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

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