// SPDX-License-Identifier: GPL-2.0-only /* display7seg.c - Driver implementation for the 7-segment display * present on Sun Microsystems CP1400 and CP1500 * * Copyright (c) 2000 Eric Brower (ebrower@usa.net) */ #include #include #include #include #include #include #include #include /* request_region */ #include #include #include #include #include #include /* put_/get_user */ #include #include #define DRIVER_NAME "d7s" #define PFX DRIVER_NAME ": " static DEFINE_MUTEX(d7s_mutex); static int sol_compat = 0; /* Solaris compatibility mode */ /* 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 "); MODULE_DESCRIPTION("7-Segment Display driver for Sun Microsystems CP1400/1500"); MODULE_LICENSE("GPL"); struct d7s { void __iomem *regs; bool flipped; }; struct d7s *d7s_device; /* * 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 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) { struct d7s *p = d7s_device; u8 regval = 0; regval = readb(p->regs); if (p->flipped) regval |= D7S_FLIP; else regval &= ~D7S_FLIP; writeb(regval, p->regs); } return 0; } static long d7s_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { struct d7s *p = d7s_device; u8 regs = readb(p->regs); int error = 0; u8 ireg = 0; if (D7S_MINOR != iminor(file_inode(file))) return -ENODEV; mutex_lock(&d7s_mutex); 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 (sol_compat) { if (regs & D7S_FLIP) ireg |= D7S_FLIP; else ireg &= ~D7S_FLIP; } writeb(ireg, p->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; writeb(regs, p->regs); break; } mutex_unlock(&d7s_mutex); return error; } static const struct file_operations d7s_fops = { .owner = THIS_MODULE, .unlocked_ioctl = d7s_ioctl, .compat_ioctl = compat_ptr_ioctl, .open = d7s_open, .release = d7s_release, .llseek = noop_llseek, }; static struct miscdevice d7s_miscdev = { .minor = D7S_MINOR, .name = DRIVER_NAME, .fops = &d7s_fops }; static int d7s_probe(struct platform_device *op) { struct device_node *opts; int err = -EINVAL; struct d7s *p; u8 regs; if (d7s_device) goto out; p = devm_kzalloc(&op->dev, sizeof(*p), GFP_KERNEL); err = -ENOMEM; if (!p) goto out; p->regs = of_ioremap(&op->resource[0], 0, sizeof(u8), "d7s"); if (!p->regs) { printk(KERN_ERR PFX "Cannot map chip registers\n"); goto out; } err = misc_register(&d7s_miscdev); if (err) { printk(KERN_ERR PFX "Unable to acquire miscdevice minor %i\n", D7S_MINOR); goto out_iounmap; } /* OBP option "d7s-flipped?" is honored as default for the * device, and reset default when detached */ regs = readb(p->regs); opts = of_find_node_by_path("/options"); if (opts) p->flipped = of_property_read_bool(opts, "d7s-flipped?"); if (p->flipped) regs |= D7S_FLIP; else regs &= ~D7S_FLIP; writeb(regs, p->regs); printk(KERN_INFO PFX "7-Segment Display%pOF at [%s:0x%llx] %s\n", op->dev.of_node, (regs & D7S_FLIP) ? " (FLIPPED)" : "", op->resource[0].start, sol_compat ? "in sol_compat mode" : ""); dev_set_drvdata(&op->dev, p); d7s_device = p; err = 0; of_node_put(opts); out: return err; out_iounmap: of_iounmap(&op->resource[0], p->regs, sizeof(u8)); goto out; } static void d7s_remove(struct platform_device *op) { struct d7s *p = dev_get_drvdata(&op->dev); u8 regs = readb(p->regs); /* Honor OBP d7s-flipped? unless operating in solaris-compat mode */ if (sol_compat) { if (p->flipped) regs |= D7S_FLIP; else regs &= ~D7S_FLIP; writeb(regs, p->regs); } misc_deregister(&d7s_miscdev); of_iounmap(&op->resource[0], p->regs, sizeof(u8)); } static const struct of_device_id d7s_match[] = { { .name = "display7seg", }, {}, }; MODULE_DEVICE_TABLE(of, d7s_match); static struct platform_driver d7s_driver = { .driver = { .name = DRIVER_NAME, .of_match_table = d7s_match, }, .probe = d7s_probe, .remove = d7s_remove, }; module_platform_driver(d7s_driver);