Re: [PATCH 9/9] arm64: dts: renesas: rzg3s-smarc-som: Enable I3C

[Claudiu Beznea]

Hi, Wolfram,

On 5/22/26 15:29, Wolfram Sang wrote:
> The driver should
> know what to do, or? Am I missing something?

Could you please let me know what do you consider we should do here? Do you 
think we could drop these pin controller setting and do some particular I3C 
controller settings instead?

The documentation on the I3C_SET.STBN is limited. There are 2 places in the 
manual (Rev 1.20) that references it, both in the pin controller chapter.

The 1st is the "Figure 45.13 I3C (I3C_SDA, I3C_SCL)".

The 2nd is I3C_SET register documentation where it states:

Control the standby mode of I3C Interface.
0b: Standby mode*1
1b: Normal mode (Initial value)

With the note 1 being:

The output is fixed at Hi-Z and no data is transmitted to the inside even if 
data is input from outside. “Standby mode” is available when using I2C mode 
only. (Not available when using I3C mode).

The current driver proposal don't take into account the IP mode when setting 
STBN though pinctrl_pm_select_sleep_state()/pinctrl_pm_select_default_state() to 
keep the code simpler, relying on the "Not available when using I3C mode" part 
of the note, and considering setting it when the IP is in I3C mode is harmless.

--
Thank you,
Claudiu