On Fri, May 16, 2008 at 04:14:23PM -0600, Grant Likely wrote:

On Fri, May 16, 2008 at 4:03 PM, Anton Vorontsov [off-list ref] wrote:

quoted

On Fri, May 16, 2008 at 01:36:13PM -0600, Grant Likely wrote:

quoted

+             /* Store a pointer to the node in the device structure */
+             of_node_get(nc);
+             spi->dev.archdata.of_node = nc;
+
+             /* Register the new device */
+             rc = spi_register_device(spi);
+             if (rc) {
+                     dev_err(&master->dev, "spi_device register error %s\n",
+                             np->full_name);
+                     spi_device_release(spi);
+             }

No way to pass platform data... can you suggest any idea to use
this for things like
"[POWERPC] 86xx: mpc8610_hpcd: add support for SPI and MMC-over-SPI"
I've sent just recently...?

That's right.  platform_data being a very driver specific thing there
is no way to generically extract a pdata structure from the device
tree.  Instead, I'm storing the device node in archdata.of_node (line
immediately above spi_register_device) so that drivers can read the
device node themselves to populate a platform_device structure.
(Protected by CONFIG_OF of course).

quoted

Maybe this code could do something like
spi->dev.platform_data = nc->data;
and board code would fill nc->data at early stages? This needs to be a
convention, not just random use though.. Maybe we can expand the struct
device_node to explicitly include .platform_data for such cases?

Hmmm, as you say, this could end up being rather messy.  However, by
passing the device node pointer, the driver could extract that data on
a per case basis.  (ie. it would be decided on a per driver basis
where to get the platform data).  I'm not sure; this bears more
thought...

Sometimes it's not worth powder and shot adding OF functionality to
the drivers, I2C and SPI are major examples. Another [not mmc_spi]
example is drivers/input/touchscreen/ads7846.c, which is SPI driver
and needs platform data. There is a board that needs this (touchscreen
controller on a MPC8360E-RDK).

Also there is no way to pass functions via device tree, we're
always end up doing board-specific hooks in the generic drivers...

Finally, let's call this platform_data and be done with it. Then we
can use this for things like drivers/video/fsl-diu-fb.c (see diu_ops,
which is global struct, filled by
arch/powerpc/platforms/86xx/mpc8610_hpcd.c).

-- 
Anton Vorontsov
email: cbouatmailru@gmail.com
irc://irc.freenode.net/bd2