Maxime Ripard | 0e589d5 | 2012-05-11 15:35:33 +0200 | [diff] [blame^] | 1 | /* |
| 2 | * Driver for the ADC present in the Atmel AT91 evaluation boards. |
| 3 | * |
| 4 | * Copyright 2011 Free Electrons |
| 5 | * |
| 6 | * Licensed under the GPLv2 or later. |
| 7 | */ |
| 8 | |
| 9 | #include <linux/bitmap.h> |
| 10 | #include <linux/bitops.h> |
| 11 | #include <linux/clk.h> |
| 12 | #include <linux/err.h> |
| 13 | #include <linux/io.h> |
| 14 | #include <linux/interrupt.h> |
| 15 | #include <linux/jiffies.h> |
| 16 | #include <linux/kernel.h> |
| 17 | #include <linux/module.h> |
| 18 | #include <linux/platform_device.h> |
| 19 | #include <linux/sched.h> |
| 20 | #include <linux/slab.h> |
| 21 | #include <linux/wait.h> |
| 22 | |
| 23 | #include <linux/platform_data/at91_adc.h> |
| 24 | |
| 25 | #include <linux/iio/iio.h> |
| 26 | #include <linux/iio/buffer.h> |
| 27 | #include <linux/iio/kfifo_buf.h> |
| 28 | #include <linux/iio/trigger.h> |
| 29 | #include <linux/iio/trigger_consumer.h> |
| 30 | |
| 31 | #include <mach/at91_adc.h> |
| 32 | |
| 33 | #define AT91_ADC_CHAN(st, ch) \ |
| 34 | (st->registers->channel_base + (ch * 4)) |
| 35 | #define at91_adc_readl(st, reg) \ |
| 36 | (readl_relaxed(st->reg_base + reg)) |
| 37 | #define at91_adc_writel(st, reg, val) \ |
| 38 | (writel_relaxed(val, st->reg_base + reg)) |
| 39 | |
| 40 | struct at91_adc_state { |
| 41 | struct clk *adc_clk; |
| 42 | u16 *buffer; |
| 43 | unsigned long channels_mask; |
| 44 | struct clk *clk; |
| 45 | bool done; |
| 46 | int irq; |
| 47 | bool irq_enabled; |
| 48 | u16 last_value; |
| 49 | struct mutex lock; |
| 50 | u8 num_channels; |
| 51 | void __iomem *reg_base; |
| 52 | struct at91_adc_reg_desc *registers; |
| 53 | u8 startup_time; |
| 54 | struct iio_trigger **trig; |
| 55 | struct at91_adc_trigger *trigger_list; |
| 56 | u32 trigger_number; |
| 57 | bool use_external; |
| 58 | u32 vref_mv; |
| 59 | wait_queue_head_t wq_data_avail; |
| 60 | }; |
| 61 | |
| 62 | static irqreturn_t at91_adc_trigger_handler(int irq, void *p) |
| 63 | { |
| 64 | struct iio_poll_func *pf = p; |
| 65 | struct iio_dev *idev = pf->indio_dev; |
| 66 | struct at91_adc_state *st = iio_priv(idev); |
| 67 | struct iio_buffer *buffer = idev->buffer; |
| 68 | int i, j = 0; |
| 69 | |
| 70 | for (i = 0; i < idev->masklength; i++) { |
| 71 | if (!test_bit(i, idev->active_scan_mask)) |
| 72 | continue; |
| 73 | st->buffer[j] = at91_adc_readl(st, AT91_ADC_CHAN(st, i)); |
| 74 | j++; |
| 75 | } |
| 76 | |
| 77 | if (idev->scan_timestamp) { |
| 78 | s64 *timestamp = (s64 *)((u8 *)st->buffer + |
| 79 | ALIGN(j, sizeof(s64))); |
| 80 | *timestamp = pf->timestamp; |
| 81 | } |
| 82 | |
| 83 | buffer->access->store_to(buffer, (u8 *)st->buffer, pf->timestamp); |
| 84 | |
| 85 | iio_trigger_notify_done(idev->trig); |
| 86 | st->irq_enabled = true; |
| 87 | |
| 88 | /* Needed to ACK the DRDY interruption */ |
| 89 | at91_adc_readl(st, AT91_ADC_LCDR); |
| 90 | |
| 91 | enable_irq(st->irq); |
| 92 | |
| 93 | return IRQ_HANDLED; |
| 94 | } |
| 95 | |
| 96 | static irqreturn_t at91_adc_eoc_trigger(int irq, void *private) |
