1 /*
2 * AD7298 SPI ADC driver
3 *
4 * Copyright 2011 Analog Devices Inc.
5 *
6 * Licensed under the GPL-2.
7 */
8
9 #include <linux/device.h>
10 #include <linux/kernel.h>
11 #include <linux/slab.h>
12 #include <linux/sysfs.h>
13 #include <linux/spi/spi.h>
14 #include <linux/regulator/consumer.h>
15 #include <linux/err.h>
16 #include <linux/delay.h>
17 #include <linux/module.h>
18
19 #include "../iio.h"
20 #include "../sysfs.h"
21 #include "../buffer.h"
22
23 #include "ad7298.h"
24
25 static struct iio_chan_spec ad7298_channels[] = {
26 IIO_CHAN(IIO_TEMP, 0, 1, 0, NULL, 0, 0,
27 IIO_CHAN_INFO_SCALE_SEPARATE_BIT,
28 9, AD7298_CH_TEMP, IIO_ST('s', 32, 32, 0), 0),
29 IIO_CHAN(IIO_VOLTAGE, 0, 1, 0, NULL, 0, 0,
30 IIO_CHAN_INFO_SCALE_SHARED_BIT,
31 0, 0, IIO_ST('u', 12, 16, 0), 0),
32 IIO_CHAN(IIO_VOLTAGE, 0, 1, 0, NULL, 1, 0,
33 IIO_CHAN_INFO_SCALE_SHARED_BIT,
34 1, 1, IIO_ST('u', 12, 16, 0), 0),
35 IIO_CHAN(IIO_VOLTAGE, 0, 1, 0, NULL, 2, 0,
36 IIO_CHAN_INFO_SCALE_SHARED_BIT,
37 2, 2, IIO_ST('u', 12, 16, 0), 0),
38 IIO_CHAN(IIO_VOLTAGE, 0, 1, 0, NULL, 3, 0,
39 IIO_CHAN_INFO_SCALE_SHARED_BIT,
40 3, 3, IIO_ST('u', 12, 16, 0), 0),
41 IIO_CHAN(IIO_VOLTAGE, 0, 1, 0, NULL, 4, 0,
42 IIO_CHAN_INFO_SCALE_SHARED_BIT,
43 4, 4, IIO_ST('u', 12, 16, 0), 0),
44 IIO_CHAN(IIO_VOLTAGE, 0, 1, 0, NULL, 5, 0,
45 IIO_CHAN_INFO_SCALE_SHARED_BIT,
46 5, 5, IIO_ST('u', 12, 16, 0), 0),
47 IIO_CHAN(IIO_VOLTAGE, 0, 1, 0, NULL, 6, 0,
48 IIO_CHAN_INFO_SCALE_SHARED_BIT,
49 6, 6, IIO_ST('u', 12, 16, 0), 0),
50 IIO_CHAN(IIO_VOLTAGE, 0, 1, 0, NULL, 7, 0,
51 IIO_CHAN_INFO_SCALE_SHARED_BIT,
52 7, 7, IIO_ST('u', 12, 16, 0), 0),
53 IIO_CHAN_SOFT_TIMESTAMP(8),
54 };
55
ad7298_scan_direct(struct ad7298_state * st,unsigned ch)56 static int ad7298_scan_direct(struct ad7298_state *st, unsigned ch)
57 {
58 int ret;
59 st->tx_buf[0] = cpu_to_be16(AD7298_WRITE | st->ext_ref |
60 (AD7298_CH(0) >> ch));
61
62 ret = spi_sync(st->spi, &st->scan_single_msg);
63 if (ret)
64 return ret;
65
66 return be16_to_cpu(st->rx_buf[0]);
67 }
68
ad7298_scan_temp(struct ad7298_state * st,int * val)69 static int ad7298_scan_temp(struct ad7298_state *st, int *val)
70 {
71 int tmp, ret;
72 __be16 buf;
73
74 buf = cpu_to_be16(AD7298_WRITE | AD7298_TSENSE |
75 AD7298_TAVG | st->ext_ref);
76
77 ret = spi_write(st->spi, (u8 *)&buf, 2);
78 if (ret)
79 return ret;
80
81 buf = cpu_to_be16(0);
82
83 ret = spi_write(st->spi, (u8 *)&buf, 2);
84 if (ret)
85 return ret;
86
87 usleep_range(101, 1000); /* sleep > 100us */
88
89 ret = spi_read(st->spi, (u8 *)&buf, 2);
90 if (ret)
91 return ret;
92
93 tmp = be16_to_cpu(buf) & RES_MASK(AD7298_BITS);
94
95 /*
96 * One LSB of the ADC corresponds to 0.25 deg C.
