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SubjectRe: [PATCH v2 4/5] spi: Add OF binding support for SPI busses
On 7/2/08, Grant Likely <grant.likely@secretlab.ca> 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>
> ---
>
> drivers/of/Kconfig | 6 +++
> drivers/of/Makefile | 1 +
> drivers/of/of_spi.c | 88 ++++++++++++++++++++++++++++++++++++++++++++++++
> include/linux/of_spi.h | 18 ++++++++++
> 4 files changed, 113 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
> index 3a7a11a..edd6e92 100644
> --- a/drivers/of/Kconfig
> +++ b/drivers/of/Kconfig
> @@ -13,3 +13,9 @@ config OF_I2C
> depends on PPC_OF && I2C
> help
> OpenFirmware I2C accessors
> +
> +config OF_SPI
> + def_tristate SPI
> + depends on OF && PPC_OF && SPI
> + help
> + OpenFirmware SPI accessors
> diff --git a/drivers/of/Makefile b/drivers/of/Makefile
> index 548772e..4c3c6f8 100644
> --- a/drivers/of/Makefile
> +++ b/drivers/of/Makefile
> @@ -2,3 +2,4 @@ obj-y = base.o
> obj-$(CONFIG_OF_DEVICE) += device.o platform.o
> obj-$(CONFIG_OF_GPIO) += gpio.o
> obj-$(CONFIG_OF_I2C) += of_i2c.o
> +obj-$(CONFIG_OF_SPI) += of_spi.o
> diff --git a/drivers/of/of_spi.c b/drivers/of/of_spi.c
> new file mode 100644
> index 0000000..ed0c807
> --- /dev/null
> +++ b/drivers/of/of_spi.c
> @@ -0,0 +1,88 @@
> +/*
> + * SPI OF support routines
> + * Copyright (C) 2008 Secret Lab Technologies Ltd.
> + *
> + * Support routines for deriving SPI device attachments from the device
> + * tree.
> + */
> +
> +#include <linux/of.h>
> +#include <linux/device.h>
> +#include <linux/spi/spi.h>
> +#include <linux/of_spi.h>
> +
> +/**
> + * of_register_spi_devices - Register child devices onto the SPI bus
> + * @master: Pointer to spi_master device
> + * @np: parent node of SPI device nodes
> + *
> + * Registers an spi_device for each child node of 'np' which has a 'reg'
> + * property.
> + */
> +void of_register_spi_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",
> + nc->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",
> + nc->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)) {
> + dev_err(&master->dev, "%s has no 'max-speed' property\n",
> + nc->full_name);
> + continue;
> + }
> + spi->max_speed_hz = *prop;
> +
> + /* 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);

You're missing a request_module("%s", info.type) to make sure the
module is loaded.

It might make sense to share code with of_find_i2c_driver() so we have
a common way of guessing module names.

> +
> + /* 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_add_device(spi);
> + if (rc) {
> + dev_err(&master->dev, "spi_device register error %s\n",
> + nc->full_name);
> + spi_dev_put(spi);
> + }
> +
> + }
> +}
> +EXPORT_SYMBOL(of_register_spi_devices);
> diff --git a/include/linux/of_spi.h b/include/linux/of_spi.h
> new file mode 100644
> index 0000000..5f71ee8
> --- /dev/null
> +++ b/include/linux/of_spi.h
> @@ -0,0 +1,18 @@
> +/*
> + * OpenFirmware SPI support routines
> + * Copyright (C) 2008 Secret Lab Technologies Ltd.
> + *
> + * Support routines for deriving SPI device attachments from the device
> + * tree.
> + */
> +
> +#ifndef __LINUX_OF_SPI_H
> +#define __LINUX_OF_SPI_H
> +
> +#include <linux/of.h>
> +#include <linux/spi/spi.h>
> +
> +extern void of_register_spi_devices(struct spi_master *master,
> + struct device_node *np);
> +
> +#endif /* __LINUX_OF_SPI */
>
>


--
Jon Smirl
jonsmirl@gmail.com


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