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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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