linux-kernel - Re: [PATCH] regulator: lp873x: Update the enable mask for LDOs and BUCKs

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Message-ID: <72182869-6102-1178-91c4-0be632d4be32@ti.com>
Date:   Mon, 9 Oct 2017 18:35:14 +0300
From:   Tero Kristo <t-kristo@...com>
To:     Mark Brown <broonie@...nel.org>, Keerthy <j-keerthy@...com>
CC:     <linux-kernel@...r.kernel.org>, <lee.jones@...aro.org>,
        <linux-omap@...r.kernel.org>
Subject: Re: [PATCH] regulator: lp873x: Update the enable mask for LDOs and
 BUCKs


Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

On 09/10/17 17:20, Mark Brown wrote:
> On Wed, Sep 27, 2017 at 05:55:40PM +0530, Keerthy wrote:
>> The reset value of the EN_PIN_CTRL bit fields of LDOs and BUCKs
>> need not be set correctly. Hence update the enable mask to include
>> the EN_PIN_CTRL bit. While enabling this should be set to 1 so
>> that all the regulators are tied to EN pin.
> 
> I'm not sure I follow the logic here entirely.  It sounds like this is a
> register bit to control if the regulators are enabled and disabled via a
> GPIO instead of the register which is something that people might want
> to use in some systems.  Shouldn't this be dependent on some system
> configration instead?

The EN signal coming in to the PMIC is actually used to poweroff the 
system completely. There is no other mechanism for doing this in lp873x 
based systems, they removed the bit for controlling dev-power-off from 
the register space. If the EN bit is down for a specific regulator, it 
won't go down when attempting to poweroff the system, otherwise the 
state of a regulator is the result of (EN_PIN | EN_BIT).

I wonder if we should tie this somehow to the system-power-controller 
property though.... If the PMIC is not system-power-controller, we 
should disable the EN_PIN_CTRL from all regulators so that they don't go 
down if the EN_PIN itself is floating for example.

