media: cec-gpio: add notifier support

Add support for cec-notifier to the cec-gpio driver.

This makes it possible to associate the CEC gpio pin with an HDMI
connector. This feature was always documented in the cec-gpio bindings:

Documentation/devicetree/bindings/media/cec-gpio.txt

But support for the hdmi-phandle property was never actually implemented in
this driver.

This patch adds support for this property.

It also fixes a few incorrect error returns in the probe() function, which
skipped the call to cec_delete_adapter().

Tested on a Raspberry Pi 3B with a modified vc4 driver.
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/platform/Kconfig

@@ -588,6 +588,7 @@ config CEC_GPIO
 	depends on PREEMPT || COMPILE_TEST
 	select CEC_CORE
 	select CEC_PIN
+	select CEC_NOTIFIER
 	select GPIOLIB
 	help
 	  This is a generic GPIO-based CEC driver.

drivers/media/platform/cec-gpio/cec-gpio.c

@@ -8,10 +8,12 @@
 #include <linux/delay.h>
 #include <linux/platform_device.h>
 #include <linux/gpio/consumer.h>
+#include <media/cec-notifier.h>
 #include <media/cec-pin.h>
 
 struct cec_gpio {
 	struct cec_adapter	*adap;
+	struct cec_notifier	*notifier;
 	struct device		*dev;
 
 	struct gpio_desc	*cec_gpio;
@@ -173,9 +175,17 @@ static const struct cec_pin_ops cec_gpio_pin_ops = {
 static int cec_gpio_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
+	struct device *hdmi_dev;
 	struct cec_gpio *cec;
+	u32 caps = CEC_CAP_DEFAULTS | CEC_CAP_MONITOR_ALL | CEC_CAP_MONITOR_PIN;
 	int ret;
 
+	hdmi_dev = cec_notifier_parse_hdmi_phandle(dev);
+	if (PTR_ERR(hdmi_dev) == -EPROBE_DEFER)
+		return PTR_ERR(hdmi_dev);
+	if (IS_ERR(hdmi_dev))
+		caps |= CEC_CAP_PHYS_ADDR;
+
 	cec = devm_kzalloc(dev, sizeof(*cec), GFP_KERNEL);
 	if (!cec)
 		return -ENOMEM;
@@ -196,8 +206,7 @@ static int cec_gpio_probe(struct platform_device *pdev)
 		return PTR_ERR(cec->v5_gpio);
 
 	cec->adap = cec_pin_allocate_adapter(&cec_gpio_pin_ops,
-		cec, pdev->name, CEC_CAP_DEFAULTS | CEC_CAP_PHYS_ADDR |
-				 CEC_CAP_MONITOR_ALL | CEC_CAP_MONITOR_PIN);
+					     cec, pdev->name, caps);
 	if (IS_ERR(cec->adap))
 		return PTR_ERR(cec->adap);
 
@@ -205,7 +214,7 @@ static int cec_gpio_probe(struct platform_device *pdev)
 			       IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
 			       cec->adap->name, cec);
 	if (ret)
-		return ret;
+		goto del_adap;
 
 	cec_gpio_disable_irq(cec->adap);
 
@@ -218,7 +227,7 @@ static int cec_gpio_probe(struct platform_device *pdev)
 			IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
 			"hpd-gpio", cec);
 		if (ret)
-			return ret;
+			goto del_adap;
 	}
 
 	if (cec->v5_gpio) {
@@ -230,23 +239,37 @@ static int cec_gpio_probe(struct platform_device *pdev)
 			IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
 			"v5-gpio", cec);
 		if (ret)
-			return ret;
+			goto del_adap;
 	}
 
-	ret = cec_register_adapter(cec->adap, &pdev->dev);
-	if (ret) {
-		cec_delete_adapter(cec->adap);
-		return ret;
+	if (!IS_ERR(hdmi_dev)) {
+		cec->notifier = cec_notifier_cec_adap_register(hdmi_dev, NULL,
+							       cec->adap);
+		if (!cec->notifier) {
+			ret = -ENOMEM;
+			goto del_adap;
+		}
 	}
 
+	ret = cec_register_adapter(cec->adap, &pdev->dev);
+	if (ret)
+		goto unreg_notifier;
+
 	platform_set_drvdata(pdev, cec);
 	return 0;
+
+unreg_notifier:
+	cec_notifier_cec_adap_unregister(cec->notifier);
+del_adap:
+	cec_delete_adapter(cec->adap);
+	return ret;
 }
 
 static int cec_gpio_remove(struct platform_device *pdev)
 {
 	struct cec_gpio *cec = platform_get_drvdata(pdev);
 
+	cec_notifier_cec_adap_unregister(cec->notifier);
 	cec_unregister_adapter(cec->adap);
 	return 0;
 }