Looking for issues/features for my first contribution

[Aleksandar Markovic]

On Saturday, November 9, 2019, Rajath Shashidhara <address@hidden> wrote:
> On 11/9/19 1:46 PM, Aleksandar Markovic wrote:
>
> > 
> > 
> > Hi, Rajath.
> > 
> > No, it doesn't. Linux kernel has a driver for DS3231. Take a closer look.
>
> Kernel driver found here:
> https://elixir.bootlin.com/linux/v5.4-rc6/source/drivers/rtc/rtc-ds3232.c
> did register NVMEM of 236 bytes with the kernel. As long as this NVMEM
> is never accessed, the same driver should work for both DS3231 and DS3232.
>
> Is there any other driver you are referring to ? Please let me know if I
> missed something here.

The official DS3231 driver is (hidden) in:

https://elixir.bootlin.com/linux/v5.4-rc6/source/drivers/rtc/rtc-ds1307.c

This driver actually supports around 15 RTC chips, and DS3231 among them. It contains fairly sophisticated "feature control" that enables it to support multiple RTC chips.

 

> > 
> > But, in any case, you base your QEMU emulation on the *datasheet*.
> > 
> > The OS drivers may be helpful, but they are not a reference you base
> > your solution on. The drivers may be obsolete, incorrect, incomplete, or
> > just plain wrong. Additionally, as QEMU, of course, supports emulation
> > of systems running variety of OSs, the existence of the Linux kernel
> > driver is not a necessary condition for QEMU implementation. QEMU
> > emulates many systems that Linux never ran on, and could not be run at all.
> > 
>
> I was only looking at the Kernel drivers to setup a test framework. I
> plan to test my implementation using a Raspi emulation with qemu,
> configure it with a DS3231 device. After this, I should be able to use
> ioctl() on /dev/rtc to test the functionality:
> https://linux.die.net/man/4/rtc
>
> If you have a better approach to testing, do let me know.

Your method sounds good to me. Hopefully it won't be too difficult to you to execute it.

Best wishes,

Aleksandar

 

> Thanks,
> Rajath Shashidhara