[PATCH v5 01/11] i2c: Enhance i2c_new_ancillary_device API

[Biju Das]

Hi Geert,

Thanks for the feedback.

> Subject: Re: [PATCH v5 01/11] i2c: Enhance i2c_new_ancillary_device API
> 
> Hi Wolfram,
> 
> On Mon, Jun 12, 2023 at 10:43 PM Wolfram Sang <wsa at kernel.org> wrote:
> > > Perhaps we should first think through what an ancillary device
> > > really is.  My understanding is that it is used to talk to secondary
> > > addresses of a multi-address I2C slave device.
> >
> > As I mentioned somewhere before, this is not the case. Ancillary
> > devices are when one *driver* handles more than one address.
> > Everything else has been handled differently in the past (for  all the
> uses I am aware of).
> >
> > Yet, I have another idea which is so simple that I wonder if it maybe
> > has already been discussed so far?
> >
> > * have two regs in the bindings
> > * use the second reg with i2c_new_client_device to instantiate the
> >   RTC sibling. 'struct i2c_board_info', which is one parameter, should
> >   have enough options to pass data, e.g it has a software_node.
> >
> > Should work or did I miss something here?
> 
> That should work, mostly (i2c_new_dummy_device() also calls
> i2c_new_client_device()).  And as i2c_board_info has an of_node member
> (something I had missed before!), the new I2C device can access the clocks
> in the DT node using the standard way.

Looks like, I cannot assign of_node member like below as it results in pinctrl failure[1]
during device bind.

info.of_node = client->dev.of_node;

[1]
pinctrl-rzg2l 11030000.pinctrl: pin P43_0 already requested by 3-0012; cannot claim for 3-006f
pinctrl-rzg2l 11030000.pinctrl: pin-344 (3-006f) status -22
pinctrl-rzg2l 11030000.pinctrl: could not request pin 344 (P43_0) from group pmic  on device pinctrl-rzg2l
raa215300 3-006f: Error applying setting, reverse things back

Cheers,
Biju