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_hw_array(base, uint, ioport, &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
stx104_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)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
stx104_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)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
stx104_gpio_get_direction(struct gpio_chip * chip,unsigned int offset)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
stx104_gpio_direction_input(struct gpio_chip * chip,unsigned int offset)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
stx104_gpio_direction_output(struct gpio_chip * chip,unsigned int offset,int value)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
stx104_gpio_get(struct gpio_chip * chip,unsigned int offset)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
stx104_gpio_set(struct gpio_chip * chip,unsigned int offset,int value)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
stx104_gpio_set_multiple(struct gpio_chip * chip,unsigned long * mask,unsigned long * bits)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
stx104_probe(struct device * dev,unsigned int id)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 indio_dev->dev.parent = dev;
322
323 priv = iio_priv(indio_dev);
324 priv->base = base[id];
325
326 /* configure device for software trigger operation */
327 outb(0, base[id] + 9);
328
329 /* initialize gain setting to x1 */
330 outb(0, base[id] + 11);
331
332 /* initialize DAC output to 0V */
333 outw(0, base[id] + 4);
334 outw(0, base[id] + 6);
335
336 stx104gpio->chip.label = dev_name(dev);
337 stx104gpio->chip.parent = dev;
338 stx104gpio->chip.owner = THIS_MODULE;
339 stx104gpio->chip.base = -1;
340 stx104gpio->chip.ngpio = STX104_NGPIO;
341 stx104gpio->chip.names = stx104_names;
342 stx104gpio->chip.get_direction = stx104_gpio_get_direction;
343 stx104gpio->chip.direction_input = stx104_gpio_direction_input;
344 stx104gpio->chip.direction_output = stx104_gpio_direction_output;
345 stx104gpio->chip.get = stx104_gpio_get;
346 stx104gpio->chip.set = stx104_gpio_set;
347 stx104gpio->chip.set_multiple = stx104_gpio_set_multiple;
348 stx104gpio->base = base[id] + 3;
349 stx104gpio->out_state = 0x0;
350
351 spin_lock_init(&stx104gpio->lock);
352
353 err = devm_gpiochip_add_data(dev, &stx104gpio->chip, stx104gpio);
354 if (err) {
355 dev_err(dev, "GPIO registering failed (%d)\n", err);
356 return err;
357 }
358
359 return devm_iio_device_register(dev, indio_dev);
360 }
361
362 static struct isa_driver stx104_driver = {
363 .probe = stx104_probe,
364 .driver = {
365 .name = "stx104"
366 },
367 };
368
369 module_isa_driver(stx104_driver, num_stx104);
370
371 MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
372 MODULE_DESCRIPTION("Apex Embedded Systems STX104 IIO driver");
373 MODULE_LICENSE("GPL v2");
374