drivers/i2c/chips/twl4030-madc.c

   1 /*
   2  * drivers/i2c/chips/twl4030-madc.c
   3  *
   4  * TWL4030 MADC module driver
   5  *
   6  * Copyright (C) 2008 Nokia Corporation
   7  * Mikko Ylinen <mikko.k.ylinen@nokia.com>
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License
  11  * version 2 as published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  21  * 02110-1301 USA
  22  *
  23  */
  24
  25 #include <linux/init.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/kernel.h>
  28 #include <linux/types.h>
  29 #include <linux/module.h>
  30 #include <linux/delay.h>
  31 #include <linux/fs.h>
  32 #include <linux/miscdevice.h>
  33 #include <linux/i2c/twl4030.h>
  34 #include <linux/i2c/twl4030-madc.h>
  35
  36 #include <asm/uaccess.h>
  37
  38 #define TWL4030_MADC_PFX        "twl4030-madc: "
  39
  40 static struct twl4030_madc_data {
  41         struct mutex            lock;
  42         struct work_struct      ws;
  43         struct twl4030_madc_request     requests[TWL4030_MADC_NUM_METHODS];
  44 } twl4030_madc;
  45
  46 static const char irq_pin = 1; /* XXX Read from platfrom data */
  47
  48 static
  49 const struct twl4030_madc_conversion_method twl4030_conversion_methods[] = {
  50         [TWL4030_MADC_RT] = {
  51                 .sel    = TWL4030_MADC_RTSELECT_LSB,
  52                 .avg    = TWL4030_MADC_RTAVERAGE_LSB,
  53                 .rbase  = TWL4030_MADC_RTCH0_LSB,
  54         },
  55         [TWL4030_MADC_SW1] = {
  56                 .sel    = TWL4030_MADC_SW1SELECT_LSB,
  57                 .avg    = TWL4030_MADC_SW1AVERAGE_LSB,
  58                 .rbase  = TWL4030_MADC_GPCH0_LSB,
  59                 .ctrl   = TWL4030_MADC_CTRL_SW1,
  60         },
  61         [TWL4030_MADC_SW2] = {
  62                 .sel    = TWL4030_MADC_SW2SELECT_LSB,
  63                 .avg    = TWL4030_MADC_SW2AVERAGE_LSB,
  64                 .rbase  = TWL4030_MADC_GPCH0_LSB,
  65                 .ctrl   = TWL4030_MADC_CTRL_SW2,
  66         },
  67 };
  68
  69 static void twl4030_madc_read(u8 reg, u8 *val)
  70 {
  71         int ret = twl4030_i2c_read_u8(TWL4030_MODULE_MADC, val, reg);
  72         if (ret)
  73                 printk(KERN_ERR TWL4030_MADC_PFX
  74                        "unable to read register 0x%X\n", reg);
  75 }
  76
  77 static void twl4030_madc_write(u8 reg, u8 val)
  78 {
  79         int ret = twl4030_i2c_write_u8(TWL4030_MODULE_MADC, val, reg);
  80         if (ret)
  81                 printk(KERN_ERR TWL4030_MADC_PFX
  82                        "unable to write register 0x%X\n", reg);
  83 }
  84
  85 static int twl4030_madc_channel_raw_read(u8 reg)
  86 {
  87         u8 msb, lsb;
  88
  89         /* For each ADC channel, we have MSB and LSB register pair. MSB address
  90          * is always LSB address+1. reg parameter is the addr of LSB register */
  91         twl4030_madc_read(reg+1, &msb);
  92         twl4030_madc_read(reg, &lsb);
  93
  94         return (int)(((msb << 8) | lsb) >> 6);
  95 }
  96
  97 static int twl4030_madc_read_channels(u8 reg_base, u16 channels, int *buf)
  98 {
  99         int count = 0;
 100         u8 reg, i;
 101
 102         if (unlikely(!buf))
 103                 return 0;
 104
 105         for (i = 0; i < TWL4030_MADC_MAX_CHANNELS; i++) {
 106                 if (channels & (1<<i)) {
 107                         reg = reg_base + 2*i;
 108                         buf[i] = twl4030_madc_channel_raw_read(reg);
 109                         count++;
 110                 }
 111         }
 112         return count;
 113 }
 114
 115 static void twl4030_madc_enable_irq(int id)
 116 {
 117         u8 val;
 118
 119         static u8 imr = (irq_pin == 1) ? TWL4030_MADC_IMR1 : TWL4030_MADC_IMR2;
 120
 121         twl4030_madc_read(imr, &val);
