Date:   Fri, 17 Dec 2021 07:54:39 +0100
From:   gregkh <gregkh@linuxfoundation.org>
To:     Tony Huang =?utf-8?B?6buD5oe35Y6a?= <tony.huang@sunplus.com>
Cc:     Arnd Bergmann <arnd@arndb.de>, DTML <devicetree@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Derek Kiernan <derek.kiernan@xilinx.com>,
        Dragan Cvetic <dragan.cvetic@xilinx.com>,
        Rob Herring <robh+dt@kernel.org>,
        Wells Lu =?utf-8?B?5ZGC6Iqz6aiw?= <wells.lu@sunplus.com>,
        =?utf-8?B?6buD5oe35Y6a?= <tonyhuang.sunplus@gmail.com>
Subject: Re: [PATCH v4 2/2] misc: Add iop driver for Sunplus SP7021
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References: <cover.1639557112.git.tonyhuang.sunplus@gmail.com>
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On Fri, Dec 17, 2021 at 02:44:43AM +0000, Tony Huang 黃懷厚 wrote:
> Dear Arnd:
> 
> On Thu, Dec 16, 2021 at 2:38 AM Tony Huang <tonyhuang.sunplus@gmail.com<mailto:tonyhuang.sunplus@gmail.com>> 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@gmail.com<mailto:tonyhuang.sunplus@gmail.com>>
> >> ---
> >> 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.
> 2. Wake up the system by relying on the 8051 internal RTC wake-up mechanism and external GPIO input signals to wake up.
> 3.So you ask me to control IOP(8051) through file_operations, not through DEVICE_ATTR

Your DEVICE_ATTR() calls did not do anything normal, they did not print
out or accept data through sysfs at all.  That is not ok.

thanks,

greg k-h