linux/drivers/gpio/gpio-sch.c

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/*
* 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>
static DEFINE_SPINLOCK(gpio_lock);
#define CGEN (0x00)
#define CGIO (0x04)
#define CGLV (0x08)
#define RGEN (0x20)
#define RGIO (0x24)
#define RGLV (0x28)
static unsigned short gpio_ba;
static int sch_gpio_core_direction_in(struct gpio_chip *gc, unsigned gpio_num)
{
u8 curr_dirs;
unsigned short offset, bit;
spin_lock(&gpio_lock);
offset = CGIO + gpio_num / 8;
bit = gpio_num % 8;
curr_dirs = inb(gpio_ba + offset);
if (!(curr_dirs & (1 << bit)))
outb(curr_dirs | (1 << bit), gpio_ba + offset);
spin_unlock(&gpio_lock);
return 0;
}
static int sch_gpio_core_get(struct gpio_chip *gc, unsigned gpio_num)
{
int res;
unsigned short offset, bit;
offset = CGLV + gpio_num / 8;
bit = gpio_num % 8;
res = !!(inb(gpio_ba + offset) & (1 << bit));
return res;
}
static void sch_gpio_core_set(struct gpio_chip *gc, unsigned gpio_num, int val)
{
u8 curr_vals;
unsigned short offset, bit;
spin_lock(&gpio_lock);
offset = CGLV + gpio_num / 8;
bit = gpio_num % 8;
curr_vals = inb(gpio_ba + offset);
if (val)
outb(curr_vals | (1 << bit), gpio_ba + offset);
else
outb((curr_vals & ~(1 << bit)), gpio_ba + offset);
spin_unlock(&gpio_lock);
}
static int sch_gpio_core_direction_out(struct gpio_chip *gc,
unsigned gpio_num, int val)
{
u8 curr_dirs;
unsigned short offset, bit;
spin_lock(&gpio_lock);
offset = CGIO + gpio_num / 8;
bit = gpio_num % 8;
curr_dirs = inb(gpio_ba + offset);
if (curr_dirs & (1 << bit))
outb(curr_dirs & ~(1 << bit), gpio_ba + offset);
spin_unlock(&gpio_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_core_set(gc, gpio_num, val);
return 0;
}
static struct gpio_chip sch_gpio_core = {
.label = "sch_gpio_core",
.owner = THIS_MODULE,
.direction_input = sch_gpio_core_direction_in,
.get = sch_gpio_core_get,
.direction_output = sch_gpio_core_direction_out,
.set = sch_gpio_core_set,
};
static int sch_gpio_resume_direction_in(struct gpio_chip *gc,
unsigned gpio_num)
{
u8 curr_dirs;
unsigned short offset, bit;
spin_lock(&gpio_lock);
offset = RGIO + gpio_num / 8;
bit = gpio_num % 8;
curr_dirs = inb(gpio_ba + offset);
if (!(curr_dirs & (1 << bit)))
outb(curr_dirs | (1 << bit), gpio_ba + offset);
spin_unlock(&gpio_lock);
return 0;
}
static int sch_gpio_resume_get(struct gpio_chip *gc, unsigned gpio_num)
{
unsigned short offset, bit;
offset = RGLV + gpio_num / 8;
bit = gpio_num % 8;
return !!(inb(gpio_ba + offset) & (1 << bit));
}
static void sch_gpio_resume_set(struct gpio_chip *gc,
unsigned gpio_num, int val)
{
u8 curr_vals;
unsigned short offset, bit;
spin_lock(&gpio_lock);
offset = RGLV + gpio_num / 8;
bit = gpio_num % 8;
curr_vals = inb(gpio_ba + offset);
if (val)
outb(curr_vals | (1 << bit), gpio_ba + offset);
else
outb((curr_vals & ~(1 << bit)), gpio_ba + offset);
spin_unlock(&gpio_lock);
}
static int sch_gpio_resume_direction_out(struct gpio_chip *gc,
unsigned gpio_num, int val)
{
u8 curr_dirs;
unsigned short offset, bit;
offset = RGIO + gpio_num / 8;
bit = gpio_num % 8;
spin_lock(&gpio_lock);
curr_dirs = inb(gpio_ba + offset);
if (curr_dirs & (1 << bit))
outb(curr_dirs & ~(1 << bit), gpio_ba + offset);
spin_unlock(&gpio_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_resume_set(gc, gpio_num, val);
return 0;
}
static struct gpio_chip sch_gpio_resume = {
.label = "sch_gpio_resume",
.owner = THIS_MODULE,
.direction_input = sch_gpio_resume_direction_in,
.get = sch_gpio_resume_get,
.direction_output = sch_gpio_resume_direction_out,
.set = sch_gpio_resume_set,
};
static int sch_gpio_probe(struct platform_device *pdev)
{
struct resource *res;
int err, id;
id = pdev->id;
if (!id)
return -ENODEV;
res = platform_get_resource(pdev, IORESOURCE_IO, 0);
if (!res)
return -EBUSY;
if (!request_region(res->start, resource_size(res), pdev->name))
return -EBUSY;
gpio_ba = res->start;
switch (id) {
case PCI_DEVICE_ID_INTEL_SCH_LPC:
sch_gpio_core.base = 0;
sch_gpio_core.ngpio = 10;
sch_gpio_resume.base = 10;
sch_gpio_resume.ngpio = 4;
/*
* GPIO[6:0] enabled by default
* GPIO7 is configured by the CMC as SLPIOVR
* Enable GPIO[9:8] core powered gpios explicitly
*/
outb(0x3, gpio_ba + CGEN + 1);
/*
* SUS_GPIO[2:0] enabled by default
* Enable SUS_GPIO3 resume powered gpio explicitly
*/
outb(0x8, gpio_ba + RGEN);
break;
case PCI_DEVICE_ID_INTEL_ITC_LPC:
sch_gpio_core.base = 0;
sch_gpio_core.ngpio = 5;
sch_gpio_resume.base = 5;
sch_gpio_resume.ngpio = 9;
break;
case PCI_DEVICE_ID_INTEL_CENTERTON_ILB:
sch_gpio_core.base = 0;
sch_gpio_core.ngpio = 21;
sch_gpio_resume.base = 21;
sch_gpio_resume.ngpio = 9;
break;
default:
err = -ENODEV;
goto err_sch_gpio_core;
}
sch_gpio_core.dev = &pdev->dev;
sch_gpio_resume.dev = &pdev->dev;
err = gpiochip_add(&sch_gpio_core);
if (err < 0)
goto err_sch_gpio_core;
err = gpiochip_add(&sch_gpio_resume);
if (err < 0)
goto err_sch_gpio_resume;
return 0;
err_sch_gpio_resume:
gpiochip_remove(&sch_gpio_core);
err_sch_gpio_core:
release_region(res->start, resource_size(res));
gpio_ba = 0;
return err;
}
static int sch_gpio_remove(struct platform_device *pdev)
{
struct resource *res;
if (gpio_ba) {
gpiochip_remove(&sch_gpio_core);
gpiochip_remove(&sch_gpio_resume);
res = platform_get_resource(pdev, IORESOURCE_IO, 0);
release_region(res->start, resource_size(res));
gpio_ba = 0;
}
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");