[U-Boot] [PATCH v2 07/22] clock-uclass: allow disabling a peripheral clock

[Simon Glass]

+Stephen

Hi Benjamin,

On 20 June 2016 at 12:26, Benjamin Tietz <uboot at dresden.micronet24.de> wrote:
> From: Benjamin Tietz <benjamin at micronet24.de>
>
> Currently, clocks can be enabled, only. To be feature-complete - and allow
> a bit of power-saving in applications - disabling a clock should be
> possible, too.
>
> This extend the API of the DM clock driver to allow a clock to be disabled.
>
> The corresponding operation is optional for not breaking existing drivers.

What does this mean? I can't see how it is optional.

Also please can you rebase to mainline and resend, as the API has
changed (sorry).

> ---
>  drivers/clk/clk-uclass.c |   10 ++++++++++
>  include/clk.h            |   18 ++++++++++++++++++
>  2 files changed, 28 insertions(+)
>
> diff --git a/drivers/clk/clk-uclass.c b/drivers/clk/clk-uclass.c
> index b483c1e..462f5f8 100644
> --- a/drivers/clk/clk-uclass.c
> +++ b/drivers/clk/clk-uclass.c
> @@ -44,6 +44,16 @@ int clk_enable(struct udevice *dev, int periph)
>         return ops->enable(dev, periph);
>  }
>
> +int clk_disable(struct udevice *dev, int periph)
> +{
> +       struct clk_ops *ops = clk_get_ops(dev);
> +
> +       if (!ops->disable)
> +               return -ENOSYS;
> +
> +       return ops->disable(dev, periph);
> +}
> +
>  ulong clk_get_periph_rate(struct udevice *dev, int periph)
>  {
>         struct clk_ops *ops = clk_get_ops(dev);
> diff --git a/include/clk.h b/include/clk.h
> index ca20c3d..395f813 100644
> --- a/include/clk.h
> +++ b/include/clk.h
> @@ -43,6 +43,15 @@ struct clk_ops {
>         int (*enable)(struct udevice *dev, int periph);
>
>         /**
> +        * disable() - Disable the clock for a peripheral
> +        *
> +        * @dev:        clock provider
> +        * @periph:     Peripheral ID to enable

disable

> +        * @return zero on success, or -ve error code
> +        */
> +       int (*disable)(struct udevice *dev, int periph);
> +
> +       /**
>          * get_periph_rate() - Get clock rate for a peripheral
>          *
>          * @dev:        Device to check (UCLASS_CLK)
> @@ -90,6 +99,15 @@ ulong clk_set_rate(struct udevice *dev, ulong rate);
>  int clk_enable(struct udevice *dev, int periph);
>
>  /**
> + * clk_disable() - Disable the clock for a peripheral
> + *
> + * @dev:       clock provider
> + * @periph:    Peripheral ID to enable
> + * @return zero on success, or -ve error code
> + */
> +int clk_disable(struct udevice *dev, int periph);
> +
> +/**
>   * clk_get_periph_rate() - Get current clock rate for a peripheral
>   *
>   * @dev:       Device to check (UCLASS_CLK)
>
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