linux-kernel - Re: [PATCH v3 1/2] MFD: MAX77693: add MAX77693 MFD driver

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Date:	Mon, 14 May 2012 19:08:03 +0900
From:	Chanwoo Choi <cw00.choi@...sung.com>
To:	Mark Brown <broonie@...nsource.wolfsonmicro.com>
Cc:	sameo@...ux.intel.com, myungjoo.ham@...sung.com,
	kyungmin.park@...sung.com, jonghwa3.lee@...sung.com,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 1/2] MFD: MAX77693: add MAX77693 MFD driver

Hi Mark,

On 05/14/2012 06:19 PM, Mark Brown wrote:

> On Mon, May 14, 2012 at 02:20:30PM +0900, Chanwoo Choi wrote:
> 
>> Signef-off-by: Chanwoo Choi <cw00.choi@...sung.com>
> 
> Typo :)
> 
>> +int max77693_read_reg(struct regmap *map, u8 reg, u8 *dest)
>> +{
>> +	unsigned int val;
>> +	int ret;
>> +
>> +	ret = regmap_read(map, reg, &val);
>> +	val &= 0xff;
>> +	*dest = val;
> 
> Should be no need for the val &= 0xff - if there is there's a bug we
> ought to fix in regmap.
> 
>> +int max77693_update_reg(struct regmap *map, u8 reg, u8 val, u8 mask)
>> +{
>> +	unsigned int old_val, new_val;
>> +	int ret;
>> +
>> +	ret = regmap_read(map, reg, &old_val);
>> +	old_val &= 0xff;
>> +	new_val = (val & mask) | (old_val & (~mask));
>> +	ret = regmap_write(map, reg, new_val);
> 
> This should be using regmap_update_bits(), the current code is buggy as
> it does not lock which means that multiple simultaneous updaters could
> conflict with each other.
> 
>> +static struct regmap_config max77693_regmap_config = {
>> +	.reg_bits = 8,
>> +	.val_bits = 8,
> 
> Defining max_register would let you see the register map in debugfs but
> this is optional.
> 
>> +	max77693->regmap = regmap_init_i2c(i2c, &max77693_regmap_config);
>> +	if (IS_ERR(max77693->regmap)) {
> 
> devm_regmap_init_i2c().


I modify all of it according of your comment.

Thank you for your comment.

Best Regards,
Chanwoo Choi
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