drm/omap: displays: connector-hdmi: Support for hot plug detection

If the hpd_gpio is valid, use interrupt handler to react to HPD changes.
In case the hpd_gpio is not valid, try to enable hpd detection on the
encoder if it supports it.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

drivers/gpu/drm/omapdrm/displays/connector-hdmi.c

@@ -15,6 +15,7 @@
 #include <linux/platform_device.h>
 #include <linux/of.h>
 #include <linux/of_gpio.h>
+#include <linux/mutex.h>
 
 #include <drm/drm_edid.h>
 
@@ -37,6 +38,10 @@ static const struct videomode hdmic_default_vm = {
 struct panel_drv_data {
 	struct omap_dss_device dssdev;
 	struct omap_dss_device *in;
+	void (*hpd_cb)(void *cb_data, enum drm_connector_status status);
+	void *hpd_cb_data;
+	bool hpd_enabled;
+	struct mutex hpd_lock;
 
 	struct device *dev;
 
@@ -167,6 +172,70 @@ static bool hdmic_detect(struct omap_dss_device *dssdev)
 		return in->ops.hdmi->detect(in);
 }
 
+static int hdmic_register_hpd_cb(struct omap_dss_device *dssdev,
+				 void (*cb)(void *cb_data,
+					    enum drm_connector_status status),
+				 void *cb_data)
+{
+	struct panel_drv_data *ddata = to_panel_data(dssdev);
+	struct omap_dss_device *in = ddata->in;
+
+	if (gpio_is_valid(ddata->hpd_gpio)) {
+		mutex_lock(&ddata->hpd_lock);
+		ddata->hpd_cb = cb;
+		ddata->hpd_cb_data = cb_data;
+		mutex_unlock(&ddata->hpd_lock);
+		return 0;
+	} else if (in->ops.hdmi->register_hpd_cb) {
+		return in->ops.hdmi->register_hpd_cb(in, cb, cb_data);
+	}
+
+	return -ENOTSUPP;
+}
+
+static void hdmic_unregister_hpd_cb(struct omap_dss_device *dssdev)
+{
+	struct panel_drv_data *ddata = to_panel_data(dssdev);
+	struct omap_dss_device *in = ddata->in;
+
+	if (gpio_is_valid(ddata->hpd_gpio)) {
+		mutex_lock(&ddata->hpd_lock);
+		ddata->hpd_cb = NULL;
+		ddata->hpd_cb_data = NULL;
+		mutex_unlock(&ddata->hpd_lock);
+	} else if (in->ops.hdmi->unregister_hpd_cb) {
+		in->ops.hdmi->unregister_hpd_cb(in);
+	}
+}
+
+static void hdmic_enable_hpd(struct omap_dss_device *dssdev)
+{
+	struct panel_drv_data *ddata = to_panel_data(dssdev);
+	struct omap_dss_device *in = ddata->in;
+
+	if (gpio_is_valid(ddata->hpd_gpio)) {
+		mutex_lock(&ddata->hpd_lock);
+		ddata->hpd_enabled = true;
+		mutex_unlock(&ddata->hpd_lock);
+	} else if (in->ops.hdmi->enable_hpd) {
+		in->ops.hdmi->enable_hpd(in);
+	}
+}
+
+static void hdmic_disable_hpd(struct omap_dss_device *dssdev)
+{
+	struct panel_drv_data *ddata = to_panel_data(dssdev);
+	struct omap_dss_device *in = ddata->in;
+
+	if (gpio_is_valid(ddata->hpd_gpio)) {
+		mutex_lock(&ddata->hpd_lock);
+		ddata->hpd_enabled = false;
+		mutex_unlock(&ddata->hpd_lock);
+	} else if (in->ops.hdmi->disable_hpd) {
+		in->ops.hdmi->disable_hpd(in);
+	}
+}
+
 static int hdmic_set_hdmi_mode(struct omap_dss_device *dssdev, bool hdmi_mode)
 {
 	struct panel_drv_data *ddata = to_panel_data(dssdev);
@@ -197,10 +266,34 @@ static struct omap_dss_driver hdmic_driver = {
 
 	.read_edid		= hdmic_read_edid,
 	.detect			= hdmic_detect,
+	.register_hpd_cb	= hdmic_register_hpd_cb,
+	.unregister_hpd_cb	= hdmic_unregister_hpd_cb,
+	.enable_hpd		= hdmic_enable_hpd,
+	.disable_hpd		= hdmic_disable_hpd,
 	.set_hdmi_mode		= hdmic_set_hdmi_mode,
 	.set_hdmi_infoframe	= hdmic_set_infoframe,
 };
 
+static irqreturn_t hdmic_hpd_isr(int irq, void *data)
+{
+	struct panel_drv_data *ddata = data;
+
+	mutex_lock(&ddata->hpd_lock);
+	if (ddata->hpd_enabled && ddata->hpd_cb) {
+		enum drm_connector_status status;
+
+		if (hdmic_detect(&ddata->dssdev))
+			status = connector_status_connected;
+		else
+			status = connector_status_disconnected;
+
+		ddata->hpd_cb(ddata->hpd_cb_data, status);
+	}
+	mutex_unlock(&ddata->hpd_lock);
+
+	return IRQ_HANDLED;
+}
+
 static int hdmic_probe_of(struct platform_device *pdev)
 {
 	struct panel_drv_data *ddata = platform_get_drvdata(pdev);
@@ -246,11 +339,22 @@ static int hdmic_probe(struct platform_device *pdev)
 	if (r)
 		return r;
 
+	mutex_init(&ddata->hpd_lock);
+
 	if (gpio_is_valid(ddata->hpd_gpio)) {
 		r = devm_gpio_request_one(&pdev->dev, ddata->hpd_gpio,
 				GPIOF_DIR_IN, "hdmi_hpd");
 		if (r)
 			goto err_reg;
+
+		r = devm_request_threaded_irq(&pdev->dev,
+				gpio_to_irq(ddata->hpd_gpio),
+				NULL, hdmic_hpd_isr,
+				IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING |
+				IRQF_ONESHOT,
+				"hdmic hpd", ddata);
+		if (r)
+			goto err_reg;
 	}
 
 	ddata->vm = hdmic_default_vm;