linux-kernel - Re: [PATCH] regulator: pfuze100: Simplify pfuze100_set_ramp

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Date:	Wed, 31 Jul 2013 23:47:17 +0800
From:	Robin Gong <b38343@...escale.com>
To:	Axel Lin <axel.lin@...ics.com>
CC:	Mark Brown <broonie@...nel.org>,
	Liam Girdwood <lgirdwood@...il.com>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] regulator: pfuze100: Simplify pfuze100_set_ramp_delay
 implementation

>From software view this patch looks better, although original code match better
with the data sheet. Thanks Axel.

Reviewed-by: Robin Gong <b38343@...escale.com>
Thanks.
On Tue, Jul 30, 2013 at 10:47:44PM +0800, Axel Lin wrote:
> Simplify the equation to calculate ramp_delay.
> Below equations are equivalent:
>   ramp_delay = 25000 / (2 * ramp_delay);
>   ramp_delay = 50000 / (4 * ramp_delay);
>   ramp_delay = 25000 / (2 * ramp_delay);
>   ramp_delay = 12500 / ramp_delay;
> So we don't need to read BIT6 of rdev->desc->vsel_reg for applying different
> equations.
> 
> Also use rdev->desc->vsel_reg instead of run-time calculate register address.
> 
> Signed-off-by: Axel Lin <axel.lin@...ics.com>
> ---
>  drivers/regulator/pfuze100-regulator.c | 21 +++++----------------
>  1 file changed, 5 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/regulator/pfuze100-regulator.c b/drivers/regulator/pfuze100-regulator.c
> index e02d9b9..bda5561 100644
> --- a/drivers/regulator/pfuze100-regulator.c
> +++ b/drivers/regulator/pfuze100-regulator.c
> @@ -93,26 +93,15 @@ static int pfuze100_set_ramp_delay(struct regulator_dev *rdev, int ramp_delay)
>  {
>  	struct pfuze_chip *pfuze100 = rdev_get_drvdata(rdev);
>  	int id = rdev->desc->id;
> -	unsigned int val, ramp_bits, reg;
> +	unsigned int ramp_bits;
>  	int ret;
>  
>  	if (id < PFUZE100_SWBST) {
> -		if (id == PFUZE100_SW1AB)
> -			reg = PFUZE100_SW1ABVOL;
> -		else
> -			reg = PFUZE100_SW1CVOL + (id - PFUZE100_SW1C) * 7;
> -		regmap_read(pfuze100->regmap, reg, &val);
> -
> -		if (id <= PFUZE100_SW1C)
> -			ramp_delay = 25000 / (2 * ramp_delay);
> -		else if (val & 0x40)
> -			ramp_delay = 50000 / (4 * ramp_delay);
> -		else
> -			ramp_delay = 25000 / (2 * ramp_delay);
> -
> +		ramp_delay = 12500 / ramp_delay;
>  		ramp_bits = (ramp_delay >> 1) - (ramp_delay >> 3);
> -		ret = regmap_update_bits(pfuze100->regmap, reg + 4 , 0xc0,
> -				ramp_bits << 6);
> +		ret = regmap_update_bits(pfuze100->regmap,
> +					 rdev->desc->vsel_reg + 4,
> +					 0xc0, ramp_bits << 6);
>  		if (ret < 0)
>  			dev_err(pfuze100->dev, "ramp failed, err %d\n", ret);
>  	} else
> -- 
> 1.8.1.2
> 
> 
> 
> 

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