drivers/iio/adc/stx104.c

   1 /*
   2  * IIO driver for the Apex Embedded Systems STX104
   3  * Copyright (C) 2016 William Breathitt Gray
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License, version 2, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  */
  14 #include <linux/bitops.h>
  15 #include <linux/device.h>
  16 #include <linux/errno.h>
  17 #include <linux/gpio/driver.h>
  18 #include <linux/iio/iio.h>
  19 #include <linux/iio/types.h>
  20 #include <linux/io.h>
  21 #include <linux/ioport.h>
  22 #include <linux/isa.h>
  23 #include <linux/kernel.h>
  24 #include <linux/module.h>
  25 #include <linux/moduleparam.h>
  26 #include <linux/spinlock.h>
  27
  28 #define STX104_OUT_CHAN(chan) {                         \
  29         .type = IIO_VOLTAGE,                            \
  30         .channel = chan,                                \
  31         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
  32         .indexed = 1,                                   \
  33         .output = 1                                     \
  34 }
  35 #define STX104_IN_CHAN(chan, diff) {                                    \
  36         .type = IIO_VOLTAGE,                                            \
  37         .channel = chan,                                                \
  38         .channel2 = chan,                                               \
  39         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_HARDWAREGAIN) |   \
  40                 BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_SCALE),   \
  41         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),                   \
  42         .indexed = 1,                                                   \
  43         .differential = diff                                            \
  44 }
  45
  46 #define STX104_NUM_OUT_CHAN 2
  47
  48 #define STX104_EXTENT 16
  49
  50 static unsigned int base[max_num_isa_dev(STX104_EXTENT)];
  51 static unsigned int num_stx104;
  52 module_param_array(base, uint, &num_stx104, 0);
  53 MODULE_PARM_DESC(base, "Apex Embedded Systems STX104 base addresses");
  54
  55 /**
  56  * struct stx104_iio - IIO device private data structure
  57  * @chan_out_states:    channels' output states
  58  * @base:               base port address of the IIO device
  59  */
  60 struct stx104_iio {
  61         unsigned int chan_out_states[STX104_NUM_OUT_CHAN];
  62         unsigned int base;
  63 };
  64
  65 /**
  66  * struct stx104_gpio - GPIO device private data structure
  67  * @chip:       instance of the gpio_chip
  68  * @lock:       synchronization lock to prevent I/O race conditions
  69  * @base:       base port address of the GPIO device
  70  * @out_state:  output bits state
  71  */
  72 struct stx104_gpio {
  73         struct gpio_chip chip;
  74         spinlock_t lock;
  75         unsigned int base;
  76         unsigned int out_state;
  77 };
  78
  79 /**
  80  * struct stx104_dev - STX104 device private data structure
  81  * @indio_dev:  IIO device
  82  * @chip:       instance of the gpio_chip
  83  */
  84 struct stx104_dev {
  85         struct iio_dev *indio_dev;
  86         struct gpio_chip *chip;
  87 };
  88
  89 static int stx104_read_raw(struct iio_dev *indio_dev,
  90         struct iio_chan_spec const *chan, int *val, int *val2, long mask)
  91 {
  92         struct stx104_iio *const priv = iio_priv(indio_dev);
  93         unsigned int adc_config;
  94         int adbu;
  95         int gain;
  96
  97         switch (mask) {
  98         case IIO_CHAN_INFO_HARDWAREGAIN:
  99                 /* get gain configuration */
 100                 adc_config = inb(priv->base + 11);
 101                 gain = adc_config & 0x3;
 102
 103                 *val = 1 << gain;
 104                 return IIO_VAL_INT;
 105         case IIO_CHAN_INFO_RAW:
 106                 if (chan->output) {
 107                         *val = priv->chan_out_states[chan->channel];
 108                         return IIO_VAL_INT;
 109                 }
 110
 111                 /* select ADC channel */
 112                 outb(chan->channel | (chan->channel << 4), priv->base + 2);
 113
 114                 /* trigger ADC sample capture and wait for completion */
 115                 outb(0, priv->base);
 116                 while (inb(priv->base + 8) & BIT(7));
 117
 118                 *val = inw(priv->base);
 119                 return IIO_VAL_INT;
 120         case IIO_CHAN_INFO_OFFSET:
 121                 /* get ADC bipolar/unipolar configuration */
 122                 adc_config = inb(priv->base + 11);