| 97 | { |
| 98 | struct iio_dev *idev = private; |
| 99 | struct at91_adc_state *st = iio_priv(idev); |
| 100 | u32 status = at91_adc_readl(st, st->registers->status_register); |
| 101 | |
| 102 | if (!(status & st->registers->drdy_mask)) |
| 103 | return IRQ_HANDLED; |
| 104 | |
| 105 | if (iio_buffer_enabled(idev)) { |
| 106 | disable_irq_nosync(irq); |
| 107 | st->irq_enabled = false; |
| 108 | iio_trigger_poll(idev->trig, iio_get_time_ns()); |
| 109 | } else { |
| 110 | st->last_value = at91_adc_readl(st, AT91_ADC_LCDR); |
| 111 | st->done = true; |
| 112 | wake_up_interruptible(&st->wq_data_avail); |
| 113 | } |
| 114 | |
| 115 | return IRQ_HANDLED; |
| 116 | } |
| 117 | |
| 118 | static int at91_adc_channel_init(struct iio_dev *idev) |
| 119 | { |
| 120 | struct at91_adc_state *st = iio_priv(idev); |
| 121 | struct iio_chan_spec *chan_array, *timestamp; |
| 122 | int bit, idx = 0; |
| 123 | |
| 124 | idev->num_channels = bitmap_weight(&st->channels_mask, |
| 125 | st->num_channels) + 1; |
| 126 | |
| 127 | chan_array = devm_kzalloc(&idev->dev, |
| 128 | ((idev->num_channels + 1) * |
| 129 | sizeof(struct iio_chan_spec)), |
| 130 | GFP_KERNEL); |
| 131 | |
| 132 | if (!chan_array) |
| 133 | return -ENOMEM; |
| 134 | |
| 135 | for_each_set_bit(bit, &st->channels_mask, st->num_channels) { |
| 136 | struct iio_chan_spec *chan = chan_array + idx; |
| 137 | |
| 138 | chan->type = IIO_VOLTAGE; |
| 139 | chan->indexed = 1; |
| 140 | chan->channel = bit; |
| 141 | chan->scan_index = idx; |
| 142 | chan->scan_type.sign = 'u'; |
| 143 | chan->scan_type.realbits = 10; |
| 144 | chan->scan_type.storagebits = 16; |
| 145 | chan->info_mask = IIO_CHAN_INFO_SCALE_SHARED_BIT | |
| 146 | IIO_CHAN_INFO_RAW_SEPARATE_BIT; |
| 147 | idx++; |
| 148 | } |
| 149 | timestamp = chan_array + idx; |
| 150 | |
| 151 | timestamp->type = IIO_TIMESTAMP; |
| 152 | timestamp->channel = -1; |
| 153 | timestamp->scan_index = idx; |
| 154 | timestamp->scan_type.sign = 's'; |
| 155 | timestamp->scan_type.realbits = 64; |
| 156 | timestamp->scan_type.storagebits = 64; |
| 157 | |
| 158 | idev->channels = chan_array; |
| 159 | return idev->num_channels; |
| 160 | } |
| 161 | |
| 162 | static u8 at91_adc_get_trigger_value_by_name(struct iio_dev *idev, |
| 163 | struct at91_adc_trigger *triggers, |
| 164 | const char *trigger_name) |
| 165 | { |
| 166 | struct at91_adc_state *st = iio_priv(idev); |
| 167 | u8 value = 0; |
| 168 | int i; |
| 169 | |
| 170 | for (i = 0; i < st->trigger_number; i++) { |
| 171 | char *name = kasprintf(GFP_KERNEL, |
| 172 | "%s-dev%d-%s", |
| 173 | idev->name, |
| 174 | idev->id, |
| 175 | triggers[i].name); |
| 176 | if (!name) |
| 177 | return -ENOMEM; |
| 178 | |
| 179 | if (strcmp(trigger_name, name) == 0) { |
| 180 | value = triggers[i].value; |
| 181 | kfree(name); |
| 182 | break; |
| 183 | } |
| 184 | |
| 185 | kfree(name); |
| 186 | } |
| 187 | |
| 188 | return value; |
| 189 | } |
| 190 | |
| 191 | static int at91_adc_configure_trigger(struct iio_trigger *trig, bool state) |
| 192 | { |
