine.h
> index f738d50cc17d..6f7ddce88fb8 100644
> --- a/include/linux/gpio/machine.h
> +++ b/include/linux/gpio/machine.h
> @@ -58,6 +58,8 @@ struct gpiod_lookup_table {
>  
>  #ifdef CONFIG_GPIOLIB
>  void gpiod_add_lookup_table(struct gpiod_lookup_table *table);
> +void gpiod_add_lookup_tables(struct gpiod_lookup_table **tables,
> +			     unsigned int n);
>  void gpiod_remove_lookup_table(struct gpiod_lookup_table *table);
>  #else
>  static inline
> -- 
> 2.14.0.rc0.400.g1c36432dff-goog
> 
> 

-- 
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy