From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean-Christophe PLAGNIOL-VILLARD Subject: [PATCH 1/3] of_spi: add generic binding support to specify ncs gpio in the slave Date: Mon, 30 Jan 2012 16:27:49 +0100 Message-ID: <1327937271-23668-1-git-send-email-plagnioj@jcrosoft.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: spi-devel-general@lists.sourceforge.net, devicetree-discuss@lists.ozlabs.org, Jean-Christophe PLAGNIOL-VILLARD To: linux-arm-kernel@lists.infradead.org Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org List-Id: linux-spi.vger.kernel.org This will allow to use gpio for chip select with no modification in the driver binding When use the ncs-gpio, the gpio number will be passed via the controller_data and the number of chip select will automatically increased. When a spi master have only gpio chip select and is probe via dt check the number of chip select only when adding slave. Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD Cc: devicetree-discuss@lists.ozlabs.org Cc: spi-devel-general@lists.sourceforge.net --- Documentation/devicetree/bindings/spi/spi-bus.txt | 9 ++++++- drivers/of/of_spi.c | 27 ++++++++++++++------ drivers/spi/spi.c | 2 +- 3 files changed, 28 insertions(+), 10 deletions(-) diff --git a/Documentation/devicetree/bindings/spi/spi-bus.txt b/Documentation/devicetree/bindings/spi/spi-bus.txt index e782add..1dccf35 100644 --- a/Documentation/devicetree/bindings/spi/spi-bus.txt +++ b/Documentation/devicetree/bindings/spi/spi-bus.txt @@ -21,9 +21,16 @@ 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 a gpio a specified to the SPI slave and no hardware chip select is present +the reg property #address-cells and #size-cells are not needed. + +When use the ncs-gpio the gpio number will be passed via the controller_data +and 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. +- reg - (required if no ncs-gpio) chip select address of device. +- ncs-gpio - (required if no reg) chip select gpio of device. - compatible - (required) name of SPI device following generic names recommended practice - spi-max-frequency - (required) Maximum SPI clocking speed of device in Hz 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 #include #include +#include /** * 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 b2ccdea..ccd1a6f 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -595,7 +595,7 @@ int spi_register_master(struct spi_master *master) /* even if it's just one always-selected device, there must * be at least one chipselect */ - if (master->num_chipselect == 0) + if (!master->dev.of_node && master->num_chipselect == 0) return -EINVAL; /* convention: dynamically assigned bus IDs count down from the max */ -- 1.7.7