drm/exynos: Debounce gpio hotplug interrupts

[cascardo/linux.git] / drivers / gpu / drm / exynos / exynos_hdmi.c

diff --git a/drivers/gpu/drm/exynos/exynos_hdmi.c b/drivers/gpu/drm/exynos/exynos_hdmi.c
index a884b49..153edeb 100644 (file)
--- a/drivers/gpu/drm/exynos/exynos_hdmi.c
+++ b/drivers/gpu/drm/exynos/exynos_hdmi.c
@@ -47,6 +47,8 @@
 
 #define get_hdmi_context(dev)  platform_get_drvdata(to_platform_device(dev))
 
+#define HOTPLUG_DEBOUNCE_MS            1100
+
 struct hdmi_resources {
        struct clk                      *hdmi;
        struct clk                      *sclk_hdmi;
@@ -144,8 +146,7 @@ struct hdmi_context {
        unsigned int                    external_irq;
        unsigned int                    internal_irq;
        unsigned int                    curr_irq;
-       struct workqueue_struct         *wq;
-       struct work_struct              hotplug_work;
+       struct timer_list               hotplug_timer;
 
        struct i2c_client               *ddc_port;
        struct i2c_client               *hdmiphy_port;
@@ -2099,10 +2100,9 @@ static struct exynos_panel_ops hdmi_ops = {
 /*
  * Handle hotplug events outside the interrupt handler proper.
  */
-static void hdmi_hotplug_func(struct work_struct *work)
+static void hdmi_hotplug_timer_func(unsigned long data)
 {
-       struct hdmi_context *hdata =
-               container_of(work, struct hdmi_context, hotplug_work);
+       struct hdmi_context *hdata = (struct hdmi_context *)data;
 
        drm_helper_hpd_irq_event(hdata->drm_dev);
 }
@@ -2110,7 +2110,8 @@ static void hdmi_hotplug_func(struct work_struct *work)
 static irqreturn_t hdmi_irq_handler(int irq, void *arg)
 {
        struct hdmi_context *hdata = arg;
-       u32 intc_flag;
+       u32 intc_flag, time_ms = HOTPLUG_DEBOUNCE_MS;
+
        if (hdata->is_hdmi_powered_on) {
                intc_flag = hdmi_reg_read(hdata, HDMI_INTC_FLAG);
                /* clearing flags for HPD plug/unplug */
@@ -2126,10 +2127,17 @@ static irqreturn_t hdmi_irq_handler(int irq, void *arg)
                        hdmi_reg_writemask(hdata, HDMI_INTC_FLAG, ~0,
                                HDMI_INTC_FLAG_HPD_PLUG);
                }
+
+               /*
+                * No need to debounce if we're powered on, the hardware
+                * has already done it for us.
+                */
+               time_ms = 0;
        }
 
        if (hdata->drm_dev && hdata->hpd_handle)
-               queue_work(hdata->wq, &hdata->hotplug_work);
+               mod_timer(&hdata->hotplug_timer,
+                               jiffies + msecs_to_jiffies(time_ms));
 
        return IRQ_HANDLED;
 }
@@ -2393,21 +2401,11 @@ static int __devinit hdmi_probe(struct platform_device *pdev)
 
        hdata->external_irq = gpio_to_irq(hdata->hpd_gpio);
 
-       /* create workqueue and hotplug work */
-       hdata->wq = alloc_workqueue("exynos-drm-hdmi",
-                       WQ_UNBOUND | WQ_NON_REENTRANT, 1);
-       if (hdata->wq == NULL) {
-               DRM_ERROR("Failed to create workqueue.\n");
-               ret = -ENOMEM;
-               goto err_hdmiphy;
-       }
-       INIT_WORK(&hdata->hotplug_work, hdmi_hotplug_func);
-
        ret = request_irq(hdata->internal_irq, hdmi_irq_handler,
                        IRQF_SHARED, "int_hdmi", hdata);
        if (ret) {
                DRM_ERROR("request int interrupt failed.\n");
-               goto err_workqueue;
+               goto err_hdmiphy;
        }
        disable_irq(hdata->internal_irq);
 
@@ -2420,6 +2418,9 @@ static int __devinit hdmi_probe(struct platform_device *pdev)
        }
        disable_irq(hdata->external_irq);
 
+       setup_timer(&hdata->hotplug_timer, hdmi_hotplug_timer_func,
+                       (unsigned long)hdata);
+
        if (of_device_is_compatible(dev->of_node,
                "samsung,exynos5-hdmi")) {
                ret = hdmi_register_audio_device(pdev);
@@ -2445,8 +2446,6 @@ err_ext_irq:
        free_irq(hdata->external_irq, hdata);
 err_int_irq:
        free_irq(hdata->internal_irq, hdata);
- err_workqueue:
-       destroy_workqueue(hdata->wq);
 err_hdmiphy:
        put_device(&hdata->hdmiphy_port->dev);
 err_ddc:
@@ -2478,8 +2477,7 @@ static int __devexit hdmi_remove(struct platform_device *pdev)
        free_irq(hdata->internal_irq, hdata);
        free_irq(hdata->external_irq, hdata);
 
-       cancel_work_sync(&hdata->hotplug_work);
-       destroy_workqueue(hdata->wq);
+       del_timer(&hdata->hotplug_timer);
 
        clk_disable(res->hdmi);
        clk_disable(res->sclk_hdmi);