-Tero

> 
>>
>> Signed-off-by: Keerthy <j-keerthy@...com>
>> ---
>>   drivers/regulator/lp873x-regulator.c | 19 ++++++++++---------
>>   include/linux/mfd/lp873x.h           |  4 ++++
>>   2 files changed, 14 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/regulator/lp873x-regulator.c b/drivers/regulator/lp873x-regulator.c
>> index 70e3df6..77bea82 100644
>> --- a/drivers/regulator/lp873x-regulator.c
>> +++ b/drivers/regulator/lp873x-regulator.c
>> @@ -20,7 +20,7 @@
>>   #include <linux/mfd/lp873x.h>
>>   
>>   #define LP873X_REGULATOR(_name, _id, _of, _ops, _n, _vr, _vm, _er, _em, \
>> -			 _delay, _lr, _cr)				\
>> +			 _dv, _delay, _lr, _cr)				\
>>   	[_id] = {							\
>>   		.desc = {						\
>>   			.name			= _name,		\
>> @@ -36,6 +36,7 @@
>>   			.vsel_mask		= _vm,			\
>>   			.enable_reg		= _er,			\
>>   			.enable_mask		= _em,			\
>> +			.disable_val		= _dv,			\
>>   			.ramp_delay		= _delay,		\
>>   			.linear_ranges		= _lr,			\
>>   			.n_linear_ranges	= ARRAY_SIZE(_lr),	\
>> @@ -175,21 +176,21 @@ static int lp873x_buck_get_current_limit(struct regulator_dev *rdev)
>>   	LP873X_REGULATOR("BUCK0", LP873X_BUCK_0, "buck0", lp873x_buck01_ops,
>>   			 256, LP873X_REG_BUCK0_VOUT,
>>   			 LP873X_BUCK0_VOUT_BUCK0_VSET, LP873X_REG_BUCK0_CTRL_1,
>> -			 LP873X_BUCK0_CTRL_1_BUCK0_EN, 10000,
>> -			 buck0_buck1_ranges, LP873X_REG_BUCK0_CTRL_2),
>> +			 LP873X_BUCK_ENABLE_MASK, LP873X_BUCK_DISABLE_VAL,
>> +			 10000, buck0_buck1_ranges, LP873X_REG_BUCK0_CTRL_2),
>>   	LP873X_REGULATOR("BUCK1", LP873X_BUCK_1, "buck1", lp873x_buck01_ops,
>>   			 256, LP873X_REG_BUCK1_VOUT,
>>   			 LP873X_BUCK1_VOUT_BUCK1_VSET, LP873X_REG_BUCK1_CTRL_1,
>> -			 LP873X_BUCK1_CTRL_1_BUCK1_EN, 10000,
>> -			 buck0_buck1_ranges, LP873X_REG_BUCK1_CTRL_2),
>> +			 LP873X_BUCK_ENABLE_MASK, LP873X_BUCK_DISABLE_VAL,
>> +			 10000, buck0_buck1_ranges, LP873X_REG_BUCK1_CTRL_2),
>>   	LP873X_REGULATOR("LDO0", LP873X_LDO_0, "ldo0", lp873x_ldo01_ops, 26,
>>   			 LP873X_REG_LDO0_VOUT, LP873X_LDO0_VOUT_LDO0_VSET,
>> -			 LP873X_REG_LDO0_CTRL,
>> -			 LP873X_LDO0_CTRL_LDO0_EN, 0, ldo0_ldo1_ranges, 0xFF),
>> +			 LP873X_REG_LDO0_CTRL, LP873X_LDO_ENABLE_MASK,
>> +			 LP873X_LDO_DISABLE_VAL, 0, ldo0_ldo1_ranges, 0xFF),
>>   	LP873X_REGULATOR("LDO1", LP873X_LDO_1, "ldo1", lp873x_ldo01_ops, 26,
>>   			 LP873X_REG_LDO1_VOUT, LP873X_LDO1_VOUT_LDO1_VSET,
>> -			 LP873X_REG_LDO1_CTRL,
>> -			 LP873X_LDO1_CTRL_LDO1_EN, 0, ldo0_ldo1_ranges, 0xFF),
>> +			 LP873X_REG_LDO1_CTRL, LP873X_LDO_ENABLE_MASK,
>> +			 LP873X_LDO_DISABLE_VAL, 0, ldo0_ldo1_ranges, 0xFF),
>>   };
>>   
>>   static int lp873x_regulator_probe(struct platform_device *pdev)
>> diff --git a/include/linux/mfd/lp873x.h b/include/linux/mfd/lp873x.h
>> index edbec83..53888d4 100644
>> --- a/include/linux/mfd/lp873x.h
>> +++ b/include/linux/mfd/lp873x.h
>> @@ -77,6 +77,8 @@
>>   #define LP873X_BUCK0_CTRL_1_BUCK0_RDIS_EN	BIT(2)
>>   #define LP873X_BUCK0_CTRL_1_BUCK0_EN_PIN_CTRL	BIT(1)
>>   #define LP873X_BUCK0_CTRL_1_BUCK0_EN		BIT(0)
>> +#define LP873X_BUCK_ENABLE_MASK			(BIT(0) | BIT(1))
>> +#define	LP873X_BUCK_DISABLE_VAL			BIT(1)
>>   
>>   #define LP873X_BUCK0_CTRL_2_BUCK0_ILIM		0x38
>>   #define LP873X_BUCK0_CTRL_2_BUCK0_SLEW_RATE	0x07
>> @@ -96,6 +98,8 @@
>>   #define LP873X_LDO0_CTRL_LDO0_RDIS_EN		BIT(2)
>>   #define LP873X_LDO0_CTRL_LDO0_EN_PIN_CTRL	BIT(1)
>>   #define LP873X_LDO0_CTRL_LDO0_EN		BIT(0)
>> +#define LP873X_LDO_ENABLE_MASK			(BIT(0) | BIT(1))
>> +#define LP873X_LDO_DISABLE_VAL			BIT(1)
>>   
>>   #define LP873X_LDO1_CTRL_LDO1_RDIS_EN		BIT(2)
>>   #define LP873X_LDO1_CTRL_LDO1_EN_PIN_CTRL	BIT(1)
>> -- 
>> 1.9.1
>>