drivers/cbus/retu.c

   1 /**
   2  * drivers/cbus/retu.c
   3  *
   4  * Support functions for Retu ASIC
   5  *
   6  * Copyright (C) 2004, 2005 Nokia Corporation
   7  *
   8  * Written by Juha Yrjölä <juha.yrjola@nokia.com>,
   9  *            David Weinehall <david.weinehall@nokia.com>, and
  10  *            Mikko Ylinen <mikko.k.ylinen@nokia.com>
  11  *
  12  * This file is subject to the terms and conditions of the GNU General
  13  * Public License. See the file "COPYING" in the main directory of this
  14  * archive for more details.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  24  */
  25
  26 #include <linux/module.h>
  27 #include <linux/init.h>
  28
  29 #include <linux/kernel.h>
  30 #include <linux/errno.h>
  31 #include <linux/device.h>
  32 #include <linux/miscdevice.h>
  33 #include <linux/poll.h>
  34 #include <linux/fs.h>
  35 #include <linux/irq.h>
  36 #include <linux/interrupt.h>
  37 #include <linux/platform_device.h>
  38 #include <linux/gpio.h>
  39
  40 #include <asm/uaccess.h>
  41 #include <asm/mach-types.h>
  42
  43 #include <plat/mux.h>
  44 #include <plat/board.h>
  45
  46 #include "cbus.h"
  47 #include "retu.h"
  48
  49 #define RETU_ID                 0x01
  50 #define PFX                     "retu: "
  51
  52 static int retu_initialized;
  53 static int retu_irq_pin;
  54 static int retu_is_vilma;
  55
  56 static struct tasklet_struct retu_tasklet;
  57 spinlock_t retu_lock = SPIN_LOCK_UNLOCKED;
  58
  59 static struct completion device_release;
  60
  61 struct retu_irq_handler_desc {
  62         int (*func)(unsigned long);
  63         unsigned long arg;
  64         char name[8];
  65 };
  66
  67 static struct retu_irq_handler_desc retu_irq_handlers[MAX_RETU_IRQ_HANDLERS];
  68
  69 /**
  70  * retu_read_reg - Read a value from a register in Retu
  71  * @reg: the register to read from
  72  *
  73  * This function returns the contents of the specified register
  74  */
  75 int retu_read_reg(int reg)
  76 {
  77         BUG_ON(!retu_initialized);
  78         return cbus_read_reg(cbus_host, RETU_ID, reg);
  79 }
  80
  81 /**
  82  * retu_write_reg - Write a value to a register in Retu
  83  * @reg: the register to write to
  84  * @reg: the value to write to the register
  85  *
  86  * This function writes a value to the specified register
  87  */
  88 void retu_write_reg(int reg, u16 val)
  89 {
  90         BUG_ON(!retu_initialized);
  91         cbus_write_reg(cbus_host, RETU_ID, reg, val);
  92 }
  93
  94 void retu_set_clear_reg_bits(int reg, u16 set, u16 clear)
  95 {
  96         unsigned long flags;
  97         u16 w;
  98
  99         spin_lock_irqsave(&retu_lock, flags);
 100         w = retu_read_reg(reg);
 101         w &= ~clear;
 102         w |= set;
 103         retu_write_reg(reg, w);
 104         spin_unlock_irqrestore(&retu_lock, flags);
 105 }
 106
 107 #define ADC_MAX_CHAN_NUMBER     13
 108
 109 int retu_read_adc(int channel)
 110 {
 111         unsigned long flags;
 112         int res;
 113
 114         if (channel < 0 || channel > ADC_MAX_CHAN_NUMBER)
 115                 return -EINVAL;
 116
 117         spin_lock_irqsave(&retu_lock, flags);
 118
 119         if ((channel == 8) && retu_is_vilma) {
 120                 int scr = retu_read_reg(RETU_REG_ADCSCR);
 121                 int ch = (retu_read_reg(RETU_REG_ADCR) >> 10) & 0xf;
 122                 if (((scr & 0xff) != 0) && (ch != 8))
 123                         retu_write_reg (RETU_REG_ADCSCR, (scr & ~0xff));
 124         }
 125
 126         /* Select the channel and read result */
 127         retu_write_reg(RETU_REG_ADCR, channel << 10);
 128         res = retu_read_reg(RETU_REG_ADCR) & 0x3ff;
 129
 130         if (retu_is_vilma)
