counter: microchip-tcb-capture: Add IRQ handling

Add interrupt servicing to allow userspace to wait for the following:
* Change-of-state caused by external trigger
* Capture of timer value into RA/RB
* Compare to RC register
* Overflow

Signed-off-by: Bence Csókás <csokas.bence@prolan.hu>
Link: https://lore.kernel.org/r/20250306134441.582819-2-csokas.bence@prolan.hu
Signed-off-by: William Breathitt Gray <wbg@kernel.org>

1 files changed, 74 insertions, 0 deletions

diff --git a/drivers/counter/microchip-tcb-capture.c b/drivers/counter/microchip-tcb-capture.c
index 2f096a5b973d..16707099bd69 100644
--- a/drivers/counter/microchip-tcb-capture.c
+++ b/drivers/counter/microchip-tcb-capture.c
@@ -6,18 +6,24 @@
  */
 #include <linux/clk.h>
 #include <linux/counter.h>
+#include <linux/interrupt.h>
 #include <linux/mfd/syscon.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/of.h>
+#include <linux/of_irq.h>
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
+#include <uapi/linux/counter/microchip-tcb-capture.h>
 #include <soc/at91/atmel_tcb.h>
 
 #define ATMEL_TC_CMR_MASK	(ATMEL_TC_LDRA_RISING | ATMEL_TC_LDRB_FALLING | \
 				 ATMEL_TC_ETRGEDG_RISING | ATMEL_TC_LDBDIS | \
 				 ATMEL_TC_LDBSTOP)
 
+#define ATMEL_TC_DEF_IRQS	(ATMEL_TC_ETRGS | ATMEL_TC_COVFS | \
+				 ATMEL_TC_LDRAS | ATMEL_TC_LDRBS | ATMEL_TC_CPCS)
+
 #define ATMEL_TC_QDEN			BIT(8)
 #define ATMEL_TC_POSEN			BIT(9)
 
@@ -294,6 +300,65 @@ static const struct of_device_id atmel_tc_of_match[] = {
 	{ /* sentinel */ }
 };
 
+static irqreturn_t mchp_tc_isr(int irq, void *dev_id)
+{
+	struct counter_device *const counter = dev_id;
+	struct mchp_tc_data *const priv = counter_priv(counter);
+	u32 sr, mask;
+
+	regmap_read(priv->regmap, ATMEL_TC_REG(priv->channel[0], SR), &sr);
+	regmap_read(priv->regmap, ATMEL_TC_REG(priv->channel[0], IMR), &mask);
+
+	sr &= mask;
+	if (!(sr & ATMEL_TC_ALL_IRQ))
+		return IRQ_NONE;
+
+	if (sr & ATMEL_TC_ETRGS)
+		counter_push_event(counter, COUNTER_EVENT_CHANGE_OF_STATE,
+				   COUNTER_MCHP_EVCHN_CV);
+	if (sr & ATMEL_TC_LDRAS)
+		counter_push_event(counter, COUNTER_EVENT_CAPTURE,
+				   COUNTER_MCHP_EVCHN_RA);
+	if (sr & ATMEL_TC_LDRBS)
+		counter_push_event(counter, COUNTER_EVENT_CAPTURE,
+				   COUNTER_MCHP_EVCHN_RB);
+	if (sr & ATMEL_TC_CPCS)
+		counter_push_event(counter, COUNTER_EVENT_THRESHOLD,
+				   COUNTER_MCHP_EVCHN_RC);
+	if (sr & ATMEL_TC_COVFS)
+		counter_push_event(counter, COUNTER_EVENT_OVERFLOW,
+				   COUNTER_MCHP_EVCHN_CV);
+
+	return IRQ_HANDLED;
+}
+
+static void mchp_tc_irq_remove(void *ptr)
+{
+	struct mchp_tc_data *priv = ptr;
+
+	regmap_write(priv->regmap, ATMEL_TC_REG(priv->channel[0], IDR), ATMEL_TC_DEF_IRQS);
+}
+
+static int mchp_tc_irq_enable(struct counter_device *const counter, int irq)
+{
+	struct mchp_tc_data *const priv = counter_priv(counter);
+	int ret = devm_request_irq(counter->parent, irq, mchp_tc_isr, 0,
+				   dev_name(counter->parent), counter);
+
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_write(priv->regmap, ATMEL_TC_REG(priv->channel[0], IER), ATMEL_TC_DEF_IRQS);
+	if (ret < 0)
+		return ret;
+
+	ret = devm_add_action_or_reset(counter->parent, mchp_tc_irq_remove, priv);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
 static void mchp_tc_clk_remove(void *ptr)
 {
 	clk_disable_unprepare((struct clk *)ptr);
@@ -378,6 +443,15 @@ static int mchp_tc_probe(struct platform_device *pdev)
 	counter->num_signals = ARRAY_SIZE(mchp_tc_count_signals);
 	counter->signals = mchp_tc_count_signals;
 
+	i = of_irq_get(np->parent, 0);
+	if (i == -EPROBE_DEFER)
+		return -EPROBE_DEFER;
+	if (i > 0) {
+		ret = mchp_tc_irq_enable(counter, i);
+		if (ret < 0)
+			return dev_err_probe(&pdev->dev, ret, "Failed to set up IRQ");
+	}
+
 	ret = devm_counter_add(&pdev->dev, counter);
 	if (ret < 0)
 		return dev_err_probe(&pdev->dev, ret, "Failed to add counter\n");