| 193 | struct iio_dev *idev = trig->private_data; |
| 194 | struct at91_adc_state *st = iio_priv(idev); |
| 195 | struct iio_buffer *buffer = idev->buffer; |
| 196 | struct at91_adc_reg_desc *reg = st->registers; |
| 197 | u32 status = at91_adc_readl(st, reg->trigger_register); |
| 198 | u8 value; |
| 199 | u8 bit; |
| 200 | |
| 201 | value = at91_adc_get_trigger_value_by_name(idev, |
| 202 | st->trigger_list, |
| 203 | idev->trig->name); |
| 204 | if (value == 0) |
| 205 | return -EINVAL; |
| 206 | |
| 207 | if (state) { |
| 208 | st->buffer = kmalloc(idev->scan_bytes, GFP_KERNEL); |
| 209 | if (st->buffer == NULL) |
| 210 | return -ENOMEM; |
| 211 | |
| 212 | at91_adc_writel(st, reg->trigger_register, |
| 213 | status | value); |
| 214 | |
| 215 | for_each_set_bit(bit, buffer->scan_mask, |
| 216 | st->num_channels) { |
| 217 | struct iio_chan_spec const *chan = idev->channels + bit; |
| 218 | at91_adc_writel(st, AT91_ADC_CHER, |
| 219 | AT91_ADC_CH(chan->channel)); |
| 220 | } |
| 221 | |
| 222 | at91_adc_writel(st, AT91_ADC_IER, reg->drdy_mask); |
| 223 | |
| 224 | } else { |
| 225 | at91_adc_writel(st, AT91_ADC_IDR, reg->drdy_mask); |
| 226 | |
| 227 | at91_adc_writel(st, reg->trigger_register, |
| 228 | status & ~value); |
| 229 | |
| 230 | for_each_set_bit(bit, buffer->scan_mask, |
| 231 | st->num_channels) { |
| 232 | struct iio_chan_spec const *chan = idev->channels + bit; |
| 233 | at91_adc_writel(st, AT91_ADC_CHDR, |
| 234 | AT91_ADC_CH(chan->channel)); |
| 235 | } |
| 236 | kfree(st->buffer); |
| 237 | } |
| 238 | |
| 239 | return 0; |
| 240 | } |
| 241 | |
| 242 | static const struct iio_trigger_ops at91_adc_trigger_ops = { |
| 243 | .owner = THIS_MODULE, |
| 244 | .set_trigger_state = &at91_adc_configure_trigger, |
| 245 | }; |
| 246 | |
| 247 | static struct iio_trigger *at91_adc_allocate_trigger(struct iio_dev *idev, |
| 248 | struct at91_adc_trigger *trigger) |
| 249 | { |
| 250 | struct iio_trigger *trig; |
| 251 | int ret; |
| 252 | |
| 253 | trig = iio_trigger_alloc("%s-dev%d-%s", idev->name, |
| 254 | idev->id, trigger->name); |
| 255 | if (trig == NULL) |
| 256 | return NULL; |
| 257 | |
| 258 | trig->dev.parent = idev->dev.parent; |
| 259 | trig->private_data = idev; |
| 260 | trig->ops = &at91_adc_trigger_ops; |
| 261 | |
| 262 | ret = iio_trigger_register(trig); |
| 263 | if (ret) |
| 264 | return NULL; |
| 265 | |
| 266 | return trig; |
| 267 | } |
| 268 | |
| 269 | static int at91_adc_trigger_init(struct iio_dev *idev) |
| 270 | { |
| 271 | struct at91_adc_state *st = iio_priv(idev); |
| 272 | int i, ret; |
| 273 | |
| 274 | st->trig = devm_kzalloc(&idev->dev, |
| 275 | st->trigger_number * sizeof(st->trig), |
| 276 | GFP_KERNEL); |
| 277 | |
| 278 | if (st->trig == NULL) { |
| 279 | ret = -ENOMEM; |
| 280 | goto error_ret; |
| 281 | } |
| 282 | |
| 283 | for (i = 0; i < st->trigger_number; i++) { |
| 284 | if (st->trigger_list[i].is_external && !(st->use_external)) |
| 285 | continue; |
| 286 | |
| 287 | st->trig[i] = at91_adc_allocate_trigger(idev, |
| 288 | st->trigger_list + i); |
| 289 | if (st->trig[i] == NULL) { |
