OF devices and non OF devices

Kári Davíðsson kari.davidsson at marel.is
Wed Jul 4 22:00:31 EST 2007

John, thank you for your answare.

Enabling CONFIG_FSL_SOC only enabled the execution of the init function (fsl_i2c_init())
of the fsl-i2c driver (i2c-mpc.c). The .probe function of the driver was never called
until I converted the driver to the OF model and added the .match_table to the driver structure.

Then I get the .probe function (fsl_i2c_probe()) called and the i2c bus set up.

Similar thing happens for the i2c device PCF8563 i.e., the init functin of the driver (pcf8563_init())
is called the driver is registered with the kernel, but the .probe (pcf8563_probe()) is never called.

The driver pcf8563 has _NO_ exported structures or functions so I basically have no handle on it
that I can utilize in board specific setup.

The way I suspect this is supposed to work is that from the board settup files I would do
rtc_dev = platform_device_register_simple("pcf8563", -1, NULL, 0);
which should later trigger the calling of the pcf8563_probe() function.

This is doing things in the same way as the fsl i2c code, i.e.
i2c_dev = platform_device_register_simple("i2c", i, r, 2);
which by the way does not work untill I have converted the fsl_i2c (i2c-mpc.c) driver to the OF structure.

So still the method of gluing together the OF drivers and non OF drivers eludes me.


P.S. I did check the 2.6.21-RC7-git3 and found that the i2c-mpc.c and the rtc-pcf85763.c are basically the same
as what I am working with in 2.6.20+ 

From: John Rigby [mailto:jcrigby at gmail.com] 
Sent: 3. júlí 2007 16:31
To: Kári Davíðsson
Cc: linuxppc-embedded at ozlabs.org
Subject: Re: OF devices and non OF devices

One place to find binding between OF devices and non OF devices is in arch/powerpc/sysdev/fsl_soc.c
The typical pattern is:
    if of_find_compatible_node "of-device-name"
        platform_device_register_simple ""platform-device-name" 
        platform_device_add_data ...


On 7/3/07, Kári Davíðsson <kari.davidsson at marel.is> wrote: 

	I am attempting to get some non OF devices working for an mpc 5200 board, in particular 
	PCF8563 RTC.
	This device has an non OF device interface which I believe is correct. After all it should work
	on non OF platforms.
	I have managed to get the board to run the i2c initialization (and probe) for the fsl-mpc i2c driver by 
	converting the fsl-mpc i2c driver to OF driver (I found some patch here that I based this work on).

fsl-i2c is one of the devices handled by fsl_soc.c so you shouldn't need to change anything to 
make it work in the latest kernel.  CONFIG_FSL_SOC was only added to lite5200_defconfig recently so 
that may explain why it's not on in your kernel.

	Since the PCF8563 driver is not OF driver only its initaliziation code is run but the .probe function
	of the driver is never run. Basically (as far as I can understand) the .probe is never run because the
	driver is not an OF driver. 
	I could convert the PCF8563 driver to OF driver and make it work for our puposes but I feel this is
	1) Wrong
	2) therefore wasted work.

Since the driver must run on non OF platforms then it should not be converted.  You just need to add a platform_device_register somewhere. 
I don't think fsl_soc.c is  the right place since it is not part of an freescale SOC.
You could probably put it in a board specific startup routine.

	What seems to elude me is some glue that glues together the OF part of the driver space to the non OF part
	of the driver space.
	Any hints or pointers on where to find this glue?
	P.S. Kernel is post 2.6.20.
	Kári Davíðsson                   | kari.davidsson at marel.is
	Hugbúnaðargerð                   | www.marel.com
	Tel: 563-8156 Fax: +354 563 8001 
	Linuxppc-embedded mailing list
	Linuxppc-embedded at ozlabs.org

More information about the Linuxppc-embedded mailing list