- 根目录:
- drivers
- gpio
- gpio-vx855.c
/*
* Linux GPIOlib driver for the VIA VX855 integrated southbridge GPIO
*
* Copyright (C) 2009 VIA Technologies, Inc.
* Copyright (C) 2010 One Laptop per Child
* Author: Harald Welte <HaraldWelte@viatech.com>
* All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* 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; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/gpio.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/pci.h>
#include <linux/io.h>
#define MODULE_NAME "vx855_gpio"
/* The VX855 south bridge has the following GPIO pins:
* GPI 0...13 General Purpose Input
* GPO 0...12 General Purpose Output
* GPIO 0...14 General Purpose I/O (Open-Drain)
*/
#define NR_VX855_GPI 14
#define NR_VX855_GPO 13
#define NR_VX855_GPIO 15
#define NR_VX855_GPInO (NR_VX855_GPI + NR_VX855_GPO)
#define NR_VX855_GP (NR_VX855_GPI + NR_VX855_GPO + NR_VX855_GPIO)
struct vx855_gpio {
struct gpio_chip gpio;
spinlock_t lock;
u32 io_gpi;
u32 io_gpo;
bool gpi_reserved;
bool gpo_reserved;
};
/* resolve a GPIx into the corresponding bit position */
static inline u_int32_t gpi_i_bit(int i)
{
if (i < 10)
return 1 << i;
else
return 1 << (i + 14);
}
static inline u_int32_t gpo_o_bit(int i)
{
if (i < 11)
return 1 << i;
else
return 1 << (i + 14);
}
static inline u_int32_t gpio_i_bit(int i)
{
if (i < 14)
return 1 << (i + 10);
else
return 1 << (i + 14);
}
static inline u_int32_t gpio_o_bit(int i)
{
if (i < 14)
return 1 << (i + 11);
else
return 1 << (i + 13);
}
/* Mapping betwee numeric GPIO ID and the actual GPIO hardware numbering:
* 0..13 GPI 0..13
* 14..26 GPO 0..12
* 27..41 GPIO 0..14
*/
static int vx855gpio_direction_input(struct gpio_chip *gpio,
unsigned int nr)
{
struct vx855_gpio *vg = container_of(gpio, struct vx855_gpio, gpio);
unsigned long flags;
u_int32_t reg_out;
/* Real GPI bits are always in input direction */
if (nr < NR_VX855_GPI)
return 0;
/* Real GPO bits cannot be put in output direction */
if (nr < NR_VX855_GPInO)
return -EINVAL;
/* Open Drain GPIO have to be set to one */
spin_lock_irqsave(&vg->lock, flags);
reg_out = inl(vg->io_gpo);
reg_out |= gpio_o_bit(nr - NR_VX855_GPInO);
outl(reg_out, vg->io_gpo);
spin_unlock_irqrestore(&vg->lock, flags);
return 0;
}
static int vx855gpio_get(struct gpio_chip *gpio, unsigned int nr)
{
struct vx855_gpio *vg = container_of(gpio, struct vx855_gpio, gpio);
u_int32_t reg_in;
int ret = 0;
if (nr < NR_VX855_GPI) {
reg_in = inl(vg->io_gpi);
if (reg_in & gpi_i_bit(nr))
ret = 1;
} else if (nr < NR_VX855_GPInO) {
/* GPO don't have an input bit, we need to read it
* back from the output register */
reg_in = inl(vg->io_gpo);
if (reg_in & gpo_o_bit(nr - NR_VX855_GPI))
ret = 1;
} else {
reg_in = inl(vg->io_gpi);
if (reg_in & gpio_i_bit(nr - NR_VX855_GPInO))
ret = 1;
}
return ret;
}
static void vx855gpio_set(struct gpio_chip *gpio, unsigned int nr,
int val)
{
struct vx855_gpio *vg = container_of(gpio, struct vx855_gpio, gpio);
unsigned long flags;
u_int32_t reg_out;
/* True GPI cannot be switched to output mode */
if (nr < NR_VX855_GPI)
return;
spin_lock_irqsave(&vg->lock, flags);
reg_out = inl(vg->io_gpo);
if (nr < NR_VX855_GPInO) {
if (val)
reg_out |= gpo_o_bit(nr - NR_VX855_GPI);
else
reg_out &= ~gpo_o_bit(nr - NR_VX855_GPI);
} else {
if (val)
reg_out |= gpio_o_bit(nr - NR_VX855_GPInO);
else
reg_out &= ~gpio_o_bit(nr - NR_VX855_GPInO);
}
outl(reg_out, vg->io_gpo);
spin_unlock_irqrestore(&vg->lock, flags);
}
static int vx855gpio_direction_output(struct gpio_chip *gpio,
unsigned int nr, int val)
{
/* True GPI cannot be switched to output mode */
if (nr < NR_VX855_GPI)
return -EINVAL;
/* True GPO don't need to be switched to output mode,
* and GPIO are open-drain, i.e. also need no switching,