| 290 | dev_err(&idev->dev, |
| 291 | "Could not allocate trigger %d\n", i); |
| 292 | ret = -ENOMEM; |
| 293 | goto error_trigger; |
| 294 | } |
| 295 | } |
| 296 | |
| 297 | return 0; |
| 298 | |
| 299 | error_trigger: |
| 300 | for (i--; i >= 0; i--) { |
| 301 | iio_trigger_unregister(st->trig[i]); |
| 302 | iio_trigger_free(st->trig[i]); |
| 303 | } |
| 304 | error_ret: |
| 305 | return ret; |
| 306 | } |
| 307 | |
| 308 | static void at91_adc_trigger_remove(struct iio_dev *idev) |
| 309 | { |
| 310 | struct at91_adc_state *st = iio_priv(idev); |
| 311 | int i; |
| 312 | |
| 313 | for (i = 0; i < st->trigger_number; i++) { |
| 314 | iio_trigger_unregister(st->trig[i]); |
| 315 | iio_trigger_free(st->trig[i]); |
| 316 | } |
| 317 | } |
| 318 | |
| 319 | static const struct iio_buffer_setup_ops at91_adc_buffer_ops = { |
| 320 | .preenable = &iio_sw_buffer_preenable, |
| 321 | .postenable = &iio_triggered_buffer_postenable, |
| 322 | .predisable = &iio_triggered_buffer_predisable, |
| 323 | }; |
| 324 | |
| 325 | static int at91_adc_buffer_init(struct iio_dev *idev) |
| 326 | { |
| 327 | int ret; |
| 328 | |
| 329 | idev->buffer = iio_kfifo_allocate(idev); |
| 330 | if (!idev->buffer) { |
| 331 | ret = -ENOMEM; |
| 332 | goto error_ret; |
| 333 | } |
| 334 | |
| 335 | idev->pollfunc = iio_alloc_pollfunc(&iio_pollfunc_store_time, |
| 336 | &at91_adc_trigger_handler, |
| 337 | IRQF_ONESHOT, |
| 338 | idev, |
| 339 | "%s-consumer%d", |
| 340 | idev->name, |
| 341 | idev->id); |
| 342 | if (idev->pollfunc == NULL) { |
| 343 | ret = -ENOMEM; |
| 344 | goto error_pollfunc; |
| 345 | } |
| 346 | |
| 347 | idev->setup_ops = &at91_adc_buffer_ops; |
| 348 | idev->modes |= INDIO_BUFFER_TRIGGERED; |
| 349 | |
| 350 | ret = iio_buffer_register(idev, |
| 351 | idev->channels, |
| 352 | idev->num_channels); |
| 353 | if (ret) |
| 354 | goto error_register; |
| 355 | |
| 356 | return 0; |
| 357 | |
| 358 | error_register: |
| 359 | iio_dealloc_pollfunc(idev->pollfunc); |
| 360 | error_pollfunc: |
| 361 | iio_kfifo_free(idev->buffer); |
| 362 | error_ret: |
| 363 | return ret; |
| 364 | } |
| 365 | |
| 366 | static void at91_adc_buffer_remove(struct iio_dev *idev) |
| 367 | { |
| 368 | iio_buffer_unregister(idev); |
| 369 | iio_dealloc_pollfunc(idev->pollfunc); |
| 370 | iio_kfifo_free(idev->buffer); |
| 371 | } |
| 372 | |
| 373 | static int at91_adc_read_raw(struct iio_dev *idev, |
| 374 | struct iio_chan_spec const *chan, |
| 375 | int *val, int *val2, long mask) |
| 376 | { |
| 377 | struct at91_adc_state *st = iio_priv(idev); |
| 378 | int ret; |
| 379 | |
| 380 | switch (mask) { |
| 381 | case IIO_CHAN_INFO_RAW: |
| 382 | mutex_lock(&st->lock); |
| 383 | |
| 384 | at91_adc_writel(st, AT91_ADC_CHER, |
| 385 | AT91_ADC_CH(chan->channel)); |
| 386 | at91_adc_writel(st, AT91_ADC_IER, st->registers->drdy_mask); |
| 387 | at91_adc_writel(st, AT91_ADC_CR, AT91_ADC_START); |
| 388 | |
| 389 | ret = wait_event_interruptible_timeout(st->wq_data_avail, |
| 390 | st->done, |
| 391 | msecs_to_jiffies(1000)); |
| 392 | if (ret == 0) |
