[PATCH 2/3] of_spi: add generic binding support to specify ncs gpio
Jean-Christophe PLAGNIOL-VILLARD
plagnioj at jcrosoft.com
Mon Feb 20 20:56:39 EST 2012
Hi Grant,
can I have a feedback
the Atmel SPI depend on it
Best Regards,
J.
On 05:24 Tue 14 Feb , Jean-Christophe PLAGNIOL-VILLARD wrote:
> Hi Grant,
>
> ping
>
> Best Regards,
> J.
> On 17:14 Thu 09 Feb , Jean-Christophe PLAGNIOL-VILLARD wrote:
> > This will allow to use gpio for chip select with no modification in the
> > driver binding
> >
> > When use the ncs-gpios, the gpio number will be passed via the controller_data
> > and the number of chip select will automatically increased.
> >
> > Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com>
> > Cc: devicetree-discuss at lists.ozlabs.org
> > Cc: spi-devel-general at lists.sourceforge.net
> > ---
> > Documentation/devicetree/bindings/spi/spi-bus.txt | 6 +++
> > drivers/of/of_spi.c | 27 ++++++++---
> > drivers/spi/spi.c | 51 +++++++++++++++++++-
> > include/linux/spi/spi.h | 5 ++
> > 4 files changed, 78 insertions(+), 11 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/spi/spi-bus.txt b/Documentation/devicetree/bindings/spi/spi-bus.txt
> > index e782add..5a24729 100644
> > --- a/Documentation/devicetree/bindings/spi/spi-bus.txt
> > +++ b/Documentation/devicetree/bindings/spi/spi-bus.txt
> > @@ -12,6 +12,7 @@ The SPI master node requires the following properties:
> > - #size-cells - should be zero.
> > - compatible - name of SPI bus controller following generic names
> > recommended practice.
> > +- ncs-gpios - (optional) gpios chip select.
> > No other properties are required in the SPI bus node. It is assumed
> > that a driver for an SPI bus device will understand that it is an SPI bus.
> > However, the binding does not attempt to define the specific method for
> > @@ -21,6 +22,8 @@ assumption that board specific platform code will be used to manage
> > chip selects. Individual drivers can define additional properties to
> > support describing the chip select layout.
> >
> > +If ncs-gpios is used the number of chip select will automatically increased.
> > +
> > SPI slave nodes must be children of the SPI master node and can
> > contain the following properties.
> > - reg - (required) chip select address of device.
> > @@ -34,6 +37,9 @@ contain the following properties.
> > - spi-cs-high - (optional) Empty property indicating device requires
> > chip select active high
> >
> > +If a gpio chipselect is used for the SPI slave the gpio number will be passed
> > +via the controller_data
> > +
> > SPI example for an MPC5200 SPI bus:
> > spi at f00 {
> > #address-cells = <1>;
> > diff --git a/drivers/of/of_spi.c b/drivers/of/of_spi.c
> > index 6dbc074..0d41407 100644
> > --- a/drivers/of/of_spi.c
> > +++ b/drivers/of/of_spi.c
> > @@ -12,6 +12,7 @@
> > #include <linux/spi/spi.h>
> > #include <linux/of_irq.h>
> > #include <linux/of_spi.h>
> > +#include <linux/of_gpio.h>
> >
> > /**
> > * of_register_spi_devices - Register child devices onto the SPI bus
> > @@ -27,6 +28,7 @@ void of_register_spi_devices(struct spi_master *master)
> > const __be32 *prop;
> > int rc;
> > int len;
> > + int ncs_pin;
> >
> > if (!master->dev.of_node)
> > return;
> > @@ -50,15 +52,24 @@ void of_register_spi_devices(struct spi_master *master)
> > 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);
> > - spi_dev_put(spi);
> > - continue;
> > + /* ncs gpio */
> > + ncs_pin = of_get_named_gpio(nc, "ncs-gpio", 0);
> > +
> > + if (gpio_is_valid(ncs_pin)) {
> > + spi->controller_data = (void *)ncs_pin;
> > + spi->chip_select = master->num_chipselect;
> > + master->num_chipselect++;
> > + } else {
> > + /* 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);
> > + spi_dev_put(spi);
