Re: [PATCH 3/4] spi: Add OF binding support for SPI busses

Anton Vorontsov
2008-05-16T22:04:14Z

On Fri, May 16, 2008 at 01:36:13PM -0600, Grant Likely wrote:
> From: Grant Likely <grant.likely@secretlab.ca>
>
> This patch adds support for populating an SPI bus based on data in the
> OF device tree. This is useful for powerpc platforms which use the
> device tree instead of discrete code for describing platform layout.
>
> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
> ---
[...]
> +void spi_of_register_devices(struct spi_master *master, struct device_node *np)
> +{
> + struct spi_device *spi;
> + struct device_node *nc;
> + const u32 *prop;
> + const char *sprop;
> + int rc;
> + int len;
> +
> + for_each_child_of_node(np, nc) {
> + /* Alloc an spi_device */
> + spi = spi_alloc_device(master);
> + if (!spi) {
> + dev_err(&master->dev, "spi_device alloc error for %s\n",
> + np->full_name);
> + continue;
> + }
> +
> + /* Device address */
> + prop = of_get_property(nc, "reg", &len);
> + if (!prop || len < sizeof(*prop)) {
> + dev_err(&master->dev, "%s has no 'reg' property\n",
> + np->full_name);
> + continue;
> + }
> + spi->chip_select = *prop;
> +
> + /* Mode (clock phase/polarity/etc. */
> + if (of_find_property(nc, "spi,cpha", NULL))
> + spi->mode |= SPI_CPHA;
> + if (of_find_property(nc, "spi,cpol", NULL))
> + spi->mode |= SPI_CPOL;
> +
> + /* Device speed */
> + prop = of_get_property(nc, "max-speed", &len);
> + if (prop && len >= sizeof(*prop))
> + spi->max_speed_hz = *prop;
> + else
> + spi->max_speed_hz = 100000;
> +
> + /* IRQ */
> + spi->irq = irq_of_parse_and_map(nc, 0);
> +
> + /* Select device driver */
> + sprop = of_get_property(nc, "linux,modalias", &len);
> + if (sprop && len > 0)
> + strncpy(spi->modalias, sprop, KOBJ_NAME_LEN);
> + else
> + strncpy(spi->modalias, "spidev", KOBJ_NAME_LEN);
> +
> + /* 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...?

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?

Thanks,

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