| 393 | return -ETIMEDOUT; |
| 394 | else if (ret < 0) |
| 395 | return ret; |
| 396 | |
| 397 | *val = st->last_value; |
| 398 | |
| 399 | at91_adc_writel(st, AT91_ADC_CHDR, |
| 400 | AT91_ADC_CH(chan->channel)); |
| 401 | at91_adc_writel(st, AT91_ADC_IDR, st->registers->drdy_mask); |
| 402 | |
| 403 | st->last_value = 0; |
| 404 | st->done = false; |
| 405 | mutex_unlock(&st->lock); |
| 406 | return IIO_VAL_INT; |
| 407 | |
| 408 | case IIO_CHAN_INFO_SCALE: |
| 409 | *val = (st->vref_mv * 1000) >> chan->scan_type.realbits; |
| 410 | *val2 = 0; |
| 411 | return IIO_VAL_INT_PLUS_MICRO; |
| 412 | default: |
| 413 | break; |
| 414 | } |
| 415 | return -EINVAL; |
| 416 | } |
| 417 | |
| 418 | static int at91_adc_probe_pdata(struct at91_adc_state *st, |
| 419 | struct platform_device *pdev) |
| 420 | { |
| 421 | struct at91_adc_data *pdata = pdev->dev.platform_data; |
| 422 | |
| 423 | if (!pdata) |
| 424 | return -EINVAL; |
| 425 | |
| 426 | st->use_external = pdata->use_external_triggers; |
| 427 | st->vref_mv = pdata->vref; |
| 428 | st->channels_mask = pdata->channels_used; |
| 429 | st->num_channels = pdata->num_channels; |
| 430 | st->startup_time = pdata->startup_time; |
| 431 | st->trigger_number = pdata->trigger_number; |
| 432 | st->trigger_list = pdata->trigger_list; |
| 433 | st->registers = pdata->registers; |
| 434 | |
| 435 | return 0; |
| 436 | } |
| 437 | |
| 438 | static const struct iio_info at91_adc_info = { |
| 439 | .driver_module = THIS_MODULE, |
| 440 | .read_raw = &at91_adc_read_raw, |
| 441 | }; |
| 442 | |
| 443 | static int __devinit at91_adc_probe(struct platform_device *pdev) |
| 444 | { |
| 445 | unsigned int prsc, mstrclk, ticks, adc_clk; |
| 446 | int ret; |
| 447 | struct iio_dev *idev; |
| 448 | struct at91_adc_state *st; |
| 449 | struct resource *res; |
| 450 | |
| 451 | idev = iio_device_alloc(sizeof(struct at91_adc_state)); |
| 452 | if (idev == NULL) { |
| 453 | ret = -ENOMEM; |
| 454 | goto error_ret; |
| 455 | } |
| 456 | |
| 457 | st = iio_priv(idev); |
| 458 | |
| 459 | ret = at91_adc_probe_pdata(st, pdev); |
| 460 | if (ret) { |
| 461 | dev_err(&pdev->dev, "No platform data available.\n"); |
| 462 | ret = -EINVAL; |
| 463 | goto error_free_device; |
| 464 | } |
| 465 | |
| 466 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| 467 | if (!res) { |
| 468 | dev_err(&pdev->dev, "No resource defined\n"); |
| 469 | ret = -ENXIO; |
| 470 | goto error_ret; |
| 471 | } |
| 472 | |
| 473 | platform_set_drvdata(pdev, idev); |
| 474 | |
| 475 | idev->dev.parent = &pdev->dev; |
| 476 | idev->name = dev_name(&pdev->dev); |
| 477 | idev->modes = INDIO_DIRECT_MODE; |
| 478 | idev->info = &at91_adc_info; |
| 479 | |
| 480 | st->irq = platform_get_irq(pdev, 0); |
| 481 | if (st->irq < 0) { |
| 482 | dev_err(&pdev->dev, "No IRQ ID is designated\n"); |
| 483 | ret = -ENODEV; |
| 484 | goto error_free_device; |
| 485 | } |
| 486 | |
| 487 | if (!request_mem_region(res->start, resource_size(res), |
| 488 | "AT91 adc registers")) { |
| 489 | dev_err(&pdev->dev, "Resources are unavailable.\n"); |
| 490 | ret = -EBUSY; |