 131                 retu_write_reg(RETU_REG_ADCR, (1 << 13));
 132
 133         /* Unlock retu */
 134         spin_unlock_irqrestore(&retu_lock, flags);
 135
 136         return res;
 137 }
 138
 139
 140 static u16 retu_disable_bogus_irqs(u16 mask)
 141 {
 142        int i;
 143
 144        for (i = 0; i < MAX_RETU_IRQ_HANDLERS; i++) {
 145                if (mask & (1 << i))
 146                        continue;
 147                if (retu_irq_handlers[i].func != NULL)
 148                        continue;
 149                /* an IRQ was enabled but we don't have a handler for it */
 150                printk(KERN_INFO PFX "disabling bogus IRQ %d\n", i);
 151                mask |= (1 << i);
 152        }
 153        return mask;
 154 }
 155
 156 /*
 157  * Disable given RETU interrupt
 158  */
 159 void retu_disable_irq(int id)
 160 {
 161         unsigned long flags;
 162         u16 mask;
 163
 164         spin_lock_irqsave(&retu_lock, flags);
 165         mask = retu_read_reg(RETU_REG_IMR);
 166         mask |= 1 << id;
 167         mask = retu_disable_bogus_irqs(mask);
 168         retu_write_reg(RETU_REG_IMR, mask);
 169         spin_unlock_irqrestore(&retu_lock, flags);
 170 }
 171
 172 /*
 173  * Enable given RETU interrupt
 174  */
 175 void retu_enable_irq(int id)
 176 {
 177         unsigned long flags;
 178         u16 mask;
 179
 180         if (id == 3) {
 181                 printk("Enabling Retu IRQ %d\n", id);
 182                 dump_stack();
 183         }
 184         spin_lock_irqsave(&retu_lock, flags);
 185         mask = retu_read_reg(RETU_REG_IMR);
 186         mask &= ~(1 << id);
 187         mask = retu_disable_bogus_irqs(mask);
 188         retu_write_reg(RETU_REG_IMR, mask);
 189         spin_unlock_irqrestore(&retu_lock, flags);
 190 }
 191
 192 /*
 193  * Acknowledge given RETU interrupt
 194  */
 195 void retu_ack_irq(int id)
 196 {
 197         retu_write_reg(RETU_REG_IDR, 1 << id);
 198 }
 199
 200 /*
 201  * RETU interrupt handler. Only schedules the tasklet.
 202  */
 203 static irqreturn_t retu_irq_handler(int irq, void *dev_id)
 204 {
 205         tasklet_schedule(&retu_tasklet);
 206         return IRQ_HANDLED;
 207 }
 208
 209 /*
 210  * Tasklet handler
 211  */
 212 static void retu_tasklet_handler(unsigned long data)
 213 {
 214         struct retu_irq_handler_desc *hnd;
 215         u16 id;
 216         u16 im;
 217         int i;
 218
 219         for (;;) {
 220                 id = retu_read_reg(RETU_REG_IDR);
 221                 im = ~retu_read_reg(RETU_REG_IMR);
 222                 id &= im;
 223
 224                 if (!id)
 225                         break;
 226
 227                 for (i = 0; id != 0; i++, id >>= 1) {
 228                         if (!(id & 1))
 229                                 continue;
 230                         hnd = &retu_irq_handlers[i];
 231                         if (hnd->func == NULL) {
 232                                /* Spurious retu interrupt - disable and ack it */
 233                                 printk(KERN_INFO "Spurious Retu interrupt "
 234                                                  "(id %d)\n", i);
 235                                 retu_disable_irq(i);
 236                                 retu_ack_irq(i);
 237                                 continue;
 238                         }
 239                         hnd->func(hnd->arg);
 240                         /*
 241                          * Don't acknowledge the interrupt here
 242                          * It must be done explicitly
 243                          */
 244                 }
 245         }
 246 }
 247
 248 /*
 249  * Register the handler for a given RETU interrupt source.
