linux-kernel - Re: [PATCH v3 2/2] regulator: Add support for MAX77686.

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Date:	Wed, 23 May 2012 09:46:19 +0530
From:	Yadwinder Singh Brar <yadi.brar01@...il.com>
To:	jonghwa3.lee@...sung.com
Cc:	linux-kernel@...r.kernel.org, linux-samsung-soc@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	Mark Brown <broonie@...nsource.wolfsonmicro.com>,
	Liam Girdwood <lrg@...com>,
	Yadwinder Singh Brar <yadi.brar@...sung.com>,
	Kyungmin Park <kmpark@...radead.org>,
	Samuel Ortiz <sameo@...ux.intel.com>
Subject: Re: [PATCH v3 2/2] regulator: Add support for MAX77686.

(adding Kyungmin Park and Samuel Ortiz)

Hi,

Yes, It happened unintentionally. I didn't know about your patch
before submitting
the initial version of my patches. I agree with you, I will review
your patches and
will try to incorporate extra features from your patches.

On Wed, May 23, 2012 at 7:10 AM,  <jonghwa3.lee@...sung.com> wrote:
> Hi, Yadwinder,
> As you know, both of us, recently, had competition for one driver
> whether you intend or not. And now, i think it is time to stop this and
> to find appropriate goal. From now on, i won't update this driver no
> more. I recommend you to review my patch and apply feature that you can
> apply. And also check comments that i wrote below.
>
> On 2012년 05월 22일 14:57, yadi.brar01@...il.com wrote:
>
>> From: Yadwinder Singh Brar <yadi.brar@...sung.com>
>>
>> Add support for PMIC/regulator portion of MAX77686 multifunction device.
>> MAX77686 provides LDOs[1-26] and BUCKs[1-9]. This is initial release of driv
>> which supports setting and getting the voltage of a regulator with I2C
>> interface.

>> +     return DIV_ROUND_UP(rdev->desc->uV_step *
>> +                         abs(new_sel - old_sel),
>> +                         100);
>> +}
>> +
>
>
> Does LDO also need waiting for voltage change? I afraid it's not.
>

Yes, according to technical reference manual which I have, ramp rate for
LDOs is also 100mV/us.

>> +
>> +     if (pdata->ramp_delay < MAX77686_RAMP_RATE_13MV ||
>> +             pdata->ramp_delay > MAX77686_RAMP_RATE_100MV)
>> +             pdata->ramp_delay = MAX77686_RAMP_RATE_27MV;    /* default */

If pdata doesn't have proper ramp_delay, it will get value
MAX77686_RAMP_RATE_27MV.

>> +
>> +     max77686->ramp_delay = pdata->ramp_delay - 1;
>
>
> I think it is better to check pdata->ramp_delay is available.
> If pdata doesn't have ramp_delay member it might be error.
>

Yes, we have taken care of this case above before setting value of
max77686->ramp_delay.

>> +     max77686_update_reg(i2c, MAX77686_REG_BUCK2CTRL1,
>> +             max77686->ramp_delay << 6, RAMP_MASK);
>> +     max77686_update_reg(i2c, MAX77686_REG_BUCK3CTRL1,
>> +             max77686->ramp_delay << 6, RAMP_MASK);
>> +     max77686_update_reg(i2c, MAX77686_REG_BUCK4CTRL1,
>> +             max77686->ramp_delay << 6, RAMP_MASK);
>> +
>
>
> Why do you use i2c client still? If you registered regmap you can use
> its API. I recommend you to use regmap_update_bits() directly.
>
>

Yes, we are using regmap_update_bits().  max77686_update_reg() is just
a wrapper over it.

>> +     platform_set_drvdata(pdev, max77686);
>> +

>
> MAX77686 has crystal oscillator in it. And original version of this
> driver which was written by Chiwoon Byun, registers it as a regulator.
> As Mark says, we have to change it to use generic clock API. Where do
> you think should we put them into? In my opinion, it is proper that just
> leave them in regulator driver because this driver is almost core of
> PMIC. I already applied generic API in my local repository but i
> couldn't test yet. Because it crashed with SOC's private clock API.
> Anyway if you register 32khz clock with generic API ,DEFINE_CLK_GATE()
> will help you out which defined in linux/clk-private.h.
>

Yes, I was also thinking about where to put it. I am not sure whether this
is a proper place to put them. Anyway I will again think about it.

Thanks,
Yadwinder.
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