Re: [PATCH 03/17] i3c: renesas: Restore STDBR and EXTBR registers on resume

[Claudiu Beznea <claudiu.beznea@kernel.org>]

Hi, Frank,

On 5/22/26 22:10, Frank Li wrote:
> On Fri, May 22, 2026 at 01:18:01PM +0300, Claudiu Beznea wrote:
>> From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
>>
>> The Renesas RZ/G3S supports a power saving state where power to the most
>> SoC componentes (including I3C) is lost.
>>
>> The STDBR and EXTBR are configured in initialization phase though the
>> struct i3c_master_controller_ops::bus_init. Set them on resume function
>> as well to keep the same state of the controller after a suspend with
>> power loss and a similar initialization sequence as in bus_init.
>>
>> Fixes: e7218986319b ("i3c: renesas: Add suspend/resume support")
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
>> ---
>>   drivers/i3c/master/renesas-i3c.c | 10 ++++++----
>>   1 file changed, 6 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/i3c/master/renesas-i3c.c b/drivers/i3c/master/renesas-i3c.c
>> index 1917549cf6d5..6c23f956ad2a 100644
>> --- a/drivers/i3c/master/renesas-i3c.c
>> +++ b/drivers/i3c/master/renesas-i3c.c
>> @@ -260,6 +260,7 @@ struct renesas_i3c {
>>   	u32 dyn_addr;
>>   	u32 i2c_STDBR;
>>   	u32 i3c_STDBR;
>> +	u32 extbr;
> 
> can you keep consisent with above 2 register, use upcase EXTBR,

Using upper case for this will mislead the compiler. There is already a macro 
defined for EXTBR:

#define EXTBR                   0x78

Defining this member as:

u32 EXTBR;

will make the compiler try to replace the EXTBR in "i3c->EXTBR" at preprocessing 
time:

   CC [M]  drivers/i3c/master/renesas-i3c.o
../drivers/i3c/master/renesas-i3c.c:65:17: error: expected identifier or ‘(’ 
before numeric constant
    65 | #define EXTBR   0x78
       |                 ^~~~
../drivers/i3c/master/renesas-i3c.c:263:6: note: in expansion of macro ‘EXTBR’
   263 |  u32 EXTBR;
       |      ^~~~~
../drivers/i3c/master/renesas-i3c.c: In function ‘renesas_i3c_bus_init’:
../drivers/i3c/master/renesas-i3c.c:65:17: error: expected identifier before 
numeric constant
    65 | #define EXTBR   0x78
       |                 ^~~~
../drivers/i3c/master/renesas-i3c.c:611:7: note: in expansion of macro ‘EXTBR’
   611 |  i3c->EXTBR = EXTBR_EBRLO(od_low_ticks) | EXTBR_EBRHO(od_high_ticks) |
       |       ^~~~~
../drivers/i3c/master/renesas-i3c.c:65:17: error: expected identifier before 
numeric constant
    65 | #define EXTBR   0x78
       |                 ^~~~
../drivers/i3c/master/renesas-i3c.c:613:40: note: in expansion of macro ‘EXTBR’
   613 |  renesas_writel(i3c->regs, EXTBR, i3c->EXTBR);
       |                                        ^~~~~
../drivers/i3c/master/renesas-i3c.c: In function ‘renesas_i3c_resume_noirq’:
../drivers/i3c/master/renesas-i3c.c:65:17: error: expected identifier before 
numeric constant
    65 | #define EXTBR   0x78
       |                 ^~~~
../drivers/i3c/master/renesas-i3c.c:1451:40: note: in expansion of macro ‘EXTBR’
  1451 |  renesas_writel(i3c->regs, EXTBR, i3c->EXTBR);
       |                                        ^~~~~

The register contains both i3c and i2c specific fields. I'm not sure using 
i2c_i3c_EXTBR is the best way to go forward for this or just keeping it as is.

-- 
Thank you,
Claudiu


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