[PATCH v4 7/9] drm: sun4i: Add support for enabling DDC I2C bus power to dw_hdmi glue

[megous@xxxxxxxxxx]

From: Ondrej Jirman <megous@xxxxxxxxxx>

Orange Pi 3 board requires enabling DDC I2C bus via some GPIO connected
transistors, before the bus can be used.

Model this as a power supply for DDC bus on the HDMI connector connected
to the output port (port 1) of the HDMI controller.

Signed-off-by: Ondrej Jirman <megous@xxxxxxxxxx>
---
 drivers/gpu/drm/sun4i/sun8i_dw_hdmi.c | 61 ++++++++++++++++++++++++++-
 drivers/gpu/drm/sun4i/sun8i_dw_hdmi.h |  2 +
 2 files changed, 61 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/sun4i/sun8i_dw_hdmi.c b/drivers/gpu/drm/sun4i/sun8i_dw_hdmi.c
index 39d8509d96a0..acf89780260d 100644
--- a/drivers/gpu/drm/sun4i/sun8i_dw_hdmi.c
+++ b/drivers/gpu/drm/sun4i/sun8i_dw_hdmi.c
@@ -98,6 +98,30 @@ static u32 sun8i_dw_hdmi_find_possible_crtcs(struct drm_device *drm,
 	return crtcs;
 }
 
+static int sun8i_dw_hdmi_find_connector_pdev(struct device *dev,
+					     struct platform_device **pdev_out)
+{
+	struct platform_device *pdev;
+	struct device_node *remote;
+
+	remote = of_graph_get_remote_node(dev->of_node, 1, -1);
+	if (!remote)
+		return -ENODEV;
+
+	if (!of_device_is_compatible(remote, "hdmi-connector")) {
+		of_node_put(remote);
+		return -ENODEV;
+	}
+
+	pdev = of_find_device_by_node(remote);
+	of_node_put(remote);
+	if (!pdev)
+		return -ENODEV;
+
+	*pdev_out = pdev;
+	return 0;
+}
+
 static int sun8i_dw_hdmi_bind(struct device *dev, struct device *master,
 			      void *data)
 {
@@ -151,16 +175,35 @@ static int sun8i_dw_hdmi_bind(struct device *dev, struct device *master,
 		return PTR_ERR(hdmi->regulator);
 	}
 
+	ret = sun8i_dw_hdmi_find_connector_pdev(dev, &hdmi->connector_pdev);
+	if (!ret) {
+		hdmi->ddc_regulator = regulator_get(&hdmi->connector_pdev->dev,
+						    "ddc");
+		if (IS_ERR(hdmi->ddc_regulator)) {
+			platform_device_put(hdmi->connector_pdev);
+			dev_err(dev, "Couldn't get ddc regulator\n");
+			return PTR_ERR(hdmi->ddc_regulator);
+		}
+	}
+
 	ret = regulator_enable(hdmi->regulator);
 	if (ret) {
 		dev_err(dev, "Failed to enable regulator\n");
-		return ret;
+		goto err_unref_ddc_regulator;
+	}
+
+	if (hdmi->ddc_regulator) {
+		ret = regulator_enable(hdmi->ddc_regulator);
+		if (ret) {
+			dev_err(dev, "Failed to enable ddc regulator\n");
+			goto err_disable_regulator;
+		}
 	}
 
 	ret = reset_control_deassert(hdmi->rst_ctrl);
 	if (ret) {
 		dev_err(dev, "Could not deassert ctrl reset control\n");
-		goto err_disable_regulator;
+		goto err_disable_ddc_regulator;
 	}
 
 	ret = clk_prepare_enable(hdmi->clk_tmds);
@@ -213,8 +256,15 @@ static int sun8i_dw_hdmi_bind(struct device *dev, struct device *master,
 	clk_disable_unprepare(hdmi->clk_tmds);
 err_assert_ctrl_reset:
 	reset_control_assert(hdmi->rst_ctrl);
+err_disable_ddc_regulator:
+	if (hdmi->ddc_regulator)
+		regulator_disable(hdmi->ddc_regulator);
 err_disable_regulator:
 	regulator_disable(hdmi->regulator);
+err_unref_ddc_regulator:
+	if (hdmi->ddc_regulator)
+		regulator_put(hdmi->ddc_regulator);
+	platform_device_put(hdmi->connector_pdev);
 
 	return ret;
 }
@@ -229,6 +279,13 @@ static void sun8i_dw_hdmi_unbind(struct device *dev, struct device *master,
 	clk_disable_unprepare(hdmi->clk_tmds);
 	reset_control_assert(hdmi->rst_ctrl);
 	regulator_disable(hdmi->regulator);
+
+	if (hdmi->ddc_regulator) {
+		regulator_disable(hdmi->ddc_regulator);
+		regulator_put(hdmi->ddc_regulator);
+	}
+
+	platform_device_put(hdmi->connector_pdev);
 }
 
 static const struct component_ops sun8i_dw_hdmi_ops = {
diff --git a/drivers/gpu/drm/sun4i/sun8i_dw_hdmi.h b/drivers/gpu/drm/sun4i/sun8i_dw_hdmi.h
index 720c5aa8adc1..60f5200aee73 100644
--- a/drivers/gpu/drm/sun4i/sun8i_dw_hdmi.h
+++ b/drivers/gpu/drm/sun4i/sun8i_dw_hdmi.h
@@ -188,8 +188,10 @@ struct sun8i_dw_hdmi {
 	struct sun8i_hdmi_phy		*phy;
 	struct dw_hdmi_plat_data	plat_data;
 	struct regulator		*regulator;
+	struct regulator		*ddc_regulator;
 	const struct sun8i_dw_hdmi_quirks *quirks;
 	struct reset_control		*rst_ctrl;
+	struct platform_device		*connector_pdev;
 };
 
 static inline struct sun8i_dw_hdmi *
-- 
2.21.0