Hi Thomas,
On Thu, Jun 25, 2020 at 2:00 PM Thomas Zimmermann <tzimmermann@xxxxxxx> 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@xxxxxxx>
Thanks for your patch!
> --- a/drivers/gpu/drm/tiny/simplekms.c
> +++ b/drivers/gpu/drm/tiny/simplekms.c
> @@ -210,6 +218,103 @@ static struct simplekms_device *simplekms_device_of_dev(struct drm_device *dev)
> return container_of(dev, struct simplekms_device, dev);
> }
>
> +/*
> + * Hardware
> + */
> +
> +#if defined CONFIG_OF && defined CONFIG_COMMON_CLK
> +/*
> + * Clock handling code.
> + *
> + * Here we handle the clocks property of our "simple-framebuffer" dt node.
> + * This is necessary so that we can make sure that any clocks needed by
> + * the display engine that the bootloader set up for us (and for which it
> + * provided a simplefb dt node), stay up, for the life of the simplefb
> + * driver.
> + *
> + * When the driver unloads, we cleanly disable, and then release the clocks.
> + *
> + * We only complain about errors here, no action is taken as the most likely
> + * error can only happen due to a mismatch between the bootloader which set
> + * up simplefb, and the clock definitions in the device tree. Chances are
> + * that there are no adverse effects, and if there are, a clean teardown of
> + * the fb probe will not help us much either. So just complain and carry on,
> + * and hope that the user actually gets a working fb at the end of things.
> + */
> +
> +static void simplekms_device_release_clocks(void *res)
> +{
> + struct simplekms_device *sdev = simplekms_device_of_dev(res);
> + unsigned int i;
> +
> + for (i = 0; i < sdev->clk_count; ++i) {
> + if (sdev->clks[i]) {
> + clk_disable_unprepare(sdev->clks[i]);
> + clk_put(sdev->clks[i]);
> + }
> + }
> +}
> +
> +static int simplekms_device_init_clocks(struct simplekms_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);
clk_bulk_get_all()?
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
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
_______________________________________________
dri-devel mailing list
dri-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/dri-devel
