linux-kernel - Re: [PATCH v2 07/12] i2c: riic: Define individual arrays to describe the register offsets

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Date: Fri, 28 Jun 2024 11:12:45 +0300
From: claudiu beznea <claudiu.beznea@...on.dev>
To: Biju Das <biju.das.jz@...renesas.com>,
 Chris Brandt <Chris.Brandt@...esas.com>,
 "andi.shyti@...nel.org" <andi.shyti@...nel.org>,
 "robh@...nel.org" <robh@...nel.org>, "krzk+dt@...nel.org"
 <krzk+dt@...nel.org>, "conor+dt@...nel.org" <conor+dt@...nel.org>,
 "geert+renesas@...der.be" <geert+renesas@...der.be>,
 "magnus.damm@...il.com" <magnus.damm@...il.com>,
 "mturquette@...libre.com" <mturquette@...libre.com>,
 "sboyd@...nel.org" <sboyd@...nel.org>,
 "p.zabel@...gutronix.de" <p.zabel@...gutronix.de>,
 "wsa+renesas@...g-engineering.com" <wsa+renesas@...g-engineering.com>
Cc: "linux-renesas-soc@...r.kernel.org" <linux-renesas-soc@...r.kernel.org>,
 "linux-i2c@...r.kernel.org" <linux-i2c@...r.kernel.org>,
 "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
 "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
 "linux-clk@...r.kernel.org" <linux-clk@...r.kernel.org>,
 Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
Subject: Re: [PATCH v2 07/12] i2c: riic: Define individual arrays to describe
 the register offsets



On 28.06.2024 11:09, Biju Das wrote:
> 
> Hi Claudiu,
> 
>> -----Original Message-----
>> From: claudiu beznea <claudiu.beznea@...on.dev>
>> Sent: Friday, June 28, 2024 9:03 AM
>> Subject: Re: [PATCH v2 07/12] i2c: riic: Define individual arrays to describe the register offsets
>>
>>
>>
>> On 28.06.2024 10:55, Biju Das wrote:
>>> Hi Claudiu,
>>>
>>>> -----Original Message-----
>>>> From: claudiu beznea <claudiu.beznea@...on.dev>
>>>> Sent: Friday, June 28, 2024 8:32 AM
>>>> Subject: Re: [PATCH v2 07/12] i2c: riic: Define individual arrays to
>>>> describe the register offsets
>>>>
>>>> Hi, Biju,
>>>>
>>>> On 28.06.2024 08:59, Biju Das wrote:
>>>>> Hi Claudiu,
>>>>>
>>>>>> -----Original Message-----
>>>>>> From: Claudiu <claudiu.beznea@...on.dev>
>>>>>> Sent: Tuesday, June 25, 2024 1:14 PM
>>>>>> Subject: [PATCH v2 07/12] i2c: riic: Define individual arrays to
>>>>>> describe the register offsets
>>>>>>
>>>>>> From: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
>>>>>>
>>>>>> Define individual arrays to describe the register offsets. In this
>>>>>> way we can describe different IP variants that share the same
>>>>>> register offsets but have differences in other characteristics.
>>>>>> Commit prepares for the addition
>>>> of fast mode plus.
>>>>>>
>>>>>> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
>>>>>> ---
>>>>>>
>>>>>> Changes in v2:
>>>>>> - none
>>>>>>
>>>>>>  drivers/i2c/busses/i2c-riic.c | 58
>>>>>> +++++++++++++++++++----------------
>>>>>>  1 file changed, 31 insertions(+), 27 deletions(-)
>>>>>>
>>>>>> diff --git a/drivers/i2c/busses/i2c-riic.c
>>>>>> b/drivers/i2c/busses/i2c-riic.c index
>>>>>> 9fe007609076..8ffbead95492 100644
>>>>>> --- a/drivers/i2c/busses/i2c-riic.c
>>>>>> +++ b/drivers/i2c/busses/i2c-riic.c
>>>>>> @@ -91,7 +91,7 @@ enum riic_reg_list {  };
>>>>>>
>>>>>>  struct riic_of_data {
>>>>>> -	u8 regs[RIIC_REG_END];
>>>>>> +	const u8 *regs;
>>>>>
>>>>>
>>>>> Since you are touching this part, can we drop struct and Use u8* as
>>>>> device_data instead?
>>>>
>>>> Patch 09/12 "i2c: riic: Add support for fast mode plus" adds a new member to struct
>> riic_of_data.
>>>> That new member is needed to differentiate b/w hardware versions
>>>> supporting fast mode plus based on compatible.
>>>
>>> Are we sure RZ/A does not support fast mode plus?
>>
>> From commit description of patch 09/12:
>>
>> Fast mode plus is available on most of the IP variants that RIIC driver is working with. The
>> exception is (according to HW manuals of the SoCs where this IP is available) the Renesas RZ/A1H.
>> For this, patch introduces the struct riic_of_data::fast_mode_plus.
>>
>> I checked the manuals of all the SoCs where this driver is used.
>>
>> I haven't checked the H/W manual?
>>
>> On the manual I've downloaded from Renesas web site the FMPE bit of RIICnFER is not available on
>> RZ/A1H.
> 
> I just found RZ/A2M manual, it supports FMP and register layout looks similar to RZ/G2L.

I introduced struct riic_of_data::fast_mode_plus because of RZ/A1H.

> Wolfram tested it with r7s72100 genmai board acessing an eeprom. Not sure is it RZ/A1 or RZ/A2?
> 
> Cheers,
> Biju
>