![Jonathan Corbet](/assets/img/avatar_default.png)
All of the open() functions which don't need the BKL on their face may still depend on its acquisition to serialize opens against driver initialization. So make those functions acquire then release the BKL to be on the safe side. Signed-off-by: Jonathan Corbet <corbet@lwn.net>
350 lines
8.7 KiB
C
350 lines
8.7 KiB
C
/* linux/drivers/char/pc8736x_gpio.c
|
|
|
|
National Semiconductor PC8736x GPIO driver. Allows a user space
|
|
process to play with the GPIO pins.
|
|
|
|
Copyright (c) 2005,2006 Jim Cromie <jim.cromie@gmail.com>
|
|
|
|
adapted from linux/drivers/char/scx200_gpio.c
|
|
Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>,
|
|
*/
|
|
|
|
#include <linux/fs.h>
|
|
#include <linux/module.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/init.h>
|
|
#include <linux/cdev.h>
|
|
#include <linux/io.h>
|
|
#include <linux/ioport.h>
|
|
#include <linux/mutex.h>
|
|
#include <linux/nsc_gpio.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/smp_lock.h>
|
|
#include <asm/uaccess.h>
|
|
|
|
#define DEVNAME "pc8736x_gpio"
|
|
|
|
MODULE_AUTHOR("Jim Cromie <jim.cromie@gmail.com>");
|
|
MODULE_DESCRIPTION("NatSemi/Winbond PC-8736x GPIO Pin Driver");
|
|
MODULE_LICENSE("GPL");
|
|
|
|
static int major; /* default to dynamic major */
|
|
module_param(major, int, 0);
|
|
MODULE_PARM_DESC(major, "Major device number");
|
|
|
|
static DEFINE_MUTEX(pc8736x_gpio_config_lock);
|
|
static unsigned pc8736x_gpio_base;
|
|
static u8 pc8736x_gpio_shadow[4];
|
|
|
|
#define SIO_BASE1 0x2E /* 1st command-reg to check */
|
|
#define SIO_BASE2 0x4E /* alt command-reg to check */
|
|
|
|
#define SIO_SID 0x20 /* SuperI/O ID Register */
|
|
#define SIO_SID_VALUE 0xe9 /* Expected value in SuperI/O ID Register */
|
|
|
|
#define SIO_CF1 0x21 /* chip config, bit0 is chip enable */
|
|
|
|
#define PC8736X_GPIO_RANGE 16 /* ioaddr range */
|
|
#define PC8736X_GPIO_CT 32 /* minors matching 4 8 bit ports */
|
|
|
|
#define SIO_UNIT_SEL 0x7 /* unit select reg */
|
|
#define SIO_UNIT_ACT 0x30 /* unit enable */
|
|
#define SIO_GPIO_UNIT 0x7 /* unit number of GPIO */
|
|
#define SIO_VLM_UNIT 0x0D
|
|
#define SIO_TMS_UNIT 0x0E
|
|
|
|
/* config-space addrs to read/write each unit's runtime addr */
|
|
#define SIO_BASE_HADDR 0x60
|
|
#define SIO_BASE_LADDR 0x61
|
|
|
|
/* GPIO config-space pin-control addresses */
|
|
#define SIO_GPIO_PIN_SELECT 0xF0
|
|
#define SIO_GPIO_PIN_CONFIG 0xF1
|
|
#define SIO_GPIO_PIN_EVENT 0xF2
|
|
|
|
static unsigned char superio_cmd = 0;
|
|
static unsigned char selected_device = 0xFF; /* bogus start val */
|
|
|
|
/* GPIO port runtime access, functionality */
|
|
static int port_offset[] = { 0, 4, 8, 10 }; /* non-uniform offsets ! */
|
|
/* static int event_capable[] = { 1, 1, 0, 0 }; ports 2,3 are hobbled */
|
|
|
|
#define PORT_OUT 0
|
|
#define PORT_IN 1
|
|
#define PORT_EVT_EN 2
|
|
#define PORT_EVT_STST 3
|
|
|
|
static struct platform_device *pdev; /* use in dev_*() */
|
|
|
|
static inline void superio_outb(int addr, int val)
|
|
{
|
|
outb_p(addr, superio_cmd);
|
|
outb_p(val, superio_cmd + 1);
|
|
}
|
|
|
|
static inline int superio_inb(int addr)
|
|
{
|
|
outb_p(addr, superio_cmd);
|
|
return inb_p(superio_cmd + 1);
|
|
}
|
|
|
|
static int pc8736x_superio_present(void)
|
|
{
|
|
/* try the 2 possible values, read a hardware reg to verify */
|
|
superio_cmd = SIO_BASE1;
|
|
