regulator: Add LTC3589 support

This patch adds support for the Linear Technology LTC3589, LTC3589-1,
and LTC3589-2 8-output I2C voltage regulator ICs.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Mark Brown <broonie@linaro.org>
3 files changed