 122         val &= ~(1 << id);
 123         twl4030_madc_write(imr, val);
 124 }
 125
 126 static void twl4030_madc_disable_irq(int id)
 127 {
 128         u8 val;
 129
 130         static u8 imr = (irq_pin == 1) ? TWL4030_MADC_IMR1 : TWL4030_MADC_IMR2;
 131
 132         twl4030_madc_read(imr, &val);
 133         val |= (1 << id);
 134         twl4030_madc_write(imr, val);
 135 }
 136
 137 static irqreturn_t twl4030_madc_irq_handler(int irq, void *madc_dev)
 138 {
 139         u8 isr_val, imr_val;
 140         static u8 isr, imr;
 141         int i;
 142
 143         imr = (irq_pin == 1) ? TWL4030_MADC_IMR1 : TWL4030_MADC_IMR2;
 144         isr = (irq_pin == 1) ? TWL4030_MADC_ISR1 : TWL4030_MADC_ISR2;
 145
 146         /* Use COR to ack interrupts since we have no shared IRQs in ISRx */
 147         twl4030_madc_read(isr, &isr_val);
 148         twl4030_madc_read(imr, &imr_val);
 149
 150         isr_val &= ~imr_val;
 151
 152         for (i = 0; i < TWL4030_MADC_NUM_METHODS; i++) {
 153
 154                 if (!(isr_val & (1<<i)))
 155                         continue;
 156
 157                 twl4030_madc_disable_irq(i);
 158                 twl4030_madc.requests[i].result_pending = 1;
 159         }
 160
 161         schedule_work(&twl4030_madc.ws);
 162
 163         return IRQ_HANDLED;
 164 }
 165
 166 static void twl4030_madc_work(struct work_struct *ws)
 167 {
 168         const struct twl4030_madc_conversion_method *method;
 169         struct twl4030_madc_request *r;
 170         int len, i;
 171
 172         mutex_lock(&twl4030_madc.lock);
 173
 174         for (i = 0; i < TWL4030_MADC_NUM_METHODS; i++) {
 175
 176                 r = &twl4030_madc.requests[i];
 177
 178                 /* No pending results for this method, move to next one */
 179                 if (!r->result_pending)
 180                         continue;
 181
 182                 method = &twl4030_conversion_methods[r->method];
 183
 184                 /* Read results */
 185                 len = twl4030_madc_read_channels(method->rbase,
 186                                                  r->channels, r->rbuf);
 187
 188                 /* Return results to caller */
 189                 if (r->func_cb != NULL) {
 190                         r->func_cb(len, r->channels, r->rbuf);
 191                         r->func_cb = NULL;
 192                 }
 193
 194                 /* Free request */
 195                 r->result_pending = 0;
 196                 r->active         = 0;
 197         }
 198
 199         mutex_unlock(&twl4030_madc.lock);
 200 }
 201
 202 static int twl4030_madc_set_irq(struct twl4030_madc_request *req)
 203 {
 204         struct twl4030_madc_request *p;
 205
 206         p = &twl4030_madc.requests[req->method];
 207
 208         memcpy(p, req, sizeof *req);
 209
 210         twl4030_madc_enable_irq(req->method);
 211
 212         return 0;
 213 }
 214
 215 static inline void twl4030_madc_start_conversion(int conv_method)
 216 {
 217         const struct twl4030_madc_conversion_method *method;
 218
 219         method = &twl4030_conversion_methods[conv_method];
 220
 221         switch (conv_method) {
 222         case TWL4030_MADC_SW1:
 223         case TWL4030_MADC_SW2:
 224                 twl4030_madc_write(method->ctrl, TWL4030_MADC_SW_START);
 225                 break;
 226         case TWL4030_MADC_RT:
 227         default:
 228                 break;
 229         }
 230 }
 231
 232 static void twl4030_madc_wait_conversion_ready_ms(u8 *time, u8 status_reg)
 233 {
 234         u8 reg = 0;
 235
 236         do {
 237                 msleep(1);
 238                 (*time)--;
 239                 twl4030_madc_read(status_reg, &reg);
 240         } while (((reg & TWL4030_MADC_BUSY) && !(reg & TWL4030_MADC_EOC_SW)) &&