 250  */
 251 int retu_request_irq(int id, void *irq_handler, unsigned long arg, char *name)
 252 {
 253         struct retu_irq_handler_desc *hnd;
 254
 255         if (irq_handler == NULL || id >= MAX_RETU_IRQ_HANDLERS ||
 256             name == NULL) {
 257                 printk(KERN_ERR PFX "Invalid arguments to %s\n",
 258                        __FUNCTION__);
 259                 return -EINVAL;
 260         }
 261         hnd = &retu_irq_handlers[id];
 262         if (hnd->func != NULL) {
 263                 printk(KERN_ERR PFX "IRQ %d already reserved\n", id);
 264                 return -EBUSY;
 265         }
 266         printk(KERN_INFO PFX "Registering interrupt %d for device %s\n",
 267                id, name);
 268         hnd->func = irq_handler;
 269         hnd->arg = arg;
 270         strlcpy(hnd->name, name, sizeof(hnd->name));
 271
 272         retu_ack_irq(id);
 273         retu_enable_irq(id);
 274
 275         return 0;
 276 }
 277
 278 /*
 279  * Unregister the handler for a given RETU interrupt source.
 280  */
 281 void retu_free_irq(int id)
 282 {
 283         struct retu_irq_handler_desc *hnd;
 284
 285         if (id >= MAX_RETU_IRQ_HANDLERS) {
 286                 printk(KERN_ERR PFX "Invalid argument to %s\n",
 287                        __FUNCTION__);
 288                 return;
 289         }
 290         hnd = &retu_irq_handlers[id];
 291         if (hnd->func == NULL) {
 292                 printk(KERN_ERR PFX "IRQ %d already freed\n", id);
 293                 return;
 294         }
 295
 296         retu_disable_irq(id);
 297         hnd->func = NULL;
 298 }
 299
 300 /**
 301  * retu_power_off - Shut down power to system
 302  *
 303  * This function puts the system in power off state
 304  */
 305 static void retu_power_off(void)
 306 {
 307         /* Ignore power button state */
 308         retu_write_reg(RETU_REG_CC1, retu_read_reg(RETU_REG_CC1) | 2);
 309         /* Expire watchdog immediately */
 310         retu_write_reg(RETU_REG_WATCHDOG, 0);
 311         /* Wait for poweroff*/
 312         for (;;);
 313 }
 314
 315 /**
 316  * retu_probe - Probe for Retu ASIC
 317  * @dev: the Retu device
 318  *
 319  * Probe for the Retu ASIC and allocate memory
 320  * for its device-struct if found
 321  */
 322 static int __devinit retu_probe(struct device *dev)
 323 {
 324         int rev, ret;
 325
 326         /* Prepare tasklet */
 327         tasklet_init(&retu_tasklet, retu_tasklet_handler, 0);
 328
 329         /* REVISIT: Pass these from board-*.c files in platform_data */
 330         if (machine_is_nokia770()) {
 331                 retu_irq_pin = 62;
 332         } else if (machine_is_nokia_n800() || machine_is_nokia_n810() ||
 333                         machine_is_nokia_n810_wimax()) {
 334                 retu_irq_pin = 108;
 335         } else {
 336                 printk(KERN_ERR "cbus: Unsupported board for tahvo\n");
 337                 return -ENODEV;
 338         }
 339
 340         if ((ret = gpio_request(retu_irq_pin, "RETU irq")) < 0) {
 341                 printk(KERN_ERR PFX "Unable to reserve IRQ GPIO\n");
 342                 return ret;
 343         }
 344
 345         /* Set the pin as input */
 346         gpio_direction_input(retu_irq_pin);
 347
 348         /* Rising edge triggers the IRQ */
 349         set_irq_type(gpio_to_irq(retu_irq_pin), IRQ_TYPE_EDGE_RISING);
 350
 351         retu_initialized = 1;
 352
 353         rev = retu_read_reg(RETU_REG_ASICR) & 0xff;
 354         if (rev & (1 << 7))
