On Sun, 3 Dec 2017 22:40:50 +0100, Javier Martinez Canillas <javierm@xxxxxxxxxx> wrote: > The buses should honor the firmware interface used to register the device, > but the I2C core reports a MODALIAS of the form i2c:<device> even for I2C > devices registered via OF. > > This means that user-space will never get an OF stype uevent MODALIAS even > when the drivers modules contain aliases exported from both the I2C and OF > device ID tables. For example, an Atmel maXTouch Touchscreen registered by > a DT node with compatible "atmel,maxtouch" has the following module alias: > > $ cat /sys/class/i2c-adapter/i2c-8/8-004b/modalias > i2c:maxtouch > > So udev won't be able to auto-load a module for an OF-only device driver. > Many OF-only drivers duplicate the OF device ID table entries in an I2C ID > table only has a workaround for how the I2C core reports the module alias. > > This patch changes the I2C core to report an OF related MODALIAS uevent if > the device was registered via OF. So for the previous example, after this > patch, the reported MODALIAS for the Atmel maXTouch will be the following: > > $ cat /sys/class/i2c-adapter/i2c-8/8-004b/modalias > of:NtrackpadT<NULL>Catmel,maxtouch > > NOTE: This patch may break out-of-tree drivers that were relying on this > behavior, and only had an I2C device ID table even when the device > was registered via OF. There are no remaining drivers in mainline > that do this, but out-of-tree drivers have to be fixed and define > a proper OF device ID table to have module auto-loading working. > Hello Javier, thank you for your patch! I had problem with auto-loading max9611 module, because it has no I2C device ID table: $ cat /sys/class/i2c-adapter/i2c-0/0-0070/modalias of:Nmax9611_0_70T<NULL>Cmaxim,max9611 With your patch it has been auto-loaded well: [ 0.796180] i2c i2c-0: of_i2c: register /ocp/i2c@44e0b000/max9611_0_70@70 [ 0.796431] i2c i2c-0: client [max9611] registered with bus id 0-0070 [ 6.260710] i2c-core: driver [max9611] registered Additionally I use several modules with both I2C and OF device ID tables, they work well with or without the patch (max1363, pinctrl_mcp23s08). Regards, Dmitry Tested-by: Dmitry Mastykin <mastichi@xxxxxxxxx> > Signed-off-by: Javier Martinez Canillas <javierm@xxxxxxxxxx> > --- > drivers/i2c/i2c-core-base.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c > index bf52cca87363..1596aa718bc8 100644 > --- a/drivers/i2c/i2c-core-base.c > +++ b/drivers/i2c/i2c-core-base.c > @@ -124,6 +124,10 @@ 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; > @@ -416,6 +420,10 @@ show_modalias(struct device *dev, struct > device_attribute *attr, char *buf) > struct i2c_client *client = to_i2c_client(dev); > int len; > > + len = of_device_modalias(dev, buf, PAGE_SIZE); > + if (len != -ENODEV) > + return len; > + > len = acpi_device_modalias(dev, buf, PAGE_SIZE -1); > if (len != -ENODEV) > return len;
