Messages in this thread | | | Date | Sat, 26 Mar 2016 16:50:41 -0700 | Subject | Re: [PATCH 2/2] regulator: core: Ensure we are at least in bounds for our constraints | From | Bjorn Andersson <> |
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On Thu, Mar 24, 2016 at 12:18 AM, Krzysztof Kozlowski <k.kozlowski@samsung.com> wrote: > On Thu, Mar 24, 2016 at 3:11 PM, Krzysztof Kozlowski > <k.kozlowski@samsung.com> wrote: >> On Tue, Mar 22, 2016 at 6:06 AM, Ivaylo Dimitrov >> <ivo.g.dimitrov.75@gmail.com> wrote: >>> Hi, >>> >>> On 21.03.2016 21:18, Mark Brown wrote: >>>> >>>> Currently we only attempt to set the voltage during constraints >>>> application if an exact voltage is specified. Extend this so that if >>>> the currently set voltage for the regualtor is outside the bounds set in >>> >>> >>> regulator >>> >>>> constraints we will move the voltage to the nearest constraint, raising >>>> to the minimum or lowering to the maximum as needed. This ensures that >>>> drivers can probe without the hardware being driven out of spec. >>>> >>>> Reported-by: Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com> >>>> Signed-off-by: Mark Brown <broonie@kernel.org> >>>> --- >>>> >>>> Untested so far, will give it a spin later/tomorrow. >>>> >>>> drivers/regulator/core.c | 32 +++++++++++++++++++++++++------- >>>> 1 file changed, 25 insertions(+), 7 deletions(-) >>>> >>> >>> Patch 1 does not apply cleanly on 4.5-rc5, so I applied it by hand, however, >>> you may add: >>> >>> Tested-by: Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com> >> >> >> Cc: Ulf, mmc >> >> I bisected today's next MMC/SD card failure to this patch. Plugging a >> SD card on Odroid XU3/XU4 (Exynos5422) causes: >> [ 11.759954] mmc1: card never left busy state >> [ 11.762795] mmc1: error -110 whilst initialising SD card >>
Mark,
I'm facing the same issue on my Qualcomm based boards; my eMMCs fails to talk to me because I'm not powering them.
The problem in my case comes from the vmmc regulator having min_uV == max_uV and patch 1 in this series changes the logic of of_get_regulation_constraints() to no longer set apply_uV. I.e. we end up never calling set_voltage(), ever.
When the mmc framework calls regulator_set_load() to change voltage REGULATOR_CHANGE_VOLTAGE is not set (because min == max) so we will never call set_voltage().
Before patch 1 apply_uV was set and we did set up the voltage earlier, so regulator_get_voltage() will return a valid voltage and regulator_set_voltage() will succeed for the valid voltages (if the range spans the current setting).
Reinstating the following snippet in of_get_regulation_constraints() sort this out: if (constraints->min_uV && constraints->max_uV) constraints->apply_uV = true;
I did look at an alternative of having regulator_set_voltage() pass and call set_voltage() if the requested voltage matches the constraints, but this does indeed seem to mess things up. So checking in with you before continuing on that hack.
Regards, Bjorn
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