 123                 adbu = !(adc_config & BIT(2));
 124
 125                 *val = -32768 * adbu;
 126                 return IIO_VAL_INT;
 127         case IIO_CHAN_INFO_SCALE:
 128                 /* get ADC bipolar/unipolar and gain configuration */
 129                 adc_config = inb(priv->base + 11);
 130                 adbu = !(adc_config & BIT(2));
 131                 gain = adc_config & 0x3;
 132
 133                 *val = 5;
 134                 *val2 = 15 - adbu + gain;
 135                 return IIO_VAL_FRACTIONAL_LOG2;
 136         }
 137
 138         return -EINVAL;
 139 }
 140
 141 static int stx104_write_raw(struct iio_dev *indio_dev,
 142         struct iio_chan_spec const *chan, int val, int val2, long mask)
 143 {
 144         struct stx104_iio *const priv = iio_priv(indio_dev);
 145
 146         switch (mask) {
 147         case IIO_CHAN_INFO_HARDWAREGAIN:
 148                 /* Only four gain states (x1, x2, x4, x8) */
 149                 switch (val) {
 150                 case 1:
 151                         outb(0, priv->base + 11);
 152                         break;
 153                 case 2:
 154                         outb(1, priv->base + 11);
 155                         break;
 156                 case 4:
 157                         outb(2, priv->base + 11);
 158                         break;
 159                 case 8:
 160                         outb(3, priv->base + 11);
 161                         break;
 162                 default:
 163                         return -EINVAL;
 164                 }
 165
 166                 return 0;
 167         case IIO_CHAN_INFO_RAW:
 168                 if (chan->output) {
 169                         /* DAC can only accept up to a 16-bit value */
 170                         if ((unsigned int)val > 65535)
 171                                 return -EINVAL;
 172
 173                         priv->chan_out_states[chan->channel] = val;
 174                         outw(val, priv->base + 4 + 2 * chan->channel);
 175
 176                         return 0;
 177                 }
 178                 return -EINVAL;
 179         }
 180
 181         return -EINVAL;
 182 }
 183
 184 static const struct iio_info stx104_info = {
 185         .driver_module = THIS_MODULE,
 186         .read_raw = stx104_read_raw,
 187         .write_raw = stx104_write_raw
 188 };
 189
 190 /* single-ended input channels configuration */
 191 static const struct iio_chan_spec stx104_channels_sing[] = {
 192         STX104_OUT_CHAN(0), STX104_OUT_CHAN(1),
 193         STX104_IN_CHAN(0, 0), STX104_IN_CHAN(1, 0), STX104_IN_CHAN(2, 0),
 194         STX104_IN_CHAN(3, 0), STX104_IN_CHAN(4, 0), STX104_IN_CHAN(5, 0),
 195         STX104_IN_CHAN(6, 0), STX104_IN_CHAN(7, 0), STX104_IN_CHAN(8, 0),
 196         STX104_IN_CHAN(9, 0), STX104_IN_CHAN(10, 0), STX104_IN_CHAN(11, 0),
 197         STX104_IN_CHAN(12, 0), STX104_IN_CHAN(13, 0), STX104_IN_CHAN(14, 0),
 198         STX104_IN_CHAN(15, 0)
 199 };
 200 /* differential input channels configuration */
 201 static const struct iio_chan_spec stx104_channels_diff[] = {
 202         STX104_OUT_CHAN(0), STX104_OUT_CHAN(1),
 203         STX104_IN_CHAN(0, 1), STX104_IN_CHAN(1, 1), STX104_IN_CHAN(2, 1),
 204         STX104_IN_CHAN(3, 1), STX104_IN_CHAN(4, 1), STX104_IN_CHAN(5, 1),
 205         STX104_IN_CHAN(6, 1), STX104_IN_CHAN(7, 1)
 206 };
 207
 208 static int stx104_gpio_get_direction(struct gpio_chip *chip,
 209         unsigned int offset)
 210 {
 211         /* GPIO 0-3 are input only, while the rest are output only */
 212         if (offset < 4)
 213                 return 1;
 214
 215         return 0;
 216 }
 217
 218 static int stx104_gpio_direction_input(struct gpio_chip *chip,
 219         unsigned int offset)
 220 {
 221         if (offset >= 4)
 222                 return -EINVAL;
 223
 224         return 0;
 225 }
 226
 227 static int stx104_gpio_direction_output(struct gpio_chip *chip,
 228         unsigned int offset, int value)
 229 {
 230         if (offset < 4)
 231                 return -EINVAL;
 232
 233         chip->set(chip, offset, value);
 234         return 0;
 235 }
 236
 237 static int stx104_gpio_get(struct gpio_chip *chip, unsigned int offset)
 238 {
 239         struct stx104_gpio *const stx104gpio = gpiochip_get_data(chip);
 240
 241         if (offset >= 4)
 242                 return -EINVAL;
 243
 244         return !!(inb(stx104gpio->base) & BIT(offset));
 245 }
 246
 247 static void stx104_gpio_set(struct gpio_chip *chip, unsigned int offset,
 248         int value)
 249 {
 250         struct stx104_gpio *const stx104gpio = gpiochip_get_data(chip);
