Commit 0cffbde2 authored by Thierry Reding's avatar Thierry Reding
Browse files

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: default avatarThierry Reding <treding@nvidia.com>
parent d6b9bc02

drivers/gpu/drm/tegra/hub.c

+46 −2
Original line number Diff line number Diff line
@@ -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);

drivers/gpu/drm/tegra/hub.h

+3 −0
Original line number Diff line number Diff line
@@ -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;

};

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