[v2 PATCH 02/14] of_spi: add generic binding support to specify cs gpio
From: Wenyou Yang <hidden>
Date: 2012-12-04 08:01:32
Also in:
linux-devicetree, linux-spi, lkml
Subsystem:
open firmware and flattened device tree bindings, spi subsystem, the rest · Maintainers:
Rob Herring, Krzysztof Kozlowski, Conor Dooley, Mark Brown, Linus Torvalds
From: Jean-Christophe PLAGNIOL-VILLARD <redacted> This will allow to use gpio for chip select with no modification in the driver binding When use the cs-gpios, the gpio number will be passed via the cs_gpio field and the number of chip select will automatically increased. Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <redacted> Cc: devicetree-discuss at lists.ozlabs.org Cc: spi-devel-general at lists.sourceforge.net Cc: grant.likely at secretlab.ca Cc: rob.herring at calxeda.com Cc: rob at landley.net Cc: richard.genoud at gmail.com --- Hi, Richard, This patch based on the original patch from Jean-Christophe, [PATCH] of_spi: add generic binding support to specify cs gpio and merge the patch from Richard Genoud, [PATCH] [BUG] SPI: array out of bound => no CS Could you sign your signature in this patch? Best Regards, Wenyou Yang Documentation/devicetree/bindings/spi/spi-bus.txt | 6 +++ drivers/spi/spi.c | 55 +++++++++++++++++++-- include/linux/spi/spi.h | 3 ++ 3 files changed, 61 insertions(+), 3 deletions(-)
diff --git a/Documentation/devicetree/bindings/spi/spi-bus.txt b/Documentation/devicetree/bindings/spi/spi-bus.txt
index d2c33d0..7f59ae30 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. +- cs-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 cs-gpios is used the number of chip select will automatically increased. + Optional property: - num-cs : total number of chipselects
@@ -37,6 +40,9 @@ 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 84c2861..74e6577 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c@@ -30,6 +30,7 @@ #include <linux/slab.h> #include <linux/mod_devicetable.h> #include <linux/spi/spi.h> +#include <linux/of_gpio.h> #include <linux/pm_runtime.h> #include <linux/export.h> #include <linux/sched.h>
@@ -327,6 +328,7 @@ struct spi_device *spi_alloc_device(struct spi_master *master) spi->dev.parent = &master->dev; spi->dev.bus = &spi_bus_type; spi->dev.release = spidev_release; + spi->cs_gpio = -EINVAL; device_initialize(&spi->dev); return spi; }
@@ -344,15 +346,16 @@ 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; }
@@ -376,6 +379,9 @@ int spi_add_device(struct spi_device *spi) goto done; } + if (master->cs_gpios) + spi->cs_gpio = master->cs_gpios[spi->chip_select]; + /* 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...
@@ -946,6 +952,45 @@ struct spi_master *spi_alloc_master(struct device *dev, unsigned size) } EXPORT_SYMBOL_GPL(spi_alloc_master); +#ifdef CONFIG_OF +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, "cs-gpios"); + + if (nb < 1) + return 0; + + cs = devm_kzalloc(&master->dev, + sizeof(int) * (master->num_chipselect + nb), + GFP_KERNEL); + master->cs_gpios = cs; + + if (!master->cs_gpios) + return -ENOMEM; + + memset(cs, -EINVAL, master->num_chipselect); + cs += master->num_chipselect; + master->num_chipselect += nb; + + for (i = 0; i < nb; i++) + cs[i] = of_get_named_gpio(np, "cs-gpios", i); + + return 0; +} +#else +static int of_spi_register_master(struct spi_master *master) +{ + return 0; +} +#endif + /** * spi_register_master - register SPI master controller * @master: initialized master, originally from spi_alloc_master()
@@ -977,6 +1022,10 @@ 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@least one chipselect */
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index fa702ae..f629189 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h@@ -90,6 +90,7 @@ struct spi_device { void *controller_state; void *controller_data; char modalias[SPI_NAME_SIZE]; + int cs_gpio; /* chip select gpio */ /* * likely need more hooks for more protocol options affecting how
@@ -362,6 +363,8 @@ struct spi_master { int (*transfer_one_message)(struct spi_master *master, struct spi_message *mesg); int (*unprepare_transfer_hardware)(struct spi_master *master); + /* gpio chip select */ + int *cs_gpios; }; static inline void *spi_master_get_devdata(struct spi_master *master)
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1.7.9.5