linux-kernel - Re: [PATCH RFT] regulator: max8972: Fix setting ramp delay

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Date:	Mon, 30 May 2016 10:48:28 +0200
From:	Krzysztof Kozlowski <k.kozlowski@...sung.com>
To:	Axel Lin <axel.lin@...ics.com>, Mark Brown <broonie@...nel.org>
Cc:	Laxman Dewangan <ldewangan@...dia.com>,
	Mikko Perttunen <mperttunen@...dia.com>,
	Liam Girdwood <lgirdwood@...il.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH RFT] regulator: max8972: Fix setting ramp delay

On 05/29/2016 01:16 PM, Axel Lin wrote:
> Current code can set ramp delay to a wrong setting that the return value
> from .set_voltage_time_sel is not enough for proper delay.

I don't understand what yo wanted to say here. What wrong setting is
possible? Why do you mention set_voltage_time_sel() here?

Can you elaborate?

The only difference I spotted is how you round up the ramp_delay values.

Best regards,
Krzysztof

> Fix the logic in .set_ramp_delay and also remove unused ret_val variable.
> 
> Signed-off-by: Axel Lin <axel.lin@...ics.com>
> ---
>  drivers/regulator/max8973-regulator.c | 16 ++++++----------
>  1 file changed, 6 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/regulator/max8973-regulator.c b/drivers/regulator/max8973-regulator.c
> index 08d2f13..3958f50 100644
> --- a/drivers/regulator/max8973-regulator.c
> +++ b/drivers/regulator/max8973-regulator.c
> @@ -271,22 +271,18 @@ static int max8973_set_ramp_delay(struct regulator_dev *rdev,
>  	struct max8973_chip *max = rdev_get_drvdata(rdev);
>  	unsigned int control;
>  	int ret;
> -	int ret_val;
>  
>  	/* Set ramp delay */
> -	if (ramp_delay < 25000) {
> +	if (ramp_delay <= 12000)
>  		control = MAX8973_RAMP_12mV_PER_US;
> -		ret_val = 12000;
> -	} else if (ramp_delay < 50000) {
> +	else if (ramp_delay <= 25000)
>  		control = MAX8973_RAMP_25mV_PER_US;
> -		ret_val = 25000;
> -	} else if (ramp_delay < 200000) {
> +	else if (ramp_delay <= 50000)
>  		control = MAX8973_RAMP_50mV_PER_US;
> -		ret_val = 50000;
> -	} else {
> +	else if (ramp_delay <= 200000)
>  		control = MAX8973_RAMP_200mV_PER_US;
> -		ret_val = 200000;
> -	}
> +	else
> +		return -EINVAL;
>  
>  	ret = regmap_update_bits(max->regmap, MAX8973_CONTROL1,
>  			MAX8973_RAMP_MASK, control);
>