Re: [PATCH v9 1/2] regulator: Add driver for max77802 PMIC PMIC regulators

Yuvaraj Cd
2014-08-25T10:46:10Z

On Mon, Aug 25, 2014 at 2:37 PM, Javier Martinez Canillas
<javier.martinez@collabora.co.uk> wrote:
> Hello Yuvaraj,
>
> On 08/25/2014 10:22 AM, Yuvaraj Cd wrote:
>>>> Good question. I'm not that familiar with the dw_mmc host controller nor
>>>> its driver implementation so I'll let Yuvaraj or Doug to answer that.
>> Well,here it goes!
>> 1. Power ON the board LDO4CTRL1[7:6] 11b
>> 2. dw_mmc driver enable the vqmmc.
>> 3. checks for UHS support, complete the voltage switching t0 1.8V
>> 4. Does warm reset by reboot command.
>> 5. mmc core calls mmc_set_ios() with MMC_POWER_OFF.
>> 6. dw_mmc driver cut-off the regulator with LDO4CTRL1[7:6] is 00b
>> 7.dw_mmc driver enable the vqmmc.
>> But after step 7 also, LD4CTRL[7:6] is 00b.
>
> Ok, so the dw_mmc driver is enabling vqmmc, that's good.
>
>>>
>>> I haven't seen the issue that Yuvaraj is reporting (but I also haven't
>>> picked up all of the relevant patches and tried to reproduce), so I'm
>>> going to have to leave it to Yuvaraj to answer.
>> static int max77802_enable(struct regulator_dev *rdev)
>> {
>> struct max77802_regulator_prv *max77802 = rdev_get_drvdata(rdev);
>> int id = rdev_get_id(rdev);
>> int shift = max77802_get_opmode_shift(id);
>> return regmap_update_bits(rdev->regmap,
>> rdev->desc->enable_reg,rdev->desc->enable_mask,max77802->opmode[id] <<
>> shift);
>> }
>> I think in the above code snippet, the "val" is what we got it during
>> the probe.We always write that value for enabling this regulator(which
>> is LDO4CTRL1[7:6] 00b after warm reset) which is not correct according
>> the MAX77802 manual.
>>>
>
> I see, so probably until we have a way to define the operating mode for
> each regulator using DT we should set the opmode to normal when enabling a
> regulator independently of the value the hardware register reported on probe.
>
> Can you please test the following change [0] so I can post as a proper
> patch? Doug, Mark do you think that forcing the regulator to opmode normal
> when enabling is the right solution here?
>
> Best regards,
> Javier
>
> [0]
> diff --git a/drivers/regulator/max77802.c b/drivers/regulator/max77802.c
> index ad1caa9..917b5ab 100644
> --- a/drivers/regulator/max77802.c
> +++ b/drivers/regulator/max77802.c
> @@ -180,7 +180,7 @@ static int max77802_enable(struct regulator_dev *rdev)
>
> return regmap_update_bits(rdev->regmap, rdev->desc->enable_reg,
> rdev->desc->enable_mask,
> - max77802->opmode[id] << shift);
> + MAX77802_OPMODE_NORMAL << shift);
> }
It works.