/* $Id: display7seg.c,v 1.6 2002/01/08 16:00:16 davem Exp $
*
* display7seg - Driver implementation for the 7-segment display
* present on Sun Microsystems CP1400 and CP1500
*
* Copyright (c) 2000 Eric Brower (ebrower@usa.net)
*
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/errno.h>
#include <linux/major.h>
#include <linux/init.h>
#include <linux/miscdevice.h>
#include <linux/ioport.h> /* request_region */
#include <linux/smp_lock.h>
#include <asm/atomic.h>
#include <asm/ebus.h> /* EBus device */
#include <asm/oplib.h> /* OpenProm Library */
#include <asm/uaccess.h> /* put_/get_user */
#include <asm/display7seg.h>
#define D7S_MINOR 193
#define D7S_OBPNAME "display7seg"
#define D7S_DEVNAME "d7s"
static int sol_compat = 0; /* Solaris compatibility mode */
#ifdef MODULE
/* Solaris compatibility flag -
* The Solaris implementation omits support for several
* documented driver features (ref Sun doc 806-0180-03).
* By default, this module supports the documented driver
* abilities, rather than the Solaris implementation:
*
* 1) Device ALWAYS reverts to OBP-specified FLIPPED mode
* upon closure of device or module unload.
* 2) Device ioctls D7SIOCRD/D7SIOCWR honor toggling of
* FLIP bit
*
* If you wish the device to operate as under Solaris,
* omitting above features, set this parameter to non-zero.
*/
module_param
(sol_compat, int, 0);
MODULE_PARM_DESC
(sol_compat,
"Disables documented functionality omitted from Solaris driver");
MODULE_AUTHOR
("Eric Brower <ebrower@usa.net>");
MODULE_DESCRIPTION
("7-Segment Display driver for Sun Microsystems CP1400/1500");
MODULE_LICENSE("GPL");
MODULE_SUPPORTED_DEVICE
("d7s");
#endif /* ifdef MODULE */
/*
* Register block address- see header for details
* -----------------------------------------
* | DP | ALARM | FLIP | 4 | 3 | 2 | 1 | 0 |
* -----------------------------------------
*
* DP - Toggles decimal point on/off
* ALARM - Toggles "Alarm" LED green/red
* FLIP - Inverts display for upside-down mounted board
* bits 0-4 - 7-segment display contents
*/
static void __iomem* d7s_regs;
static inline void d7s_free(void)
{
iounmap(d7s_regs);
}
static inline int d7s_obpflipped(void)
{
int opt_node;
opt_node = prom_getchild(prom_root_node);
opt_node = prom_searchsiblings(opt_node, "options");
return ((-1 != prom_getintdefault(opt_node, "d7s-flipped?", -1)) ? 0 : 1);
}
static atomic_t d7s_users = ATOMIC_INIT(0);
static int d7s_open(struct inode *inode, struct file *f)
{
if (D7S_MINOR != iminor(inode))
return -ENODEV;
atomic_inc(&d7s_users);
return 0;
}
static int d7s_release(struct inode *inode, struct file *f)
{
/* Reset flipped state to OBP default only if
* no other users have the device open and we
* are not operating in solaris-compat mode
*/
if (atomic_dec_and_test(&d7s_users) && !sol_compat) {
int regval = 0;
regval = readb(d7s_regs);
(0 == d7s_obpflipped()) ?
writeb(regval |= D7S_FLIP, d7s_regs):
writeb(regval &= ~D7S_FLIP, d7s_regs);
}
return 0;
}
static long d7s_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
__u8 regs = readb(d7s_regs);
__u8 ireg = 0;
int error = 0;
if (D7S_MINOR != iminor(file->f_dentry->d_inode))
return -ENODEV;
lock_kernel();
switch (cmd) {
case D7SIOCWR:
/* assign device register values
* we mask-out D7S_FLIP if in sol_compat mode
*/
if (get_user(ireg, (int __user *) arg)) {
error = -EFAULT;
break;
}
if (0 != sol_compat) {
(regs & D7S_FLIP) ?
(ireg |= D7S_FLIP) : (ireg &= ~D7S_FLIP);
}
writeb(ireg, d7s_regs);
break;
case D7SIOCRD:
/* retrieve device register values
* NOTE: Solaris implementation returns D7S_FLIP bit
* as toggled by user, even though it does not honor it.
* This driver will not misinform you about the state
* of your hardware while in sol_compat mode
*/
if (put_user(regs, (int __user *) arg)) {
error = -EFAULT;
break;
}
break;
case D7SIOCTM:
/* toggle device mode-- flip display orientation */
(regs & D7S_FLIP) ?
(regs &= ~D7S_FLIP) : (regs |= D7S_FLIP);
writeb(regs, d7s_regs);
break;
};
unlock_kernel();
return error;
}
static struct file_operations d7s_fops = {
.owner = THIS_MODULE,
.unlocked_ioctl = d7s_ioctl,
.compat_ioctl = d7s_ioctl,
.open = d7s_open,
.release = d7s_release,
};
static struct miscdevice d7s_miscdev = { D7S_MINOR, D7S_DEVNAME, &d7s_fops };
static int __init d7s_init(void)
{
struct linux_ebus *ebus = NULL;
struct linux_ebus_device *edev = NULL;
int iTmp = 0, regs = 0;
for_each_ebus(ebus) {
for_each_ebusdev(edev, ebus) {
if (!strcmp(edev->prom_node->name, D7S_OBPNAME))
goto ebus_done;
}
}
ebus_done:
if(!edev) {
printk("%s: unable to locate device\n", D7S_DEVNAME);
return -ENODEV;
}
d7s_regs = ioremap(edev->resource[0].start, sizeof(__u8));
iTmp = misc_register(&d7s_miscdev);
if (0 != iTmp) {
printk("%s: unable to acquire miscdevice minor %i\n",
D7S_DEVNAME, D7S_MINOR);
iounmap(d7s_regs);
return iTmp;
}
/* OBP option "d7s-flipped?" is honored as default
* for the device, and reset default when detached
*/
regs = readb(d7s_regs);
iTmp = d7s_obpflipped();
(0 == iTmp) ?
writeb(regs |= D7S_FLIP, d7s_regs):
writeb(regs &= ~D7S_FLIP, d7s_regs);
printk("%s: 7-Segment Display%s at 0x%lx %s\n",
D7S_DEVNAME,
(0 == iTmp) ? (" (FLIPPED)") : (""),
edev->resource[0].start,
(0 != sol_compat) ? ("in sol_compat mode") : (""));
return 0;
}
static void __exit d7s_cleanup(void)
{
int regs = readb(d7s_regs);
/* Honor OBP d7s-flipped? unless operating in solaris-compat mode */
if (0 == sol_compat) {
(0 == d7s_obpflipped()) ?
writeb(regs |= D7S_FLIP, d7s_regs):
writeb(regs &= ~D7S_FLIP, d7s_regs);
}
misc_deregister(&d7s_miscdev);
d7s_free();
}
module_init(d7s_init);
module_exit(d7s_cleanup);
