Re: [PATCH 1/2] regulator: s5m8767: Modify parse_dt function to parse data related to ramp

[Chanwoo Choi <cw00.choi@samsung.com>]

On 10/10/2013 07:28 PM, Mark Rutland wrote:
> On Thu, Oct 10, 2013 at 02:41:35AM +0100, Chanwoo Choi wrote:
>> This patch parse 'buck[2-4]_ramp_enable and buck_ramp_delay' platform data
>> from dts file.
> 
> Why?
> 
> What do these describe? Why do we need them?

Turn on ramp control of buck2/3/4.

> 
>>
>> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
>> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
>> ---
>>  drivers/regulator/s5m8767.c | 16 ++++++++++++++++
>>  1 file changed, 16 insertions(+)
>>
>> diff --git a/drivers/regulator/s5m8767.c b/drivers/regulator/s5m8767.c
>> index c24448b..cb6cdb3 100644
>> --- a/drivers/regulator/s5m8767.c
>> +++ b/drivers/regulator/s5m8767.c
>> @@ -640,6 +640,22 @@ static int s5m8767_pmic_dt_parse_pdata(struct platform_device *pdev,
>>  		return -EINVAL;
>>  	}
>>  
>> +	if (of_get_property(pmic_np, "s5m8767,pmic-buck2-ramp-enable", NULL))
>> +		pdata->buck2_ramp_enable = true;
> 
> Please describe what this is and why we need it.

buck2/3/4_ramp_enable is used to protect the chip from the in-rush current.

> 
> For reading boolean proeprties, use of_property_read_bool.

I'll fix it.

> 
>> +
>> +	if (of_get_property(pmic_np, "s5m8767,pmic-buck3-ramp-enable", NULL))
>> +		pdata->buck3_ramp_enable = true;
>> +
>> +	if (of_get_property(pmic_np, "s5m8767,pmic-buck4-ramp-enable", NULL))
>> +		pdata->buck4_ramp_enable = true;
>> +
>> +	if (pdata->buck2_ramp_enable || pdata->buck3_ramp_enable
>> +			|| pdata->buck4_ramp_enable) {
>> +		if (of_property_read_u32(pmic_np, "s5m8767,pmic-buck-ramp-delay",
>> +				&pdata->buck_ramp_delay))
>> +			pdata->buck_ramp_delay = 0;
> 
> Why not initialise pdata->buck_ramp_delay to 0 beforehand?
> 
> That way you don't need to check the return value of
> of_property_read_u32 here.
> 
> I note that pdata->buck_ramp_delay is an int, not a u32. Please use a
> u32 temporary variable.

I'll fix it

> 
>> +	}
>> +
> 
> NAK. None of these seem to be documented in mainline's
> Documentation/devicetree/bindings/regulator/s5m8767-regulator.txt, nor
> does documentation seem to be added here. Until there's some description
> of what these are and why they're needed, I don't think they're
> suitable.

I'll add description about this patch.