Re: [rtc-linux] Re: i2c/rtc init dependency problem

[Jean Delvare <khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org>]

On Fri, 25 Sep 2009 14:38:39 -0400, Jon Ringle wrote:
> Alexander:
> 
> On Fri, Sep 25, 2009 at 10:49 AM, Jon Ringle <jon-7zJyie9iPacdnm+yROfE0A@public.gmane.org> wrote:
> > However, it still does not work with your patch. In the dump below I see:
> > [    0.250000] i2c-core: driver [dummy] registered
> > ...
> > [    0.290000] i2c-adapter i2c-0: adapter [IOP3xx-I2C] registered
> > ...
> > [    3.780000] i2c-core: driver [rtc-m41t80] registered
> [Note: missing i2c-adapter i2c-0 debug msgs expected when rtc-m41t80 probe]
> > [    3.790000] i2c /dev entries driver
> > [    3.790000] i2c-core: driver [dev_driver] registered
> > [    3.800000] i2c-dev: adapter [IOP3xx-I2C] registered as minor 0
> > [    3.800000] i2c-core: driver [lm75] registered
> > [    3.830000] i2c-adapter i2c-0: found normal entry for adapter 0, addr 0x48
> > ...
> > [    4.050000] drivers/rtc/hctosys.c: unable to open rtc device (rtc0)
> 
> I think the problem is that rtc-m41t80 does not provide either of the following:
>     struct i2c_driver: detect and address_data (both are null)
> as required by i2c_detect()

This should be OK. detect and address_data are optional and only needed
for drivers which autodetect their devices. The rtc-m41t80 probably
doesn't want to do this. The device should be declared by the arch or
platform.

>   -> called by __attach_adapter()
>   -> called by i2c_register_driver()
>   -> called by i2c_add_driver()
>   -> called by m41t80_rtc_init()
> 
> *or*
>     struct i2c_driver: attach_adapter (null)

This legacy method no longer exists, so I certainly hope it isn't
implemented ;)

> as required by __attach_adapter()
>   -> called by i2c_register_driver()
>   -> called by i2c_add_driver()
>   -> called by m41t80_rtc_init()

-- 
Jean Delvare