if (superio_inb(SIO_SID) == SIO_SID_VALUE)
|
|
return superio_cmd;
|
|
|
|
superio_cmd = SIO_BASE2;
|
|
if (superio_inb(SIO_SID) == SIO_SID_VALUE)
|
|
return superio_cmd;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void device_select(unsigned devldn)
|
|
{
|
|
superio_outb(SIO_UNIT_SEL, devldn);
|
|
selected_device = devldn;
|
|
}
|
|
|
|
static void select_pin(unsigned iminor)
|
|
{
|
|
/* select GPIO port/pin from device minor number */
|
|
device_select(SIO_GPIO_UNIT);
|
|
superio_outb(SIO_GPIO_PIN_SELECT,
|
|
((iminor << 1) & 0xF0) | (iminor & 0x7));
|
|
}
|
|
|
|
static inline u32 pc8736x_gpio_configure_fn(unsigned index, u32 mask, u32 bits,
|
|
u32 func_slct)
|
|
{
|
|
u32 config, new_config;
|
|
|
|
mutex_lock(&pc8736x_gpio_config_lock);
|
|
|
|
device_select(SIO_GPIO_UNIT);
|
|
select_pin(index);
|
|
|
|
/* read current config value */
|
|
config = superio_inb(func_slct);
|
|
|
|
/* set new config */
|
|
new_config = (config & mask) | bits;
|
|
superio_outb(func_slct, new_config);
|
|
|
|
mutex_unlock(&pc8736x_gpio_config_lock);
|
|
|
|
return config;
|
|
}
|
|
|
|
static u32 pc8736x_gpio_configure(unsigned index, u32 mask, u32 bits)
|
|
{
|
|
return pc8736x_gpio_configure_fn(index, mask, bits,
|
|
SIO_GPIO_PIN_CONFIG);
|
|
}
|
|
|
|
static int pc8736x_gpio_get(unsigned minor)
|
|
{
|
|
int port, bit, val;
|
|
|
|
port = minor >> 3;
|
|
bit = minor & 7;
|
|
val = inb_p(pc8736x_gpio_base + port_offset[port] + PORT_IN);
|
|
val >>= bit;
|
|
val &= 1;
|
|
|
|
dev_dbg(&pdev->dev, "_gpio_get(%d from %x bit %d) == val %d\n",
|
|
minor, pc8736x_gpio_base + port_offset[port] + PORT_IN, bit,
|
|
val);
|
|
|
|
return val;
|
|
}
|
|
|
|
static void pc8736x_gpio_set(unsigned minor, int val)
|
|
{
|
|
int port, bit, curval;
|
|
|
|
minor &= 0x1f;
|
|
port = minor >> 3;
|
|
bit = minor & 7;
|
|
curval = inb_p(pc8736x_gpio_base + port_offset[port] + PORT_OUT);
|
|
|
|
dev_dbg(&pdev->dev, "addr:%x cur:%x bit-pos:%d cur-bit:%x + new:%d -> bit-new:%d\n",
|
|
pc8736x_gpio_base + port_offset[port] + PORT_OUT,
|
|
curval, bit, (curval & ~(1 << bit)), val, (val << bit));
|
|
|
|
val = (curval & ~(1 << bit)) | (val << bit);
|
|
|
|
dev_dbg(&pdev->dev, "gpio_set(minor:%d port:%d bit:%d)"
|
|
" %2x -> %2x\n", minor, port, bit, curval, val);
|
|
|
|
outb_p(val, pc8736x_gpio_base + port_offset[port] + PORT_OUT);
|
|
|
|
curval = inb_p(pc8736x_gpio_base + port_offset[port] + PORT_OUT);
|
|
val = inb_p(pc8736x_gpio_base + port_offset[port] + PORT_IN);
|
|
|
|
dev_dbg(&pdev->dev, "wrote %x, read: %x\n", curval, val);
|
|
pc8736x_gpio_shadow[port] = val;
|
|
}
|
|
|
|
static int pc8736x_gpio_current(unsigned minor)
|
|
{
|
|
int port, bit;
|
|
minor &= 0x1f;
|
|
port = minor >> 3;
|
|
bit = minor & 7;
|
|
return ((pc8736x_gpio_shadow[port] >> bit) & 0x01);
|
|
}
|
|
|
|
static void pc8736x_gpio_change(unsigned index)
|
|
{
|
|
pc8736x_gpio_set(index, !pc8736x_gpio_current(index));
|
|
}
|
|
|
|
static struct nsc_gpio_ops pc8736x_gpio_ops = {
|
|
.owner = THIS_MODULE,
|
|
.gpio_config = pc8736x_gpio_configure,
|
|
.gpio_dump = nsc_gpio_dump,
|
|
.gpio_get = pc8736x_gpio_get,
|
|
.gpio_set = pc8736x_gpio_set,
|
|
.gpio_change = pc8736x_gpio_change,
|
|
.gpio_current = pc8736x_gpio_current
|
|
};
|
|
|
|
static int pc8736x_gpio_open(struct inode *inode, struct file *file)
|
|
{
|
|
unsigned m = iminor(inode);
|
|
file->private_data = &pc8736x_gpio_ops;
|
|
|
|
cycle_kernel_lock();
