linux-kernel - Re: [PATCH] regulator: Simplify MAX8997_REG_BUCK1DVS/MAX8997_REG_BUCK2DVS/MAX8997_REG

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Date:	Mon, 16 May 2011 16:05:11 +0800
From:	Axel Lin <axel.lin@...il.com>
To:	myungjoo.ham@...sung.com
Cc:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	박경민 <kyungmin.park@...sung.com>,
	Liam Girdwood <lrg@...mlogic.co.uk>,
	Mark Brown <broonie@...nsource.wolfsonmicro.com>,
	Samuel Ortiz <sameo@...ux.intel.com>,
	"myungjoo.ham@...il.com" <myungjoo.ham@...il.com>
Subject: Re: [PATCH] regulator: Simplify MAX8997_REG_BUCK1DVS/MAX8997_REG_BUCK2DVS/MAX8997_REG_BUCK5DVS
 macros

Hi MyungJoo,

2011/5/16 함명주 <myungjoo.ham@...sung.com>:
> Hello,
>
>> Sender : Axel Lin<axel.lin@...il.com>
>> Date : 2011-05-16 15:52 (GMT+09:00)
>> Title : [PATCH] regulator: Simplify MAX8997_REG_BUCK1DVS/MAX8997_REG_BUCK2DVS/MAX8997_REG_BUCK5DVS macros
>>
>> Looks like the original macro implementation assumes the caller pass the
>> parameter starting from 1.
>> Since now we have +1 operation from all the caller, it would be easier to
>> assume the caller pass the parameter starting from 0.
>> Then we can simplify the +1 operation from the caller and then -1 operation
>> in the macro implementation.
>>
>> I think this change also improves readability.
>>
>> Signed-off-by: Axel Lin
>
> Well, I'd rather just change the for loop statement for your purpose, which I also agree.
>
> The reason I've used BUCKxDVS1 as the starting point is because of the register names; register names of BUCKxDVS starts from 1, not from 0.

Ok. I got your point for the implementation.

> Thus, in order to maintain the consistency between the code and the chip manual, I'd rather not change that part, but change like this:
>
> ---
> diff --git a/drivers/regulator/max8997.c b/drivers/regulator/max8997.c
> index b1c1444..aad85e4 100644
> --- a/drivers/regulator/max8997.c
> +++ b/drivers/regulator/max8997.c
> @@ -1031,12 +1031,12 @@ static __devinit int max8997_pmic_probe(struct platform_device *pdev)
>        }
>
>        /* For the safety, set max voltage before setting up */
> -       for (i = 0; i < 8; i++) {
> -               max8997_update_reg(i2c, MAX8997_REG_BUCK1DVS(i + 1),
> +       for (i = 1; i <= 8; i++) {
> +               max8997_update_reg(i2c, MAX8997_REG_BUCK1DVS(i),
>                                max_buck1, 0x3f);
> -               max8997_update_reg(i2c, MAX8997_REG_BUCK2DVS(i + 1),
> +               max8997_update_reg(i2c, MAX8997_REG_BUCK2DVS(i),
>                                max_buck2, 0x3f);
> -               max8997_update_reg(i2c, MAX8997_REG_BUCK5DVS(i + 1),
> +               max8997_update_reg(i2c, MAX8997_REG_BUCK5DVS(i),
>                                max_buck5, 0x3f);
>        }
>
> --
> 1.7.4.1
>
> How about this one?
>
But it doesn't apply for below case because max8997->buck1_vol[i] is
start from 0.


        for (i = 0; i < 8; i++) {
                max8997_update_reg(i2c, MAX8997_REG_BUCK1DVS(i),
                                max8997->buck1_vol[i],
                                0x3f);

Maybe consider to remove the macro may make things simpler.
If you agree, I'll send a v2.

diff --git a/drivers/regulator/max8997.c b/drivers/regulator/max8997.c
index b1c1444..10d5a1d 100644
--- a/drivers/regulator/max8997.c
+++ b/drivers/regulator/max8997.c
@@ -1032,11 +1032,11 @@ static __devinit int max8997_pmic_probe(struct
platform_device *pdev)

 	/* For the safety, set max voltage before setting up */
 	for (i = 0; i < 8; i++) {
-		max8997_update_reg(i2c, MAX8997_REG_BUCK1DVS(i + 1),
+		max8997_update_reg(i2c, MAX8997_REG_BUCK1DVS1 + i,
 				max_buck1, 0x3f);
-		max8997_update_reg(i2c, MAX8997_REG_BUCK2DVS(i + 1),
+		max8997_update_reg(i2c, MAX8997_REG_BUCK2DVS1 + i,
 				max_buck2, 0x3f);
-		max8997_update_reg(i2c, MAX8997_REG_BUCK5DVS(i + 1),
+		max8997_update_reg(i2c, MAX8997_REG_BUCK5DVS1 + i,
 				max_buck5, 0x3f);
 	}

@@ -1113,13 +1113,13 @@ static __devinit int max8997_pmic_probe(struct
platform_device *pdev)

 	/* Initialize all the DVS related BUCK registers */
 	for (i = 0; i < 8; i++) {
-		max8997_update_reg(i2c, MAX8997_REG_BUCK1DVS(i + 1),
+		max8997_update_reg(i2c, MAX8997_REG_BUCK1DVS1 + i,
 				max8997->buck1_vol[i],
 				0x3f);
-		max8997_update_reg(i2c, MAX8997_REG_BUCK2DVS(i + 1),
+		max8997_update_reg(i2c, MAX8997_REG_BUCK2DVS1 + i,
 				max8997->buck2_vol[i],
 				0x3f);
-		max8997_update_reg(i2c, MAX8997_REG_BUCK5DVS(i + 1),
+		max8997_update_reg(i2c, MAX8997_REG_BUCK5DVS1 + i,
 				max8997->buck5_vol[i],
 				0x3f);
 	}
diff --git a/include/linux/mfd/max8997-private.h
b/include/linux/mfd/max8997-private.h
index 69d1010..5ff2400 100644
--- a/include/linux/mfd/max8997-private.h
+++ b/include/linux/mfd/max8997-private.h
@@ -311,10 +311,6 @@ enum max8997_irq {
 	MAX8997_IRQ_NR,
 };

-#define MAX8997_REG_BUCK1DVS(x)	(MAX8997_REG_BUCK1DVS1 + (x) - 1)
-#define MAX8997_REG_BUCK2DVS(x)	(MAX8997_REG_BUCK2DVS1 + (x) - 1)
-#define MAX8997_REG_BUCK5DVS(x)	(MAX8997_REG_BUCK5DVS1 + (x) - 1)
-
 #define MAX8997_NUM_GPIO	12
 struct max8997_dev {
 	struct device *dev;


Regards,
Axel
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