linux-kernel - [PATCH] counter: interrupt-cnt: Implement watch

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Date:   Mon, 15 Aug 2022 18:50:58 -0400
From:   William Breathitt Gray <william.gray@...aro.org>
To:     linux@...pel-privat.de, kernel@...gutronix.de
Cc:     linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org,
        William Breathitt Gray <william.gray@...aro.org>
Subject: [PATCH] counter: interrupt-cnt: Implement watch_validate callback

The interrupt-cnt counter driver only pushes one type of event on only
one channel: COUNTER_EVENT_CHANGE_OF_STATE on channel 0. The
interrupt_cnt_watch_validate() watch_valid callback is implemented to
ensure watch configurations are valid for this driver.

Cc: Oleksij Rempel <linux@...pel-privat.de>
Cc: Pengutronix Kernel Team <kernel@...gutronix.de>
Signed-off-by: William Breathitt Gray <william.gray@...aro.org>
---
 drivers/counter/interrupt-cnt.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/counter/interrupt-cnt.c b/drivers/counter/interrupt-cnt.c
index 3b13f56bbb11..05a5d3e2d2b0 100644
--- a/drivers/counter/interrupt-cnt.c
+++ b/drivers/counter/interrupt-cnt.c
@@ -139,12 +139,23 @@ static int interrupt_cnt_signal_read(struct counter_device *counter,
 	return 0;
 }
 
+static int interrupt_cnt_watch_validate(struct counter_device *counter,
+					const struct counter_watch *watch)
+{
+	if (watch->channel != 0 ||
+	    watch->event != COUNTER_EVENT_CHANGE_OF_STATE)
+		return -EINVAL;
+
+	return 0;
+}
+
 static const struct counter_ops interrupt_cnt_ops = {
 	.action_read = interrupt_cnt_action_read,
 	.count_read = interrupt_cnt_read,
 	.count_write = interrupt_cnt_write,
 	.function_read = interrupt_cnt_function_read,
 	.signal_read  = interrupt_cnt_signal_read,
+	.watch_validate  = interrupt_cnt_watch_validate,
 };
 
 static int interrupt_cnt_probe(struct platform_device *pdev)

base-commit: 568035b01cfb107af8d2e4bd2fb9aea22cf5b868
-- 
2.37.2