[PATCH v3 4/9] drm/fsl-dcu: add extra clock for pixel clock

[Stefan Agner]

The Vybrid DCU variant has two independent clock inputs, one
for the registers (IPG bus clock) and one for the pixel clock.
Support this distinction in the DCU DRM driver while staying
backward compatible for old device trees.

Signed-off-by: Stefan Agner <stefan at agner.ch>
---
 Documentation/devicetree/bindings/display/fsl,dcu.txt | 11 +++++++----
 drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c            |  2 +-
 drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c             | 16 +++++++++++++++-
 drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.h             |  1 +
 4 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/Documentation/devicetree/bindings/display/fsl,dcu.txt b/Documentation/devicetree/bindings/display/fsl,dcu.txt
index ebf1be9..2703cf2 100644
--- a/Documentation/devicetree/bindings/display/fsl,dcu.txt
+++ b/Documentation/devicetree/bindings/display/fsl,dcu.txt
@@ -6,8 +6,11 @@ Required properties:
 	* "fsl,vf610-dcu".
 
 - reg:			Address and length of the register set for dcu.
-- clocks:		From common clock binding: handle to dcu clock.
-- clock-names:		From common clock binding: Shall be "dcu".
+- clocks:		Handle to "dcu" and "pix" clock (in the order below)
+			This can be the same clock (e.g. LS1021a)
+			See ../clocks/clock-bindings.txt for details.
+- clock-names:		Should be "dcu" and "pix"
+			See ../clocks/clock-bindings.txt for details.
 - big-endian		Boolean property, LS1021A DCU registers are big-endian.
 - fsl,panel:		The phandle to panel node.
 
@@ -15,8 +18,8 @@ Examples:
 dcu: dcu at 2ce0000 {
 	compatible = "fsl,ls1021a-dcu";
 	reg = <0x0 0x2ce0000 0x0 0x10000>;
-	clocks = <&platform_clk 0>;
-	clock-names = "dcu";
+	clocks = <&platform_clk 0>, <&platform_clk 0>;
+	clock-names = "dcu", "pix";
 	big-endian;
 	fsl,panel = <&panel>;
 };
diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c
index 35876e3..68f72fb 100644
--- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c
+++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c
@@ -79,7 +79,7 @@ static void fsl_dcu_drm_crtc_mode_set_nofb(struct drm_crtc *crtc)
 	unsigned long dcuclk;
 
 	index = drm_crtc_index(crtc);
-	dcuclk = clk_get_rate(fsl_dev->clk);
+	dcuclk = clk_get_rate(fsl_dev->pix_clk);
 	div = dcuclk / mode->clock / 1000;
 
 	/* Configure timings: */
diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
index f2a9c1b..f80c116 100644
--- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
+++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
@@ -331,10 +331,21 @@ static int fsl_dcu_drm_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	fsl_dev->pix_clk = devm_clk_get(dev, "pix");
+	if (IS_ERR(fsl_dev->pix_clk)) {
+		/* legancy binding, use dcu clock as pixel clock */
+		fsl_dev->pix_clk = fsl_dev->clk;
+	}
+	ret = clk_prepare_enable(fsl_dev->pix_clk);
+	if (ret < 0) {
+		dev_err(dev, "failed to enable pix clk\n");
+		goto disable_clk;
+	}
+
 	drm = drm_dev_alloc(driver, dev);
 	if (!drm) {
 		ret = -ENOMEM;
-		goto disable_clk;
+		goto disable_pix_clk;
 	}
 
 	fsl_dev->dev = dev;
@@ -355,6 +366,8 @@ static int fsl_dcu_drm_probe(struct platform_device *pdev)
 
 unref:
 	drm_dev_unref(drm);
+disable_pix_clk:
+	clk_disable_unprepare(fsl_dev->pix_clk);
 disable_clk:
 	clk_disable_unprepare(fsl_dev->clk);
 	return ret;
@@ -365,6 +378,7 @@ static int fsl_dcu_drm_remove(struct platform_device *pdev)
 	struct fsl_dcu_drm_device *fsl_dev = platform_get_drvdata(pdev);
 
 	clk_disable_unprepare(fsl_dev->clk);
+	clk_disable_unprepare(fsl_dev->pix_clk);
 	drm_put_dev(fsl_dev->drm);
 
 	return 0;
diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.h b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.h
index af3a707..f60ec0a 100644
--- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.h
+++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.h
@@ -183,6 +183,7 @@ struct fsl_dcu_drm_device {
 	struct regmap *regmap;
 	int irq;
 	struct clk *clk;
+	struct clk *pix_clk;
 	/*protects hardware register*/
 	spinlock_t irq_lock;
 	struct drm_device *drm;
-- 
2.7.4