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 static int stx104_read_raw(struct iio_dev *indio_dev,
  80         struct iio_chan_spec const *chan, int *val, int *val2, long mask)
  81 {
  82         struct stx104_iio *const priv = iio_priv(indio_dev);
  83         unsigned int adc_config;
  84         int adbu;
  85         int gain;
  86
  87         switch (mask) {
  88         case IIO_CHAN_INFO_HARDWAREGAIN:
  89                 /* get gain configuration */
  90                 adc_config = inb(priv->base + 11);
  91                 gain = adc_config & 0x3;
  92
  93                 *val = 1 << gain;
  94                 return IIO_VAL_INT;
  95         case IIO_CHAN_INFO_RAW:
  96                 if (chan->output) {
  97                         *val = priv->chan_out_states[chan->channel];
  98                         return IIO_VAL_INT;
  99                 }
 100
 101                 /* select ADC channel */
 102                 outb(chan->channel | (chan->channel << 4), priv->base + 2);
 103
 104                 /* trigger ADC sample capture and wait for completion */
 105                 outb(0, priv->base);
 106                 while (inb(priv->base + 8) & BIT(7));
 107
 108                 *val = inw(priv->base);
 109                 return IIO_VAL_INT;
 110         case IIO_CHAN_INFO_OFFSET:
 111                 /* get ADC bipolar/unipolar configuration */
 112                 adc_config = inb(priv->base + 11);
 113                 adbu = !(adc_config & BIT(2));
 114
 115                 *val = -32768 * adbu;
 116                 return IIO_VAL_INT;
 117         case IIO_CHAN_INFO_SCALE:
 118                 /* get ADC bipolar/unipolar and gain configuration */
 119                 adc_config = inb(priv->base + 11);
 120                 adbu = !(adc_config & BIT(2));
 121                 gain = adc_config & 0x3;
 122
 123                 *val = 5;
 124                 *val2 = 15 - adbu + gain;
 125                 return IIO_VAL_FRACTIONAL_LOG2;
 126         }
 127
 128         return -EINVAL;
 129 }
 130
 131 static int stx104_write_raw(struct iio_dev *indio_dev,
 132         struct iio_chan_spec const *chan, int val, int val2, long mask)
 133 {
 134         struct stx104_iio *const priv = iio_priv(indio_dev);
 135
 136         switch (mask) {
 137         case IIO_CHAN_INFO_HARDWAREGAIN:
 138                 /* Only four gain states (x1, x2, x4, x8) */
 139                 switch (val) {
 140                 case 1:
 141                         outb(0, priv->base + 11);
 142                         break;
 143                 case 2:
 144                         outb(1, priv->base + 11);
 145                         break;
 146                 case 4:
 147                         outb(2, priv->base + 11);
 148                         break;
 149                 case 8:
 150                         outb(3, priv->base + 11);
 151                         break;
 152                 default:
 153                         return -EINVAL;
 154                 }
 155
 156                 return 0;
 157         case IIO_CHAN_INFO_RAW:
 158                 if (chan->output) {
 159                         /* DAC can only accept up to a 16-bit value */
 160                         if ((unsigned int)val > 65535)
 161                                 return -EINVAL;
 162
 163                         priv->chan_out_states[chan->channel] = val;
 164                         outw(val, priv->base + 4 + 2 * chan->channel);
 165
 166                         return 0;
 167                 }
 168                 return -EINVAL;
 169         }
 170
 171         return -EINVAL;
