linux/drivers/power/avs/Kconfig
Heiko Stübner 662a958638 PM / AVS: rockchip-io: add driver handling Rockchip io domains
IO domain voltages on some Rockchip SoCs are variable but need to be
kept in sync between the regulators and the SoC using a special
register.

A specific example using rk3288:
- If the regulator hooked up to a pin like SDMMC0_VDD is 3.3V then
  bit 7 of GRF_IO_VSEL needs to be 0.  If the regulator hooked up to
  that same pin is 1.8V then bit 7 of GRF_IO_VSEL needs to be 1.

Said another way, this driver simply handles keeping bits in the SoC's
general register file (GRF) in sync with the actual value of a voltage
hooked up to the pins.

Note that this driver specifically doesn't include:
- any logic for deciding what voltage we should set regulators to
- any logic for deciding whether regulators (or internal SoC blocks)
  should have power or not have power

If there were some other software that had the smarts of making
decisions about regulators, it would work in conjunction with this
driver.  When that other software adjusted a regulator's voltage then
this driver would handle telling the SoC about it.  A good example is
vqmmc for SD.  In that case the dw_mmc driver simply is told about a
regulator.  It changes the regulator between 3.3V and 1.8V at the
right time.  This driver notices the change and makes sure that the
SoC is on the same page.

Signed-off-by: Heiko Stübner <heiko@sntech.de>
Signed-off-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
[khilman: fix compiler warnings]
Signed-off-by: Kevin Hilman <khilman@linaro.org>
2014-09-25 09:57:23 -07:00

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menuconfig POWER_AVS
bool "Adaptive Voltage Scaling class support"
help
AVS is a power management technique which finely controls the
operating voltage of a device in order to optimize (i.e. reduce)
its power consumption.
At a given operating point the voltage is adapted depending on
static factors (chip manufacturing process) and dynamic factors
(temperature depending performance).
AVS is also called SmartReflex on OMAP devices.
Say Y here to enable Adaptive Voltage Scaling class support.
config ROCKCHIP_IODOMAIN
tristate "Rockchip IO domain support"
depends on ARCH_ROCKCHIP && OF
help
Say y here to enable support io domains on Rockchip SoCs. It is
necessary for the io domain setting of the SoC to match the
voltage supplied by the regulators.