 241                   (*time != 0));
 242 }
 243
 244 int twl4030_madc_conversion(struct twl4030_madc_request *req)
 245 {
 246         const struct twl4030_madc_conversion_method *method;
 247         u8 wait_time, ch_msb, ch_lsb;
 248         int ret;
 249
 250         if (unlikely(!req))
 251                 return -EINVAL;
 252
 253         /* Do we have a conversion request ongoing */
 254         if (twl4030_madc.requests[req->method].active)
 255                 return -EBUSY;
 256
 257         ch_msb = (req->channels >> 8) & 0xff;
 258         ch_lsb = req->channels & 0xff;
 259
 260         method = &twl4030_conversion_methods[req->method];
 261
 262         mutex_lock(&twl4030_madc.lock);
 263
 264         /* Select channels to be converted */
 265         twl4030_madc_write(method->sel + 1, ch_msb);
 266         twl4030_madc_write(method->sel, ch_lsb);
 267
 268         /* Select averaging for all channels if do_avg is set */
 269         if (req->do_avg) {
 270                 twl4030_madc_write(method->avg + 1, ch_msb);
 271                 twl4030_madc_write(method->avg, ch_lsb);
 272         }
 273
 274         if ((req->type == TWL4030_MADC_IRQ_ONESHOT) && (req->func_cb != NULL)) {
 275                 twl4030_madc_set_irq(req);
 276                 twl4030_madc_start_conversion(req->method);
 277                 twl4030_madc.requests[req->method].active = 1;
 278                 ret = 0;
 279                 goto out;
 280         }
 281
 282         /* With RT method we should not be here anymore */
 283         if (req->method == TWL4030_MADC_RT) {
 284                 ret = -EINVAL;
 285                 goto out;
 286         }
 287
 288         twl4030_madc_start_conversion(req->method);
 289         twl4030_madc.requests[req->method].active = 1;
 290
 291         /* Wait until conversion is ready (ctrl register returns EOC) */
 292         wait_time = 50;
 293         twl4030_madc_wait_conversion_ready_ms(&wait_time, method->ctrl);
 294         if (wait_time == 0) {
 295                 printk(KERN_ERR TWL4030_MADC_PFX "conversion timeout!\n");
 296                 ret = -EAGAIN;
 297                 goto out;
 298         }
 299
 300         ret = twl4030_madc_read_channels(method->rbase, req->channels,
 301                                          req->rbuf);
 302
 303         twl4030_madc.requests[req->method].active = 0;
 304
 305 out:
 306         mutex_unlock(&twl4030_madc.lock);
 307
 308         return ret;
 309 }
 310
 311 EXPORT_SYMBOL(twl4030_madc_conversion);
 312
 313 static int twl4030_madc_set_current_generator(int chan, int on)
 314 {
 315         int ret;
 316         u8 regval;
 317
 318         /* Current generator is only available for ADCIN0 and ADCIN1. NB:
 319          * ADCIN1 current generator only works when AC or VBUS is present */
 320         if (chan > 1)
 321                 return EINVAL;
 322
 323         ret = twl4030_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE,
 324                                   &regval, TWL4030_BCI_BCICTL1);
 325         if (on)
 326                 regval |= (chan) ? TWL4030_BCI_ITHEN : TWL4030_BCI_TYPEN;
 327         else
 328                 regval &= (chan) ? ~TWL4030_BCI_ITHEN : ~TWL4030_BCI_TYPEN;
 329         ret = twl4030_i2c_write_u8(TWL4030_MODULE_MAIN_CHARGE,
 330                                    regval, TWL4030_BCI_BCICTL1);
 331
 332         return ret;
 333 }
 334
 335 static int twl4030_madc_set_power(int on)
 336 {
 337         u8 regval;
 338
 339         twl4030_madc_read(TWL4030_MADC_CTRL1, &regval);
 340         if (on)
 341                 regval |= TWL4030_MADC_MADCON;
 342         else
 343                 regval &= ~TWL4030_MADC_MADCON;
 344         twl4030_madc_write(TWL4030_MADC_CTRL1, regval);
