[PATCH 2/2] iio: light: vcnl4000: add shared IRQ support

[Tsz Shan Chan]

Use the IRQ trigger type set by firmware instead, and fall back to
IRQF_TRIGGER_FALLING if no trigger type is specified to maintain current
behaviour.

Support IRQF_TRIGGER_FALLING and IRQF_TRIGGER_LOW, which match the open
drain active low interrupt output. Reject unsupported trigger types.

Request the interrupt with IRQF_SHARED, and return IRQ_NONE in the irq
handler when there is no interrupt pending.

Signed-off-by: Tsz Shan Chan <tchan@xxxxxxxxxxxxxx>
---
 drivers/iio/light/vcnl4000.c | 27 ++++++++++++++++++++-------
 1 file changed, 20 insertions(+), 7 deletions(-)

diff --git a/drivers/iio/light/vcnl4000.c b/drivers/iio/light/vcnl4000.c
index 663e623da833..9fff00ae515e 100644
--- a/drivers/iio/light/vcnl4000.c
+++ b/drivers/iio/light/vcnl4000.c
@@ -1469,8 +1469,8 @@ static irqreturn_t vcnl4040_irq_thread(int irq, void *p)
 	int ret;
 
 	ret = i2c_smbus_read_word_data(data->client, data->chip_spec->int_reg);
-	if (ret < 0)
-		return IRQ_HANDLED;
+	if (ret <= 0)
+		return IRQ_NONE;
 
 	if (ret & VCNL4040_PS_IF_CLOSE) {
 		iio_push_event(indio_dev,
@@ -1525,8 +1525,8 @@ static irqreturn_t vcnl4010_irq_thread(int irq, void *p)
 	int ret;
 
 	ret = i2c_smbus_read_byte_data(data->client, VCNL4010_ISR);
-	if (ret < 0)
-		goto end;
+	if (ret <= 0)
+		return IRQ_NONE;
 
 	isr = ret;
 
@@ -1558,7 +1558,6 @@ static irqreturn_t vcnl4010_irq_thread(int irq, void *p)
 	if (isr & VCNL4010_INT_DRDY && iio_buffer_enabled(indio_dev))
 		iio_trigger_poll_nested(indio_dev->trig);
 
-end:
 	return IRQ_HANDLED;
 }
 
@@ -1979,10 +1978,24 @@ static int vcnl4000_probe(struct i2c_client *client)
 	}
 
 	if (client->irq && data->chip_spec->irq_thread) {
+		u32 irq_type = irq_get_trigger_type(client->irq);
+
+		switch (irq_type) {
+		case IRQF_TRIGGER_FALLING:
+		case IRQF_TRIGGER_LOW:
+			break;
+		case IRQF_TRIGGER_NONE:
+			irq_type = IRQF_TRIGGER_FALLING;
+			break;
+		default:
+			return dev_err_probe(dev, -EINVAL,
+					"unsupported irq trigger type %x\n",
+					irq_type);
+		}
 		ret = devm_request_threaded_irq(dev, client->irq, NULL,
 						data->chip_spec->irq_thread,
-						IRQF_TRIGGER_FALLING |
-						IRQF_ONESHOT,
+						IRQF_ONESHOT | IRQF_SHARED |
+						irq_type,
 						"vcnl4000_irq",
 						indio_dev);
 		if (ret < 0)

-- 
2.55.0