 172 }
 173
 174 static const struct iio_info stx104_info = {
 175         .driver_module = THIS_MODULE,
 176         .read_raw = stx104_read_raw,
 177         .write_raw = stx104_write_raw
 178 };
 179
 180 /* single-ended input channels configuration */
 181 static const struct iio_chan_spec stx104_channels_sing[] = {
 182         STX104_OUT_CHAN(0), STX104_OUT_CHAN(1),
 183         STX104_IN_CHAN(0, 0), STX104_IN_CHAN(1, 0), STX104_IN_CHAN(2, 0),
 184         STX104_IN_CHAN(3, 0), STX104_IN_CHAN(4, 0), STX104_IN_CHAN(5, 0),
 185         STX104_IN_CHAN(6, 0), STX104_IN_CHAN(7, 0), STX104_IN_CHAN(8, 0),
 186         STX104_IN_CHAN(9, 0), STX104_IN_CHAN(10, 0), STX104_IN_CHAN(11, 0),
 187         STX104_IN_CHAN(12, 0), STX104_IN_CHAN(13, 0), STX104_IN_CHAN(14, 0),
 188         STX104_IN_CHAN(15, 0)
 189 };
 190 /* differential input channels configuration */
 191 static const struct iio_chan_spec stx104_channels_diff[] = {
 192         STX104_OUT_CHAN(0), STX104_OUT_CHAN(1),
 193         STX104_IN_CHAN(0, 1), STX104_IN_CHAN(1, 1), STX104_IN_CHAN(2, 1),
 194         STX104_IN_CHAN(3, 1), STX104_IN_CHAN(4, 1), STX104_IN_CHAN(5, 1),
 195         STX104_IN_CHAN(6, 1), STX104_IN_CHAN(7, 1)
 196 };
 197
 198 static int stx104_gpio_get_direction(struct gpio_chip *chip,
 199         unsigned int offset)
 200 {
 201         /* GPIO 0-3 are input only, while the rest are output only */
 202         if (offset < 4)
 203                 return 1;
 204
 205         return 0;
 206 }
 207
 208 static int stx104_gpio_direction_input(struct gpio_chip *chip,
 209         unsigned int offset)
 210 {
 211         if (offset >= 4)
 212                 return -EINVAL;
 213
 214         return 0;
 215 }
 216
 217 static int stx104_gpio_direction_output(struct gpio_chip *chip,
 218         unsigned int offset, int value)
 219 {
 220         if (offset < 4)
 221                 return -EINVAL;
 222
 223         chip->set(chip, offset, value);
 224         return 0;
 225 }
 226
 227 static int stx104_gpio_get(struct gpio_chip *chip, unsigned int offset)
 228 {
 229         struct stx104_gpio *const stx104gpio = gpiochip_get_data(chip);
 230
 231         if (offset >= 4)
 232                 return -EINVAL;
 233
 234         return !!(inb(stx104gpio->base) & BIT(offset));
 235 }
 236
 237 static void stx104_gpio_set(struct gpio_chip *chip, unsigned int offset,
 238         int value)
 239 {
 240         struct stx104_gpio *const stx104gpio = gpiochip_get_data(chip);
 241         const unsigned int mask = BIT(offset) >> 4;
 242         unsigned long flags;
 243
 244         if (offset < 4)
 245                 return;
 246
 247         spin_lock_irqsave(&stx104gpio->lock, flags);
 248
 249         if (value)
 250                 stx104gpio->out_state |= mask;
 251         else
 252                 stx104gpio->out_state &= ~mask;
 253
 254         outb(stx104gpio->out_state, stx104gpio->base);
 255
 256         spin_unlock_irqrestore(&stx104gpio->lock, flags);
 257 }
 258
 259 #define STX104_NGPIO 8
 260 static const char *stx104_names[STX104_NGPIO] = {
 261         "DIN0", "DIN1", "DIN2", "DIN3", "DOUT0", "DOUT1", "DOUT2", "DOUT3"
 262 };
 263
 264 static void stx104_gpio_set_multiple(struct gpio_chip *chip,
 265         unsigned long *mask, unsigned long *bits)
 266 {
 267         struct stx104_gpio *const stx104gpio = gpiochip_get_data(chip);
 268         unsigned long flags;
 269
 270         /* verify masked GPIO are output */
 271         if (!(*mask & 0xF0))
 272                 return;
 273
 274         *mask >>= 4;
 275         *bits >>= 4;
 276
