Re: [PATCH V5 4/9] mmc: bcm2835: Introduce proper clock handling

[Ulf Hansson <ulf.hansson@linaro.org>]

On Fri, 25 Oct 2024 at 12:36, Stefan Wahren <wahrenst@gmx.net> wrote:
>
> The custom sdhost controller on BCM2835 is feed by the critical VPU clock.
> In preparation for PM suspend/resume support, add a proper clock handling
> to the driver like in the other clock consumers (e.g. I2C).
>
> Move the clock handling behind mmc_of_parse(), because it could return
> with -EPROBE_DEFER and we want to minimize potential clock operation during
> boot phase.
>
> Signed-off-by: Stefan Wahren <wahrenst@gmx.net>

Applied for next, thanks!

Kind regards
Uffe


> ---
>  drivers/mmc/host/bcm2835.c | 29 ++++++++++++++++++-----------
>  1 file changed, 18 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/mmc/host/bcm2835.c b/drivers/mmc/host/bcm2835.c
> index 3d3eda5a337c..107666b7c1c8 100644
> --- a/drivers/mmc/host/bcm2835.c
> +++ b/drivers/mmc/host/bcm2835.c
> @@ -148,6 +148,7 @@ struct bcm2835_host {
>         void __iomem            *ioaddr;
>         u32                     phys_addr;
>
> +       struct clk              *clk;
>         struct platform_device  *pdev;
>
>         unsigned int            clock;          /* Current clock speed */
> @@ -1345,7 +1346,6 @@ static int bcm2835_add_host(struct bcm2835_host *host)
>  static int bcm2835_probe(struct platform_device *pdev)
>  {
>         struct device *dev = &pdev->dev;
> -       struct clk *clk;
>         struct bcm2835_host *host;
>         struct mmc_host *mmc;
>         const __be32 *regaddr_p;
> @@ -1393,15 +1393,6 @@ static int bcm2835_probe(struct platform_device *pdev)
>                 /* Ignore errors to fall back to PIO mode */
>         }
>
> -
> -       clk = devm_clk_get(dev, NULL);
> -       if (IS_ERR(clk)) {
> -               ret = dev_err_probe(dev, PTR_ERR(clk), "could not get clk\n");
> -               goto err;
> -       }
> -
> -       host->max_clk = clk_get_rate(clk);
> -
>         host->irq = platform_get_irq(pdev, 0);
>         if (host->irq < 0) {
>                 ret = host->irq;
> @@ -1412,16 +1403,30 @@ static int bcm2835_probe(struct platform_device *pdev)
>         if (ret)
>                 goto err;
>
> -       ret = bcm2835_add_host(host);
> +       host->clk = devm_clk_get(dev, NULL);
> +       if (IS_ERR(host->clk)) {
> +               ret = dev_err_probe(dev, PTR_ERR(host->clk), "could not get clk\n");
> +               goto err;
> +       }
> +
> +       ret = clk_prepare_enable(host->clk);
>         if (ret)
>                 goto err;
>
> +       host->max_clk = clk_get_rate(host->clk);
> +
> +       ret = bcm2835_add_host(host);
> +       if (ret)
> +               goto err_clk;
> +
>         platform_set_drvdata(pdev, host);
>
>         dev_dbg(dev, "%s -> OK\n", __func__);
>
>         return 0;
>
> +err_clk:
> +       clk_disable_unprepare(host->clk);
>  err:
>         dev_dbg(dev, "%s -> err %d\n", __func__, ret);
>         if (host->dma_chan_rxtx)
> @@ -1445,6 +1450,8 @@ static void bcm2835_remove(struct platform_device *pdev)
>         cancel_work_sync(&host->dma_work);
>         cancel_delayed_work_sync(&host->timeout_work);
>
> +       clk_disable_unprepare(host->clk);
> +
>         if (host->dma_chan_rxtx)
>                 dma_release_channel(host->dma_chan_rxtx);
>
> --
> 2.34.1
>