1 /* display7seg.c - Driver implementation for the 7-segment display 2 * present on Sun Microsystems CP1400 and CP1500 3 * 4 * Copyright (c) 2000 Eric Brower (ebrower@usa.net) 5 */ 6 7 #include <linux/kernel.h> 8 #include <linux/module.h> 9 #include <linux/fs.h> 10 #include <linux/errno.h> 11 #include <linux/major.h> 12 #include <linux/miscdevice.h> 13 #include <linux/ioport.h> /* request_region */ 14 #include <linux/slab.h> 15 #include <linux/mutex.h> 16 #include <linux/of.h> 17 #include <linux/of_device.h> 18 #include <linux/atomic.h> 19 #include <asm/uaccess.h> /* put_/get_user */ 20 #include <asm/io.h> 21 22 #include <asm/display7seg.h> 23 24 #define D7S_MINOR 193 25 #define DRIVER_NAME "d7s" 26 #define PFX DRIVER_NAME ": " 27 28 static DEFINE_MUTEX(d7s_mutex); 29 static int sol_compat = 0; /* Solaris compatibility mode */ 30 31 /* Solaris compatibility flag - 32 * The Solaris implementation omits support for several 33 * documented driver features (ref Sun doc 806-0180-03). 34 * By default, this module supports the documented driver 35 * abilities, rather than the Solaris implementation: 36 * 37 * 1) Device ALWAYS reverts to OBP-specified FLIPPED mode 38 * upon closure of device or module unload. 39 * 2) Device ioctls D7SIOCRD/D7SIOCWR honor toggling of 40 * FLIP bit 41 * 42 * If you wish the device to operate as under Solaris, 43 * omitting above features, set this parameter to non-zero. 44 */ 45 module_param(sol_compat, int, 0); 46 MODULE_PARM_DESC(sol_compat, 47 "Disables documented functionality omitted from Solaris driver"); 48 49 MODULE_AUTHOR("Eric Brower <ebrower@usa.net>"); 50 MODULE_DESCRIPTION("7-Segment Display driver for Sun Microsystems CP1400/1500"); 51 MODULE_LICENSE("GPL"); 52 MODULE_SUPPORTED_DEVICE("d7s"); 53 54 struct d7s { 55 void __iomem *regs; 56 bool flipped; 57 }; 58 struct d7s *d7s_device; 59 60 /* 61 * Register block address- see header for details 62 * ----------------------------------------- 63 * | DP | ALARM | FLIP | 4 | 3 | 2 | 1 | 0 | 64 * ----------------------------------------- 65 * 66 * DP - Toggles decimal point on/off 67 * ALARM - Toggles "Alarm" LED green/red 68 * FLIP - Inverts display for upside-down mounted board 69 * bits 0-4 - 7-segment display contents 70 */ 71 static atomic_t d7s_users = ATOMIC_INIT(0); 72 73 static int d7s_open(struct inode *inode, struct file *f) 74 { 75 if (D7S_MINOR != iminor(inode)) 76 return -ENODEV; 77 atomic_inc(&d7s_users); 78 return 0; 79 } 80 81 static int d7s_release(struct inode *inode, struct file *f) 82 { 83 /* Reset flipped state to OBP default only if 84 * no other users have the device open and we 85 * are not operating in solaris-compat mode 86 */ 87 if (atomic_dec_and_test(&d7s_users) && !sol_compat) { 88 struct d7s *p = d7s_device; 89 u8 regval = 0; 90 91 regval = readb(p->regs); 92 if (p->flipped) 93 regval |= D7S_FLIP; 94 else 95 regval &= ~D7S_FLIP; 96 writeb(regval, p->regs); 97 } 98 99 return 0; 100 } 101 102 static long d7s_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 103 { 104 struct d7s *p = d7s_device; 105 u8 regs = readb(p->regs); 106 int error = 0; 107 u8 ireg = 0; 108 109 if (D7S_MINOR != iminor(file_inode(file))) 110 return -ENODEV; 111 112 mutex_lock(&d7s_mutex); 113 switch (cmd) { 114 case D7SIOCWR: 115 /* assign device register values we mask-out D7S_FLIP 116 * if in sol_compat mode 117 */ 118 if (get_user(ireg, (int __user *) arg)) { 119 error = -EFAULT; 120 break; 121 } 122 if (sol_compat) { 