| 491 | goto error_free_device; |
| 492 | } |
| 493 | |
| 494 | st->reg_base = ioremap(res->start, resource_size(res)); |
| 495 | if (!st->reg_base) { |
| 496 | dev_err(&pdev->dev, "Failed to map registers.\n"); |
| 497 | ret = -ENOMEM; |
| 498 | goto error_release_mem; |
| 499 | } |
| 500 | |
| 501 | /* |
| 502 | * Disable all IRQs before setting up the handler |
| 503 | */ |
| 504 | at91_adc_writel(st, AT91_ADC_CR, AT91_ADC_SWRST); |
| 505 | at91_adc_writel(st, AT91_ADC_IDR, 0xFFFFFFFF); |
| 506 | ret = request_irq(st->irq, |
| 507 | at91_adc_eoc_trigger, |
| 508 | 0, |
| 509 | pdev->dev.driver->name, |
| 510 | idev); |
| 511 | if (ret) { |
| 512 | dev_err(&pdev->dev, "Failed to allocate IRQ.\n"); |
| 513 | goto error_unmap_reg; |
| 514 | } |
| 515 | |
| 516 | st->clk = clk_get(&pdev->dev, "adc_clk"); |
| 517 | if (IS_ERR(st->clk)) { |
| 518 | dev_err(&pdev->dev, "Failed to get the clock.\n"); |
| 519 | ret = PTR_ERR(st->clk); |
| 520 | goto error_free_irq; |
| 521 | } |
| 522 | |
| 523 | ret = clk_prepare(st->clk); |
| 524 | if (ret) { |
| 525 | dev_err(&pdev->dev, "Could not prepare the clock.\n"); |
| 526 | goto error_free_clk; |
| 527 | } |
| 528 | |
| 529 | ret = clk_enable(st->clk); |
| 530 | if (ret) { |
| 531 | dev_err(&pdev->dev, "Could not enable the clock.\n"); |
| 532 | goto error_unprepare_clk; |
| 533 | } |
| 534 | |
| 535 | st->adc_clk = clk_get(&pdev->dev, "adc_op_clk"); |
| 536 | if (IS_ERR(st->adc_clk)) { |
| 537 | dev_err(&pdev->dev, "Failed to get the ADC clock.\n"); |
| 538 | ret = PTR_ERR(st->clk); |
| 539 | goto error_disable_clk; |
| 540 | } |
| 541 | |
| 542 | ret = clk_prepare(st->adc_clk); |
| 543 | if (ret) { |
| 544 | dev_err(&pdev->dev, "Could not prepare the ADC clock.\n"); |
| 545 | goto error_free_adc_clk; |
| 546 | } |
| 547 | |
| 548 | ret = clk_enable(st->adc_clk); |
| 549 | if (ret) { |
| 550 | dev_err(&pdev->dev, "Could not enable the ADC clock.\n"); |
| 551 | goto error_unprepare_adc_clk; |
| 552 | } |
| 553 | |
| 554 | /* |
| 555 | * Prescaler rate computation using the formula from the Atmel's |
| 556 | * datasheet : ADC Clock = MCK / ((Prescaler + 1) * 2), ADC Clock being |
| 557 | * specified by the electrical characteristics of the board. |
| 558 | */ |
| 559 | mstrclk = clk_get_rate(st->clk); |
| 560 | adc_clk = clk_get_rate(st->adc_clk); |
| 561 | prsc = (mstrclk / (2 * adc_clk)) - 1; |
| 562 | |
| 563 | if (!st->startup_time) { |
| 564 | dev_err(&pdev->dev, "No startup time available.\n"); |
| 565 | ret = -EINVAL; |
| 566 | goto error_disable_adc_clk; |
| 567 | } |
| 568 | |
| 569 | /* |
| 570 | * Number of ticks needed to cover the startup time of the ADC as |
| 571 | * defined in the electrical characteristics of the board, divided by 8. |
| 572 | * The formula thus is : Startup Time = (ticks + 1) * 8 / ADC Clock |
| 573 | */ |
| 574 | ticks = round_up((st->startup_time * adc_clk / |
| 575 | 1000000) - 1, 8) / 8; |
| 576 | at91_adc_writel(st, AT91_ADC_MR, |
| 577 | (AT91_ADC_PRESCAL_(prsc) & AT91_ADC_PRESCAL) | |
| 578 | (AT91_ADC_STARTUP_(ticks) & AT91_ADC_STARTUP)); |
| 579 | |
