linux-kernel - [PATCH v2] iio: light: cm32181: Fix PM support on system with 2 I2C resources

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Message-Id: <20230118170422.339619-1-kai.heng.feng@canonical.com>
Date:   Thu, 19 Jan 2023 01:04:22 +0800
From:   Kai-Heng Feng <kai.heng.feng@...onical.com>
To:     ktsai@...ellamicro.com, jic23@...nel.org, lars@...afoo.de
Cc:     hdegoede@...hat.com, Kai-Heng Feng <kai.heng.feng@...onical.com>,
        Wahaj <wahajaved@...tonmail.com>, linux-iio@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v2] iio: light: cm32181: Fix PM support on system with 2 I2C resources

Commit c1e62062ff54 ("iio: light: cm32181: Handle CM3218 ACPI devices
with 2 I2C resources") creates a second client for the actual I2C
address, but the "struct device" passed to PM ops is the first I2C
client that can't talk to the sensor.

That means the I2C transfers in both suspend and resume routines can
fail and blocking the whole suspend process.

Instead of using the first client for I2C transfer, use the I2C client
stored in the cm32181 private struct so the PM ops can get the correct
I2C client to really talk to the sensor device.

Fixes: 68c1b3dd5c48 ("iio: light: cm32181: Add PM support")
BugLink: https://bugs.launchpad.net/bugs/1988346
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2152281
Tested-by: Wahaj <wahajaved@...tonmail.com>
Signed-off-by: Kai-Heng Feng <kai.heng.feng@...onical.com>
---
v2:
 - Removed setting drvdata to the dummy client.
 - Added bug links.
 - Wording.

 drivers/iio/light/cm32181.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/iio/light/cm32181.c b/drivers/iio/light/cm32181.c
index 001055d097509..b1674a5bfa368 100644
--- a/drivers/iio/light/cm32181.c
+++ b/drivers/iio/light/cm32181.c
@@ -440,6 +440,8 @@ static int cm32181_probe(struct i2c_client *client)
 	if (!indio_dev)
 		return -ENOMEM;
 
+	i2c_set_clientdata(client, indio_dev);
+
 	/*
 	 * Some ACPI systems list 2 I2C resources for the CM3218 sensor, the
 	 * SMBus Alert Response Address (ARA, 0x0c) and the actual I2C address.
@@ -460,8 +462,6 @@ static int cm32181_probe(struct i2c_client *client)
 			return PTR_ERR(client);
 	}
 
-	i2c_set_clientdata(client, indio_dev);
-
 	cm32181 = iio_priv(indio_dev);
 	cm32181->client = client;
 	cm32181->dev = dev;
@@ -490,7 +490,8 @@ static int cm32181_probe(struct i2c_client *client)
 
 static int cm32181_suspend(struct device *dev)
 {
-	struct i2c_client *client = to_i2c_client(dev);
+	struct cm32181_chip *cm32181 = iio_priv(dev_get_drvdata(dev));
+	struct i2c_client *client = cm32181->client;
 
 	return i2c_smbus_write_word_data(client, CM32181_REG_ADDR_CMD,
 					 CM32181_CMD_ALS_DISABLE);
@@ -498,8 +499,8 @@ static int cm32181_suspend(struct device *dev)
 
 static int cm32181_resume(struct device *dev)
 {
-	struct i2c_client *client = to_i2c_client(dev);
 	struct cm32181_chip *cm32181 = iio_priv(dev_get_drvdata(dev));
+	struct i2c_client *client = cm32181->client;
 
 	return i2c_smbus_write_word_data(client, CM32181_REG_ADDR_CMD,
 					 cm32181->conf_regs[CM32181_REG_ADDR_CMD]);
-- 
2.34.1