drm/exynos: dp: support hotplug detection via GPIO
Certain bridge chips use a GPIO to indicate the cable status instead
of the I_DP_HPD pin. This adds an optional device-tree property,
"samsung,hpd-gpio", to the exynos-dp controller which indicates that
the specified GPIO should be used for hotplug detection.
The GPIO is then set up as an edge-triggered interrupt where the
rising edge indicates hotplug-in and the falling edge indicates hotplug-out.
Signed-off-by: Andrew Bresticker <abrestic@chromium.org>
Signed-off-by: Rahul Sharma <rahul.sharma@samsung.com>
Signed-off-by: Ajay Kumar <ajaykumar.rs@samsung.com>
Acked-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
diff --git a/drivers/gpu/drm/exynos/exynos_dp_core.c b/drivers/gpu/drm/exynos/exynos_dp_core.c
index 1f8914b..2b30c55 100644
--- a/drivers/gpu/drm/exynos/exynos_dp_core.c
+++ b/drivers/gpu/drm/exynos/exynos_dp_core.c
@@ -18,6 +18,8 @@
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/of.h>
+#include <linux/of_gpio.h>
+#include <linux/gpio.h>
#include <linux/component.h>
#include <linux/phy/phy.h>
#include <video/of_display_timing.h>
@@ -1217,6 +1219,7 @@
struct drm_device *drm_dev = data;
struct resource *res;
struct exynos_dp_device *dp;
+ unsigned int irq_flags;
int ret = 0;
@@ -1254,7 +1257,30 @@
if (IS_ERR(dp->reg_base))
return PTR_ERR(dp->reg_base);
- dp->irq = platform_get_irq(pdev, 0);
+ dp->hpd_gpio = of_get_named_gpio(dev->of_node, "samsung,hpd-gpio", 0);
+
+ if (gpio_is_valid(dp->hpd_gpio)) {
+ /*
+ * Set up the hotplug GPIO from the device tree as an interrupt.
+ * Simply specifying a different interrupt in the device tree
+ * doesn't work since we handle hotplug rather differently when
+ * using a GPIO. We also need the actual GPIO specifier so
+ * that we can get the current state of the GPIO.
+ */
+ ret = devm_gpio_request_one(&pdev->dev, dp->hpd_gpio, GPIOF_IN,
+ "hpd_gpio");
+ if (ret) {
+ dev_err(&pdev->dev, "failed to get hpd gpio\n");
+ return ret;
+ }
+ dp->irq = gpio_to_irq(dp->hpd_gpio);
+ irq_flags = IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING;
+ } else {
+ dp->hpd_gpio = -ENODEV;
+ dp->irq = platform_get_irq(pdev, 0);
+ irq_flags = 0;
+ }
+
if (dp->irq == -ENXIO) {
dev_err(&pdev->dev, "failed to get irq\n");
return -ENODEV;
@@ -1266,8 +1292,8 @@
exynos_dp_init_dp(dp);
- ret = devm_request_irq(&pdev->dev, dp->irq, exynos_dp_irq_handler, 0,
- "exynos-dp", dp);
+ ret = devm_request_irq(&pdev->dev, dp->irq, exynos_dp_irq_handler,
+ irq_flags, "exynos-dp", dp);
if (ret) {
dev_err(&pdev->dev, "failed to request irq\n");
return ret;