mirror of
https://github.com/torvalds/linux
synced 2024-09-21 19:47:35 +00:00
of_spi: add generic binding support to specify cs gpio
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 with max(hw cs, gpio cs). So if for example the controller has 2 CS lines, and the cs-gpios property looks like this: cs-gpios = <&gpio1 0 0> <0> <&gpio1 1 0> <&gpio1 2 0>; Then it should be configured so that num_chipselect = 4 with the following mapping: cs0 : &gpio1 0 0 cs1 : native cs2 : &gpio1 1 0 cs3 : &gpio1 2 0 Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com> Cc: devicetree-discuss@lists.ozlabs.org Cc: spi-devel-general@lists.sourceforge.net Signed-off-by: Richard Genoud <richard.genoud@gmail.com> [grant.likely: fixed up type of cs count so min() can do type checking] Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
This commit is contained in:
parent
15d0983f5c
commit
7431798490
|
@ -12,6 +12,7 @@ The SPI master node requires the following properties:
|
||||||
- #size-cells - should be zero.
|
- #size-cells - should be zero.
|
||||||
- compatible - name of SPI bus controller following generic names
|
- compatible - name of SPI bus controller following generic names
|
||||||
recommended practice.
|
recommended practice.
|
||||||
|
- cs-gpios - (optional) gpios chip select.
|
||||||
No other properties are required in the SPI bus node. It is assumed
|
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.
|
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
|
However, the binding does not attempt to define the specific method for
|
||||||
|
@ -24,6 +25,22 @@ support describing the chip select layout.
|
||||||
Optional property:
|
Optional property:
|
||||||
- num-cs : total number of chipselects
|
- num-cs : total number of chipselects
|
||||||
|
|
||||||
|
If cs-gpios is used the number of chip select will automatically increased
|
||||||
|
with max(cs-gpios > hw cs)
|
||||||
|
|
||||||
|
So if for example the controller has 2 CS lines, and the cs-gpios
|
||||||
|
property looks like this:
|
||||||
|
|
||||||
|
cs-gpios = <&gpio1 0 0> <0> <&gpio1 1 0> <&gpio1 2 0>;
|
||||||
|
|
||||||
|
Then it should be configured so that num_chipselect = 4 with the
|
||||||
|
following mapping:
|
||||||
|
|
||||||
|
cs0 : &gpio1 0 0
|
||||||
|
cs1 : native
|
||||||
|
cs2 : &gpio1 1 0
|
||||||
|
cs3 : &gpio1 2 0
|
||||||
|
|
||||||
SPI slave nodes must be children of the SPI master node and can
|
SPI slave nodes must be children of the SPI master node and can
|
||||||
contain the following properties.
|
contain the following properties.
|
||||||
- reg - (required) chip select address of device.
|
- reg - (required) chip select address of device.
|
||||||
|
@ -37,6 +54,9 @@ contain the following properties.
|
||||||
- spi-cs-high - (optional) Empty property indicating device requires
|
- spi-cs-high - (optional) Empty property indicating device requires
|
||||||
chip select active high
|
chip select active high
|
||||||
|
|
||||||
|
If a gpio chipselect is used for the SPI slave the gpio number will be passed
|
||||||
|
via the cs_gpio
|
||||||
|
|
||||||
SPI example for an MPC5200 SPI bus:
|
SPI example for an MPC5200 SPI bus:
|
||||||
spi@f00 {
|
spi@f00 {
|
||||||
#address-cells = <1>;
|
#address-cells = <1>;
|
||||||
|
|
|
@ -30,6 +30,7 @@
|
||||||
#include <linux/slab.h>
|
#include <linux/slab.h>
|
||||||
#include <linux/mod_devicetable.h>
|
#include <linux/mod_devicetable.h>
|
||||||
#include <linux/spi/spi.h>
|
#include <linux/spi/spi.h>
|
||||||
|
#include <linux/of_gpio.h>
|
||||||
#include <linux/pm_runtime.h>
|
#include <linux/pm_runtime.h>
|
||||||
#include <linux/export.h>
|
#include <linux/export.h>
|
||||||
#include <linux/sched.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.parent = &master->dev;
|
||||||
spi->dev.bus = &spi_bus_type;
|
spi->dev.bus = &spi_bus_type;
|
||||||
spi->dev.release = spidev_release;
|
spi->dev.release = spidev_release;
|
||||||
|
spi->cs_gpio = -EINVAL;
|
||||||
device_initialize(&spi->dev);
|
device_initialize(&spi->dev);
|
||||||
return spi;
|
return spi;
|
||||||
}
|
}
|
||||||
|
@ -344,15 +346,16 @@ EXPORT_SYMBOL_GPL(spi_alloc_device);
|
||||||
int spi_add_device(struct spi_device *spi)
|
int spi_add_device(struct spi_device *spi)
|
||||||
{
|
{
|
||||||
static DEFINE_MUTEX(spi_add_lock);
|
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;
|
struct device *d;
|
||||||
int status;
|
int status;
|
||||||
|
|
||||||
/* Chipselects are numbered 0..max; validate. */
|
/* 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",
|
dev_err(dev, "cs%d >= max %d\n",
|
||||||
spi->chip_select,
|
spi->chip_select,
|
||||||
spi->master->num_chipselect);
|
master->num_chipselect);
|
||||||
return -EINVAL;
|
return -EINVAL;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
@ -376,6 +379,9 @@ int spi_add_device(struct spi_device *spi)
|
||||||
goto done;
|
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
|
/* Drivers may modify this initial i/o setup, but will
|
||||||
* normally rely on the device being setup. Devices
|
* normally rely on the device being setup. Devices
|
||||||
* using SPI_CS_HIGH can't coexist well otherwise...
