[PATCH] i2c: change the id to let the i2c device work

Mark Brown broonie at opensource.wolfsonmicro.com
Fri Oct 12 01:53:02 EDT 2012

On Fri, Oct 12, 2012 at 01:45:48PM +0800, Bo Shen wrote:
> On 10/12/2012 13:14, Mark Brown wrote:

> >No, this still makes no sense to me.  This is clearly a non-DT device
> >registration, what does DT have to do with anything here?  What is the

> Yes, this is non-DT device registration.
> As the Linux kernel code is transferring to DT which doesn't use
> platform device id. however here, modified unconsciously. So correct
> this error.

What error and what does DT have to do with any of this?  DT has no
impact on non-DT systems.

> >practical problem you are seeing in your system and how does this help
> >with it?

> In non-DT kernel, we use platform device id to distinguish between
> each device.

> So, in this case, if the id = -1, i2c core will dynamically assign a
> bus id to this bus when running, the dynamically assigned bus id is
> unknown when writing the code. So, when we use
> i2c_register_board_info(int busnum, ...) to register device on
> busnum. we don't know which value to be use.

The I2C bus number assigned to the controller should be independant of
the platform device ID used to register the device; a better fix if this
is an issue would be to update the i2c-gpio driver to allow a fixed bus
number to be specified in platform data.

More information about the linux-arm-kernel mailing list