From mboxrd@z Thu Jan 1 00:00:00 1970 From: plagnioj@jcrosoft.com (Jean-Christophe PLAGNIOL-VILLARD) Date: Sat, 3 Mar 2012 04:45:26 +0100 Subject: [PATCH 2/3 v3] of_spi: add generic binding support to specify ncs gpio In-Reply-To: <20120303023207.7241E3E2D8A@localhost> References: <1330682587-20636-1-git-send-email-plagnioj@jcrosoft.com> <1330682587-20636-2-git-send-email-plagnioj@jcrosoft.com> <20120303023207.7241E3E2D8A@localhost> Message-ID: <20120303034526.GC21255@game.jcrosoft.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 19:32 Fri 02 Mar , Grant Likely wrote: > On Fri, 2 Mar 2012 11:03:06 +0100, 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 > > Cc: devicetree-discuss at lists.ozlabs.org > > Cc: spi-devel-general at lists.sourceforge.net > > Cc: Grant Likely > > --- > > 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? for not chipslelect will remove > > > 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/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 > > #include > > #include > > +#include > > #include > > #include > > > > @@ -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. I want to have this transparent for the driver I don't want it to manage this. The driver just need to known it's cs-gpio and wich one > > > + > > + spi->controller_data = (void*)master->chipselect_gpios[num]; > > Controller_data cannot be used here since it is provided for use > by the controller driver. a new entry cs_gpio in the spi_device > > > + } > > + > > /* 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. it's the case here it's just the management on the binding > > > + > > + 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 ok > > > }; Best Regards, J. > > > > static inline void *spi_master_get_devdata(struct spi_master *master) > > -- > > 1.7.7 > > > > -- > email sent from notmuch.vim plugin