drm/nouveau/tegra: Set clock rate if not set

If the GPU clock has not had a rate set, initialize it to the maximum
clock rate to make sure it does run.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/device/tegra.c b/drivers/gpu/drm/nouveau/nvkm/engine/device/tegra.c
index 747a775..d0d52c1 100644 (file)
--- a/drivers/gpu/drm/nouveau/nvkm/engine/device/tegra.c
+++ b/drivers/gpu/drm/nouveau/nvkm/engine/device/tegra.c
@@ -279,6 +279,7 @@ nvkm_device_tegra_new(const struct nvkm_device_tegra_func *func,
                      struct nvkm_device **pdevice)
 {
        struct nvkm_device_tegra *tdev;
+       unsigned long rate;
        int ret;
 
        if (!(tdev = kzalloc(sizeof(*tdev), GFP_KERNEL)))
@@ -307,6 +308,17 @@ nvkm_device_tegra_new(const struct nvkm_device_tegra_func *func,
                goto free;
        }
 
+       rate = clk_get_rate(tdev->clk);
+       if (rate == 0) {
+               ret = clk_set_rate(tdev->clk, ULONG_MAX);
+               if (ret < 0)
+                       goto free;
+
+               rate = clk_get_rate(tdev->clk);
+
+               dev_dbg(&pdev->dev, "GPU clock set to %lu\n", rate);
+       }
+
        if (func->require_ref_clk)
                tdev->clk_ref = devm_clk_get(&pdev->dev, "ref");
        if (IS_ERR(tdev->clk_ref)) {