linux-kernel - Re: [PATCH v3 3/3] spmi: spmi-pmic-arb: add support for PMIC arbiter v8

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Message-ID: <784de75a-2821-46f2-a6d0-a4c4a6a13dfe@oss.qualcomm.com>
Date: Mon, 27 Oct 2025 14:54:45 +0530
From: Jishnu Prakash <jishnu.prakash@....qualcomm.com>
To: Neil Armstrong <neil.armstrong@...aro.org>,
        Stephen Boyd <sboyd@...nel.org>, Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley
 <conor+dt@...nel.org>,
        David Collins <david.collins@....qualcomm.com>
Cc: linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org, aiqun.yu@....qualcomm.com,
        kamal.wadhwa@....qualcomm.com, jingyi.wang@....qualcomm.com
Subject: Re: [PATCH v3 3/3] spmi: spmi-pmic-arb: add support for PMIC arbiter
 v8

Hi Neil,

On 10/24/2025 3:48 PM, Neil Armstrong wrote:
> Hi,
> 
> On 10/24/25 11:33, Jishnu Prakash wrote:
>> From: David Collins <david.collins@....qualcomm.com>
>>
>> PMIC arbiter v8 supports up to 4 SPMI buses and up to 8192 PMIC
>> peripherals.  Its register map differs from v7 as several fields
>> increased in size. Add support for PMIC arbiter version 8.
>>
>> Signed-off-by: David Collins <david.collins@....qualcomm.com>
>> Signed-off-by: Kamal Wadhwa <kamal.wadhwa@....qualcomm.com>
>> Signed-off-by: Jishnu Prakash <jishnu.prakash@....qualcomm.com>
>> ---
>>   drivers/spmi/spmi-pmic-arb.c | 324 +++++++++++++++++++++++++++++++++++++++----
>>   1 file changed, 294 insertions(+), 30 deletions(-)
>>
>> diff --git a/drivers/spmi/spmi-pmic-arb.c b/drivers/spmi/spmi-pmic-arb.c
>> index 91581974ef84..612736973e4b 100644
>> --- a/drivers/spmi/spmi-pmic-arb.c
>> +++ b/drivers/spmi/spmi-pmic-arb.c
>> @@ -3,6 +3,7 @@
>>    * Copyright (c) 2012-2015, 2017, 2021, The Linux Foundation. All rights reserved.
>>    */
>>   #include <linux/bitmap.h>
>> +#include <linux/bitfield.h>
>>   #include <linux/delay.h>
>>   #include <linux/err.h>
>>   #include <linux/interrupt.h>
>> @@ -25,10 +26,12 @@
>>   #define PMIC_ARB_VERSION_V3_MIN        0x30000000
>>   #define PMIC_ARB_VERSION_V5_MIN        0x50000000
>>   #define PMIC_ARB_VERSION_V7_MIN        0x70000000
>> +#define PMIC_ARB_VERSION_V8_MIN        0x80000000
>>   #define PMIC_ARB_INT_EN            0x0004
>>     #define PMIC_ARB_FEATURES        0x0004
>>   #define PMIC_ARB_FEATURES_PERIPH_MASK    GENMASK(10, 0)
>> +#define PMIC_ARB_FEATURES_V8_PERIPH_MASK    GENMASK(12, 0)
>>     #define PMIC_ARB_FEATURES1        0x0008
>>   @@ -50,9 +53,10 @@
>>   #define SPMI_MAPPING_BIT_IS_1_RESULT(X)    (((X) >> 0) & 0xFF)
>>     #define SPMI_MAPPING_TABLE_TREE_DEPTH    16    /* Maximum of 16-bits */
>> -#define PMIC_ARB_MAX_PPID        BIT(12) /* PPID is 12bit */
>> +#define PMIC_ARB_MAX_PPID        BIT(13)
>>   #define PMIC_ARB_APID_VALID        BIT(15)
>>   #define PMIC_ARB_CHAN_IS_IRQ_OWNER(reg)    ((reg) & BIT(24))
>> +#define PMIC_ARB_V8_CHAN_IS_IRQ_OWNER(reg)    ((reg) & BIT(31))
>>   #define INVALID_EE                0xFF
>>     /* Ownership Table */
>> @@ -96,30 +100,33 @@ enum pmic_arb_channel {
>>       PMIC_ARB_CHANNEL_OBS,
>>   };
>>   -#define PMIC_ARB_MAX_BUSES        2
>> +#define PMIC_ARB_MAX_BUSES        4
> 
> Why PMIC_ARB_MAX_BUSES is changed to 4 ?

PMIC_ARB_MAX_BUSES is used only in the definition of
struct spmi_pmic_arb, for this member:

	struct spmi_pmic_arb_bus *buses[PMIC_ARB_MAX_BUSES];

The PMIC Arbiter v8 is capable of supporting up to 4
SPMI buses, so this change is needed to support it.

Thanks,
Jishnu

> 
> Neil
> 
> <snip>
>