SPI devices and OF

[Milton Miller]

On Wed Apr 4 21:09:16 EST 2007, Sascha Hauer wrote:

> I'm currently writing a driver for the mpc5200 spi controller (the
> dedicated one, not the PSC ones).
>
> The driver has the form of a of_platform_driver. My problem is that I
> don't know how to define the spi devices on the spi bus. My current
> approach is having something like this in the OF tree:
>
>
>         spi at f00 {
>                 device_type = "spi";
>                 compatible = "mpc5200b-spi\0mpc5200-spi";
>                 reg = <f00 20>;
>                 interrupts = <2 d 0 2 e 0>;
>                 interrupt-parent = <500>;
>                 mmc at 0 {
>                         device_type = "mmc_spi";
>                         compatible = "mmc_spi";

Why is the device_type mmc_spi?   Is this a MMC adapter?
The type of a network card is "network", not "pci_network".


>                 };
>         };
>
> I can then parse the children in my spi driver with
>
>         while( (child = of_get_next_child(odev->node, child))) {
>                 struct spi_board_info info;
                 (fill out info) ...
>                 spi_register_board_info(&info, 1);
>         }
>
> I think it will work this way but I found no way getting the
> platform_data for the spi devices.

Why do you need platform_data for the devices?  I understand for
the master.   Actually, spi_device_info has a nice platform_info 
pointer.

> I could also define the spi devices in a board specific c file but 
> there
> I would not know which spi bus is which if there is more than one.

The device tree is definately preferred.

> Any thoughts on this or am I completely on the wrong track?
>
> Sascha

First of all, I have no knowledge of SPI.

However, looking at drivers/spi/spi.c, it looks
spi_register_board_info is for staticly determined tables that are
known at _init and the spi master busses are enumerated in some
platform-dtermined way.  Since your proposed binding doesn't have
an enumeration of the spi master, that does not match.  I guess you
could register them with sequential numbers as you encounter the
masters in the device tree.  However, if this is code is in your
driver, it seems to be the wrong point in time, you need something
_init_or_module.

Looking through the code, It seems you want to use spi_new_device()
after calling spi_alloc_master() and spi_register_master().

However