media: cec-gpio: use disable/enable_irq

Due to limitations in gpiolib it was impossible to disable the interrupt of
an input gpio and then switch it to gpio output and drive it. The only way
to achieve that was to free the interrupt first, then switch the direction.

When going back to gpio input and using interrupts to read the gpio pin you
had to request the irq again.

This limitation was lifted in gpiolib in kernel 4.20, but the cec-gpio driver
was still using the old workaround implementation.

This patch updates the cec-gpio driver to just enable and disable the irq.
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

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

@@ -17,7 +17,6 @@ struct cec_gpio {
 	struct gpio_desc	*cec_gpio;
 	int			cec_irq;
 	bool			cec_is_low;
-	bool			cec_have_irq;
 
 	struct gpio_desc	*hpd_gpio;
 	int			hpd_irq;
@@ -55,9 +54,6 @@ static void cec_gpio_low(struct cec_adapter *adap)
 
 	if (cec->cec_is_low)
 		return;
-	if (WARN_ON_ONCE(cec->cec_have_irq))
-		free_irq(cec->cec_irq, cec);
-	cec->cec_have_irq = false;
 	cec->cec_is_low = true;
 	gpiod_set_value(cec->cec_gpio, 0);
 }
@@ -114,14 +110,7 @@ static bool cec_gpio_enable_irq(struct cec_adapter *adap)
 {
 	struct cec_gpio *cec = cec_get_drvdata(adap);
 
-	if (cec->cec_have_irq)
-		return true;
-
-	if (request_irq(cec->cec_irq, cec_gpio_irq_handler,
-			IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
-			adap->name, cec))
-		return false;
-	cec->cec_have_irq = true;
+	enable_irq(cec->cec_irq);
 	return true;
 }
 
@@ -129,9 +118,7 @@ static void cec_gpio_disable_irq(struct cec_adapter *adap)
 {
 	struct cec_gpio *cec = cec_get_drvdata(adap);
 
-	if (cec->cec_have_irq)
-		free_irq(cec->cec_irq, cec);
-	cec->cec_have_irq = false;
+	disable_irq(cec->cec_irq);
 }
 
 static void cec_gpio_status(struct cec_adapter *adap, struct seq_file *file)
@@ -139,8 +126,7 @@ static void cec_gpio_status(struct cec_adapter *adap, struct seq_file *file)
 	struct cec_gpio *cec = cec_get_drvdata(adap);
 
 	seq_printf(file, "mode: %s\n", cec->cec_is_low ? "low-drive" : "read");
-	if (cec->cec_have_irq)
-		seq_printf(file, "using irq: %d\n", cec->cec_irq);
+	seq_printf(file, "using irq: %d\n", cec->cec_irq);
 	if (cec->hpd_gpio)
 		seq_printf(file, "hpd: %s\n",
 			   cec->hpd_is_high ? "high" : "low");
@@ -215,6 +201,14 @@ static int cec_gpio_probe(struct platform_device *pdev)
 	if (IS_ERR(cec->adap))
 		return PTR_ERR(cec->adap);
 
+	ret = devm_request_irq(dev, cec->cec_irq, cec_gpio_irq_handler,
+			       IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
+			       cec->adap->name, cec);
+	if (ret)
+		return ret;
+
+	cec_gpio_disable_irq(cec->adap);
+
 	if (cec->hpd_gpio) {
 		cec->hpd_irq = gpiod_to_irq(cec->hpd_gpio);
 		ret = devm_request_threaded_irq(dev, cec->hpd_irq,