Drivers that call regulator_get_optional are tolerant to the absence of
that regulator.  By modifying the value returned from the stub function
to match that seen when a regulator isn't present, callers can wrap the
regulator logic with an IS_ERR based conditional even if they happen to
call regulator_is_supported_voltage.  This improves efficiency as well
as eliminates the possibility for a very subtle bug.

Signed-off-by: Tim Kryger <tim.kryger@linaro.org>
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Mark Brown <broonie@linaro.org>

This patch extends the regulator helpers to account for device that use
multiple bits for control when using regmap enable/disable/bypass ops.

The actual regulator helpers wrongly assume that the regulator control
is always performed using single bits, using in the regulator_desc
struct only two parameters *_reg and *_mask defining register and mask
for control.

This patch extends this struct and introduces the helpers to take into
account devices where control is performed using multiple bits and
specific multi-bit values are used for enabling/disabling/bypassing the
regulator.

Signed-off-by: Carlo Caione <carlo@caione.org>
Signed-off-by: Mark Brown <broonie@linaro.org>

support pfuze200 chip which remove SW1C and SW4 based on pfuze100.

Signed-off-by: Robin Gong <b38343@freescale.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
Signed-off-by: Mark Brown <broonie@linaro.org>