1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * mpc624.c
4 * Hardware driver for a Micro/sys inc. MPC-624 PC/104 board
5 *
6 * COMEDI - Linux Control and Measurement Device Interface
7 * Copyright (C) 2000 David A. Schleef <ds@schleef.org>
8 */
9
10 /*
11 * Driver: mpc624
12 * Description: Micro/sys MPC-624 PC/104 board
13 * Devices: [Micro/sys] MPC-624 (mpc624)
14 * Author: Stanislaw Raczynski <sraczynski@op.pl>
15 * Updated: Thu, 15 Sep 2005 12:01:18 +0200
16 * Status: working
17 *
18 * The Micro/sys MPC-624 board is based on the LTC2440 24-bit sigma-delta
19 * ADC chip.
20 *
21 * Subdevices supported by the driver:
22 * - Analog In: supported
23 * - Digital I/O: not supported
24 * - LEDs: not supported
25 * - EEPROM: not supported
26 *
27 * Configuration Options:
28 * [0] - I/O base address
29 * [1] - conversion rate
30 * Conversion rate RMS noise Effective Number Of Bits
31 * 0 3.52kHz 23uV 17
32 * 1 1.76kHz 3.5uV 20
33 * 2 880Hz 2uV 21.3
34 * 3 440Hz 1.4uV 21.8
35 * 4 220Hz 1uV 22.4
36 * 5 110Hz 750uV 22.9
37 * 6 55Hz 510nV 23.4
38 * 7 27.5Hz 375nV 24
39 * 8 13.75Hz 250nV 24.4
40 * 9 6.875Hz 200nV 24.6
41 * [2] - voltage range
42 * 0 -1.01V .. +1.01V
43 * 1 -10.1V .. +10.1V
44 */
45
46 #include <linux/module.h>
47 #include "../comedidev.h"
48
49 #include <linux/delay.h>
50
51 /* Offsets of different ports */
52 #define MPC624_MASTER_CONTROL 0 /* not used */
53 #define MPC624_GNMUXCH 1 /* Gain, Mux, Channel of ADC */
54 #define MPC624_ADC 2 /* read/write to/from ADC */
55 #define MPC624_EE 3 /* read/write to/from serial EEPROM via I2C */
56 #define MPC624_LEDS 4 /* write to LEDs */
57 #define MPC624_DIO 5 /* read/write to/from digital I/O ports */
58 #define MPC624_IRQ_MASK 6 /* IRQ masking enable/disable */
59
60 /* Register bits' names */
61 #define MPC624_ADBUSY BIT(5)
62 #define MPC624_ADSDO BIT(4)
63 #define MPC624_ADFO BIT(3)
64 #define MPC624_ADCS BIT(2)
65 #define MPC624_ADSCK BIT(1)
66 #define MPC624_ADSDI BIT(0)
67
68 /* 32-bit output value bits' names */
69 #define MPC624_EOC_BIT BIT(31)
70 #define MPC624_DMY_BIT BIT(30)
71 #define MPC624_SGN_BIT BIT(29)
72
73 /* SDI Speed/Resolution Programming bits */
74 #define MPC624_OSR(x) (((x) & 0x1f) << 27)
75 #define MPC624_SPEED_3_52_KHZ MPC624_OSR(0x11)
76 #define MPC624_SPEED_1_76_KHZ MPC624_OSR(0x12)
77 #define MPC624_SPEED_880_HZ MPC624_OSR(0x13)
78 #define MPC624_SPEED_440_HZ MPC624_OSR(0x14)
79 #define MPC624_SPEED_220_HZ MPC624_OSR(0x15)
80 #define MPC624_SPEED_110_HZ MPC624_OSR(0x16)
81 #define MPC624_SPEED_55_HZ MPC624_OSR(0x17)
82 #define MPC624_SPEED_27_5_HZ MPC624_OSR(0x18)
83 #define MPC624_SPEED_13_75_HZ MPC624_OSR(0x19)
84 #define MPC624_SPEED_6_875_HZ MPC624_OSR(0x1f)
85
86 struct mpc624_private {
87 unsigned int ai_speed;
88 };
89
90 /* -------------------------------------------------------------------------- */
91 static const struct comedi_lrange range_mpc624_bipolar1 = {