 355                 retu_is_vilma = 1;
 356
 357         printk(KERN_INFO "%s v%d.%d found\n", retu_is_vilma ? "Vilma" : "Retu",
 358                (rev >> 4) & 0x07, rev & 0x0f);
 359
 360         /* Mask all RETU interrupts */
 361         retu_write_reg(RETU_REG_IMR, 0xffff);
 362
 363         ret = request_irq(gpio_to_irq(retu_irq_pin), retu_irq_handler, 0,
 364                           "retu", 0);
 365         if (ret < 0) {
 366                 printk(KERN_ERR PFX "Unable to register IRQ handler\n");
 367                 gpio_free(retu_irq_pin);
 368                 return ret;
 369         }
 370         set_irq_wake(gpio_to_irq(retu_irq_pin), 1);
 371
 372         /* Register power off function */
 373         pm_power_off = retu_power_off;
 374
 375 #ifdef CONFIG_CBUS_RETU_USER
 376         /* Initialize user-space interface */
 377         if (retu_user_init() < 0) {
 378                 printk(KERN_ERR "Unable to initialize driver\n");
 379                 free_irq(gpio_to_irq(retu_irq_pin), 0);
 380                 gpio_free(retu_irq_pin);
 381                 return ret;
 382         }
 383 #endif
 384
 385         return 0;
 386 }
 387
 388 static int retu_remove(struct device *dev)
 389 {
 390 #ifdef CONFIG_CBUS_RETU_USER
 391         retu_user_cleanup();
 392 #endif
 393         /* Mask all RETU interrupts */
 394         retu_write_reg(RETU_REG_IMR, 0xffff);
 395         free_irq(gpio_to_irq(retu_irq_pin), 0);
 396         gpio_free(retu_irq_pin);
 397         tasklet_kill(&retu_tasklet);
 398
 399         return 0;
 400 }
 401
 402 static void retu_device_release(struct device *dev)
 403 {
 404         complete(&device_release);
 405 }
 406
 407 static struct device_driver retu_driver = {
 408         .name           = "retu",
 409         .bus            = &platform_bus_type,
 410         .probe          = retu_probe,
 411         .remove         = retu_remove,
 412 };
 413
 414 static struct platform_device retu_device = {
 415         .name           = "retu",
 416         .id             = -1,
 417         .dev = {
 418                 .release = retu_device_release,
 419         }
 420 };
 421
 422 /**
 423  * retu_init - initialise Retu driver
 424  *
 425  * Initialise the Retu driver and return 0 if everything worked ok
 426  */
 427 static int __init retu_init(void)
 428 {
 429         int ret = 0;
 430
 431         printk(KERN_INFO "Retu/Vilma driver initialising\n");
 432
 433         init_completion(&device_release);
 434
 435         if ((ret = driver_register(&retu_driver)) < 0)
 436                 return ret;
 437
 438         if ((ret = platform_device_register(&retu_device)) < 0) {
 439                 driver_unregister(&retu_driver);
 440                 return ret;
 441         }
 442         return 0;
 443 }
 444
 445 /*
 446  * Cleanup
 447  */
 448 static void __exit retu_exit(void)
 449 {
 450         platform_device_unregister(&retu_device);
 451         driver_unregister(&retu_driver);
 452         wait_for_completion(&device_release);
 453 }
 454
 455 EXPORT_SYMBOL(retu_request_irq);
 456 EXPORT_SYMBOL(retu_free_irq);
 457 EXPORT_SYMBOL(retu_enable_irq);
 458 EXPORT_SYMBOL(retu_disable_irq);
 459 EXPORT_SYMBOL(retu_ack_irq);
 460 EXPORT_SYMBOL(retu_read_reg);
 461 EXPORT_SYMBOL(retu_write_reg);
 462
 463 subsys_initcall(retu_init);
 464 module_exit(retu_exit);
 465
 466 MODULE_DESCRIPTION("Retu ASIC control");
 467 MODULE_LICENSE("GPL");
 468 MODULE_AUTHOR("Juha Yrjölä, David Weinehall, and Mikko Ylinen");