Re: [PATCH v9 6/7] i2c: xiic: use numbered adapter registration

On Feb 3, 2026, at 10:31 AM, Andrew Lunn [off-list ref] wrote:

On Tue, Feb 03, 2026 at 10:14:49AM -0800, Abdurrahman Hussain wrote:

quoted

quoted

On Feb 3, 2026, at 7:45 AM, Andy Shevchenko [off-list ref] wrote:

On Mon, Feb 02, 2026 at 08:37:23PM +0000, Abdurrahman Hussain via B4 Relay wrote:

quoted

Use i2c_add_numbered_adapter() to allow platform devices to specify
fixed bus numbers when needed.

Not sure about this. Doesn't it break the current approach? Please, double
check that.

-- 
With Best Regards,
Andy Shevchenko

If pdev->id is PLATFORM_DEVID_NONE(-1) then i2c_add_numbered_adapter()
falls back to dynamic allocation and calls i2c_add_adapter().

Many existing i2c drivers use the same approach, see i2c-pxa.c and
i2c-pnx.c etc.

It is not about if other drivers do this. Its about does this change
the behaviour of this driver, so that I2C busses get different IDs
then before, and so cause regressions?

You need to explain in the commit message why you think this is safe.

   Andrew

Before, the driver was always doing the dynamic allocation due to
i2c_add_adapter(). So there could not have been a system that relied on
consistent i2c bus numbering. Even between reboots bus numbering could change.

The systems that did set pdev->id and were expecting a consistent i2c bus
numbering were broken to begin with.

This patch won’t break any existing systems or cause regressions.