Hi Thomas,
On Thu, Jun 25, 2020 at 2:00 PM 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
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