On Wed, Sep 14, 2016 at 09:52:10AM -0700, Matthias Kaehlcke wrote: > From: Douglas Anderson <dianders@xxxxxxxxxxxx> > > On some boards it is possible that transitioning the regulator downwards > too fast will trigger the over voltage protection (OVP) on the > regulator. This is because until the voltage actually falls there is > time when the requested voltage is much lower than the actual voltage. > > We'll fix this OVP problem by allowing users to specify the maximum > voltage that we can safely fall. The maximum safe voltage decrease > is specified as a percentage of the current voltage. The driver will > then break things into separate steps with a delay in between. > > In order to figure out what the delay should be we need to figure out > how slowly the voltage rail might fall in the worst (slowest) case. > We'll assume this worst case is present and delay so we know for sure > that we've finished each step. > > In this patch we actually block returning from the set_voltage() call > until we've finished delaying. A future patch atop this one might > choose to return more immediately and let the voltages fall in the > background. That would possibly allow us to cancel a slow downward > decay if there was a request to go back up. > > Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx> > Signed-off-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx> > --- > Changes in v5: > - Leave set_voltage tracepoints where they were > - Fixed error handling in code dealing with the device tree, return an error if configuration is invalid > - Fixed coding style and formatting issues > - Updated commit message > > .../devicetree/bindings/regulator/regulator.txt | 7 ++++ For the binding: Acked-by: Rob Herring <robh@xxxxxxxxxx> > drivers/regulator/core.c | 49 +++++++++++++++++++--- > drivers/regulator/of_regulator.c | 42 ++++++++++++++++++- > include/linux/regulator/machine.h | 2 + > 4 files changed, 93 insertions(+), 7 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