|
|
dev_dbg(&pdev->dev, "open %d\n", m);
|
|
|
|
if (m >= PC8736X_GPIO_CT)
|
|
return -EINVAL;
|
|
return nonseekable_open(inode, file);
|
|
}
|
|
|
|
static const struct file_operations pc8736x_gpio_fileops = {
|
|
.owner = THIS_MODULE,
|
|
.open = pc8736x_gpio_open,
|
|
.write = nsc_gpio_write,
|
|
.read = nsc_gpio_read,
|
|
};
|
|
|
|
static void __init pc8736x_init_shadow(void)
|
|
{
|
|
int port;
|
|
|
|
/* read the current values driven on the GPIO signals */
|
|
for (port = 0; port < 4; ++port)
|
|
pc8736x_gpio_shadow[port]
|
|
= inb_p(pc8736x_gpio_base + port_offset[port]
|
|
+ PORT_OUT);
|
|
|
|
}
|
|
|
|
static struct cdev pc8736x_gpio_cdev;
|
|
|
|
static int __init pc8736x_gpio_init(void)
|
|
{
|
|
int rc;
|
|
dev_t devid;
|
|
|
|
pdev = platform_device_alloc(DEVNAME, 0);
|
|
if (!pdev)
|
|
return -ENOMEM;
|
|
|
|
rc = platform_device_add(pdev);
|
|
if (rc) {
|
|
rc = -ENODEV;
|
|
goto undo_platform_dev_alloc;
|
|
}
|
|
dev_info(&pdev->dev, "NatSemi pc8736x GPIO Driver Initializing\n");
|
|
|
|
if (!pc8736x_superio_present()) {
|
|
rc = -ENODEV;
|
|
dev_err(&pdev->dev, "no device found\n");
|
|
goto undo_platform_dev_add;
|
|
}
|
|
pc8736x_gpio_ops.dev = &pdev->dev;
|
|
|
|
/* Verify that chip and it's GPIO unit are both enabled.
|
|
My BIOS does this, so I take minimum action here
|
|
*/
|
|
rc = superio_inb(SIO_CF1);
|
|
if (!(rc & 0x01)) {
|
|
rc = -ENODEV;
|
|
dev_err(&pdev->dev, "device not enabled\n");
|
|
goto undo_platform_dev_add;
|
|
}
|
|
device_select(SIO_GPIO_UNIT);
|
|
if (!superio_inb(SIO_UNIT_ACT)) {
|
|
rc = -ENODEV;
|
|
dev_err(&pdev->dev, "GPIO unit not enabled\n");
|
|
goto undo_platform_dev_add;
|
|
}
|
|
|
|
/* read the GPIO unit base addr that chip responds to */
|
|
pc8736x_gpio_base = (superio_inb(SIO_BASE_HADDR) << 8
|
|
| superio_inb(SIO_BASE_LADDR));
|
|
|
|
if (!request_region(pc8736x_gpio_base, PC8736X_GPIO_RANGE, DEVNAME)) {
|
|
rc = -ENODEV;
|
|
dev_err(&pdev->dev, "GPIO ioport %x busy\n",
|
|
pc8736x_gpio_base);
|
|
goto undo_platform_dev_add;
|
|
}
|
|
dev_info(&pdev->dev, "GPIO ioport %x reserved\n", pc8736x_gpio_base);
|
|
|
|
if (major) {
|
|
devid = MKDEV(major, 0);
|
|
rc = register_chrdev_region(devid, PC8736X_GPIO_CT, DEVNAME);
|
|
} else {
|
|
rc = alloc_chrdev_region(&devid, 0, PC8736X_GPIO_CT, DEVNAME);
|
|
major = MAJOR(devid);
|
|
}
|
|
|
|
if (rc < 0) {
|
|
dev_err(&pdev->dev, "register-chrdev failed: %d\n", rc);
|
|
goto undo_request_region;
|
|
}
|
|
if (!major) {
|
|
major = rc;
|
|
dev_dbg(&pdev->dev, "got dynamic major %d\n", major);
|
|
}
|
|
|
|
pc8736x_init_shadow();
|
|
|
|
/* ignore minor errs, and succeed */
|
|
cdev_init(&pc8736x_gpio_cdev, &pc8736x_gpio_fileops);
|
|
cdev_add(&pc8736x_gpio_cdev, devid, PC8736X_GPIO_CT);
|
|
|
|
return 0;
|
|
|
|
undo_request_region:
|
|
release_region(pc8736x_gpio_base, PC8736X_GPIO_RANGE);
|
|
undo_platform_dev_add:
|
|
platform_device_del(pdev);
|
|
undo_platform_dev_alloc:
|
|
platform_device_put(pdev);
|
|
|
|
return rc;
|
|
}
|
|
|
|
static void __exit pc8736x_gpio_cleanup(void)
|
|
{
|
|
dev_dbg(&pdev->dev, "cleanup\n");
|
|
|
|
cdev_del(&pc8736x_gpio_cdev);
|
|
unregister_chrdev_region(MKDEV(major,0), PC8736X_GPIO_CT);
|
|
release_region(pc8736x_gpio_base, PC8736X_GPIO_RANGE);
|
|
|
|
platform_device_del(pdev);
|
|
platform_device_put(pdev);
|
|
}
|
|
|
|
module_init(pc8736x_gpio_init);
|
|
module_exit(pc8736x_gpio_cleanup);
|