video/exynos: dp: Enable hotplug interrupts

Enable hotplug interrupts and move the hotplug scheduling into the
interrupt handler. This allows us to introduce a screen at any time
while we're running.

BUG=chrome-os-partner:10829
BUG=chrome-os-partner:11158
BUG=chrome-os-partner:12046
TEST=Tested on snow, screen came up on power-on and resume

Change-Id: I410fe3ffb9ac341a13135c09dbeb9eec8d75beef
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/29145
Reviewed-by: Olof Johansson <olofj@chromium.org>

diff --git a/drivers/video/exynos/exynos_dp_core.c b/drivers/video/exynos/exynos_dp_core.c
index ccb0438..2c87bea 100644 (file)
--- a/drivers/video/exynos/exynos_dp_core.c
+++ b/drivers/video/exynos/exynos_dp_core.c
@@ -48,10 +48,6 @@ static int exynos_dp_detect_hpd(struct exynos_dp_device *dp)
 {
        int timeout_loop = 0;
 
-       exynos_dp_init_hpd(dp);
-
-       udelay(200);
-
        while (exynos_dp_get_plug_in_status(dp) != 0) {
                timeout_loop++;
                if (DP_TIMEOUT_LOOP_COUNT < timeout_loop) {
@@ -907,8 +903,32 @@ static void exynos_dp_enable_scramble(struct exynos_dp_device *dp, bool enable)
 static irqreturn_t exynos_dp_irq_handler(int irq, void *arg)
 {
        struct exynos_dp_device *dp = arg;
-
-       dev_err(dp->dev, "exynos_dp_irq_handler\n");
+       enum dp_irq_type irq_type;
+
+       irq_type = exynos_dp_get_irq_type(dp);
+       switch (irq_type) {
+       case DP_IRQ_TYPE_HP_CABLE_IN:
+               dev_dbg(dp->dev, "Received irq - cable in\n");
+               schedule_work(&dp->hotplug_work);
+               exynos_dp_clear_hotplug_interrupts(dp);
+               break;
+       case DP_IRQ_TYPE_HP_CABLE_OUT:
+               dev_dbg(dp->dev, "Received irq - cable out\n");
+               exynos_dp_clear_hotplug_interrupts(dp);
+               break;
+       case DP_IRQ_TYPE_HP_CHANGE:
+               /*
+                * We get these change notifications once in a while, but there
+                * is nothing we can do with them. Just ignore it for now and
+                * only handle cable changes.
+                */
+               dev_dbg(dp->dev, "Received irq - hotplug change; ignoring.\n");
+               exynos_dp_clear_hotplug_interrupts(dp);
+               break;
+       default:
+               dev_err(dp->dev, "Received irq - unknown type!\n");
+               break;
+       }
        return IRQ_HANDLED;
 }
 
@@ -921,7 +941,7 @@ static void exynos_dp_hotplug(struct work_struct *work)
 
        ret = exynos_dp_detect_hpd(dp);
        if (ret) {
-               dev_err(dp->dev, "unable to detect hpd\n");
+               /* Cable has been disconnected, we're done */
                return;
        }
 
@@ -1022,6 +1042,8 @@ static int __devinit exynos_dp_probe(struct platform_device *pdev)
 
        exynos_dp_init_dp(dp);
 
+       INIT_WORK(&dp->hotplug_work, exynos_dp_hotplug);
+
        ret = request_irq(dp->irq, exynos_dp_irq_handler, 0,
                        "exynos-dp", dp);
        if (ret) {
@@ -1029,10 +1051,7 @@ static int __devinit exynos_dp_probe(struct platform_device *pdev)
                goto err_ioremap;
        }
 
-       INIT_WORK(&dp->hotplug_work, exynos_dp_hotplug);
-
        platform_set_drvdata(pdev, dp);
-       schedule_work(&dp->hotplug_work);
 
        return 0;
 
