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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/io.h>
#include <linux/of_device.h>
#include <linux/of_gpio.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(struct gpio_chip *chip, unsigned offset, int value)
{
struct of_mm_gpio_chip *mmchip = to_of_mm_gpio_chip(chip);
unsigned int data;
data = ioread32be(mmchip->regs + GEF_GPIO_OUT);
if (value)
data = data | BIT(offset);
else
data = data & ~BIT(offset);
iowrite32be(data, mmchip->regs + GEF_GPIO_OUT);
}
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 | BIT(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 value before switching to output */
gef_gpio_set(mmchip->regs + GEF_GPIO_OUT, offset, value);
data = ioread32be(mmchip->regs + GEF_GPIO_DIRECT);
data = data & ~BIT(offset);
iowrite32be(data, mmchip->regs + GEF_GPIO_DIRECT);
return 0;
}
static int gef_gpio_get(struct gpio_chip *chip, unsigned offset)
{
struct of_mm_gpio_chip *mmchip = to_of_mm_gpio_chip(chip);
return !!(ioread32be(mmchip->regs + GEF_GPIO_IN) & BIT(offset));
}
static const struct of_device_id gef_gpio_ids[] = {
{
.compatible = "gef,sbc610-gpio",
.data = (void *)19,
}, {
.compatible = "gef,sbc310-gpio",
.data = (void *)6,
}, {
.compatible = "ge,imp3a-gpio",
.data = (void *)16,
},
{ }
};
MODULE_DEVICE_TABLE(of, gef_gpio_ids);
static int __init gef_gpio_probe(struct platform_device *pdev)
{
const struct of_device_id *of_id =
of_match_device(gef_gpio_ids, &pdev->dev);
struct of_mm_gpio_chip *mmchip;
mmchip = devm_kzalloc(&pdev->dev, sizeof(*mmchip), GFP_KERNEL);
if (!mmchip)
return -ENOMEM;
/* Setup pointers to chip functions */
mmchip->gc.ngpio = (u16)(uintptr_t)of_id->data;
mmchip->gc.of_gpio_n_cells = 2;
mmchip->gc.direction_input = gef_gpio_dir_in;
mmchip->gc.direction_output = gef_gpio_dir_out;
mmchip->gc.get = gef_gpio_get;
mmchip->gc.set = gef_gpio_set;
/* This function adds a memory mapped GPIO chip */
return of_mm_gpiochip_add(pdev->dev.of_node, mmchip);
};
static struct platform_driver gef_gpio_driver = {
.driver = {
.name = "gef-gpio",
.of_match_table = gef_gpio_ids,
},
};
module_platform_driver_probe(gef_gpio_driver, gef_gpio_probe);
MODULE_DESCRIPTION("GE I/O FPGA GPIO driver");
MODULE_AUTHOR("Martyn Welch <martyn.welch@ge.com");
MODULE_LICENSE("GPL");
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