drm/tegra: hub: Enable all required clocks

The display architecture on Tegra186 and Tegra194 requires that there be
some valid clock on all domains before accessing any display register. A
further requirement is that in addition to the host1x, hub, disp and dsc
clocks, all the head clocks (pclk0-2 on Tegra186 or pclk0-3 on Tegra194)
must also be enabled.

Implement this logic within the display hub driver to ensure the clocks
are always enabled at the right time.

Signed-off-by: Thierry Reding <treding@nvidia.com>

diff --git a/drivers/gpu/drm/tegra/hub.c b/drivers/gpu/drm/tegra/hub.c
index 6112d90429799582098c01a3282fc571aa665517..922a48d5a483fbc217197e09984d9d1c7c7c2ed1 100644 (file)
--- a/drivers/gpu/drm/tegra/hub.c
+++ b/drivers/gpu/drm/tegra/hub.c
@@ -742,7 +742,9 @@ static const struct host1x_client_ops tegra_display_hub_ops = {
 
 static int tegra_display_hub_probe(struct platform_device *pdev)
 {
+       struct device_node *child = NULL;
        struct tegra_display_hub *hub;
+       struct clk *clk;
        unsigned int i;
        int err;
 
@@ -801,6 +803,34 @@ static int tegra_display_hub_probe(struct platform_device *pdev)
                        return err;
        }
 
+       hub->num_heads = of_get_child_count(pdev->dev.of_node);
+
+       hub->clk_heads = devm_kcalloc(&pdev->dev, hub->num_heads, sizeof(clk),
+                                     GFP_KERNEL);
+       if (!hub->clk_heads)
+               return -ENOMEM;
+
+       for (i = 0; i < hub->num_heads; i++) {
+               child = of_get_next_child(pdev->dev.of_node, child);
+               if (!child) {
+                       dev_err(&pdev->dev, "failed to find node for head %u\n",
+                               i);
+                       return -ENODEV;
+               }
+
+               clk = devm_get_clk_from_child(&pdev->dev, child, "dc");
+               if (IS_ERR(clk)) {
+                       dev_err(&pdev->dev, "failed to get clock for head %u\n",
+                               i);
+                       of_node_put(child);
+                       return PTR_ERR(clk);
+               }
+
+               hub->clk_heads[i] = clk;
+       }
+
+       of_node_put(child);
+
        /* XXX: enable clock across reset? */
        err = reset_control_assert(hub->rst);
        if (err < 0)
@@ -840,12 +870,16 @@ static int tegra_display_hub_remove(struct platform_device *pdev)
 static int __maybe_unused tegra_display_hub_suspend(struct device *dev)
 {
        struct tegra_display_hub *hub = dev_get_drvdata(dev);
+       unsigned int i = hub->num_heads;
        int err;
 
        err = reset_control_assert(hub->rst);
        if (err < 0)
                return err;
 
+       while (i--)
+               clk_disable_unprepare(hub->clk_heads[i]);
+
        clk_disable_unprepare(hub->clk_hub);
        clk_disable_unprepare(hub->clk_dsc);
        clk_disable_unprepare(hub->clk_disp);
@@ -856,6 +890,7 @@ static int __maybe_unused tegra_display_hub_suspend(struct device *dev)
 static int __maybe_unused tegra_display_hub_resume(struct device *dev)
 {
        struct tegra_display_hub *hub = dev_get_drvdata(dev);
+       unsigned int i;
        int err;
 
        err = clk_prepare_enable(hub->clk_disp);
@@ -870,13 +905,22 @@ static int __maybe_unused tegra_display_hub_resume(struct device *dev)
        if (err < 0)
                goto disable_dsc;
 
+       for (i = 0; i < hub->num_heads; i++) {
+               err = clk_prepare_enable(hub->clk_heads[i]);
+               if (err < 0)
+                       goto disable_heads;
+       }
+
        err = reset_control_deassert(hub->rst);
        if (err < 0)
-               goto disable_hub;
+               goto disable_heads;
 
        return 0;
 
-disable_hub:
+disable_heads:
+       while (i--)
+               clk_disable_unprepare(hub->clk_heads[i]);
+
        clk_disable_unprepare(hub->clk_hub);
 disable_dsc:
        clk_disable_unprepare(hub->clk_dsc);

diff --git a/drivers/gpu/drm/tegra/hub.h b/drivers/gpu/drm/tegra/hub.h
index 6696a85fc1f204389f2973a6839e4eddca06a1d7..479087c0705a78a65acadc6c1bbe82cbe377d1ca 100644 (file)
--- a/drivers/gpu/drm/tegra/hub.h
+++ b/drivers/gpu/drm/tegra/hub.h
@@ -49,6 +49,9 @@ struct tegra_display_hub {
        struct clk *clk_hub;
        struct reset_control *rst;
 
+       unsigned int num_heads;
+       struct clk **clk_heads;
+
        const struct tegra_display_hub_soc *soc;
        struct tegra_windowgroup *wgrps;
 };