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

Javier Martinez Canillas
2014-08-25T09:07:16Z

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);
}