 345
 346         return 0;
 347 }
 348
 349 static int twl4030_madc_ioctl(struct inode *inode, struct file *filp,
 350                               unsigned int cmd, unsigned long arg)
 351 {
 352         struct twl4030_madc_user_parms par;
 353         int val, ret;
 354
 355         ret = copy_from_user(&par, (void __user *) arg, sizeof(par));
 356         if (ret) {
 357                 printk(KERN_ERR TWL4030_MADC_PFX "copy_from_user: %d\n", ret);
 358                 return -EACCES;
 359         }
 360
 361         switch (cmd) {
 362         case TWL4030_MADC_IOCX_ADC_RAW_READ: {
 363                 struct twl4030_madc_request req;
 364                 if (par.channel >= TWL4030_MADC_MAX_CHANNELS)
 365                         return -EINVAL;
 366
 367                 req.channels = (1<<par.channel);
 368                 req.do_avg      = par.average;
 369                 req.method      = TWL4030_MADC_SW1;
 370
 371                 val = twl4030_madc_conversion(&req);
 372                 if (val <= 0) {
 373                         par.status = -1;
 374                 } else {
 375                         par.status = 0;
 376                         par.result = (u16)req.rbuf[par.channel];
 377                 }
 378                 break;
 379                                              }
 380         default:
 381                 return -EINVAL;
 382         }
 383
 384         ret = copy_to_user((void __user *) arg, &par, sizeof(par));
 385         if (ret) {
 386                 printk(KERN_ERR TWL4030_MADC_PFX "copy_to_user: %d\n", ret);
 387                 return -EACCES;
 388         }
 389
 390         return 0;
 391 }
 392
 393 static struct file_operations twl4030_madc_fileops = {
 394         .owner = THIS_MODULE,
 395         .ioctl = twl4030_madc_ioctl
 396 };
 397
 398 static struct miscdevice twl4030_madc_device = {
 399         .minor = MISC_DYNAMIC_MINOR,
 400         .name = "twl4030-adc",
 401         .fops = &twl4030_madc_fileops
 402 };
 403
 404 static int __init twl4030_madc_init(void)
 405 {
 406         int ret;
 407         u8 regval;
 408
 409         ret = misc_register(&twl4030_madc_device);
 410         if (ret == -1) {
 411                 printk(KERN_ERR TWL4030_MADC_PFX "misc_register() failed!\n");
 412                 return ret;
 413         }
 414         twl4030_madc_set_power(1);
 415         twl4030_madc_set_current_generator(0, 1);
 416
 417         ret = twl4030_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE,
 418                                   &regval, TWL4030_BCI_BCICTL1);
 419
 420         regval |= TWL4030_BCI_MESBAT;
 421
 422         ret = twl4030_i2c_write_u8(TWL4030_MODULE_MAIN_CHARGE,
 423                                    regval, TWL4030_BCI_BCICTL1);
 424
 425         ret = request_irq(TWL4030_MODIRQ_MADC, twl4030_madc_irq_handler,
 426                           IRQF_DISABLED, "twl4030_madc", &twl4030_madc);
 427         if (ret)
 428                 printk(KERN_ERR TWL4030_MADC_PFX "request_irq: %d\n", ret);
 429
 430         mutex_init(&twl4030_madc.lock);
 431
 432         INIT_WORK(&twl4030_madc.ws, twl4030_madc_work);
 433
 434         printk(KERN_INFO TWL4030_MADC_PFX "initialised\n");
 435
 436         return ret;
 437 }
 438
 439 static void __exit twl4030_madc_exit(void)
 440 {
 441         twl4030_madc_set_power(0);
 442         twl4030_madc_set_current_generator(0, 0);
 443         free_irq(TWL4030_MODIRQ_MADC, &twl4030_madc);
 444         cancel_work_sync(&twl4030_madc.ws);
 445         misc_deregister(&twl4030_madc_device);
 446 }
 447
 448 module_init(twl4030_madc_init);
 449 module_exit(twl4030_madc_exit);
 450
 451 MODULE_AUTHOR("Nokia Corporation");
 452 MODULE_DESCRIPTION("twl4030 ADC driver");
 453 MODULE_LICENSE("GPL");