On Sat, Dec 18, 2021 at 12:53:08PM +0000, Tony Huang 黃懷厚 wrote: > Dear gregkh, arnd: > > > > > wrote: > > > > > > > > > > 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> > > > > > > > > Thanks for the improvements, this again looks better than the previous > > version. > > > > I still have some minor comments, and there are a couple of details > > > > I have commented on before that would need to be addressed, but > > > > let's focus on the one main issue for now: > > > > > > > > The driver still doesn't actually /do/ anything: you load the > > > > firmware when the driver is loaded, and you shut it down when the > > > > driver is removed, but otherwise there is no way to interact with > > > > the iop. You had the miscdevice earlier, and you still register > > > > that, but there are no file_operations associated with it, so it still doesn't > > have any effect. > > > > > > > > In the original version you had a couple of user-side interfaces, > > > > for which Greg and I commented that they were not using the correct > > > > abstractions, and you still list them in the changelog text as "I/O > > > > control, RTC wake-up and cooperation with CPU & PMC in power > > management". > > > > > > > > If you want to make any progress with adding the driver, I'd say you > > > > should implement at least two of those high-level interfaces that > > > > interact with the respective kernel subsystems in order to show that the > > abstraction works. > > > > > > > > > > Q:"with respective kernel subsystems in order to show that the abstraction > > works." > > > May I ask you about repective kernel subsystem. > > > If I use the file_operation method > > > Provide user can read and write IOP(8051)'s register. > > > Is this a repective kernel subsystem? > > > if not > > > There are other driver code can give me reference > > > > > > > I still do not understand what the goal of this driver is. > > > > When the poweroff command is executed. What exactly do you mean by this? The power off command that is sent to the kernel from userspace? > 1.The 8051 has a register to control the power-on and power-off of the system(Linux kernel). > If you turn off the power through the 8051 register(DEF_PWR_EN_0=0), > The current measured by the circuit board is 0.4mA only. In order to save power. > 2.The power is not turned off through the 8051 register. > The current measured on the circuit board is 33mA > 3.When the system linux kerenl is powered off. /driver/rtc, /driver/gpio cannot operate. > 8051 is still alive and operational > 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. So what do you need to do? When the kernel needs to shut down the system, send a message to this hardware device? If so, great, just tie into the normal powerdown sequence, this is nothing new. If not, I do not understand. thanks, greg k-h