@@ -1102,7 +1121,6 @@ static int exynos_dp_resume(struct device *dev)
        clk_enable(dp->clock);
 
        exynos_dp_init_dp(dp);
-       schedule_work(&dp->hotplug_work);
 
        return 0;
 }

diff --git a/drivers/video/exynos/exynos_dp_core.h b/drivers/video/exynos/exynos_dp_core.h
index a4c0278..f53988d 100644 (file)
--- a/drivers/video/exynos/exynos_dp_core.h
+++ b/drivers/video/exynos/exynos_dp_core.h
@@ -13,6 +13,13 @@
 #ifndef _EXYNOS_DP_CORE_H
 #define _EXYNOS_DP_CORE_H
 
+enum dp_irq_type {
+       DP_IRQ_TYPE_HP_CABLE_IN,
+       DP_IRQ_TYPE_HP_CABLE_OUT,
+       DP_IRQ_TYPE_HP_CHANGE,
+       DP_IRQ_TYPE_UNKNOWN,
+};
+
 struct link_train {
        int eq_loop;
        int cr_loop[4];
@@ -50,6 +57,8 @@ void exynos_dp_set_analog_power_down(struct exynos_dp_device *dp,
                                bool enable);
 void exynos_dp_init_analog_func(struct exynos_dp_device *dp);
 void exynos_dp_init_hpd(struct exynos_dp_device *dp);
+enum dp_irq_type exynos_dp_get_irq_type(struct exynos_dp_device *dp);
+void exynos_dp_clear_hotplug_interrupts(struct exynos_dp_device *dp);
 void exynos_dp_reset_aux(struct exynos_dp_device *dp);
 void exynos_dp_init_aux(struct exynos_dp_device *dp);
 int exynos_dp_get_plug_in_status(struct exynos_dp_device *dp);

diff --git a/drivers/video/exynos/exynos_dp_reg.c b/drivers/video/exynos/exynos_dp_reg.c
index 7860dec..5467d7c 100644 (file)
--- a/drivers/video/exynos/exynos_dp_reg.c
+++ b/drivers/video/exynos/exynos_dp_reg.c
@@ -289,7 +289,7 @@ void exynos_dp_init_analog_func(struct exynos_dp_device *dp)
        writel(reg, dp->reg_base + EXYNOS_DP_FUNC_EN_2);
 }
 
-void exynos_dp_init_hpd(struct exynos_dp_device *dp)
+void exynos_dp_clear_hotplug_interrupts(struct exynos_dp_device *dp)
 {
        u32 reg;
 
@@ -298,10 +298,43 @@ void exynos_dp_init_hpd(struct exynos_dp_device *dp)
 
        reg = INT_HPD;
        writel(reg, dp->reg_base + EXYNOS_DP_INT_STA);
+}
+
+void exynos_dp_init_hpd(struct exynos_dp_device *dp)
+{
+       u32 reg;
+
+       exynos_dp_clear_hotplug_interrupts(dp);
 
        reg = readl(dp->reg_base + EXYNOS_DP_SYS_CTL_3);
        reg &= ~(F_HPD | HPD_CTRL);
        writel(reg, dp->reg_base + EXYNOS_DP_SYS_CTL_3);
+
+       /* Unmask hotplug interrupts */
+       reg = HOTPLUG_CHG | HPD_LOST | PLUG;
+       writel(reg, dp->reg_base + EXYNOS_DP_COMMON_INT_MASK_4);
+
+       reg = INT_HPD;
+       writel(reg, dp->reg_base + EXYNOS_DP_INT_STA_MASK);
+}
+
+enum dp_irq_type exynos_dp_get_irq_type(struct exynos_dp_device *dp)
+{
+       u32 reg;
+
+       /* Parse hotplug interrupt status register */
+       reg = readl(dp->reg_base + EXYNOS_DP_COMMON_INT_STA_4);
+
+       if (reg & PLUG)
+               return DP_IRQ_TYPE_HP_CABLE_IN;
+
+       if (reg & HPD_LOST)
+               return DP_IRQ_TYPE_HP_CABLE_OUT;
+
+       if (reg & HOTPLUG_CHG)
+               return DP_IRQ_TYPE_HP_CHANGE;
+
+       return DP_IRQ_TYPE_UNKNOWN;
 }
 
 void exynos_dp_reset_aux(struct exynos_dp_device *dp)