* so all we do is set the level */
vx855gpio_set(gpio, nr, val);
return 0;
}
static const char *vx855gpio_names[NR_VX855_GP] = {
"VX855_GPI0", "VX855_GPI1", "VX855_GPI2", "VX855_GPI3", "VX855_GPI4",
"VX855_GPI5", "VX855_GPI6", "VX855_GPI7", "VX855_GPI8", "VX855_GPI9",
"VX855_GPI10", "VX855_GPI11", "VX855_GPI12", "VX855_GPI13",
"VX855_GPO0", "VX855_GPO1", "VX855_GPO2", "VX855_GPO3", "VX855_GPO4",
"VX855_GPO5", "VX855_GPO6", "VX855_GPO7", "VX855_GPO8", "VX855_GPO9",
"VX855_GPO10", "VX855_GPO11", "VX855_GPO12",
"VX855_GPIO0", "VX855_GPIO1", "VX855_GPIO2", "VX855_GPIO3",
"VX855_GPIO4", "VX855_GPIO5", "VX855_GPIO6", "VX855_GPIO7",
"VX855_GPIO8", "VX855_GPIO9", "VX855_GPIO10", "VX855_GPIO11",
"VX855_GPIO12", "VX855_GPIO13", "VX855_GPIO14"
};
static void vx855gpio_gpio_setup(struct vx855_gpio *vg)
{
struct gpio_chip *c = &vg->gpio;
c->label = "VX855 South Bridge";
c->owner = THIS_MODULE;
c->direction_input = vx855gpio_direction_input;
c->direction_output = vx855gpio_direction_output;
c->get = vx855gpio_get;
c->set = vx855gpio_set;
c->dbg_show = NULL;
c->base = 0;
c->ngpio = NR_VX855_GP;
c->can_sleep = 0;
c->names = vx855gpio_names;
}
/* This platform device is ordinarily registered by the vx855 mfd driver */
static int vx855gpio_probe(struct platform_device *pdev)
{
struct resource *res_gpi;
struct resource *res_gpo;
struct vx855_gpio *vg;
int ret;
res_gpi = platform_get_resource(pdev, IORESOURCE_IO, 0);
res_gpo = platform_get_resource(pdev, IORESOURCE_IO, 1);
if (!res_gpi || !res_gpo)
return -EBUSY;
vg = kzalloc(sizeof(*vg), GFP_KERNEL);
if (!vg)
return -ENOMEM;
platform_set_drvdata(pdev, vg);
dev_info(&pdev->dev, "found VX855 GPIO controller\n");
vg->io_gpi = res_gpi->start;
vg->io_gpo = res_gpo->start;
spin_lock_init(&vg->lock);
/*
* A single byte is used to control various GPIO ports on the VX855,
* and in the case of the OLPC XO-1.5, some of those ports are used
* for switches that are interpreted and exposed through ACPI. ACPI
* will have reserved the region, so our own reservation will not
* succeed. Ignore and continue.
*/
if (!request_region(res_gpi->start, resource_size(res_gpi),
MODULE_NAME "_gpi"))
dev_warn(&pdev->dev,
"GPI I/O resource busy, probably claimed by ACPI\n");
else
vg->gpi_reserved = true;
if (!request_region(res_gpo->start, resource_size(res_gpo),
MODULE_NAME "_gpo"))
dev_warn(&pdev->dev,
"GPO I/O resource busy, probably claimed by ACPI\n");
else
vg->gpo_reserved = true;
vx855gpio_gpio_setup(vg);
ret = gpiochip_add(&vg->gpio);
if (ret) {
dev_err(&pdev->dev, "failed to register GPIOs\n");
goto out_release;
}
return 0;
out_release:
if (vg->gpi_reserved)
release_region(res_gpi->start, resource_size(res_gpi));
if (vg->gpo_reserved)
release_region(res_gpi->start, resource_size(res_gpo));
platform_set_drvdata(pdev, NULL);
kfree(vg);
return ret;
}
static int vx855gpio_remove(struct platform_device *pdev)
{
struct vx855_gpio *vg = platform_get_drvdata(pdev);
struct resource *res;
if (gpiochip_remove(&vg->gpio))
dev_err(&pdev->dev, "unable to remove gpio_chip?\n");
if (vg->gpi_reserved) {
res = platform_get_resource(pdev, IORESOURCE_IO, 0);
release_region(res->start, resource_size(res));
}
if (vg->gpo_reserved) {
res = platform_get_resource(pdev, IORESOURCE_IO, 1);
release_region(res->start, resource_size(res));
}
platform_set_drvdata(pdev, NULL);
kfree(vg);
return 0;
}
static struct platform_driver vx855gpio_driver = {
.driver = {
.name = MODULE_NAME,
.owner = THIS_MODULE,
},
.probe = vx855gpio_probe,
.remove = vx855gpio_remove,
};
module_platform_driver(vx855gpio_driver);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Harald Welte <HaraldWelte@viatech.com>");
MODULE_DESCRIPTION("GPIO driver for the VIA VX855 chipset");
MODULE_ALIAS("platform:vx855_gpio");