|
* using SPI_CS_HIGH can't coexist well otherwise...
|
||||||
|
@ -946,6 +952,44 @@ struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
|
||||||
}
|
}
|
||||||
EXPORT_SYMBOL_GPL(spi_alloc_master);
|
EXPORT_SYMBOL_GPL(spi_alloc_master);
|
||||||
|
|
||||||
|
#ifdef CONFIG_OF
|
||||||
|
static int of_spi_register_master(struct spi_master *master)
|
||||||
|
{
|
||||||
|
u16 nb;
|
||||||
|
int i, *cs;
|
||||||
|
struct device_node *np = master->dev.of_node;
|
||||||
|
|
||||||
|
if (!np)
|
||||||
|
return 0;
|
||||||
|
|
||||||
|
nb = of_gpio_named_count(np, "cs-gpios");
|
||||||
|
master->num_chipselect = max(nb, master->num_chipselect);
|
||||||
|
|
||||||
|
if (nb < 1)
|
||||||
|
return 0;
|
||||||
|
|
||||||
|
cs = devm_kzalloc(&master->dev,
|
||||||
|
sizeof(int) * master->num_chipselect,
|
||||||
|
GFP_KERNEL);
|
||||||
|
master->cs_gpios = cs;
|
||||||
|
|
||||||
|
if (!master->cs_gpios)
|
||||||
|
return -ENOMEM;
|
||||||
|
|
||||||
|
memset(cs, -EINVAL, master->num_chipselect);
|
||||||
|
|
||||||
|
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
|
* spi_register_master - register SPI master controller
|
||||||
* @master: initialized master, originally from spi_alloc_master()
|
* @master: initialized master, originally from spi_alloc_master()
|
||||||
|
@ -977,6 +1021,10 @@ int spi_register_master(struct spi_master *master)
|
||||||
if (!dev)
|
if (!dev)
|
||||||
return -ENODEV;
|
return -ENODEV;
|
||||||
|
|
||||||
|
status = of_spi_register_master(master);
|
||||||
|
if (status)
|
||||||
|
return status;
|
||||||
|
|
||||||
/* even if it's just one always-selected device, there must
|
/* even if it's just one always-selected device, there must
|
||||||
* be at least one chipselect
|
* be at least one chipselect
|
||||||
*/
|
*/
|
||||||
|
|
|
@ -90,6 +90,7 @@ struct spi_device {
|
||||||
void *controller_state;
|
void *controller_state;
|
||||||
void *controller_data;
|
void *controller_data;
|
||||||
char modalias[SPI_NAME_SIZE];
|
char modalias[SPI_NAME_SIZE];
|
||||||
|
int cs_gpio; /* chip select gpio */
|
||||||
|
|
||||||
/*
|
/*
|
||||||
* likely need more hooks for more protocol options affecting how
|
* 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,
|
int (*transfer_one_message)(struct spi_master *master,
|
||||||
struct spi_message *mesg);
|
struct spi_message *mesg);
|
||||||
int (*unprepare_transfer_hardware)(struct spi_master *master);
|
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)
|
static inline void *spi_master_get_devdata(struct spi_master *master)
|
||||||
|
|
Loading…
Reference in a new issue