Re: [PATCH v2 08/10] drm/simpledrm: Acquire clocks from DT device node

[Geert Uytterhoeven <geert@linux-m68k.org>]

Hi Thomas,

On Thu, Mar 18, 2021 at 11:29 AM Thomas Zimmermann <tzimmermann@suse.de> wrote:
> Make sure required hardware clocks are enabled while the firmware
> framebuffer is in use.
>
> The basic code has been taken from the simplefb driver and adapted
> to DRM. Clocks are released automatically via devres helpers.
>
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> Tested-by: nerdopolis <bluescreen_avenger@verizon.net>

Thanks for your patch!

> --- a/drivers/gpu/drm/tiny/simpledrm.c
> +++ b/drivers/gpu/drm/tiny/simpledrm.c

> +static int simpledrm_device_init_clocks(struct simpledrm_device *sdev)
> +{
> +       struct drm_device *dev = &sdev->dev;
> +       struct platform_device *pdev = sdev->pdev;
> +       struct device_node *of_node = pdev->dev.of_node;
> +       struct clk *clock;
> +       unsigned int i;
> +       int ret;
> +
> +       if (dev_get_platdata(&pdev->dev) || !of_node)
> +               return 0;
> +
> +       sdev->clk_count = of_clk_get_parent_count(of_node);
> +       if (!sdev->clk_count)
> +               return 0;
> +
> +       sdev->clks = drmm_kzalloc(dev, sdev->clk_count * sizeof(sdev->clks[0]),
> +                                 GFP_KERNEL);
> +       if (!sdev->clks)
> +               return -ENOMEM;
> +
> +       for (i = 0; i < sdev->clk_count; ++i) {
> +               clock = of_clk_get(of_node, i);
> +               if (IS_ERR(clock)) {
> +                       ret = PTR_ERR(clock);
> +                       if (ret == -EPROBE_DEFER)
> +                               goto err;
> +                       drm_err(dev, "clock %u not found: %d\n", i, ret);
> +                       continue;
> +               }
> +               ret = clk_prepare_enable(clock);
> +               if (ret) {
> +                       drm_err(dev, "failed to enable clock %u: %d\n",
> +                               i, ret);
> +                       clk_put(clock);
> +               }
> +               sdev->clks[i] = clock;
> +       }

of_clk_bulk_get_all() + clk_bulk_prepare_enable()?

There's also devm_clk_bulk_get_all(), but not for the OF variant.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
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