| 580 | /* Setup the ADC channels available on the board */ |
| 581 | ret = at91_adc_channel_init(idev); |
| 582 | if (ret < 0) { |
| 583 | dev_err(&pdev->dev, "Couldn't initialize the channels.\n"); |
| 584 | goto error_disable_adc_clk; |
| 585 | } |
| 586 | |
| 587 | init_waitqueue_head(&st->wq_data_avail); |
| 588 | mutex_init(&st->lock); |
| 589 | |
| 590 | ret = at91_adc_buffer_init(idev); |
| 591 | if (ret < 0) { |
| 592 | dev_err(&pdev->dev, "Couldn't initialize the buffer.\n"); |
| 593 | goto error_disable_adc_clk; |
| 594 | } |
| 595 | |
| 596 | ret = at91_adc_trigger_init(idev); |
| 597 | if (ret < 0) { |
| 598 | dev_err(&pdev->dev, "Couldn't setup the triggers.\n"); |
| 599 | goto error_unregister_buffer; |
| 600 | } |
| 601 | |
| 602 | ret = iio_device_register(idev); |
| 603 | if (ret < 0) { |
| 604 | dev_err(&pdev->dev, "Couldn't register the device.\n"); |
| 605 | goto error_remove_triggers; |
| 606 | } |
| 607 | |
| 608 | return 0; |
| 609 | |
| 610 | error_remove_triggers: |
| 611 | at91_adc_trigger_remove(idev); |
| 612 | error_unregister_buffer: |
| 613 | at91_adc_buffer_remove(idev); |
| 614 | error_disable_adc_clk: |
| 615 | clk_disable(st->adc_clk); |
| 616 | error_unprepare_adc_clk: |
| 617 | clk_unprepare(st->adc_clk); |
| 618 | error_free_adc_clk: |
| 619 | clk_put(st->adc_clk); |
| 620 | error_disable_clk: |
| 621 | clk_disable(st->clk); |
| 622 | error_unprepare_clk: |
| 623 | clk_unprepare(st->clk); |
| 624 | error_free_clk: |
| 625 | clk_put(st->clk); |
| 626 | error_free_irq: |
| 627 | free_irq(st->irq, idev); |
| 628 | error_unmap_reg: |
| 629 | iounmap(st->reg_base); |
| 630 | error_release_mem: |
| 631 | release_mem_region(res->start, resource_size(res)); |
| 632 | error_free_device: |
| 633 | iio_device_free(idev); |
| 634 | error_ret: |
| 635 | return ret; |
| 636 | } |
| 637 | |
| 638 | static int __devexit at91_adc_remove(struct platform_device *pdev) |
| 639 | { |
| 640 | struct iio_dev *idev = platform_get_drvdata(pdev); |
| 641 | struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| 642 | struct at91_adc_state *st = iio_priv(idev); |
| 643 | |
| 644 | iio_device_unregister(idev); |
| 645 | at91_adc_trigger_remove(idev); |
| 646 | at91_adc_buffer_remove(idev); |
| 647 | clk_disable_unprepare(st->adc_clk); |
| 648 | clk_put(st->adc_clk); |
| 649 | clk_disable(st->clk); |
| 650 | clk_unprepare(st->clk); |
| 651 | clk_put(st->clk); |
| 652 | free_irq(st->irq, idev); |
| 653 | iounmap(st->reg_base); |
| 654 | release_mem_region(res->start, resource_size(res)); |
| 655 | iio_device_free(idev); |
| 656 | |
| 657 | return 0; |
| 658 | } |
| 659 | |
| 660 | static struct platform_driver at91_adc_driver = { |
| 661 | .probe = at91_adc_probe, |
| 662 | .remove = __devexit_p(at91_adc_remove), |
| 663 | .driver = { |
| 664 | .name = "at91_adc", |
| 665 | }, |
| 666 | }; |
| 667 | |
| 668 | module_platform_driver(at91_adc_driver); |
| 669 | |
| 670 | MODULE_LICENSE("GPL"); |
| 671 | MODULE_DESCRIPTION("Atmel AT91 ADC Driver"); |
| 672 | MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>"); |