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