drm: sti: allow to change hdmi ddc i2c adapter

Depending of the board configuration i2c for ddc could change,
this patch allow to use a phandle to specify which i2c controller to use.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>

3 files changed, 29 insertions, 13 deletions

diff --git a/Documentation/devicetree/bindings/gpu/st,stih4xx.txt b/Documentation/devicetree/bindings/gpu/st,stih4xx.txt
index 2d150c311a05..8885d9e203fc 100644
--- a/Documentation/devicetree/bindings/gpu/st,stih4xx.txt
+++ b/Documentation/devicetree/bindings/gpu/st,stih4xx.txt
@@ -69,6 +69,7 @@ STMicroelectronics stih4xx platforms
   - clock-names: names of the clocks listed in clocks property in the same
     order.
   - hdmi,hpd-gpio: gpio id to detect if an hdmi cable is plugged or not.
+  - ddc: phandle of an I2C controller used for DDC EDID probing
 
 sti-hda:
   Required properties:
diff --git a/drivers/gpu/drm/sti/sti_hdmi.c b/drivers/gpu/drm/sti/sti_hdmi.c
index b22968c08d1f..fed1b5fe4842 100644
--- a/drivers/gpu/drm/sti/sti_hdmi.c
+++ b/drivers/gpu/drm/sti/sti_hdmi.c
@@ -480,17 +480,15 @@ static const struct drm_bridge_funcs sti_hdmi_bridge_funcs = {
 
 static int sti_hdmi_connector_get_modes(struct drm_connector *connector)
 {
-        struct i2c_adapter *i2c_adap;
+        struct sti_hdmi_connector *hdmi_connector
+                = to_sti_hdmi_connector(connector);
+        struct sti_hdmi *hdmi = hdmi_connector->hdmi;
         struct edid *edid;
         int count;
 
         DRM_DEBUG_DRIVER("\n");
 
-        i2c_adap = i2c_get_adapter(1);
-        if (!i2c_adap)
-                goto fail;
-
-        edid = drm_get_edid(connector, i2c_adap);
+        edid = drm_get_edid(connector, hdmi->ddc_adapt);
         if (!edid)
                 goto fail;
 
@@ -603,29 +601,38 @@ static int sti_hdmi_bind(struct device *dev, struct device *master, void *data)
         struct sti_hdmi_connector *connector;
         struct drm_connector *drm_connector;
         struct drm_bridge *bridge;
-        struct i2c_adapter *i2c_adap;
+        struct device_node *ddc;
         int err;
 
-        i2c_adap = i2c_get_adapter(1);
-        if (!i2c_adap)
-                return -EPROBE_DEFER;
+        ddc = of_parse_phandle(dev->of_node, "ddc", 0);
+        if (ddc) {
+                hdmi->ddc_adapt = of_find_i2c_adapter_by_node(ddc);
+                if (!hdmi->ddc_adapt) {
+                        err = -EPROBE_DEFER;
+                        of_node_put(ddc);
+                        return err;
+                }
+
+                of_node_put(ddc);
+        }
 
         /* Set the drm device handle */
         hdmi->drm_dev = drm_dev;
 
         encoder = sti_hdmi_find_encoder(drm_dev);
         if (!encoder)
-                return -ENOMEM;
+                goto err_adapt;
 
         connector = devm_kzalloc(dev, sizeof(*connector), GFP_KERNEL);
         if (!connector)
-                return -ENOMEM;
+                goto err_adapt;
+
 
         connector->hdmi = hdmi;
 
         bridge = devm_kzalloc(dev, sizeof(*bridge), GFP_KERNEL);
         if (!bridge)
-                return -ENOMEM;
+                goto err_adapt;
 
         bridge->driver_private = hdmi;
         drm_bridge_init(drm_dev, bridge, &sti_hdmi_bridge_funcs);
@@ -662,6 +669,8 @@ err_sysfs:
 err_connector:
         drm_bridge_cleanup(bridge);
         drm_connector_cleanup(drm_connector);
+err_adapt:
+        put_device(&hdmi->ddc_adapt->dev);
         return -EINVAL;
 }
 
@@ -788,6 +797,11 @@ static int sti_hdmi_probe(struct platform_device *pdev)
 
 static int sti_hdmi_remove(struct platform_device *pdev)
 {
+        struct sti_hdmi *hdmi = dev_get_drvdata(&pdev->dev);
+
+        if (hdmi->ddc_adapt)
+                put_device(&hdmi->ddc_adapt->dev);
+
         component_del(&pdev->dev, &sti_hdmi_ops);
         return 0;
 }
diff --git a/drivers/gpu/drm/sti/sti_hdmi.h b/drivers/gpu/drm/sti/sti_hdmi.h
index 61bec6557ceb..d00a3e0d807f 100644
--- a/drivers/gpu/drm/sti/sti_hdmi.h
+++ b/drivers/gpu/drm/sti/sti_hdmi.h
@@ -62,6 +62,7 @@ struct sti_hdmi {
         wait_queue_head_t wait_event;
         bool event_received;
         struct reset_control *reset;
+        struct i2c_adapter *ddc_adapt;
 };
 
 u32 hdmi_read(struct sti_hdmi *hdmi, int offset);