[U-Boot] [PATCH v2 03/17] dm: clk: Define clk_get_parent_rate() for clk operations

[Simon Glass]

+Stephen

Hi Lukasz,

On Thu, 31 Jan 2019 at 02:04, Lukasz Majewski <lukma at denx.de> wrote:
>
> This commit adds the clk_get_parent_rate() function, which is responsible
> for getting the rate of parent clock.
> Unfortunately, u-boot's DM support for getting parent is different
> (the parent relationship is in udevice) than the one in common clock
> framework (CCF) in Linux.
>
> To alleviate this problem - the clk_get_parent_rate() function has been
> introduced to clk-uclass.c.
>
> As written in the in-code comment - some clocks do not set clk->id (and
> require it to be set to 0) and hence the standard ckl_{request|get_rate|
> free} API is used.
>
> Signed-off-by: Lukasz Majewski <lukma at denx.de>
> ---
>
> Changes in v2: None
>
>  drivers/clk/clk-uclass.c | 41 +++++++++++++++++++++++++++++++++++++++++
>  include/clk.h            |  9 +++++++++
>  2 files changed, 50 insertions(+)

Can we please call this from test/dm/clk.c?

>
> diff --git a/drivers/clk/clk-uclass.c b/drivers/clk/clk-uclass.c
> index 6d7a514006..f1640dda67 100644
> --- a/drivers/clk/clk-uclass.c
> +++ b/drivers/clk/clk-uclass.c
> @@ -340,6 +340,47 @@ ulong clk_get_rate(struct clk *clk)
>         return ops->get_rate(clk);
>  }
>
> +ulong clk_get_parent_rate(struct clk *clk)
> +{
> +       const struct clk_ops *ops;
> +       struct udevice *pdev;
> +       struct clk pclk;
> +       ulong rate;
> +       int ret;
> +
> +       debug("%s(clk=%p)\n", __func__, clk);
> +
> +       pdev = clk->dev->parent;

dev_get_parent(clk->dev)

> +       if (!pdev)
> +               return -ENODEV;

Not needed, all devices have parents except the root, which is not in UCLASS_CLK

> +
> +       ops = clk_dev_ops(pdev);
> +       if (!ops->get_rate)
> +               return -ENOSYS;
> +
> +       /*
> +        * We do use memset, clk_{request|get_rate|free}
> +        * as there are clocks - like the "fixed" ones, which
> +        * doesn't posses the clk wrapper struct (just added to
> +        * UCLASS_CLK) and explicitly check if clk->id = 0.
> +        *
> +        * In fact the "clock" resources (like ops, description)
> +        * are accessed via udevice structure (pdev - parent's one)
> +        */
> +

drop blank line. Also is that comment wrapped to use the full number of columns?

Also, this seems like a bug that should be fixed?

> +       memset(&pclk, 0, sizeof(pclk));
> +       ret = clk_request(pdev, &pclk);
> +       if (ret) {
> +               printf("%s: pclk: %s request failed!\n", __func__, pdev->name);
> +               return ret;
> +       }
> +
> +       rate = clk_get_rate(&pclk);
> +       clk_free(&pclk);
> +
> +       return rate;
> +}
> +
>  ulong clk_set_rate(struct clk *clk, ulong rate)
>  {
>         const struct clk_ops *ops = clk_dev_ops(clk->dev);
> diff --git a/include/clk.h b/include/clk.h
> index f6fbcc6634..8224295ec3 100644
> --- a/include/clk.h
> +++ b/include/clk.h
> @@ -238,6 +238,15 @@ int clk_free(struct clk *clk);
>  ulong clk_get_rate(struct clk *clk);
>
>  /**
> + * clk_get_parent_rate() - Get parent of current clock rate.
> + *
> + * @clk:       A clock struct that was previously successfully requested by
> + *             clk_request/get_by_*().
> + * @return clock rate in Hz, or -ve error code.
> + */
> +ulong clk_get_parent_rate(struct clk *clk);
> +
> +/**
>   * clk_set_rate() - Set current clock rate.
>   *
>   * @clk:       A clock struct that was previously successfully requested by
> --
> 2.11.0
>

Regards,
Simon