Merge branch 'linux-4.6' of git://github.com/skeggsb/linux into drm-fixes

Just a single fix to prevent GM20B systems hanging at boot.

* 'linux-4.6' of git://github.com/skeggsb/linux:
  drm/nouveau/tegra: acquire and enable reference clock if needed

3 files changed, 28 insertions, 1 deletions

diff --git a/drivers/gpu/drm/nouveau/include/nvkm/core/tegra.h b/drivers/gpu/drm/nouveau/include/nvkm/core/tegra.h
index 16641cec18a2..b5370cb56e3c 100644
--- a/drivers/gpu/drm/nouveau/include/nvkm/core/tegra.h
+++ b/drivers/gpu/drm/nouveau/include/nvkm/core/tegra.h
@@ -11,6 +11,7 @@ struct nvkm_device_tegra {
 
         struct reset_control *rst;
         struct clk *clk;
+        struct clk *clk_ref;
         struct clk *clk_pwr;
 
         struct regulator *vdd;
@@ -36,6 +37,10 @@ struct nvkm_device_tegra_func {
          * bypassed). A value of 0 means an IOMMU is never used.
          */
         u8 iommu_bit;
+        /*
+         * Whether the chip requires a reference clock
+         */
+        bool require_ref_clk;
 };
 
 int nvkm_device_tegra_new(const struct nvkm_device_tegra_func *,
diff --git a/drivers/gpu/drm/nouveau/nouveau_platform.c b/drivers/gpu/drm/nouveau/nouveau_platform.c
index 2dfe58af12e4..4c4cc2260257 100644
--- a/drivers/gpu/drm/nouveau/nouveau_platform.c
+++ b/drivers/gpu/drm/nouveau/nouveau_platform.c
@@ -55,6 +55,11 @@ static const struct nvkm_device_tegra_func gk20a_platform_data = {
         .iommu_bit = 34,
 };
 
+static const struct nvkm_device_tegra_func gm20b_platform_data = {
+        .iommu_bit = 34,
+        .require_ref_clk = true,
+};
+
 static const struct of_device_id nouveau_platform_match[] = {
         {
                 .compatible = "nvidia,gk20a",
@@ -62,7 +67,7 @@ static const struct of_device_id nouveau_platform_match[] = {
         },
         {
                 .compatible = "nvidia,gm20b",
-                .data = &gk20a_platform_data,
+                .data = &gm20b_platform_data,
         },
         { }
 };
diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/device/tegra.c b/drivers/gpu/drm/nouveau/nvkm/engine/device/tegra.c
index 9afa5f3e3c1c..ec12efb4689a 100644
--- a/drivers/gpu/drm/nouveau/nvkm/engine/device/tegra.c
+++ b/drivers/gpu/drm/nouveau/nvkm/engine/device/tegra.c
@@ -35,6 +35,11 @@ nvkm_device_tegra_power_up(struct nvkm_device_tegra *tdev)
         ret = clk_prepare_enable(tdev->clk);
         if (ret)
                 goto err_clk;
+        if (tdev->clk_ref) {
+                ret = clk_prepare_enable(tdev->clk_ref);
+                if (ret)
+                        goto err_clk_ref;
+        }
         ret = clk_prepare_enable(tdev->clk_pwr);
         if (ret)
                 goto err_clk_pwr;
@@ -57,6 +62,9 @@ nvkm_device_tegra_power_up(struct nvkm_device_tegra *tdev)
 err_clamp:
         clk_disable_unprepare(tdev->clk_pwr);
 err_clk_pwr:
+        if (tdev->clk_ref)
+                clk_disable_unprepare(tdev->clk_ref);
+err_clk_ref:
         clk_disable_unprepare(tdev->clk);
 err_clk:
         regulator_disable(tdev->vdd);
@@ -71,6 +79,8 @@ nvkm_device_tegra_power_down(struct nvkm_device_tegra *tdev)
         udelay(10);
 
         clk_disable_unprepare(tdev->clk_pwr);
+        if (tdev->clk_ref)
+                clk_disable_unprepare(tdev->clk_ref);
         clk_disable_unprepare(tdev->clk);
         udelay(10);
 
@@ -274,6 +284,13 @@ nvkm_device_tegra_new(const struct nvkm_device_tegra_func *func,
                 goto free;
         }
 
+        if (func->require_ref_clk)
+                tdev->clk_ref = devm_clk_get(&pdev->dev, "ref");
+        if (IS_ERR(tdev->clk_ref)) {
+                ret = PTR_ERR(tdev->clk_ref);
+                goto free;
+        }
+
         tdev->clk_pwr = devm_clk_get(&pdev->dev, "pwr");
         if (IS_ERR(tdev->clk_pwr)) {
                 ret = PTR_ERR(tdev->clk_pwr);