Dear Arnd: > > >> > > >> IOP (IO Processor) embedded inside SP7021 which is used as > > >> Processor for I/O control, RTC wake-up and cooperation with CPU & > > >> PMC in power management purpose. > > >> The IOP core is DQ8051, so also named IOP8051, it supports > > >> dedicated JTAG debug pins which share with SP7021. > > >> In standby mode operation, the power spec reach 400uA. > > >> > > >> Signed-off-by: Tony Huang <tonyhuang.sunplus@xxxxxxxxx> > > >> --- > > >> Changes in v4: > > >> - Addressed comments from Arnd Bergmann. > > > > >I don't think you did: I asked you specifically to add code to > > >interact with the existing in-kernel interfaces to use the > > >functionality provided by the device. Pick any (at least two) > > >subsystems and add support, but leave out any custom user space > > >interfaces (miscdevice, debugfs, sysfs, ...) for the moment. > > > > > > > > 1. IOP can run sp_iop_platform_driver_shudown() through the poweroff > > command and the kernel. Perform system power-off actions. > > Do you mean that this method a) cleanly shuts down the iop before the system > is powered down, or b) the driver_shutdown() callback is used to initiate the > powerdown of the system itself? > > In case of a) I would not count that as exposing functionality, what you do here > is just part of any driver. If instead you are trying to use b), this is the wrong > way of doing it, see drivers/power/reset/ for examples of how to do it right. > > > 2. Wake up the system by relying on the 8051 internal RTC wake-up > > mechanism and external GPIO input signals to wake up. > > I think those should be exposed with drivers/rtc for the RTC and drivers/gpio/ > for the GPIO driver, and then you can use the device tree to configure which > GPIO to use as a wakeup and how it's connected to the RTC. > SP7021: The system is powered off. But 8051 still has power. The 8051 has a register to control the power-on and power-off of the system. 8051 has RTC register. When the time is up, 8051 powers on the system. The 8051 can detect GPIO0~7 pins, and GPIO pin high/low can be used as a power-on judgment mechanism for the system. > > 3.So you ask me to control IOP(8051) through file_operations, not > > through DEVICE_ATTR > > No, neither of them. Use the appropriate drivers/*/ subsystems for any > functionality that has an existing subsystem. If there is something that the iop > does that does not yet have a subsystem, that requires a more thorough design > discussion for creating a new user interface, ideally in a hardware-independent > way. You should not start with that until all the normal features (rtc, wakeup, > suspend, gpio, ...) are supported. > > Arnd