 277         spin_lock_irqsave(&stx104gpio->lock, flags);
 278
 279         stx104gpio->out_state &= ~*mask;
 280         stx104gpio->out_state |= *mask & *bits;
 281         outb(stx104gpio->out_state, stx104gpio->base);
 282
 283         spin_unlock_irqrestore(&stx104gpio->lock, flags);
 284 }
 285
 286 static int stx104_probe(struct device *dev, unsigned int id)
 287 {
 288         struct iio_dev *indio_dev;
 289         struct stx104_iio *priv;
 290         struct stx104_gpio *stx104gpio;
 291         int err;
 292
 293         indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
 294         if (!indio_dev)
 295                 return -ENOMEM;
 296
 297         stx104gpio = devm_kzalloc(dev, sizeof(*stx104gpio), GFP_KERNEL);
 298         if (!stx104gpio)
 299                 return -ENOMEM;
 300
 301         if (!devm_request_region(dev, base[id], STX104_EXTENT,
 302                 dev_name(dev))) {
 303                 dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
 304                         base[id], base[id] + STX104_EXTENT);
 305                 return -EBUSY;
 306         }
 307
 308         indio_dev->info = &stx104_info;
 309         indio_dev->modes = INDIO_DIRECT_MODE;
 310
 311         /* determine if differential inputs */
 312         if (inb(base[id] + 8) & BIT(5)) {
 313                 indio_dev->num_channels = ARRAY_SIZE(stx104_channels_diff);
 314                 indio_dev->channels = stx104_channels_diff;
 315         } else {
 316                 indio_dev->num_channels = ARRAY_SIZE(stx104_channels_sing);
 317                 indio_dev->channels = stx104_channels_sing;
 318         }
 319
 320         indio_dev->name = dev_name(dev);
 321
 322         priv = iio_priv(indio_dev);
 323         priv->base = base[id];
 324
 325         /* configure device for software trigger operation */
 326         outb(0, base[id] + 9);
 327
 328         /* initialize gain setting to x1 */
 329         outb(0, base[id] + 11);
 330
 331         /* initialize DAC output to 0V */
 332         outw(0, base[id] + 4);
 333         outw(0, base[id] + 6);
 334
 335         stx104gpio->chip.label = dev_name(dev);
 336         stx104gpio->chip.parent = dev;
 337         stx104gpio->chip.owner = THIS_MODULE;
 338         stx104gpio->chip.base = -1;
 339         stx104gpio->chip.ngpio = STX104_NGPIO;
 340         stx104gpio->chip.names = stx104_names;
 341         stx104gpio->chip.get_direction = stx104_gpio_get_direction;
 342         stx104gpio->chip.direction_input = stx104_gpio_direction_input;
 343         stx104gpio->chip.direction_output = stx104_gpio_direction_output;
 344         stx104gpio->chip.get = stx104_gpio_get;
 345         stx104gpio->chip.set = stx104_gpio_set;
 346         stx104gpio->chip.set_multiple = stx104_gpio_set_multiple;
 347         stx104gpio->base = base[id] + 3;
 348         stx104gpio->out_state = 0x0;
 349
 350         spin_lock_init(&stx104gpio->lock);
 351
 352         err = devm_gpiochip_add_data(dev, &stx104gpio->chip, stx104gpio);
 353         if (err) {
 354                 dev_err(dev, "GPIO registering failed (%d)\n", err);
 355                 return err;
 356         }
 357
 358         return devm_iio_device_register(dev, indio_dev);
 359 }
 360
 361 static struct isa_driver stx104_driver = {
 362         .probe = stx104_probe,
 363         .driver = {
 364                 .name = "stx104"
 365         },
 366 };
 367
 368 module_isa_driver(stx104_driver, num_stx104);
 369
 370 MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
 371 MODULE_DESCRIPTION("Apex Embedded Systems STX104 IIO driver");
 372 MODULE_LICENSE("GPL v2");