linux/drivers/gpio/xilinx_gpio.c

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/*
* Xilinx gpio driver
*
* Copyright 2008 Xilinx, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/of_device.h>
#include <linux/of_platform.h>
#include <linux/of_gpio.h>
#include <linux/io.h>
#include <linux/gpio.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 16:04:11 +08:00
#include <linux/slab.h>
/* Register Offset Definitions */
#define XGPIO_DATA_OFFSET (0x0) /* Data register */
#define XGPIO_TRI_OFFSET (0x4) /* I/O direction register */
struct xgpio_instance {
struct of_mm_gpio_chip mmchip;
u32 gpio_state; /* GPIO state shadow register */
u32 gpio_dir; /* GPIO direction shadow register */
spinlock_t gpio_lock; /* Lock used for synchronization */
};
/**
* xgpio_get - Read the specified signal of the GPIO device.
* @gc: Pointer to gpio_chip device structure.
* @gpio: GPIO signal number.
*
* This function reads the specified signal of the GPIO device. It returns 0 if
* the signal clear, 1 if signal is set or negative value on error.
*/
static int xgpio_get(struct gpio_chip *gc, unsigned int gpio)
{
struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
return (in_be32(mm_gc->regs + XGPIO_DATA_OFFSET) >> gpio) & 1;
}
/**
* xgpio_set - Write the specified signal of the GPIO device.
* @gc: Pointer to gpio_chip device structure.
* @gpio: GPIO signal number.
* @val: Value to be written to specified signal.
*
* This function writes the specified value in to the specified signal of the
* GPIO device.
*/
static void xgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
{
unsigned long flags;
struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
struct xgpio_instance *chip =
container_of(mm_gc, struct xgpio_instance, mmchip);
spin_lock_irqsave(&chip->gpio_lock, flags);
/* Write to GPIO signal and set its direction to output */
if (val)
chip->gpio_state |= 1 << gpio;
else
chip->gpio_state &= ~(1 << gpio);
out_be32(mm_gc->regs + XGPIO_DATA_OFFSET, chip->gpio_state);
spin_unlock_irqrestore(&chip->gpio_lock, flags);
}
/**
* xgpio_dir_in - Set the direction of the specified GPIO signal as input.
* @gc: Pointer to gpio_chip device structure.
* @gpio: GPIO signal number.
*
* This function sets the direction of specified GPIO signal as input.
* It returns 0 if direction of GPIO signals is set as input otherwise it
* returns negative error value.
*/
static int xgpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
{
unsigned long flags;
struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
struct xgpio_instance *chip =
container_of(mm_gc, struct xgpio_instance, mmchip);
spin_lock_irqsave(&chip->gpio_lock, flags);
/* Set the GPIO bit in shadow register and set direction as input */
chip->gpio_dir |= (1 << gpio);
out_be32(mm_gc->regs + XGPIO_TRI_OFFSET, chip->gpio_dir);
spin_unlock_irqrestore(&chip->gpio_lock, flags);
return 0;
}
/**
* xgpio_dir_out - Set the direction of the specified GPIO signal as output.
* @gc: Pointer to gpio_chip device structure.
* @gpio: GPIO signal number.
* @val: Value to be written to specified signal.
*
* This function sets the direction of specified GPIO signal as output. If all
* GPIO signals of GPIO chip is configured as input then it returns
* error otherwise it returns 0.
*/
static int xgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
{
unsigned long flags;
struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
struct xgpio_instance *chip =
container_of(mm_gc, struct xgpio_instance, mmchip);
spin_lock_irqsave(&chip->gpio_lock, flags);
/* Write state of GPIO signal */
if (val)
chip->gpio_state |= 1 << gpio;
else
chip->gpio_state &= ~(1 << gpio);
out_be32(mm_gc->regs + XGPIO_DATA_OFFSET, chip->gpio_state);
/* Clear the GPIO bit in shadow register and set direction as output */
chip->gpio_dir &= (~(1 << gpio));
out_be32(mm_gc->regs + XGPIO_TRI_OFFSET, chip->gpio_dir);
spin_unlock_irqrestore(&chip->gpio_lock, flags);
return 0;
}
/**
* xgpio_save_regs - Set initial values of GPIO pins
* @mm_gc: pointer to memory mapped GPIO chip structure
*/
static void xgpio_save_regs(struct of_mm_gpio_chip *mm_gc)
{
struct xgpio_instance *chip =
container_of(mm_gc, struct xgpio_instance, mmchip);
out_be32(mm_gc->regs + XGPIO_DATA_OFFSET, chip->gpio_state);
out_be32(mm_gc->regs + XGPIO_TRI_OFFSET, chip->gpio_dir);
}
/**
* xgpio_of_probe - Probe method for the GPIO device.
* @np: pointer to device tree node
*
* This function probes the GPIO device in the device tree. It initializes the
* driver data structure. It returns 0, if the driver is bound to the GPIO
* device, or a negative value if there is an error.
*/
static int __devinit xgpio_of_probe(struct device_node *np)
{
struct xgpio_instance *chip;
struct of_gpio_chip *ofchip;
int status = 0;
const u32 *tree_info;
chip = kzalloc(sizeof(*chip), GFP_KERNEL);
if (!chip)
return -ENOMEM;
ofchip = &chip->mmchip.of_gc;
/* Update GPIO state shadow register with default value */
tree_info = of_get_property(np, "xlnx,dout-default", NULL);
if (tree_info)
chip->gpio_state = *tree_info;
/* Update GPIO direction shadow register with default value */
chip->gpio_dir = 0xFFFFFFFF; /* By default, all pins are inputs */
tree_info = of_get_property(np, "xlnx,tri-default", NULL);
if (tree_info)
chip->gpio_dir = *tree_info;
/* Check device node and parent device node for device width */
ofchip->gc.ngpio = 32; /* By default assume full GPIO controller */
tree_info = of_get_property(np, "xlnx,gpio-width", NULL);
if (!tree_info)
tree_info = of_get_property(np->parent,
"xlnx,gpio-width", NULL);
if (tree_info)
ofchip->gc.ngpio = *tree_info;
spin_lock_init(&chip->gpio_lock);
ofchip->gpio_cells = 2;
ofchip->gc.direction_input = xgpio_dir_in;
ofchip->gc.direction_output = xgpio_dir_out;
ofchip->gc.get = xgpio_get;
ofchip->gc.set = xgpio_set;
chip->mmchip.save_regs = xgpio_save_regs;
/* Call the OF gpio helper to setup and register the GPIO device */
status = of_mm_gpiochip_add(np, &chip->mmchip);
if (status) {
kfree(chip);
pr_err("%s: error in probe function with status %d\n",
np->full_name, status);
return status;
}
pr_info("XGpio: %s: registered\n", np->full_name);
return 0;
}
static struct of_device_id xgpio_of_match[] __devinitdata = {
{ .compatible = "xlnx,xps-gpio-1.00.a", },
{ /* end of list */ },
};
static int __init xgpio_init(void)
{
struct device_node *np;
for_each_matching_node(np, xgpio_of_match)
xgpio_of_probe(np);
return 0;
}
/* Make sure we get initialized before anyone else tries to use us */
subsys_initcall(xgpio_init);
/* No exit call at the moment as we cannot unregister of GPIO chips */
MODULE_AUTHOR("Xilinx, Inc.");
MODULE_DESCRIPTION("Xilinx GPIO driver");
MODULE_LICENSE("GPL");