Thread (27 messages) 27 messages, 2 authors, 2016-06-20

Re: [RFC PATCH 04/13] drm/tegra: Add sor-safe clock for DPAUX on Tegra210

From: Thierry Reding <hidden>
Date: 2016-06-17 16:18:19
Also in: dri-devel, linux-gpio, linux-i2c, linux-tegra

On Fri, Jun 17, 2016 at 01:03:38PM +0100, Jon Hunter wrote:
quoted hunk ↗ jump to hunk
For Tegra210 the 'sor-safe' clock needs to be enabled when using DPAUX.
Add support to the DPAUX driver for enabling this clock on Tegra210.

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
---
 drivers/gpu/drm/tegra/dpaux.c | 29 +++++++++++++++++++++++++++--
 1 file changed, 27 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/tegra/dpaux.c b/drivers/gpu/drm/tegra/dpaux.c
index aa3a037fcd3b..d696a7e45935 100644
--- a/drivers/gpu/drm/tegra/dpaux.c
+++ b/drivers/gpu/drm/tegra/dpaux.c
@@ -37,6 +37,7 @@ struct tegra_dpaux {
 
 	struct reset_control *rst;
 	struct clk *clk_parent;
+	struct clk *clk_sor;
Can we call this "clk_safe", please? On one hand that mirrors the name
of the clock in the binding and on the other hand it avoids confusion
with the real SOR clock.
quoted hunk ↗ jump to hunk
 	struct clk *clk;
 
 	struct regulator *vdd;
@@ -340,18 +341,37 @@ static int tegra_dpaux_probe(struct platform_device *pdev)
 		return PTR_ERR(dpaux->rst);
 	}
 
+	if (of_device_is_compatible(pdev->dev.of_node,
+				    "nvidia,tegra210-dpaux")) {
+		dpaux->clk_sor = devm_clk_get(&pdev->dev, "sor-safe");
+		if (IS_ERR(dpaux->clk_sor)) {
+			dev_err(&pdev->dev,
+				"failed to get sor-safe clock: %ld\n",
+				PTR_ERR(dpaux->clk_sor));
+			return PTR_ERR(dpaux->clk_sor);
+		}
+
+		err = clk_prepare_enable(dpaux->clk_sor);
+		if (err < 0) {
+			dev_err(&pdev->dev,
+				"failed to enable sor-safe clock: %d\n", err);
+			return err;
+		}
+	}
Please make this part of a struct tegra_dpaux_soc, so that we don't have
to check the compatible string again here. This could look like:

	struct tegra_dpaux_soc {
		bool needs_safe_clock;
	};

	static const struct tegra_dpaux_soc tegra124_dpaux_soc = {
		.needs_safe_clock = false,
	};

	static const struct tegra_dpaux_soc tegra210_dpaux_soc = {
		.needs_safe_clock = true,
	};

	...

	static const struct of_device_id tegra_dpaux_of_match[] = {
		{ .compatible = "nvidia,tegra210-dpaux", .data = &tegra210_dpaux_soc },
		{ .compatible = "nvidia,tegra124-dpaux", .data = &tegra124_dpaux_soc },
		{ },
	};
quoted hunk ↗ jump to hunk
@@ -434,6 +454,9 @@ disable_parent_clk:
 assert_reset:
 	reset_control_assert(dpaux->rst);
 	clk_disable_unprepare(dpaux->clk);
+disable_sor_clk:
+	if (dpaux->clk_sor)
+		clk_disable_unprepare(dpaux->clk_sor);
You can drop the extra check here, since the common clock framework
ignores NULL or ERR_PTR() pointers.
quoted hunk ↗ jump to hunk
 
 	return err;
 }
@@ -456,6 +479,8 @@ static int tegra_dpaux_remove(struct platform_device *pdev)
 	clk_disable_unprepare(dpaux->clk_parent);
 	reset_control_assert(dpaux->rst);
 	clk_disable_unprepare(dpaux->clk);
+	if (dpaux->clk_sor)
+		clk_disable_unprepare(dpaux->clk_sor);
Same here.

Thierry
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