Messages in this thread Patch in this message | | | From | "A.S. Dong" <> | Subject | RE: [PATCH] regulator: core: Allow dummy regulators for supplies | Date | Wed, 12 Apr 2017 15:33:14 +0000 |
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Hi Mark,
> -----Original Message----- > From: Mark Brown [mailto:broonie@kernel.org] > Sent: Wednesday, April 12, 2017 4:37 AM > To: A.S. Dong > Cc: Liam Girdwood; linux-kernel@vger.kernel.org; shawnguo@kernel.org; > Robin Gong > Subject: Re: [PATCH] regulator: core: Allow dummy regulators for supplies > > On Tue, Apr 11, 2017 at 09:34:37PM +0100, Mark Brown wrote: > > Rather than just not resolving the supply when there is explicitly no > > supply mapping fall through and allow a dummy supply to be substituted. > > I should mention that this is completely untested, sorry.
It did break the MX6Q cpufreq as follows: [ 3.950097] coda 2040000.vpu: Direct firmware load for vpu/vpu_fw_imx6q.bin failed with error -2 [ 3.950111] coda 2040000.vpu: firmware request failed [ 4.074044] cpu cpu0: failed to scale vddarm down: -22 [ 4.079262] cpu cpu0: failed to scale vddsoc down: -22 [ 4.084809] cpu cpu0: failed to scale vddpu down: -22
It seems the regulator supply behavior is changed a bit after apply this patch.
Before this patch, the regulator core will not report an error if can't resolve A non exist supply. (It's exactly what this patch removes)
Now we allow a supply to be a dummy regulator. But due to fc42112c0eaa ("regulator: core: Propagate voltage changes to supply regulators") which supports propagate voltage change to supply regulator, then it will certainly fail if we want to configure a dummy supply.
I tried a quick fix as follows and test seemed ok. diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index 43dafac..a1c952db 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -2935,7 +2935,8 @@ static int regulator_set_voltage_unlocked(struct regulator *regulator, if (ret < 0) goto out2; - if (rdev->supply && (rdev->desc->min_dropout_uV || + if (rdev->supply && rdev->supply->rdev != dummy_regulator_rdev && + (rdev->desc->min_dropout_uV ||
Not sure if it's a sufficient fix. Please help check it.
Regards Dong Aisheng
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