[PATCH 27/27] i2c: (RFC, don't apply) report OF style modalias when probing using DT

Javier Martinez Canillas javier at osg.samsung.com
Fri Jul 31 02:18:52 AEST 2015

An I2C driver that supports both OF and legacy platforms, will have
both a OF and I2C ID table. This means that when built as a module,
the aliases will be filled from both tables but currently always an
alias of the form i2c:<deviceId> is reported, e.g:

$ cat /sys/class/i2c-adapter/i2c-8/8-004b/modalias

So if a device is probed by matching its compatible string, udev can
get a MODALIAS uevent env var that doesn't match with one of the valid
aliases so the module won't be auto-loaded.

This patch changes the I2C core to report a OF related MODALIAS uevent
(of:N*T*C) env var instead so the module can be auto-loaded and also
report the correct alias using sysfs:

$ cat /sys/class/i2c-adapter/i2c-8/8-004b/modalias

Signed-off-by: Javier Martinez Canillas <javier at osg.samsung.com>


 drivers/i2c/i2c-core.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 92dddfeb3f39..c0668c2ed9da 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -489,6 +489,10 @@ static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
 	struct i2c_client	*client = to_i2c_client(dev);
 	int rc;
+	rc = of_device_uevent_modalias(dev, env);
+	if (rc != -ENODEV)
+		return rc;
 	rc = acpi_device_uevent_modalias(dev, env);
 	if (rc != -ENODEV)
 		return rc;
@@ -726,6 +730,10 @@ show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
 	struct i2c_client *client = to_i2c_client(dev);
 	int len;
+	len = of_device_get_modalias(dev, buf, PAGE_SIZE - 1);
+	if (len != -ENODEV)
+		return len;
 	len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
 	if (len != -ENODEV)
 		return len;

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