Viresh Kumar 93e29c8530 greybus: interface: add power_state attribute ... User space needs the capability of powering ON or OFF an Interface for multiple use cases. For example, userspace may want an Interface currently in its S3 boot stage, to boot into its S2 Loader stage to update the bridge SPI flash. Or the Interface is running its S2 Loader stage and updated the SPI flash with the new S2 Loader firmware and wants to boot into the new S2 Loader firmware. Another use case can be, Android wants to disable (not eject) a misbehaving module. Add a 'power_state' sysfs file within the interface directory. It can be read to know the current power state of the Interface and can be written to power ON or power OFF an Interface. Possible values that can be written or read from it are: "on" and "off". Testing Done: Tested by enabling/disabling camera module on EVT 2.0. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> CC: David Lin <dtwlin@google.com> Reviewed-by: Johan Hovold <johan@hovoldconsulting.com> [johan: drop es3-quirk duplication, add to power attribute group, fix return value, drop tags ] Signed-off-by: Johan Hovold <johan@hovoldconsulting.com> Reviewed-by: Alex Elder <elder@linaro.org> Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org> Reviewed-by: Sandeep Patil <sspatil@google.com> Reviewed-by: Patrick Titiano <ptitiano@baylibre.com> Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>		2016-07-20 10:16:54 -07:00
drivers/staging/greybus	greybus: interface: add power_state attribute	2016-07-20 10:16:54 -07:00