Add helper functions that allow regulator consumers to obtain low-level details about the regulator hardware, like the voltage selector register address and such. These details can be useful when configuring hardware or firmware that want to do low-level access to regulators, with no involvement from the kernel. The use-case for Tegra is a voltage-controlled oscillator clocksource which has control logic to change the supply voltage via I2C to achieve a desired output clock rate. Signed-off-by: Tuomas Tynkkynen <ttynkkynen@nvidia.com> Signed-off-by: Mark Brown <broonie@linaro.org>