/*
* GPIO interface for Intel Poulsbo SCH
*
* Copyright (c) 2010 CompuLab Ltd
* Author: Denis Turischev <denis@compulab.co.il>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License 2 as published
* by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; see the file COPYING. If not, write to
* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/io.h>
#include <linux/errno.h>
#include <linux/acpi.h>
#include <linux/platform_device.h>
#include <linux/pci_ids.h>
#include <linux/gpio.h>
#define GEN 0x00
#define GIO 0x04
#define GLV 0x08
struct sch_gpio {
struct gpio_chip chip;
spinlock_t lock;
unsigned short iobase;
unsigned short core_base;
unsigned short resume_base;
};
#define to_sch_gpio(c) container_of(c, struct sch_gpio, chip)
static unsigned sch_gpio_offset(struct sch_gpio *sch, unsigned gpio,
unsigned reg)
{
unsigned base = 0;
if (gpio >= sch->resume_base) {
gpio -= sch->resume_base;
base += 0x20;
}
return base + reg + gpio / 8;
}
static unsigned sch_gpio_bit(struct sch_gpio *sch, unsigned gpio)
{
if (gpio >= sch->resume_base)
gpio -= sch->resume_base;
return gpio % 8;
}
static void sch_gpio_enable(struct sch_gpio *sch, unsigned gpio)
{
unsigned short offset, bit;
u8 enable;
spin_lock(&sch->lock);
offset = sch_gpio_offset(sch, gpio, GEN);
bit = sch_gpio_bit(sch, gpio);
enable = inb(sch->iobase + offset);
if (!(enable & (1 << bit)))
outb(enable | (1 << bit), sch->iobase + offset);
spin_unlock(&sch->lock);
}
static int sch_gpio_direction_in(struct gpio_chip *gc, unsigned gpio_num)
{
struct sch_gpio *sch = to_sch_gpio(gc);
u8 curr_dirs;
unsigned short offset, bit;
spin_lock(&sch->lock);
offset = sch_gpio_offset(sch, gpio_num, GIO);
bit = sch_gpio_bit(sch, gpio_num);
curr_dirs = inb(sch->iobase + offset);
if (!(curr_dirs & (1 << bit)))
outb(curr_dirs | (1 << bit), sch->iobase + offset);
spin_unlock(&sch->lock);
return 0;
}
static int sch_gpio_get(struct gpio_chip *gc, unsigned gpio_num)
{
struct sch_gpio *sch = to_sch_gpio(gc);
int res;
unsigned short offset, bit;
offset = sch_gpio_offset(sch, gpio_num, GLV);
bit = sch_gpio_bit(sch, gpio_num);
res = !!(inb(sch->iobase + offset) & (1 << bit));
return res;
}
static void sch_gpio_set(struct gpio_chip *gc, unsigned gpio_num, int val)
{
struct sch_gpio *sch = to_sch_gpio(gc);
u8 curr_vals;
unsigned short offset, bit;
spin_lock(&sch->lock);
offset = sch_gpio_offset(sch, gpio_num, GLV);
bit = sch_gpio_bit(sch, gpio_num);
curr_vals = inb(sch->iobase + offset);
if (val)
outb(curr_vals | (1 << bit), sch->iobase + offset);
else
outb((curr_vals & ~(1 << bit)), sch->iobase + offset);
spin_unlock(&sch->lock);
}
static int sch_gpio_direction_out(struct gpio_chip *gc, unsigned gpio_num,
int val)
{
struct sch_gpio *sch = to_sch_gpio(gc);
u8 curr_dirs;
unsigned short offset, bit;
spin_lock(&sch->lock);
offset = sch_gpio_offset(sch, gpio_num, GIO);
bit = sch_gpio_bit(sch, gpio_num);
curr_dirs = inb(sch->iobase + offset);
if (curr_dirs & (1 << bit))
outb(curr_dirs & ~(1 << bit), sch->iobase + offset);
spin_unlock(&sch->lock);
/*
* according to the datasheet, writing to the level register has no
* effect when GPIO is programmed as input.
* Actually the the level register is read-only when configured as input.
* Thus presetting the output level before switching to output is _NOT_ possible.
* Hence we set the level after configuring the GPIO as output.
* But we cannot prevent a short low pulse if direction is set to high
* and an external pull-up is connected.
*/
sch_gpio_set(gc, gpio_num, val);
return 0;
}
static struct gpio_chip sch_gpio_chip = {
.label = "sch_gpio",
.owner = THIS_MODULE,
.direction_input = sch_gpio_direction_in,
.get = sch_gpio_get,
.direction_output = sch_gpio_direction_out,
.set = sch_gpio_set,
};
static int sch_gpio_probe(struct platform_device *pdev)
{
struct sch_gpio *sch;
struct resource *res;
sch = devm_kzalloc(&pdev->dev, sizeof(*sch), GFP_KERNEL);
if (!sch)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_IO, 0);
if (!res)
return -EBUSY;
if (!devm_request_region(&pdev->dev, res->start, resource_size(res),
pdev->name))
return -EBUSY;
spin_lock_init(&sch->lock);
sch->iobase = res->start;
sch->chip = sch_gpio_chip;
sch->chip.label = dev_name(&pdev->dev);
sch->chip.dev = &pdev->dev;
switch (pdev->id) {
case PCI_DEVICE_ID_INTEL_SCH_LPC:
sch->core_base = 0;
sch->resume_base = 10;
sch->chip.ngpio = 14;
/*
* GPIO[6:0] enabled by default
* GPIO7 is configured by the CMC as SLPIOVR
* Enable GPIO[9:8] core powered gpios explicitly
*/
sch_gpio_enable(sch, 8);
sch_gpio_enable(sch, 9);
/*
* SUS_GPIO[2:0] enabled by default
* Enable SUS_GPIO3 resume powered gpio explicitly
*/
sch_gpio_enable(sch, 13);
break;
case PCI_DEVICE_ID_INTEL_ITC_LPC:
sch->core_base = 0;
sch->resume_base = 5;
sch->chip.ngpio = 14;
break;
case PCI_DEVICE_ID_INTEL_CENTERTON_ILB:
sch->core_base = 0;
sch->resume_base = 21;
sch->chip.ngpio = 30;
break;
default:
return -ENODEV;
}
platform_set_drvdata(pdev, sch);
return gpiochip_add(&sch->chip);
}
static int sch_gpio_remove(struct platform_device *pdev)
{
struct sch_gpio *sch = platform_get_drvdata(pdev);
gpiochip_remove(&sch->chip);
return 0;
}
static struct platform_driver sch_gpio_driver = {
.driver = {
.name = "sch_gpio",
.owner = THIS_MODULE,
},
.probe = sch_gpio_probe,
.remove = sch_gpio_remove,
};
module_platform_driver(sch_gpio_driver);
MODULE_AUTHOR("Denis Turischev <denis@compulab.co.il>");
MODULE_DESCRIPTION("GPIO interface for Intel Poulsbo SCH");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:sch_gpio");
