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Commit b8b52471 authored by Andrew Bresticker's avatar Andrew Bresticker Committed by Inki Dae
Browse files

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: default avatarAndrew Bresticker <abrestic@chromium.org>
Signed-off-by: default avatarRahul Sharma <rahul.sharma@samsung.com>
Signed-off-by: default avatarAjay Kumar <ajaykumar.rs@samsung.com>
Acked-by: default avatarJingoo Han <jg1.han@samsung.com>
Signed-off-by: default avatarInki Dae <inki.dae@samsung.com>
parent fbc2063d

Documentation/devicetree/bindings/video/exynos_dp.txt

+4 −0
Original line number Diff line number Diff line
@@ -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:

drivers/gpu/drm/exynos/exynos_dp_core.c

+29 −3
Original line number Diff line number Diff line
@@ -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 @@ 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;
@@ -1254,7 +1257,30 @@ 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->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 @@ 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;

drivers/gpu/drm/exynos/exynos_dp_core.h

+1 −0
Original line number Diff line number Diff line
@@ -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;

};

drivers/gpu/drm/exynos/exynos_dp_reg.c

+32 −12
Original line number Diff line number Diff line
@@ -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 +355,13 @@ 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;

	} else {

		/* Parse hotplug interrupt status register */

		reg = readl(dp->reg_base + EXYNOS_DP_COMMON_INT_STA_4);
@@ -362,6 +376,7 @@ enum dp_irq_type exynos_dp_get_irq_type(struct exynos_dp_device *dp) 


		return DP_IRQ_TYPE_UNKNOWN;

	}

}



void exynos_dp_reset_aux(struct exynos_dp_device *dp)

{
@@ -402,9 +417,14 @@ int exynos_dp_get_plug_in_status(struct exynos_dp_device *dp) 
{

	u32 reg;



	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;

}