1 files changed, 28 insertions, 44 deletions

diff --git a/drivers/pps/clients/pps-gpio.c b/drivers/pps/clients/pps-gpio.c
index 402f910f3e25..73ec2c7335e5 100644
--- a/drivers/pps/clients/pps-gpio.c
+++ b/drivers/pps/clients/pps-gpio.c
@@ -31,38 +31,37 @@ struct pps_gpio_device_data {
 	struct gpio_desc *echo_pin;
 	struct timer_list echo_timer;	/* timer to reset echo active state */
 	bool assert_falling_edge;
-	bool capture_clear;
 	unsigned int echo_active_ms;	/* PPS echo active duration */
 	unsigned long echo_timeout;	/* timer timeout value in jiffies */
+	struct pps_event_time ts;	/* timestamp captured in hardirq */
 };
 
 /*
  * Report the PPS event
  */
 
-static irqreturn_t pps_gpio_irq_handler(int irq, void *data)
+/*
+ * Primary hardirq handler -- runs in hardirq context even on PREEMPT_RT.
+ * Only captures the timestamp; all other work is deferred to the thread.
+ */
+static irqreturn_t pps_gpio_irq_hardirq(int irq, void *data)
 {
-	const struct pps_gpio_device_data *info;
-	struct pps_event_time ts;
-	int rising_edge;
-
-	/* Get the time stamp first */
-	pps_get_ts(&ts);
-
-	info = data;
-
-	/* Small trick to bypass the check on edge's direction when capture_clear is unset */
-	rising_edge = info->capture_clear ?
-		      gpiod_get_value(info->gpio_pin) : !info->assert_falling_edge;
-	if ((rising_edge && !info->assert_falling_edge) ||
-			(!rising_edge && info->assert_falling_edge))
-		pps_event(info->pps, &ts, PPS_CAPTUREASSERT, data);
-	else if (info->capture_clear &&
-			((rising_edge && info->assert_falling_edge) ||
-			(!rising_edge && !info->assert_falling_edge)))
-		pps_event(info->pps, &ts, PPS_CAPTURECLEAR, data);
-	else
-		dev_warn_ratelimited(&info->pps->dev, "IRQ did not trigger any PPS event\n");
+	struct pps_gpio_device_data *info = data;
+
+	pps_get_ts(&info->ts);
+
+	return IRQ_WAKE_THREAD;
+}
+
+/*
+ * Threaded handler -- processes the PPS event using the timestamp
+ * captured in hardirq context above.
+ */
+static irqreturn_t pps_gpio_irq_thread(int irq, void *data)
+{
+	struct pps_gpio_device_data *info = data;
+
+	pps_event(info->pps, &info->ts, PPS_CAPTUREASSERT, data);
 
 	return IRQ_HANDLED;
 }
@@ -78,11 +77,6 @@ static void pps_gpio_echo(struct pps_device *pps, int event, void *data)
 		if (pps->params.mode & PPS_ECHOASSERT)
 			gpiod_set_value(info->echo_pin, 1);
 		break;
-
-	case PPS_CAPTURECLEAR:
-		if (pps->params.mode & PPS_ECHOCLEAR)
-			gpiod_set_value(info->echo_pin, 1);
-		break;
 	}
 
 	/* fire the timer */
@@ -144,15 +138,8 @@ static int pps_gpio_setup(struct device *dev)
 static unsigned long
 get_irqf_trigger_flags(const struct pps_gpio_device_data *data)
 {
-	unsigned long flags = data->assert_falling_edge ?
-		IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
-
-	if (data->capture_clear) {
-		flags |= ((flags & IRQF_TRIGGER_RISING) ?
-				IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING);
-	}
-
-	return flags;
+	return data->assert_falling_edge ? IRQF_TRIGGER_FALLING :
+					   IRQF_TRIGGER_RISING;
 }
 
 static int pps_gpio_probe(struct platform_device *pdev)
@@ -185,9 +172,6 @@ static int pps_gpio_probe(struct platform_device *pdev)
 	/* initialize PPS specific parts of the bookkeeping data structure. */
 	data->info.mode = PPS_CAPTUREASSERT | PPS_OFFSETASSERT |
 		PPS_ECHOASSERT | PPS_CANWAIT | PPS_TSFMT_TSPEC;
-	if (data->capture_clear)
-		data->info.mode |= PPS_CAPTURECLEAR | PPS_OFFSETCLEAR |
-			PPS_ECHOCLEAR;
 	data->info.owner = THIS_MODULE;
 	snprintf(data->info.name, PPS_MAX_NAME_LEN - 1, "%s.%d",
 		 pdev->name, pdev->id);
@@ -199,8 +183,6 @@ static int pps_gpio_probe(struct platform_device *pdev)
 
 	/* register PPS source */
 	pps_default_params = PPS_CAPTUREASSERT | PPS_OFFSETASSERT;
-	if (data->capture_clear)
-		pps_default_params |= PPS_CAPTURECLEAR | PPS_OFFSETCLEAR;
 	data->pps = pps_register_source(&data->info, pps_default_params);
 	if (IS_ERR(data->pps)) {
 		dev_err(dev, "failed to register IRQ %d as PPS source\n",
@@ -209,8 +191,10 @@ static int pps_gpio_probe(struct platform_device *pdev)
 	}
 
 	/* register IRQ interrupt handler */
-	ret = request_irq(data->irq, pps_gpio_irq_handler,
-			  get_irqf_trigger_flags(data), data->info.name, data);
+	ret = request_threaded_irq(data->irq,
+			  pps_gpio_irq_hardirq, pps_gpio_irq_thread,
+			  get_irqf_trigger_flags(data) | IRQF_ONESHOT,
+			  data->info.name, data);
 	if (ret) {
 		pps_unregister_source(data->pps);
 		dev_err(dev, "failed to acquire IRQ %d\n", data->irq);