> > + continue;
> > + }
> > + spi->chip_select = be32_to_cpup(prop);
> > }
> > - spi->chip_select = be32_to_cpup(prop);
> >
> > /* Mode (clock phase/polarity/etc.) */
> > if (of_find_property(nc, "spi-cpha", NULL))
> > diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
> > index e2f4ca0..1f5ffa6 100644
> > --- a/drivers/spi/spi.c
> > +++ b/drivers/spi/spi.c
> > @@ -28,6 +28,7 @@
> > #include <linux/mod_devicetable.h>
> > #include <linux/spi/spi.h>
> > #include <linux/of_spi.h>
> > +#include <linux/of_gpio.h>
> > #include <linux/pm_runtime.h>
> > #include <linux/export.h>
> >
> > @@ -339,15 +340,16 @@ EXPORT_SYMBOL_GPL(spi_alloc_device);
> > int spi_add_device(struct spi_device *spi)
> > {
> > static DEFINE_MUTEX(spi_add_lock);
> > - struct device *dev = spi->master->dev.parent;
> > + struct spi_master *master = spi->master;
> > + struct device *dev = master->dev.parent;
> > struct device *d;
> > int status;
> >
> > /* Chipselects are numbered 0..max; validate. */
> > - if (spi->chip_select >= spi->master->num_chipselect) {
> > + if (spi->chip_select >= master->num_chipselect) {
> > dev_err(dev, "cs%d >= max %d\n",
> > spi->chip_select,
> > - spi->master->num_chipselect);
> > + master->num_chipselect);
> > return -EINVAL;
> > }
> >
> > @@ -371,6 +373,13 @@ int spi_add_device(struct spi_device *spi)
> > goto done;
> > }
> >
> > + if (master->num_gpio_chipselect &&
> > + spi->chip_select >= master->first_gpio_chipselect) {
> > + int num = spi->chip_select = master->first_gpio_chipselect;
> > +
> > + spi->controller_data = (void*)master->chipselect_gpios[num];
> > + }
> > +
> > /* Drivers may modify this initial i/o setup, but will
> > * normally rely on the device being setup. Devices
> > * using SPI_CS_HIGH can't coexist well otherwise...
> > @@ -562,6 +571,38 @@ struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
> > }
> > EXPORT_SYMBOL_GPL(spi_alloc_master);
> >
> > +static int of_spi_register_master(struct spi_master *master)
> > +{
> > + int nb, i;
> > + int *cs;
> > + struct device_node *np = master->dev.of_node;
> > +
> > + if (!np)
> > + return 0;
> > +
> > + nb = of_gpio_named_count(np, "ncs-gpios");
> > +
> > + if (nb < 1)
> > + return 0;
> > +
> > + master->chipselect_gpios = kzalloc(sizeof(int) * nb, GFP_KERNEL);
> > +
> > + if (!master->chipselect_gpios)
> > + return -ENOMEM;
> > +
> > + master->first_gpio_chipselect = master->num_chipselect;
> > + master->num_chipselect += nb;
> > + master->num_gpio_chipselect = nb;
> > +
> > + for (i = 0; i < nb; i++) {
> > + cs = &master->chipselect_gpios[i];
> > +
> > + *cs = of_get_named_gpio(np, "ncs-gpios", i);
> > + }
> > +
> > + return 0;
> > +}
> > +
> > /**
> > * spi_register_master - register SPI master controller
> > * @master: initialized master, originally from spi_alloc_master()
> > @@ -593,6 +634,10 @@ int spi_register_master(struct spi_master *master)
> > if (!dev)
> > return -ENODEV;
> >
> > + status = of_spi_register_master(master);
> > + if (status)
> > + return status;
> > +
> > /* even if it's just one always-selected device, there must
> > * be at least one chipselect
> > */
> > diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
> > index 176fce9..d21c267 100644
> > --- a/include/linux/spi/spi.h
> > +++ b/include/linux/spi/spi.h
> > @@ -318,6 +318,11 @@ struct spi_master {
> >
> > /* called on release() to free memory provided by spi_master */
> > void (*cleanup)(struct spi_device *spi);
> > +
> > + /* gpio chip select */
> > + int *chipselect_gpios;
> > + int first_gpio_chipselect;
> > + int num_gpio_chipselect;
> > };
> >
> > static inline void *spi_master_get_devdata(struct spi_master *master)
> > --
> > 1.7.7
>
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