Thread (7 messages) 7 messages, 3 authors, 2016-11-17
STALE3496d REVIEWED: 7 (7M)
Revisions (2)
  1. v3 [diff vs current]
  2. v4 current

[PATCH v4 1/2] drm/bridge: dumb-vga-dac: Support a VDD regulator supply

From: Chen-Yu Tsai <hidden>
Date: 2016-11-16 15:42:40
Also in: dri-devel, linux-arm-kernel, lkml
Subsystem: drm drivers, drm drivers and misc gpu patches, drm drivers for bridge chips, open firmware and flattened device tree bindings, the rest · Maintainers: David Airlie, Simona Vetter, Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, Andrzej Hajda, Neil Armstrong, Robert Foss, Rob Herring, Krzysztof Kozlowski, Conor Dooley, Linus Torvalds

Some dumb VGA DACs are active components which require external power.
Add support for specifying a regulator as its power supply.

Signed-off-by: Chen-Yu Tsai <redacted>
Acked-by: Rob Herring <redacted>
---
 .../bindings/display/bridge/dumb-vga-dac.txt       |  2 ++
 drivers/gpu/drm/bridge/dumb-vga-dac.c              | 35 ++++++++++++++++++++++
 2 files changed, 37 insertions(+)
diff --git a/Documentation/devicetree/bindings/display/bridge/dumb-vga-dac.txt b/Documentation/devicetree/bindings/display/bridge/dumb-vga-dac.txt
index 003bc246a270..164cbb15f04c 100644
--- a/Documentation/devicetree/bindings/display/bridge/dumb-vga-dac.txt
+++ b/Documentation/devicetree/bindings/display/bridge/dumb-vga-dac.txt
@@ -16,6 +16,8 @@ graph bindings specified in Documentation/devicetree/bindings/graph.txt.
 - Video port 0 for RGB input
 - Video port 1 for VGA output
 
+Optional properties:
+- vdd-supply: Power supply for DAC
 
 Example
 -------
diff --git a/drivers/gpu/drm/bridge/dumb-vga-dac.c b/drivers/gpu/drm/bridge/dumb-vga-dac.c
index afec232185a7..15b549f94307 100644
--- a/drivers/gpu/drm/bridge/dumb-vga-dac.c
+++ b/drivers/gpu/drm/bridge/dumb-vga-dac.c
@@ -12,6 +12,7 @@
 
 #include <linux/module.h>
 #include <linux/of_graph.h>
+#include <linux/regulator/consumer.h>
 
 #include <drm/drmP.h>
 #include <drm/drm_atomic_helper.h>
@@ -23,6 +24,7 @@ struct dumb_vga {
 	struct drm_connector	connector;
 
 	struct i2c_adapter	*ddc;
+	struct regulator	*vdd;
 };
 
 static inline struct dumb_vga *
@@ -124,8 +126,32 @@ static int dumb_vga_attach(struct drm_bridge *bridge)
 	return 0;
 }
 
+static void dumb_vga_enable(struct drm_bridge *bridge)
+{
+	struct dumb_vga *vga = drm_bridge_to_dumb_vga(bridge);
+	int ret = 0;
+
+	if (vga->vdd)
+		ret = regulator_enable(vga->vdd);
+
+	if (ret) {
+		DRM_ERROR("Failed to enable vdd regulator: %d\n", ret);
+		return;
+	}
+}
+
+static void dumb_vga_disable(struct drm_bridge *bridge)
+{
+	struct dumb_vga *vga = drm_bridge_to_dumb_vga(bridge);
+
+	if (vga->vdd)
+		regulator_disable(vga->vdd);
+}
+
 static const struct drm_bridge_funcs dumb_vga_bridge_funcs = {
 	.attach		= dumb_vga_attach,
+	.enable		= dumb_vga_enable,
+	.disable	= dumb_vga_disable,
 };
 
 static struct i2c_adapter *dumb_vga_retrieve_ddc(struct device *dev)
@@ -169,6 +195,15 @@ static int dumb_vga_probe(struct platform_device *pdev)
 		return -ENOMEM;
 	platform_set_drvdata(pdev, vga);
 
+	vga->vdd = devm_regulator_get_optional(&pdev->dev, "vdd");
+	if (IS_ERR(vga->vdd)) {
+		ret = PTR_ERR(vga->vdd);
+		if (ret == -EPROBE_DEFER)
+			return -EPROBE_DEFER;
+		vga->vdd = NULL;
+		dev_dbg(&pdev->dev, "No vdd regulator found: %d\n", ret);
+	}
+
 	vga->ddc = dumb_vga_retrieve_ddc(&pdev->dev);
 	if (IS_ERR(vga->ddc)) {
 		if (PTR_ERR(vga->ddc) == -ENODEV) {
-- 
2.10.2

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