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

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Message-ID: <20ff64a8-e619-4281-894f-1aa08ea67f18@tuxon.dev>
Date: Fri, 28 Jun 2024 13:25:02 +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 11:24, Biju Das wrote:
> Hi Claudiu,
> 
>> -----Original Message-----
>> From: claudiu beznea <claudiu.beznea@...on.dev>
>> Sent: Friday, June 28, 2024 9:13 AM
>> 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.
> 
> Maybe make the register layout as per SoC
> 
> RZ/A1 --> &riic_rz_a_info
> RZ/A2 and RZ/{G2L,G2LC,V2L,G2UL,FIVE} --> &riic_rz_g2_info
> RZ/G3S and RZ/V2H --> &riic_rz_v2h_info

Sorry, but I don't understand. Patch 09/12 already does that but a bit
differently:

RZ/{G2L, G2LC, G2UL, V2L, FIVE} -> riic_rz_g2_info
RZ/G3S and RZ/V2H -> riic_rz_v2h_info
Everything else: riic_rz_a_info

I don't have anything at hand to test the "everything else" thus I enabled
it for RZ/{G2L, G2LC, G2UL, V2L, FIVE}, RZ/G3S and RZ/V2H.

> 
> Then except RZ/A1, set FMP. 

I cannot test all these.

> 
> Currently register layout of RZ/A2 is not matching with
> Hardware manual.

I cannot test this either. Also, I think this is not the purpose of this
series.

Thank you,
Claudiu Beznea

> 
> Cheers,
> Biju