RE: [PATCH v9 2/2] misc: Add iop driver for Sunplus SP7021

[Tony Huang 黃懷厚]

Dear Arnd, Gregkh:

> -----Original Message-----
> From: Arnd Bergmann <arnd@xxxxxxxx>
> Sent: Monday, February 21, 2022 3:20 PM
> To: Tony Huang <tonyhuang.sunplus@xxxxxxxxx>
> Cc: Rob Herring <robh+dt@xxxxxxxxxx>; DTML <devicetree@xxxxxxxxxxxxxxx>;
> Linux Kernel Mailing List <linux-kernel@xxxxxxxxxxxxxxx>; Derek Kiernan
> <derek.kiernan@xxxxxxxxxx>; Dragan Cvetic <dragan.cvetic@xxxxxxxxxx>; Arnd
> Bergmann <arnd@xxxxxxxx>; gregkh <gregkh@xxxxxxxxxxxxxxxxxxx>; Wells Lu
> 呂芳騰 <wells.lu@xxxxxxxxxxx>; Tony Huang 黃懷厚
> <tony.huang@xxxxxxxxxxx>
> Subject: Re: [PATCH v9 2/2] misc: Add iop driver for Sunplus SP7021
> 
> On Mon, Feb 21, 2022 at 3:14 AM Tony Huang
> <tonyhuang.sunplus@xxxxxxxxx> wrote:
> >
> > IOP(8051) embedded inside SP7021 which is used as Processor for I/O
> > control, monitor RTC interrupt 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 v9:
> >  - Remove custom attributes sysfs.
> 
> You are now back to a driver that does nothing at all, please make it use at
> least one kernel subsystem that it can hook up to before you send it again.
> 
monitor RTC interrupt:
SP7021 system has its own RTC device driver (rtc-sunplus.c).									
The user can set the RTC wake-up time through rtc-sunplus.c.									
The IOP code does not need to increase the RTC subsystem function, set the RTC register.									
When the linux kernel system. Only the 8051 CPU has power and can monitor the RTC wake-up interrupt.									

> Also, when listing the functionality above, describe which subsystems you want
> to use for those in the long run, this would make it clearer to see which
> direction you want to take this driver when you add back the features.
> 
>          Arnd