[v2,1/2] counter: microchip-tcb-capture: Add IRQ handling

Commit Message

Csókás Bence Feb. 3, 2025, 4:29 p.m. UTC

Add interrupt servicing to allow userspace to wait for a trigger event.

Signed-off-by: Bence Csókás <[e-mail]>
---

Notes:
    New in v2

 drivers/counter/microchip-tcb-capture.c | 60 +++++++++++++++++++++++++
 1 file changed, 60 insertions(+)

Comments

William Breathitt Gray Feb. 5, 2025, midnight UTC | #1

On Mon, Feb 03, 2025 at 05:29:52PM +0100, Bence Csókás wrote:
> Add interrupt servicing to allow userspace to wait for a trigger event.
> 
> Signed-off-by: Bence Csókás <[e-mail]>

Hi Bence,

Thank you for the patches. When you submit the next revision, please
include a cover letter as that will make it easier for us to separate
high-level discussions about the entire patchset from any individual
patch in particular.

Regarding this particular patch, update the description to mention the
specific types of events supported by this (i.e. Change-of-state and
Overflow events). Even though you expose the capture data in a
subsequent patch, you can push the Capture events in this patch so that
we introduce all the supported interrupt events at once.

Thanks,

William Breathitt Gray

Patch

diff --git a/drivers/counter/microchip-tcb-capture.c b/drivers/counter/microchip-tcb-capture.c
index 2f096a5b973d..316755c7659a 100644
--- a/drivers/counter/microchip-tcb-capture.c
+++ b/drivers/counter/microchip-tcb-capture.c
@@ -6,10 +6,12 @@ 
  */
 #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 <soc/at91/atmel_tcb.h>
@@ -18,6 +20,8 @@ 
 				 ATMEL_TC_ETRGEDG_RISING | ATMEL_TC_LDBDIS | \
 				 ATMEL_TC_LDBSTOP)
 
+#define ATMEL_TC_DEF_IRQS	(ATMEL_TC_ETRGS | ATMEL_TC_COVFS)
+
 #define ATMEL_TC_QDEN			BIT(8)
 #define ATMEL_TC_POSEN			BIT(9)
 
@@ -27,6 +31,7 @@  struct mchp_tc_data {
 	int qdec_mode;
 	int num_channels;
 	int channel[2];
+	int irq;
 };
 
 static const enum counter_function mchp_tc_count_functions[] = {
@@ -294,6 +299,54 @@  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, 0);
+	if (sr & ATMEL_TC_COVFS)
+		counter_push_event(counter, COUNTER_EVENT_OVERFLOW, 0);
+
+	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)
+{
+	struct mchp_tc_data *const priv = counter_priv(counter);
+	int ret = devm_request_irq(counter->parent, priv->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 +431,13 @@  static int mchp_tc_probe(struct platform_device *pdev)
 	counter->num_signals = ARRAY_SIZE(mchp_tc_count_signals);
 	counter->signals = mchp_tc_count_signals;
 
+	priv->irq = of_irq_get(np->parent, 0);
+	if (priv->irq > 0) {
+		ret = mchp_tc_irq_enable(counter);
+		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");