92 1,
93 {
94 /* BIP_RANGE(1.01) this is correct, */
95 /* but my MPC-624 actually seems to have a range of 2.02 */
96 BIP_RANGE(2.02)
97 }
98 };
99
100 static const struct comedi_lrange range_mpc624_bipolar10 = {
101 1,
102 {
103 /* BIP_RANGE(10.1) this is correct, */
104 /* but my MPC-624 actually seems to have a range of 20.2 */
105 BIP_RANGE(20.2)
106 }
107 };
108
109 static unsigned int mpc624_ai_get_sample(struct comedi_device *dev,
110 struct comedi_subdevice *s)
111 {
112 struct mpc624_private *devpriv = dev->private;
113 unsigned int data_out = devpriv->ai_speed;
114 unsigned int data_in = 0;
115 unsigned int bit;
116 int i;
117
118 /* Start reading data */
119 udelay(1);
120 for (i = 0; i < 32; i++) {
121 /* Set the clock low */
122 outb(0, dev->iobase + MPC624_ADC);
123 udelay(1);
124
125 /* Set the ADSDI line for the next bit (send to MPC624) */
126 bit = (data_out & BIT(31)) ? MPC624_ADSDI : 0;
127 outb(bit, dev->iobase + MPC624_ADC);
128 udelay(1);
129
130 /* Set the clock high */
131 outb(MPC624_ADSCK | bit, dev->iobase + MPC624_ADC);
132 udelay(1);
133
134 /* Read ADSDO on high clock (receive from MPC624) */
135 data_in <<= 1;
136 data_in |= (inb(dev->iobase + MPC624_ADC) & MPC624_ADSDO) >> 4;
137 udelay(1);
138
139 data_out <<= 1;
140 }
141
142 /*
143 * Received 32-bit long value consist of:
144 * 31: EOC - (End Of Transmission) bit - should be 0
145 * 30: DMY - (Dummy) bit - should be 0
146 * 29: SIG - (Sign) bit - 1 if positive, 0 if negative
147 * 28: MSB - (Most Significant Bit) - the first bit of the
148 * conversion result
149 * ....
150 * 05: LSB - (Least Significant Bit)- the last bit of the
151 * conversion result
152 * 04-00: sub-LSB - sub-LSBs are basically noise, but when
153 * averaged properly, they can increase
154 * conversion precision up to 29 bits;
155 * they can be discarded without loss of
156 * resolution.
157 */
158 if (data_in & MPC624_EOC_BIT)
159 dev_dbg(dev->class_dev, "EOC bit is set!");
160 if (data_in & MPC624_DMY_BIT)
161 dev_dbg(dev->class_dev, "DMY bit is set!");
162
163 if (data_in & MPC624_SGN_BIT) {
164 /*
165 * Voltage is positive
166 *
167 * comedi operates on unsigned numbers, so mask off EOC
168 * and DMY and don't clear the SGN bit
169 */
170 data_in &= 0x3fffffff;
171 } else {
172 /*
173 * The voltage is negative
174 *
175 * data_in contains a number in 30-bit two's complement
176 * code and we must deal with it
177 */
178 data_in |= MPC624_SGN_BIT;
179 data_in = ~data_in;
180 data_in += 1;
181 /* clear EOC and DMY bits */
182 data_in &= ~(MPC624_EOC_BIT | MPC624_DMY_BIT);
183 data_in = 0x20000000 - data_in;
184 }
185 return data_in;
186 }
187
188 static int mpc624_ai_eoc(struct comedi_device *dev,
189 struct comedi_subdevice *s,
190 struct comedi_insn *insn,
191 unsigned long context)
192 {
193 unsigned char status;
194
195 status = inb(dev->iobase + MPC624_ADC);
