[PATCH v2 1/3] iio: proximity: sx9310: keep the IRQ balanced across suspend and resume

[Arnav Kapoor]

sx9310_suspend() disables the interrupt first and returns with it still
disabled if a register access fails. Resume isn't called after a failed
suspend, so the interrupt is never enabled again. sx9310_resume() also
returns without enabling it on error. Without an interrupt line,
client->irq is 0 and both callbacks act on IRQ 0, which the driver
doesn't own.

Disable the interrupt only once the device is asleep, always enable it
in resume, and skip both when there is no interrupt.

Fixes: 72ad02b15d63 ("iio: Add SEMTECH SX9310/9311 sensor driver")
Signed-off-by: Arnav Kapoor <kapoorarnav43@xxxxxxxxx>
---
 drivers/iio/proximity/sx9310.c | 41 ++++++++++++++++++++++------------
 1 file changed, 27 insertions(+), 14 deletions(-)

diff --git a/drivers/iio/proximity/sx9310.c b/drivers/iio/proximity/sx9310.c
index 79ba46d8a0aa..fad1dcffbe26 100644
--- a/drivers/iio/proximity/sx9310.c
+++ b/drivers/iio/proximity/sx9310.c
@@ -943,8 +943,6 @@ static int sx9310_suspend(struct device *dev)
 	u8 ctrl0;
 	int ret;
 
-	disable_irq_nosync(data->client->irq);
-
 	guard(mutex)(&data->mutex);
 	ret = regmap_read(data->regmap, SX9310_REG_PROX_CTRL0,
 			  &data->suspend_ctrl);
@@ -956,7 +954,28 @@ static int sx9310_suspend(struct device *dev)
 	if (ret)
 		return ret;
 
-	return regmap_write(data->regmap, SX9310_REG_PAUSE, 0);
+	ret = regmap_write(data->regmap, SX9310_REG_PAUSE, 0);
+	if (ret)
+		return ret;
+
+	/* Only once nothing can fail, as resume isn't called on failure. */
+	if (data->client->irq)
+		disable_irq_nosync(data->client->irq);
+
+	return 0;
+}
+
+static int sx9310_wake_up(struct sx_common_data *data)
+{
+	int ret;
+
+	guard(mutex)(&data->mutex);
+	ret = regmap_write(data->regmap, SX9310_REG_PAUSE, 1);
+	if (ret)
+		return ret;
+
+	return regmap_write(data->regmap, SX9310_REG_PROX_CTRL0,
+			    data->suspend_ctrl);
 }
 
 static int sx9310_resume(struct device *dev)
@@ -964,19 +983,13 @@ static int sx9310_resume(struct device *dev)
 	struct sx_common_data *data = iio_priv(dev_get_drvdata(dev));
 	int ret;
 
-	scoped_guard(mutex, &data->mutex) {
-		ret = regmap_write(data->regmap, SX9310_REG_PAUSE, 1);
-		if (ret)
-			return ret;
+	ret = sx9310_wake_up(data);
 
-		ret = regmap_write(data->regmap, SX9310_REG_PROX_CTRL0,
-				   data->suspend_ctrl);
-		if (ret)
-			return ret;
-	}
+	/* Balance the suspend even if the device couldn't be woken up. */
+	if (data->client->irq)
+		enable_irq(data->client->irq);
 
-	enable_irq(data->client->irq);
-	return 0;
+	return ret;
 }
 
 static DEFINE_SIMPLE_DEV_PM_OPS(sx9310_pm_ops, sx9310_suspend, sx9310_resume);
-- 
2.53.0