2 * IIO driver for the Apex Embedded Systems STX104
3 * Copyright (C) 2016 William Breathitt Gray
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.
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.
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>
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>
28 #define STX104_OUT_CHAN(chan) { \
29 .type = IIO_VOLTAGE, \
31 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
35 #define STX104_IN_CHAN(chan, diff) { \
36 .type = IIO_VOLTAGE, \
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), \
43 .differential = diff \
46 #define STX104_NUM_OUT_CHAN 2
48 #define STX104_EXTENT 16
50 static unsigned int base[max_num_isa_dev(STX104_EXTENT)];
51 static unsigned int num_stx104;
52 module_param_hw_array(base, uint, ioport, &num_stx104, 0);
53 MODULE_PARM_DESC(base, "Apex Embedded Systems STX104 base addresses");
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
61 unsigned int chan_out_states[STX104_NUM_OUT_CHAN];
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
73 struct gpio_chip chip;
76 unsigned int out_state;
79 static int stx104_read_raw(struct iio_dev *indio_dev,
80 struct iio_chan_spec const *chan, int *val, int *val2, long mask)
82 struct stx104_iio *const priv = iio_priv(indio_dev);
83 unsigned int adc_config;
88 case IIO_CHAN_INFO_HARDWAREGAIN:
89 /* get gain configuration */
90 adc_config = inb(priv->base + 11);
91 gain = adc_config & 0x3;
95 case IIO_CHAN_INFO_RAW:
97 *val = priv->chan_out_states[chan->channel];
101 /* select ADC channel */
102 outb(chan->channel | (chan->channel << 4), priv->base + 2);
104 /* trigger ADC sample capture and wait for completion */
106 while (inb(priv->base + 8) & BIT(7));
108 *val = inw(priv->base);
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));
115 *val = -32768 * adbu;
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;
124 *val2 = 15 - adbu + gain;
125 return IIO_VAL_FRACTIONAL_LOG2;
131 static int stx104_write_raw(struct iio_dev *indio_dev,
132 struct iio_chan_spec const *chan, int val, int val2, long mask)
134 struct stx104_iio *const priv = iio_priv(indio_dev);
137 case IIO_CHAN_INFO_HARDWAREGAIN:
138 /* Only four gain states (x1, x2, x4, x8) */
141 outb(0, priv->base + 11);
144 outb(1, priv->base + 11);
147 outb(2, priv->base + 11);
150 outb(3, priv->base + 11);
157 case IIO_CHAN_INFO_RAW:
159 /* DAC can only accept up to a 16-bit value */
160 if ((unsigned int)val > 65535)
163 priv->chan_out_states[chan->channel] = val;
164 outw(val, priv->base + 4 + 2 * chan->channel);
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
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)
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)
198 static int stx104_gpio_get_direction(struct gpio_chip *chip,
201 /* GPIO 0-3 are input only, while the rest are output only */
208 static int stx104_gpio_direction_input(struct gpio_chip *chip,
217 static int stx104_gpio_direction_output(struct gpio_chip *chip,
218 unsigned int offset, int value)
223 chip->set(chip, offset, value);
227 static int stx104_gpio_get(struct gpio_chip *chip, unsigned int offset)
229 struct stx104_gpio *const stx104gpio = gpiochip_get_data(chip);
234 return !!(inb(stx104gpio->base) & BIT(offset));
237 static void stx104_gpio_set(struct gpio_chip *chip, unsigned int offset,
240 struct stx104_gpio *const stx104gpio = gpiochip_get_data(chip);
241 const unsigned int mask = BIT(offset) >> 4;
247 spin_lock_irqsave(&stx104gpio->lock, flags);
250 stx104gpio->out_state |= mask;
252 stx104gpio->out_state &= ~mask;
254 outb(stx104gpio->out_state, stx104gpio->base);
256 spin_unlock_irqrestore(&stx104gpio->lock, flags);
259 #define STX104_NGPIO 8
260 static const char *stx104_names[STX104_NGPIO] = {
261 "DIN0", "DIN1", "DIN2", "DIN3", "DOUT0", "DOUT1", "DOUT2", "DOUT3"
264 static void stx104_gpio_set_multiple(struct gpio_chip *chip,
265 unsigned long *mask, unsigned long *bits)
267 struct stx104_gpio *const stx104gpio = gpiochip_get_data(chip);
270 /* verify masked GPIO are output */
277 spin_lock_irqsave(&stx104gpio->lock, flags);
279 stx104gpio->out_state &= ~*mask;
280 stx104gpio->out_state |= *mask & *bits;
281 outb(stx104gpio->out_state, stx104gpio->base);
283 spin_unlock_irqrestore(&stx104gpio->lock, flags);
286 static int stx104_probe(struct device *dev, unsigned int id)
288 struct iio_dev *indio_dev;
289 struct stx104_iio *priv;
290 struct stx104_gpio *stx104gpio;
293 indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
297 stx104gpio = devm_kzalloc(dev, sizeof(*stx104gpio), GFP_KERNEL);
301 if (!devm_request_region(dev, base[id], STX104_EXTENT,
303 dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
304 base[id], base[id] + STX104_EXTENT);
308 indio_dev->info = &stx104_info;
309 indio_dev->modes = INDIO_DIRECT_MODE;
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;
316 indio_dev->num_channels = ARRAY_SIZE(stx104_channels_sing);
317 indio_dev->channels = stx104_channels_sing;
320 indio_dev->name = dev_name(dev);
322 priv = iio_priv(indio_dev);
323 priv->base = base[id];
325 /* configure device for software trigger operation */
326 outb(0, base[id] + 9);
328 /* initialize gain setting to x1 */
329 outb(0, base[id] + 11);
331 /* initialize DAC output to 0V */
332 outw(0, base[id] + 4);
333 outw(0, base[id] + 6);
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;
350 spin_lock_init(&stx104gpio->lock);
352 err = devm_gpiochip_add_data(dev, &stx104gpio->chip, stx104gpio);
354 dev_err(dev, "GPIO registering failed (%d)\n", err);
358 return devm_iio_device_register(dev, indio_dev);
361 static struct isa_driver stx104_driver = {
362 .probe = stx104_probe,
368 module_isa_driver(stx104_driver, num_stx104);
370 MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
371 MODULE_DESCRIPTION("Apex Embedded Systems STX104 IIO driver");
372 MODULE_LICENSE("GPL v2");