196 if ((status & MPC624_ADBUSY) == 0)
197 return 0;
198 return -EBUSY;
199 }
200
201 static int mpc624_ai_insn_read(struct comedi_device *dev,
202 struct comedi_subdevice *s,
203 struct comedi_insn *insn,
204 unsigned int *data)
205 {
206 int ret;
207 int i;
208
209 /*
210 * WARNING:
211 * We always write 0 to GNSWA bit, so the channel range is +-/10.1Vdc
212 */
213 outb(insn->chanspec, dev->iobase + MPC624_GNMUXCH);
214
215 for (i = 0; i < insn->n; i++) {
216 /* Trigger the conversion */
217 outb(MPC624_ADSCK, dev->iobase + MPC624_ADC);
218 udelay(1);
219 outb(MPC624_ADCS | MPC624_ADSCK, dev->iobase + MPC624_ADC);
220 udelay(1);
221 outb(0, dev->iobase + MPC624_ADC);
222 udelay(1);
223
224 /* Wait for the conversion to end */
225 ret = comedi_timeout(dev, s, insn, mpc624_ai_eoc, 0);
226 if (ret)
227 return ret;
228
229 data[i] = mpc624_ai_get_sample(dev, s);
230 }
231
232 return insn->n;
233 }
234
235 static int mpc624_attach(struct comedi_device *dev, struct comedi_devconfig *it)
236 {
237 struct mpc624_private *devpriv;
238 struct comedi_subdevice *s;
239 int ret;
240
241 ret = comedi_request_region(dev, it->options[0], 0x10);
242 if (ret)
243 return ret;
244
245 devpriv = comedi_alloc_devpriv(dev, sizeof(*devpriv));
246 if (!devpriv)
247 return -ENOMEM;
248
249 switch (it->options[1]) {
250 case 0:
251 devpriv->ai_speed = MPC624_SPEED_3_52_KHZ;
252 break;
253 case 1:
254 devpriv->ai_speed = MPC624_SPEED_1_76_KHZ;
255 break;
256 case 2:
257 devpriv->ai_speed = MPC624_SPEED_880_HZ;
258 break;
259 case 3:
260 devpriv->ai_speed = MPC624_SPEED_440_HZ;
261 break;
262 case 4:
263 devpriv->ai_speed = MPC624_SPEED_220_HZ;
264 break;
265 case 5:
266 devpriv->ai_speed = MPC624_SPEED_110_HZ;
267 break;
268 case 6:
269 devpriv->ai_speed = MPC624_SPEED_55_HZ;
270 break;
271 case 7:
272 devpriv->ai_speed = MPC624_SPEED_27_5_HZ;
273 break;
274 case 8:
275 devpriv->ai_speed = MPC624_SPEED_13_75_HZ;
276 break;
277 case 9:
278 devpriv->ai_speed = MPC624_SPEED_6_875_HZ;
279 break;
280 default:
281 devpriv->ai_speed = MPC624_SPEED_3_52_KHZ;
282 }
283
284 ret = comedi_alloc_subdevices(dev, 1);
285 if (ret)
286 return ret;
287
288 /* Analog Input subdevice */
289 s = &dev->subdevices[0];
290 s->type = COMEDI_SUBD_AI;
291 s->subdev_flags = SDF_READABLE | SDF_DIFF;
292 s->n_chan = 4;
293 s->maxdata = 0x3fffffff;
294 s->range_table = (it->options[1] == 0) ? &range_mpc624_bipolar1
295 : &range_mpc624_bipolar10;
296 s->insn_read = mpc624_ai_insn_read;
297
298 return 0;
299 }
300
301 static struct comedi_driver mpc624_driver = {
302 .driver_name = "mpc624",
303 .module = THIS_MODULE,
304 .attach = mpc624_attach,
305 .detach = comedi_legacy_detach,
306 };
307 module_comedi_driver(mpc624_driver);
308
309 MODULE_AUTHOR("Comedi http://www.comedi.org");
310 MODULE_DESCRIPTION("Comedi driver for Micro/sys MPC-624 PC/104 board");
311 MODULE_LICENSE("GPL");