123 if (regs & D7S_FLIP) 124 ireg |= D7S_FLIP; 125 else 126 ireg &= ~D7S_FLIP; 127 } 128 writeb(ireg, p->regs); 129 break; 130 131 case D7SIOCRD: 132 /* retrieve device register values 133 * NOTE: Solaris implementation returns D7S_FLIP bit 134 * as toggled by user, even though it does not honor it. 135 * This driver will not misinform you about the state 136 * of your hardware while in sol_compat mode 137 */ 138 if (put_user(regs, (int __user *) arg)) { 139 error = -EFAULT; 140 break; 141 } 142 break; 143 144 case D7SIOCTM: 145 /* toggle device mode-- flip display orientation */ 146 if (regs & D7S_FLIP) 147 regs &= ~D7S_FLIP; 148 else 149 regs |= D7S_FLIP; 150 writeb(regs, p->regs); 151 break; 152 } 153 mutex_unlock(&d7s_mutex); 154 155 return error; 156 } 157 158 static const struct file_operations d7s_fops = { 159 .owner = THIS_MODULE, 160 .unlocked_ioctl = d7s_ioctl, 161 .compat_ioctl = d7s_ioctl, 162 .open = d7s_open, 163 .release = d7s_release, 164 .llseek = noop_llseek, 165 }; 166 167 static struct miscdevice d7s_miscdev = { 168 .minor = D7S_MINOR, 169 .name = DRIVER_NAME, 170 .fops = &d7s_fops 171 }; 172 173 static int d7s_probe(struct platform_device *op) 174 { 175 struct device_node *opts; 176 int err = -EINVAL; 177 struct d7s *p; 178 u8 regs; 179 180 if (d7s_device) 181 goto out; 182 183 p = kzalloc(sizeof(*p), GFP_KERNEL); 184 err = -ENOMEM; 185 if (!p) 186 goto out; 187 188 p->regs = of_ioremap(&op->resource[0], 0, sizeof(u8), "d7s"); 189 if (!p->regs) { 190 printk(KERN_ERR PFX "Cannot map chip registers\n"); 191 goto out_free; 192 } 193 194 err = misc_register(&d7s_miscdev); 195 if (err) { 196 printk(KERN_ERR PFX "Unable to acquire miscdevice minor %i\n", 197 D7S_MINOR); 198 goto out_iounmap; 199 } 200 201 /* OBP option "d7s-flipped?" is honored as default for the 202 * device, and reset default when detached 203 */ 204 regs = readb(p->regs); 205 opts = of_find_node_by_path("/options"); 206 if (opts && 207 of_get_property(opts, "d7s-flipped?", NULL)) 208 p->flipped = true; 209 210 if (p->flipped) 211 regs |= D7S_FLIP; 212 else 213 regs &= ~D7S_FLIP; 214 215 writeb(regs, p->regs); 216 217 printk(KERN_INFO PFX "7-Segment Display%s at [%s:0x%llx] %s\n", 218 op->dev.of_node->full_name, 219 (regs & D7S_FLIP) ? " (FLIPPED)" : "", 220 op->resource[0].start, 221 sol_compat ? "in sol_compat mode" : ""); 222 223 dev_set_drvdata(&op->dev, p); 224 d7s_device = p; 225 err = 0; 226 227 out: 228 return err; 229 230 out_iounmap: 231 of_iounmap(&op->resource[0], p->regs, sizeof(u8)); 232 233 out_free: 234 kfree(p); 235 goto out; 236 } 237 238 static int d7s_remove(struct platform_device *op) 239 { 240 struct d7s *p = dev_get_drvdata(&op->dev); 241 u8 regs = readb(p->regs); 242 243 /* Honor OBP d7s-flipped? unless operating in solaris-compat mode */ 244 if (sol_compat) { 245 if (p->flipped) 246 regs |= D7S_FLIP; 247 else 248 regs &= ~D7S_FLIP; 249 writeb(regs, p->regs); 250 } 251 252 misc_deregister(&d7s_miscdev); 253 of_iounmap(&op->resource[0], p->regs, sizeof(u8)); 254 kfree(p); 255 256 return 0; 257 } 258 259 static const struct of_device_id d7s_match[] = { 260 { 261 .name = "display7seg", 262 }, 263 {}, 264 }; 265 MODULE_DEVICE_TABLE(of, d7s_match); 266 267 static struct platform_driver d7s_driver = { 268 .driver = { 269 .name = DRIVER_NAME, 270 .owner = THIS_MODULE, 271 .of_match_table = d7s_match, 272 }, 273 .probe = d7s_probe, 274 .remove = d7s_remove, 275 }; 276 277 module_platform_driver(d7s_driver); 278