[PATCH 2/4] mmc: sunxi: Make sample clocks optional

[Ulf Hansson]

On 16 July 2016 at 12:46, Hans de Goede <hdegoede at redhat.com> wrote:
> It turns out that sun4i (A10) and sun5i (A13 & co) do not have sample
> clocks, so make them optional.
>
> Since these do not have sample clocks, they cannot (reliably) do
> DDR rates, so only set MMC_CAP_1_8V_DDR when we do have sample clks.
>
> Note this patch only changes the devm_clk_get error checking and sets
> the clocks to NULL if they don't exists. All the clk_foo calls accept
> a NULL clk and will return success when called with a NULL clk, so this
> is all that is necessary.
>
> Signed-off-by: Hans de Goede <hdegoede at redhat.com>
> ---
>  drivers/mmc/host/sunxi-mmc.c | 18 +++++++++++++-----
>  1 file changed, 13 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/mmc/host/sunxi-mmc.c b/drivers/mmc/host/sunxi-mmc.c
> index 71a480b..4552ee0 100644
> --- a/drivers/mmc/host/sunxi-mmc.c
> +++ b/drivers/mmc/host/sunxi-mmc.c
> @@ -1016,14 +1016,20 @@ static int sunxi_mmc_resource_request(struct sunxi_mmc_host *host,
>
>         host->clk_output = devm_clk_get(&pdev->dev, "output");
>         if (IS_ERR(host->clk_output)) {
> -               dev_err(&pdev->dev, "Could not get output clock\n");
> -               return PTR_ERR(host->clk_output);
> +               if (PTR_ERR(host->clk_output) != -ENOENT) {

This is new to me for how to implement support for optional clocks.

Is this how the clock maintainer think it should be implemented?

> +                       dev_err(&pdev->dev, "Could not get output clock\n");
> +                       return PTR_ERR(host->clk_output);
> +               }
> +               host->clk_output = NULL;
>         }
>
>         host->clk_sample = devm_clk_get(&pdev->dev, "sample");
>         if (IS_ERR(host->clk_sample)) {
> -               dev_err(&pdev->dev, "Could not get sample clock\n");
> -               return PTR_ERR(host->clk_sample);
> +               if (PTR_ERR(host->clk_sample) != -ENOENT) {
> +                       dev_err(&pdev->dev, "Could not get sample clock\n");
> +                       return PTR_ERR(host->clk_sample);
> +               }
> +               host->clk_sample = NULL;
>         }
>
>         host->reset = devm_reset_control_get_optional(&pdev->dev, "ahb");
> @@ -1126,9 +1132,11 @@ static int sunxi_mmc_probe(struct platform_device *pdev)
>         mmc->f_min              =   400000;
>         mmc->f_max              = 52000000;
>         mmc->caps              |= MMC_CAP_MMC_HIGHSPEED | MMC_CAP_SD_HIGHSPEED |
> -                                 MMC_CAP_1_8V_DDR |
>                                   MMC_CAP_ERASE | MMC_CAP_SDIO_IRQ;
>
> +       if (host->clk_output && host->clk_sample)
> +               mmc->caps      |= MMC_CAP_1_8V_DDR;
> +
>         ret = mmc_of_parse(mmc);
>         if (ret)
>                 goto error_free_dma;
> --
> 2.7.4
>

Kind regards
Uffe