gef_gpio.c
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/*
* Driver for GE FPGA based GPIO
*
* Author: Martyn Welch <martyn.welch@ge.com>
*
* 2008 (c) GE Intelligent Platforms Embedded Systems, Inc.
*
* This file is licensed under the terms of the GNU General Public License
* version 2. This program is licensed "as is" without any warranty of any
* kind, whether express or implied.
*/
/* TODO
*
* Configuration of output modes (totem-pole/open-drain)
* Interrupt configuration - interrupts are always generated the FPGA relies on
* the I/O interrupt controllers mask to stop them propergating
*/
#include <linux/kernel.h>
#include <linux/compiler.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_platform.h>
#include <linux/of_gpio.h>
#include <linux/gpio.h>
#include <linux/slab.h>
#include <linux/module.h>
#define GEF_GPIO_DIRECT 0x00
#define GEF_GPIO_IN 0x04
#define GEF_GPIO_OUT 0x08
#define GEF_GPIO_TRIG 0x0C
#define GEF_GPIO_POLAR_A 0x10
#define GEF_GPIO_POLAR_B 0x14
#define GEF_GPIO_INT_STAT 0x18
#define GEF_GPIO_OVERRUN 0x1C
#define GEF_GPIO_MODE 0x20
static void _gef_gpio_set(void __iomem *reg, unsigned int offset, int value)
{
unsigned int data;
data = ioread32be(reg);
/* value: 0=low; 1=high */
if (value & 0x1)
data = data | (0x1 << offset);
else
data = data & ~(0x1 << offset);
iowrite32be(data, reg);
}
static int gef_gpio_dir_in(struct gpio_chip *chip, unsigned offset)
{
unsigned int data;
struct of_mm_gpio_chip *mmchip = to_of_mm_gpio_chip(chip);
data = ioread32be(mmchip->regs + GEF_GPIO_DIRECT);
data = data | (0x1 << offset);
iowrite32be(data, mmchip->regs + GEF_GPIO_DIRECT);
return 0;
}
static int gef_gpio_dir_out(struct gpio_chip *chip, unsigned offset, int value)
{
unsigned int data;
struct of_mm_gpio_chip *mmchip = to_of_mm_gpio_chip(chip);
/* Set direction before switching to input */
_gef_gpio_set(mmchip->regs + GEF_GPIO_OUT, offset, value);
data = ioread32be(mmchip->regs + GEF_GPIO_DIRECT);
data = data & ~(0x1 << offset);
iowrite32be(data, mmchip->regs + GEF_GPIO_DIRECT);
return 0;
}
static int gef_gpio_get(struct gpio_chip *chip, unsigned offset)
{
unsigned int data;
int state = 0;
struct of_mm_gpio_chip *mmchip = to_of_mm_gpio_chip(chip);
data = ioread32be(mmchip->regs + GEF_GPIO_IN);
state = (int)((data >> offset) & 0x1);
return state;
}
static void gef_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
{
struct of_mm_gpio_chip *mmchip = to_of_mm_gpio_chip(chip);
_gef_gpio_set(mmchip->regs + GEF_GPIO_OUT, offset, value);
}
static int __init gef_gpio_init(void)
{
struct device_node *np;
int retval;
struct of_mm_gpio_chip *gef_gpio_chip;
for_each_compatible_node(np, NULL, "gef,sbc610-gpio") {
pr_debug("%s: Initialising GEF GPIO\n", np->full_name);
/* Allocate chip structure */
gef_gpio_chip = kzalloc(sizeof(*gef_gpio_chip), GFP_KERNEL);
if (!gef_gpio_chip) {
pr_err("%s: Unable to allocate structure\n",
np->full_name);
continue;
}
/* Setup pointers to chip functions */
gef_gpio_chip->gc.of_gpio_n_cells = 2;
gef_gpio_chip->gc.ngpio = 19;
gef_gpio_chip->gc.direction_input = gef_gpio_dir_in;
gef_gpio_chip->gc.direction_output = gef_gpio_dir_out;
gef_gpio_chip->gc.get = gef_gpio_get;
gef_gpio_chip->gc.set = gef_gpio_set;
/* This function adds a memory mapped GPIO chip */
retval = of_mm_gpiochip_add(np, gef_gpio_chip);
if (retval) {
kfree(gef_gpio_chip);
pr_err("%s: Unable to add GPIO\n", np->full_name);
}
}
for_each_compatible_node(np, NULL, "gef,sbc310-gpio") {
pr_debug("%s: Initialising GEF GPIO\n", np->full_name);
/* Allocate chip structure */
gef_gpio_chip = kzalloc(sizeof(*gef_gpio_chip), GFP_KERNEL);
if (!gef_gpio_chip) {
pr_err("%s: Unable to allocate structure\n",
np->full_name);
continue;
}
/* Setup pointers to chip functions */
gef_gpio_chip->gc.of_gpio_n_cells = 2;
gef_gpio_chip->gc.ngpio = 6;
gef_gpio_chip->gc.direction_input = gef_gpio_dir_in;
gef_gpio_chip->gc.direction_output = gef_gpio_dir_out;
gef_gpio_chip->gc.get = gef_gpio_get;
gef_gpio_chip->gc.set = gef_gpio_set;
/* This function adds a memory mapped GPIO chip */
retval = of_mm_gpiochip_add(np, gef_gpio_chip);
if (retval) {
kfree(gef_gpio_chip);
pr_err("%s: Unable to add GPIO\n", np->full_name);
}
}
return 0;
};
arch_initcall(gef_gpio_init);
MODULE_DESCRIPTION("GE I/O FPGA GPIO driver");
MODULE_AUTHOR("Martyn Welch <martyn.welch@ge.com");
MODULE_LICENSE("GPL");