On Fri, 2 Mar 2012 11:03:06 +0100, Jean-Christophe PLAGNIOL-VILLARD <plagn...@jcrosoft.com> 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 <plagn...@jcrosoft.com> > Cc: devicetree-disc...@lists.ozlabs.org > Cc: spi-devel-general@lists.sourceforge.net > Cc: Grant Likely <grant.lik...@secretlab.ca> > --- > v3: > use devm_kzalloc > > v2: > specify the gpio array at controller level > > Best Regards, > J. > Documentation/devicetree/bindings/spi/spi-bus.txt | 6 +++ > drivers/spi/spi.c | 49 +++++++++++++++++++- > include/linux/spi/spi.h | 5 ++ > 3 files changed, 57 insertions(+), 3 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.
ncs? What does the 'n' stand for? > 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@f00 { > #address-cells = <1>; > diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c > index e2f4ca0..f3df51f 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; I'd rather see an unconditional array of gpios; which only get used if a valid gpio number is assigned. > + > + spi->controller_data = (void*)master->chipselect_gpios[num]; Controller_data cannot be used here since it is provided for use by the controller driver. > + } > + > /* 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 +571,36 @@ 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; > + > + cs = devm_kzalloc(&master->dev, sizeof(int) * nb, GFP_KERNEL); > + master->chipselect_gpios = cs; the chipselect gpios functionality should be available regardless of whether or not DT is used. This should be moved out of the of-specific register function. > + > + 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[i] = of_get_named_gpio(np, "ncs-gpios", i); > + > + return 0; > +} This function should be #ifdefed out when !OF > + > /** > * spi_register_master - register SPI master controller > * @master: initialized master, originally from spi_alloc_master() > @@ -593,6 +632,10 @@ 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; s/chipselect/cs/ would be quite a bit less verbose > }; > > static inline void *spi_master_get_devdata(struct spi_master *master) > -- > 1.7.7 > -- email sent from notmuch.vim plugin ------------------------------------------------------------------------------ Virtualization & Cloud Management Using Capacity Planning Cloud computing makes use of virtualization - but cloud computing also focuses on allowing computing to be delivered as a service. http://www.accelacomm.com/jaw/sfnl/114/51521223/ _______________________________________________ spi-devel-general mailing list spi-devel-general@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/spi-devel-general