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 11:04:51 +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 11:02, claudiu beznea wrote:
> 
> 
> 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?

That's Biju's previous statement. Sorry for not formatting it properly.

> 
> On the manual I've downloaded from Renesas web site the FMPE bit of
> RIICnFER is not available on RZ/A1H.
> 
> Thank you,
> Claudiu Beznea
> 
>> If it does not, then it make sense to keep the patch as it is.
>>
>> Cheers,
>> Biju
>>
>>>
>>> Keeping struct riic_of_data is necessary (unless I misunderstood your proposal).
>>>
>>> Thank you,
>>> Claudiu Beznea
>>>
>>>>
>>>> ie, replace const struct riic_of_data *info->const u8 *regs in struct
>>>> riic_dev and use .data = riic_rz_xx_regs in of_match_table?
>>>>
>>>> Cheers,
>>>> Biju
>>>>>  };
>>>>>
>>>>>  struct riic_dev {
>>>>> @@ -531,36 +531,40 @@ static void riic_i2c_remove(struct platform_device *pdev)
>>>>>  	pm_runtime_dont_use_autosuspend(dev);
>>>>>  }
>>>>>
>>>>> +static const u8 riic_rz_a_regs[RIIC_REG_END] = {
>>>>> +	[RIIC_ICCR1] = 0x00,
>>>>> +	[RIIC_ICCR2] = 0x04,
>>>>> +	[RIIC_ICMR1] = 0x08,
>>>>> +	[RIIC_ICMR3] = 0x10,
>>>>> +	[RIIC_ICSER] = 0x18,
>>>>> +	[RIIC_ICIER] = 0x1c,
>>>>> +	[RIIC_ICSR2] = 0x24,
>>>>> +	[RIIC_ICBRL] = 0x34,
>>>>> +	[RIIC_ICBRH] = 0x38,
>>>>> +	[RIIC_ICDRT] = 0x3c,
>>>>> +	[RIIC_ICDRR] = 0x40,
>>>>> +};
>>>>> +
>>>>>  static const struct riic_of_data riic_rz_a_info = {
>>>>> -	.regs = {
>>>>> -		[RIIC_ICCR1] = 0x00,
>>>>> -		[RIIC_ICCR2] = 0x04,
>>>>> -		[RIIC_ICMR1] = 0x08,
>>>>> -		[RIIC_ICMR3] = 0x10,
>>>>> -		[RIIC_ICSER] = 0x18,
>>>>> -		[RIIC_ICIER] = 0x1c,
>>>>> -		[RIIC_ICSR2] = 0x24,
>>>>> -		[RIIC_ICBRL] = 0x34,
>>>>> -		[RIIC_ICBRH] = 0x38,
>>>>> -		[RIIC_ICDRT] = 0x3c,
>>>>> -		[RIIC_ICDRR] = 0x40,
>>>>> -	},
>>>>> +	.regs = riic_rz_a_regs,
>>>>> +};
>>>>> +
>>>>> +static const u8 riic_rz_v2h_regs[RIIC_REG_END] = {
>>>>> +	[RIIC_ICCR1] = 0x00,
>>>>> +	[RIIC_ICCR2] = 0x01,
>>>>> +	[RIIC_ICMR1] = 0x02,
>>>>> +	[RIIC_ICMR3] = 0x04,
>>>>> +	[RIIC_ICSER] = 0x06,
>>>>> +	[RIIC_ICIER] = 0x07,
>>>>> +	[RIIC_ICSR2] = 0x09,
>>>>> +	[RIIC_ICBRL] = 0x10,
>>>>> +	[RIIC_ICBRH] = 0x11,
>>>>> +	[RIIC_ICDRT] = 0x12,
>>>>> +	[RIIC_ICDRR] = 0x13,
>>>>>  };
>>>>>
>>>>>  static const struct riic_of_data riic_rz_v2h_info = {
>>>>> -	.regs = {
>>>>> -		[RIIC_ICCR1] = 0x00,
>>>>> -		[RIIC_ICCR2] = 0x01,
>>>>> -		[RIIC_ICMR1] = 0x02,
>>>>> -		[RIIC_ICMR3] = 0x04,
>>>>> -		[RIIC_ICSER] = 0x06,
>>>>> -		[RIIC_ICIER] = 0x07,
>>>>> -		[RIIC_ICSR2] = 0x09,
>>>>> -		[RIIC_ICBRL] = 0x10,
>>>>> -		[RIIC_ICBRH] = 0x11,
>>>>> -		[RIIC_ICDRT] = 0x12,
>>>>> -		[RIIC_ICDRR] = 0x13,
>>>>> -	},
>>>>> +	.regs = riic_rz_v2h_regs,
>>>>>  };
>>>>>
>>>>>  static int riic_i2c_suspend(struct device *dev)
>>>>> --
>>>>> 2.39.2
>>>>>
>>>>