diff options
Diffstat (limited to 'drivers/sbus/char/display7seg.c')
| -rw-r--r-- | drivers/sbus/char/display7seg.c | 234 |
1 files changed, 234 insertions, 0 deletions
diff --git a/drivers/sbus/char/display7seg.c b/drivers/sbus/char/display7seg.c new file mode 100644 index 0000000..dbad7f3 --- /dev/null +++ b/drivers/sbus/char/display7seg.c @@ -0,0 +1,234 @@ +/* $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, check_region */ +#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 int d7s_ioctl(struct inode *inode, struct file *f, + unsigned int cmd, unsigned long arg) +{ + __u8 regs = readb(d7s_regs); + __u8 ireg = 0; + + if (D7S_MINOR != iminor(inode)) + return -ENODEV; + + 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)) + return -EFAULT; + 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)) + return -EFAULT; + break; + + case D7SIOCTM: + /* toggle device mode-- flip display orientation */ + (regs & D7S_FLIP) ? + (regs &= ~D7S_FLIP) : (regs |= D7S_FLIP); + writeb(regs, d7s_regs); + break; + }; + + return 0; +} + +static struct file_operations d7s_fops = { + .owner = THIS_MODULE, + .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_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); |
