linux-kernel - Re: [PATCH v8 5/9] mfd: bcm590xx: Add PMU ID/revision parsing function

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Message-ID: <7eeaa7b4-b76d-4658-ac78-705a5f8e54df@gmail.com>
Date: Tue, 6 May 2025 21:03:15 +0200
From: Artur Weber <aweber.kernel@...il.com>
To: Stanislav Jakubek <stano.jakubek@...il.com>
Cc: Lee Jones <lee@...nel.org>, Rob Herring <robh@...nel.org>,
 Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley
 <conor+dt@...nel.org>, Liam Girdwood <lgirdwood@...il.com>,
 Mark Brown <broonie@...nel.org>,
 Florian Fainelli <florian.fainelli@...adcom.com>, Ray Jui
 <rjui@...adcom.com>, Scott Branden <sbranden@...adcom.com>,
 Broadcom internal kernel review list
 <bcm-kernel-feedback-list@...adcom.com>, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
 ~postmarketos/upstreaming@...ts.sr.ht
Subject: Re: [PATCH v8 5/9] mfd: bcm590xx: Add PMU ID/revision parsing
 function

On 5/6/25 18:11, Stanislav Jakubek wrote:
> Hi Artur,
> one note below.
> 
> On Wed, Apr 30, 2025 at 09:07:09AM +0200, Artur Weber wrote:
>> The BCM590xx PMUs have two I2C registers for reading the PMU ID
>> and revision. The revision is useful for subdevice drivers, since
>> different revisions may have slight differences in behavior (for
>> example - BCM59054 has different regulator configurations for
>> revision A0 and A1).
>>
>> Check the PMU ID register and make sure it matches the DT compatible.
>> Fetch the digital and analog revision from the PMUREV register
>> so that it can be used in subdevice drivers.
>>
>> Also add some known revision values to bcm590xx.h, for convenience
>> when writing subdevice drivers.
>>
>> Signed-off-by: Artur Weber <aweber.kernel@...il.com>
>> ---
> 
> [snip]
> 
>> diff --git a/include/linux/mfd/bcm590xx.h b/include/linux/mfd/bcm590xx.h
>> index 8d146e3b102a7dbce6f4dbab9f8ae5a9c4e68c0e..fbc458e94bef923ca1b69afe2cac944adf6fedf8 100644
>> --- a/include/linux/mfd/bcm590xx.h
>> +++ b/include/linux/mfd/bcm590xx.h
>> @@ -17,6 +17,16 @@
>>   #define BCM590XX_PMUID_BCM59054		0x54
>>   #define BCM590XX_PMUID_BCM59056		0x56
>>   
>> +/* Known chip revision IDs */
>> +#define BCM59054_REV_DIGITAL_A1		1
> 
> 1 seems to be the digital revision ID for A0 (couldn't find the analog
> revision ID), see [1].
> 
> Other values seems to match downstream (as far as I can tell anyway).
> 
> [1] https://github.com/Samsung-KYLEPROXX/android_kernel_samsung_kyleproxx/blob/cm-13.0/include/linux/mfd/bcmpmu59xxx.h#L82
 From my testing on a device with the BCM59054A1 (BCM23550-based Samsung 
Galaxy Grand Neo), the digital value is also 1 on this model:

   bcm590xx 0-0008: PMU ID 0x54 (BCM59054), revision: dig 1 ana 2

(This constant is not actually used anywhere in code yet - I just
included it for the sake of completeness, since the BCM59056 headers
in downstream listed both values...)

Best regards
Artur