 251         const unsigned int mask = BIT(offset) >> 4;
 252         unsigned long flags;
 253
 254         if (offset < 4)
 255                 return;
 256
 257         spin_lock_irqsave(&stx104gpio->lock, flags);
 258
 259         if (value)
 260                 stx104gpio->out_state |= mask;
 261         else
 262                 stx104gpio->out_state &= ~mask;
 263
 264         outb(stx104gpio->out_state, stx104gpio->base);
 265
 266         spin_unlock_irqrestore(&stx104gpio->lock, flags);
 267 }
 268
 269 static int stx104_probe(struct device *dev, unsigned int id)
 270 {
 271         struct iio_dev *indio_dev;
 272         struct stx104_iio *priv;
 273         struct stx104_gpio *stx104gpio;
 274         struct stx104_dev *stx104dev;
 275         int err;
 276
 277         indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
 278         if (!indio_dev)
 279                 return -ENOMEM;
 280
 281         stx104gpio = devm_kzalloc(dev, sizeof(*stx104gpio), GFP_KERNEL);
 282         if (!stx104gpio)
 283                 return -ENOMEM;
 284
 285         stx104dev = devm_kzalloc(dev, sizeof(*stx104dev), GFP_KERNEL);
 286         if (!stx104dev)
 287                 return -ENOMEM;
 288
 289         if (!devm_request_region(dev, base[id], STX104_EXTENT,
 290                 dev_name(dev))) {
 291                 dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
 292                         base[id], base[id] + STX104_EXTENT);
 293                 return -EBUSY;
 294         }
 295
 296         indio_dev->info = &stx104_info;
 297         indio_dev->modes = INDIO_DIRECT_MODE;
 298
 299         /* determine if differential inputs */
 300         if (inb(base[id] + 8) & BIT(5)) {
 301                 indio_dev->num_channels = ARRAY_SIZE(stx104_channels_diff);
 302                 indio_dev->channels = stx104_channels_diff;
 303         } else {
 304                 indio_dev->num_channels = ARRAY_SIZE(stx104_channels_sing);
 305                 indio_dev->channels = stx104_channels_sing;
 306         }
 307
 308         indio_dev->name = dev_name(dev);
 309
 310         priv = iio_priv(indio_dev);
 311         priv->base = base[id];
 312
 313         /* configure device for software trigger operation */
 314         outb(0, base[id] + 9);
 315
 316         /* initialize gain setting to x1 */
 317         outb(0, base[id] + 11);
 318
 319         /* initialize DAC output to 0V */
 320         outw(0, base[id] + 4);
 321         outw(0, base[id] + 6);
 322
 323         stx104gpio->chip.label = dev_name(dev);
 324         stx104gpio->chip.parent = dev;
 325         stx104gpio->chip.owner = THIS_MODULE;
 326         stx104gpio->chip.base = -1;
 327         stx104gpio->chip.ngpio = 8;
 328         stx104gpio->chip.get_direction = stx104_gpio_get_direction;
 329         stx104gpio->chip.direction_input = stx104_gpio_direction_input;
 330         stx104gpio->chip.direction_output = stx104_gpio_direction_output;
 331         stx104gpio->chip.get = stx104_gpio_get;
 332         stx104gpio->chip.set = stx104_gpio_set;
 333         stx104gpio->base = base[id] + 3;
 334         stx104gpio->out_state = 0x0;
 335
 336         spin_lock_init(&stx104gpio->lock);
 337
 338         stx104dev->indio_dev = indio_dev;
 339         stx104dev->chip = &stx104gpio->chip;
 340         dev_set_drvdata(dev, stx104dev);
 341
 342         err = gpiochip_add_data(&stx104gpio->chip, stx104gpio);
 343         if (err) {
 344                 dev_err(dev, "GPIO registering failed (%d)\n", err);
 345                 return err;
 346         }
 347
 348         err = iio_device_register(indio_dev);
 349         if (err) {
 350                 dev_err(dev, "IIO device registering failed (%d)\n", err);
 351                 gpiochip_remove(&stx104gpio->chip);
 352                 return err;
 353         }
 354
 355         return 0;
 356 }
 357
 358 static int stx104_remove(struct device *dev, unsigned int id)
 359 {
 360         struct stx104_dev *const stx104dev = dev_get_drvdata(dev);
 361
 362         iio_device_unregister(stx104dev->indio_dev);
 363         gpiochip_remove(stx104dev->chip);
 364
 365         return 0;
 366 }
 367
 368 static struct isa_driver stx104_driver = {
 369         .probe = stx104_probe,
 370         .driver = {
 371                 .name = "stx104"
 372         },
 373         .remove = stx104_remove
 374 };
 375
 376 module_isa_driver(stx104_driver, num_stx104);
 377
 378 MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
 379 MODULE_DESCRIPTION("Apex Embedded Systems STX104 IIO driver");
 380 MODULE_LICENSE("GPL v2");