linux-kernel - Re: [PATCH 2/2] mfd: da9063: Make vbcore registers volatile

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Message-ID: <358de8cf-ec40-3552-da0d-98b065120649@norik.com>
Date:   Wed, 24 Nov 2021 15:04:48 +0100
From:   Andrej Picej <andrej.picej@...ik.com>
To:     Adam Thomson <Adam.Thomson.Opensource@...semi.com>,
        Support Opensource <Support.Opensource@...semi.com>,
        "lee.jones@...aro.org" <lee.jones@...aro.org>
Cc:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "s.riedmueller@...tec.de" <s.riedmueller@...tec.de>
Subject: Re: [PATCH 2/2] mfd: da9063: Make vbcore registers volatile

Hi Adam,

On 24. 11. 21 10:34, Adam Thomson wrote:
> On 24 November 2021 07:00, Andrej Picej wrote:
> 
>> From: Stefan Riedmueller <s.riedmueller@...tec.de>
>>
>> The VBCORE1_A and VBCORE2_A registers are used to set the desired output
>> voltage of the BCORE 1 and 2 buck regulators. These values can be critical
>> if used as input for core voltages. Thus make them volatile so they do not
>> get cached.
> 
> I don't understand the need for this change. What is this fixing? As I
> understand it the registers in question aren't volatile so should persist.

So basically this two patches were needed because we needed to enable 
internal LDOs bypass mode on the imx6 and in the process this PMICs regs 
needed to be somehow adjusted, which only worked if this regs were 
marked as volatile. Long story short, this method was only introduced in 
Phytec's version so upstreaming really doesn't make much sense.

I apologize for any inconvenience, but this two patches somehow slipped 
through the process and landed on the "send-to-upstream" list. I also 
talked with @Stefan Rieadmueller and he agreed that this two patches can 
be dropped.

Thanks for your time.

> 
>> Signed-off-by: Stefan Riedmueller <s.riedmueller@...tec.de>
>> Signed-off-by: Andrej Picej <andrej.picej@...ik.com>
>> ---
>>   drivers/mfd/da9063-i2c.c | 2 ++
>>   1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/mfd/da9063-i2c.c b/drivers/mfd/da9063-i2c.c
>> index 343ed6e96d87..8a3629c30382 100644
>> --- a/drivers/mfd/da9063-i2c.c
>> +++ b/drivers/mfd/da9063-i2c.c
>> @@ -161,6 +161,7 @@ static const struct regmap_range
>> da9063_ad_volatile_ranges[] = {
>>   	regmap_reg_range(DA9063_REG_ADC_RES_L,
>> DA9063_AD_REG_SECOND_D),
>>   	regmap_reg_range(DA9063_REG_SEQ, DA9063_REG_SEQ),
>>   	regmap_reg_range(DA9063_REG_EN_32K, DA9063_REG_EN_32K),
>> +	regmap_reg_range(DA9063_REG_VBCORE2_A,
>> DA9063_REG_VBCORE2_A),
>>   	regmap_reg_range(DA9063_AD_REG_MON_REG_5,
>> DA9063_AD_REG_MON_REG_6),
>>   };
>>
>> @@ -206,6 +207,7 @@ static const struct regmap_range
>> da9063_bb_da_volatile_ranges[] = {
>>   	regmap_reg_range(DA9063_REG_ADC_RES_L,
>> DA9063_BB_REG_SECOND_D),
>>   	regmap_reg_range(DA9063_REG_SEQ, DA9063_REG_SEQ),
>>   	regmap_reg_range(DA9063_REG_EN_32K, DA9063_REG_EN_32K),
>> +	regmap_reg_range(DA9063_REG_VBCORE2_A,
>> DA9063_REG_VBCORE2_A),
>>   	regmap_reg_range(DA9063_BB_REG_MON_REG_5,
>> DA9063_BB_REG_MON_REG_6),
>>   };
>>
>> --
>> 2.25.1
>