From: Andrew Bresticker abrestic@chromium.org
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 --- .../devicetree/bindings/video/exynos_dp.txt | 4 +++ drivers/gpu/drm/exynos/exynos_dp_core.c | 32 ++++++++++++++++++++-- drivers/gpu/drm/exynos/exynos_dp_core.h | 1 + drivers/gpu/drm/exynos/exynos_dp_reg.c | 26 ++++++++++++++++-- 4 files changed, 57 insertions(+), 6 deletions(-)
diff --git a/Documentation/devicetree/bindings/video/exynos_dp.txt b/Documentation/devicetree/bindings/video/exynos_dp.txt index 57ccdde..53dbccf 100644 --- a/Documentation/devicetree/bindings/video/exynos_dp.txt +++ b/Documentation/devicetree/bindings/video/exynos_dp.txt @@ -62,6 +62,10 @@ Optional properties for dp-controller: -hsync-active-high: HSYNC polarity configuration. High if defined, Low if not defined + -samsung,hpd-gpio: + Hotplug detect GPIO. + Indicates which GPIO should be used for hotplug + detection
Example:
diff --git a/drivers/gpu/drm/exynos/exynos_dp_core.c b/drivers/gpu/drm/exynos/exynos_dp_core.c index 1cc3981..18fd9c5 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> @@ -1226,6 +1228,7 @@ static int exynos_dp_bind(struct device *dev, struct device *master, void *data) struct drm_device *drm_dev = data; struct resource *res; struct exynos_dp_device *dp; + unsigned int irq_flags;
int ret = 0;
@@ -1265,7 +1268,30 @@ static int exynos_dp_bind(struct device *dev, struct device *master, void *data) 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; @@ -1277,8 +1303,8 @@ static int exynos_dp_bind(struct device *dev, struct device *master, void *data)
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; diff --git a/drivers/gpu/drm/exynos/exynos_dp_core.h b/drivers/gpu/drm/exynos/exynos_dp_core.h index d6a900d..56fa43e 100644 --- a/drivers/gpu/drm/exynos/exynos_dp_core.h +++ b/drivers/gpu/drm/exynos/exynos_dp_core.h @@ -159,6 +159,7 @@ struct exynos_dp_device { struct work_struct hotplug_work; struct phy *phy; int dpms_mode; + int hpd_gpio;
struct exynos_drm_panel_info panel; }; diff --git a/drivers/gpu/drm/exynos/exynos_dp_reg.c b/drivers/gpu/drm/exynos/exynos_dp_reg.c index b70da50..82475de 100644 --- a/drivers/gpu/drm/exynos/exynos_dp_reg.c +++ b/drivers/gpu/drm/exynos/exynos_dp_reg.c @@ -13,6 +13,7 @@ #include <linux/device.h> #include <linux/io.h> #include <linux/delay.h> +#include <linux/gpio.h>
#include "exynos_dp_core.h" #include "exynos_dp_reg.h" @@ -326,6 +327,9 @@ void exynos_dp_clear_hotplug_interrupts(struct exynos_dp_device *dp) { u32 reg;
+ if (gpio_is_valid(dp->hpd_gpio)) + return; + reg = HOTPLUG_CHG | HPD_LOST | PLUG; writel(reg, dp->reg_base + EXYNOS_DP_COMMON_INT_STA_4);
@@ -337,6 +341,9 @@ void exynos_dp_init_hpd(struct exynos_dp_device *dp) { u32 reg;
+ if (gpio_is_valid(dp->hpd_gpio)) + return; + exynos_dp_clear_hotplug_interrupts(dp);
reg = readl(dp->reg_base + EXYNOS_DP_SYS_CTL_3); @@ -348,6 +355,14 @@ enum dp_irq_type exynos_dp_get_irq_type(struct exynos_dp_device *dp) { u32 reg;
+ if (gpio_is_valid(dp->hpd_gpio)) { + reg = gpio_get_value(dp->hpd_gpio); + if (reg) + return DP_IRQ_TYPE_HP_CABLE_IN; + else + return DP_IRQ_TYPE_HP_CABLE_OUT; + } + /* Parse hotplug interrupt status register */ reg = readl(dp->reg_base + EXYNOS_DP_COMMON_INT_STA_4);
@@ -402,9 +417,14 @@ int exynos_dp_get_plug_in_status(struct exynos_dp_device *dp) { u32 reg;
- reg = readl(dp->reg_base + EXYNOS_DP_SYS_CTL_3); - if (reg & HPD_STATUS) - return 0; + if (gpio_is_valid(dp->hpd_gpio)) { + if (gpio_get_value(dp->hpd_gpio)) + return 0; + } else { + reg = readl(dp->reg_base + EXYNOS_DP_SYS_CTL_3); + if (reg & HPD_STATUS) + return 0; + }
return -EINVAL; }