97 * The temperature reading is in 12-bit twos complement format
98 */
99
100 if (tmp & (1 << (AD7298_BITS - 1))) {
101 tmp = (4096 - tmp) * 250;
102 tmp -= (2 * tmp);
103
104 } else {
105 tmp *= 250; /* temperature in milli degrees Celsius */
106 }
107
108 *val = tmp;
109
110 return 0;
111 }
112
ad7298_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long m)113 static int ad7298_read_raw(struct iio_dev *indio_dev,
114 struct iio_chan_spec const *chan,
115 int *val,
116 int *val2,
117 long m)
118 {
119 int ret;
120 struct ad7298_state *st = iio_priv(indio_dev);
121 unsigned int scale_uv;
122
123 switch (m) {
124 case 0:
125 mutex_lock(&indio_dev->mlock);
126 if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
127 ret = -EBUSY;
128 } else {
129 if (chan->address == AD7298_CH_TEMP)
130 ret = ad7298_scan_temp(st, val);
131 else
132 ret = ad7298_scan_direct(st, chan->address);
133 }
134 mutex_unlock(&indio_dev->mlock);
135
136 if (ret < 0)
137 return ret;
138
139 if (chan->address != AD7298_CH_TEMP)
140 *val = ret & RES_MASK(AD7298_BITS);
141
142 return IIO_VAL_INT;
143 case IIO_CHAN_INFO_SCALE:
144 switch (chan->type) {
145 case IIO_VOLTAGE:
146 scale_uv = (st->int_vref_mv * 1000) >> AD7298_BITS;
147 *val = scale_uv / 1000;
148 *val2 = (scale_uv % 1000) * 1000;
149 return IIO_VAL_INT_PLUS_MICRO;
150 case IIO_TEMP:
151 *val = 1;
152 *val2 = 0;
153 return IIO_VAL_INT_PLUS_MICRO;
154 default:
155 return -EINVAL;
156 }
157 }
158 return -EINVAL;
159 }
160
161 static const struct iio_info ad7298_info = {
162 .read_raw = &ad7298_read_raw,
163 .driver_module = THIS_MODULE,
164 };
165
ad7298_probe(struct spi_device * spi)166 static int __devinit ad7298_probe(struct spi_device *spi)
167 {
168 struct ad7298_platform_data *pdata = spi->dev.platform_data;
169 struct ad7298_state *st;
170 int ret;
171 struct iio_dev *indio_dev = iio_allocate_device(sizeof(*st));
172
173 if (indio_dev == NULL)
174 return -ENOMEM;
175
176 st = iio_priv(indio_dev);
177
178 st->reg = regulator_get(&spi->dev, "vcc");
179 if (!IS_ERR(st->reg)) {
180 ret = regulator_enable(st->reg);
181 if (ret)
182 goto error_put_reg;
183 }
184
185 spi_set_drvdata(spi, indio_dev);
186
187 st->spi = spi;
188
189 indio_dev->name = spi_get_device_id(spi)->name;
190 indio_dev->dev.parent = &spi->dev;
191 indio_dev->modes = INDIO_DIRECT_MODE;
192 indio_dev->channels = ad7298_channels;
193 indio_dev->num_channels = ARRAY_SIZE(ad7298_channels);
194 indio_dev->info = &ad7298_info;
195
196 /* Setup default message */
197
198 st->scan_single_xfer[0].tx_buf = &st->tx_buf[0];
199 st->scan_single_xfer[0].len = 2;
200 st->scan_single_xfer[0].cs_change = 1;
201 st->scan_single_xfer[1].tx_buf = &st->tx_buf[1];
202 st->scan_single_xfer[1].len = 2;
203 st->scan_single_xfer[1].cs_change = 1;
204 st->scan_single_xfer[2].rx_buf = &st->rx_buf[0];
205 st->scan_single_xfer[2].len = 2;
206
207 spi_message_init(&st->scan_single_msg);
208 spi_message_add_tail(&st->scan_single_xfer[0], &st->scan_single_msg);
209 spi_message_add_tail(&st->scan_single_xfer[1], &st->scan_single_msg);
210 spi_message_add_tail(&st->scan_single_xfer[2], &st->scan_single_msg);
211
212 if (pdata && pdata->vref_mv) {
213 st->int_vref_mv = pdata->vref_mv;
214 st->ext_ref = AD7298_EXTREF;
215 } else {
216 st->int_vref_mv = AD7298_INTREF_mV;
217 }
218
219 ret = ad7298_register_ring_funcs_and_init(indio_dev);
220 if (ret)
221 goto error_disable_reg;
222
223 ret = iio_buffer_register(indio_dev,
224 &ad7298_channels[1], /* skip temp0 */
225 ARRAY_SIZE(ad7298_channels) - 1);
226 if (ret)
227 goto error_cleanup_ring;
228 ret = iio_device_register(indio_dev);
229 if (ret)
230 goto error_unregister_ring;
231
232 return 0;
233
234 error_unregister_ring:
235 iio_buffer_unregister(indio_dev);
236 error_cleanup_ring:
237 ad7298_ring_cleanup(indio_dev);
238 error_disable_reg:
239 if (!IS_ERR(st->reg))
240 regulator_disable(st->reg);
241 error_put_reg:
242 if (!IS_ERR(st->reg))
243 regulator_put(st->reg);
244 iio_free_device(indio_dev);
245
246 return ret;
247 }
248
ad7298_remove(struct spi_device * spi)249 static int __devexit ad7298_remove(struct spi_device *spi)
250 {
251 struct iio_dev *indio_dev = spi_get_drvdata(spi);
252 struct ad7298_state *st = iio_priv(indio_dev);
253
254 iio_device_unregister(indio_dev);
255 iio_buffer_unregister(indio_dev);
256 ad7298_ring_cleanup(indio_dev);
257 if (!IS_ERR(st->reg)) {
258 regulator_disable(st->reg);
259 regulator_put(st->reg);
260 }
261 iio_free_device(indio_dev);
262
263 return 0;
264 }
265
266 static const struct spi_device_id ad7298_id[] = {
267 {"ad7298", 0},
268 {}
269 };
270 MODULE_DEVICE_TABLE(spi, ad7298_id);
271
272 static struct spi_driver ad7298_driver = {
273 .driver = {
274 .name = "ad7298",
275 .owner = THIS_MODULE,
276 },
277 .probe = ad7298_probe,
278 .remove = __devexit_p(ad7298_remove),
279 .id_table = ad7298_id,
280 };
281 module_spi_driver(ad7298_driver);
282
283 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
284 MODULE_DESCRIPTION("Analog Devices AD7298 ADC");
285 MODULE_LICENSE("GPL v2");
286