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