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 14:24:57 +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 13:49, Biju Das wrote:
> Hi Claudiu,
> 
>> -----Original Message-----
>> From: claudiu beznea <claudiu.beznea@...on.dev>
>> Sent: Friday, June 28, 2024 11:25 AM
>> 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:
> 
> Now register layout is added to differentiate the SoCs for adding support
> to RZ/G3S and this layout should match with the hardware manual for all supported SoCs.
> Currently it is wrong for RZ/A2 SoC, while you fixed it for all other SoCs.

I checked RZ/A2M. There is nothing broken. The only thing that I see is
that the FP+ is not enabled on RZ/A2M (please let me know if there is
anything else I missed). I don't see this broken. It is the same behavior
that was before this patch.

Anyway, I'll update it for that too, if nobody has something against, but I
cannot test it. If any hardware bug for it, I cannot say.

> 
>>
>> 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.
> 
> You don't need to test, as 
> the existing other users don't have FMP+ enabled in device tree.

It's the same as today (w/o adding specific entry for it).

> 
> Cheers,
> Biju