linux-kernel - [PATCH v8 2/8] iio: cdc: ad7150: relax return value check for IRQ get

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Message-ID: <3ad1c6f195ead3dfa8711235e1dead139d27f700.1690890774.git.mazziesaccount@gmail.com>
Date:   Tue, 1 Aug 2023 15:02:47 +0300
From:   Matti Vaittinen <mazziesaccount@...il.com>
To:     Matti Vaittinen <matti.vaittinen@...rohmeurope.com>,
        Matti Vaittinen <mazziesaccount@...il.com>
Cc:     Lars-Peter Clausen <lars@...afoo.de>,
        Michael Hennerich <Michael.Hennerich@...log.com>,
        Jonathan Cameron <jic23@...nel.org>, linux-iio@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v8 2/8] iio: cdc: ad7150: relax return value check for IRQ get

fwnode_irq_get[_byname]() were changed to not return 0 anymore. The
special error case where device-tree based IRQ mapping fails can't no
longer be reliably detected from this return value. This yields a
functional change in the driver where the mapping failure is treated as
an error.

The mapping failure can occur for example when the device-tree IRQ
information translation call-back(s) (xlate) fail, IRQ domain is not
found, IRQ type conflicts, etc. In most cases this indicates an error in
the device-tree and special handling is not really required.

One more thing to note is that ACPI APIs do not return zero for any
failures so this special handling did only apply on device-tree based
systems.

Drop the special handling for DT mapping failures as these can no longer
be separated from other errors at driver side. Change all failures in
IRQ getting to be handled by continuing without the events instead of
aborting the probe upon certain errors.

Signed-off-by: Matti Vaittinen <mazziesaccount@...il.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>

---
Revision history:
v5 => v6:
 - Never abort the probe when IRQ getting fails but continue without
   events.

Please note that I don't have the hardware to test this change.
Furthermore, testing this type of device-tree error cases is not
trivial, as the question we probably dive in is "what happens with the
existing users who have errors in the device-tree". Answering to this
question is not simple.

The patch changing the fwnode_irq_get() got merged during 5.4:
https://lore.kernel.org/all/fb7241d3-d1d1-1c37-919b-488d6d007484@gmail.com/
This is a clean-up as agreed.
---
 drivers/iio/cdc/ad7150.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/iio/cdc/ad7150.c b/drivers/iio/cdc/ad7150.c
index d656d2f12755..4c03b9e834b8 100644
--- a/drivers/iio/cdc/ad7150.c
+++ b/drivers/iio/cdc/ad7150.c
@@ -541,6 +541,7 @@ static int ad7150_probe(struct i2c_client *client)
 	const struct i2c_device_id *id = i2c_client_get_device_id(client);
 	struct ad7150_chip_info *chip;
 	struct iio_dev *indio_dev;
+	bool use_irq = true;
 	int ret;

 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*chip));
@@ -561,14 +562,13 @@ static int ad7150_probe(struct i2c_client *client)

 	chip->interrupts[0] = fwnode_irq_get(dev_fwnode(&client->dev), 0);
 	if (chip->interrupts[0] < 0)
-		return chip->interrupts[0];
-	if (id->driver_data == AD7150) {
+		use_irq = false;
+	else if (id->driver_data == AD7150) {
 		chip->interrupts[1] = fwnode_irq_get(dev_fwnode(&client->dev), 1);
 		if (chip->interrupts[1] < 0)
-			return chip->interrupts[1];
+			use_irq = false;
 	}
-	if (chip->interrupts[0] &&
-	    (id->driver_data == AD7151 || chip->interrupts[1])) {
+	if (use_irq) {
 		irq_set_status_flags(chip->interrupts[0], IRQ_NOAUTOEN);
 		ret = devm_request_threaded_irq(&client->dev,
 						chip->interrupts[0],
-- 
2.40.1

-- 
Matti Vaittinen, Linux device drivers
ROHM Semiconductors, Finland SWDC
Kiviharjunlenkki 1E
90220 OULU
FINLAND

~~~ "I don't think so," said Rene Descartes. Just then he vanished ~~~
Simon says - in Latin please.
~~~ "non cogito me" dixit Rene Descarte, deinde evanescavit ~~~
Thanks to Simon Glass for the translation =] 

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