1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * ltc2497-core.c - Common code for Analog Devices/Linear Technology
4 * LTC2496 and LTC2497 ADCs
5 *
6 * Copyright (C) 2017 Analog Devices Inc.
7 */
8
9 #include <linux/delay.h>
10 #include <linux/iio/iio.h>
11 #include <linux/iio/driver.h>
12 #include <linux/module.h>
13 #include <linux/mutex.h>
14 #include <linux/regulator/consumer.h>
15
16 #include "ltc2497.h"
17
18 #define LTC2497_SGL BIT(4)
19 #define LTC2497_DIFF 0
20 #define LTC2497_SIGN BIT(3)
21
ltc2497core_wait_conv(struct ltc2497core_driverdata * ddata)22 static int ltc2497core_wait_conv(struct ltc2497core_driverdata *ddata)
23 {
24 s64 time_elapsed;
25
26 time_elapsed = ktime_ms_delta(ktime_get(), ddata->time_prev);
27
28 if (time_elapsed < LTC2497_CONVERSION_TIME_MS) {
29 /* delay if conversion time not passed
30 * since last read or write
31 */
32 if (msleep_interruptible(
33 LTC2497_CONVERSION_TIME_MS - time_elapsed))
34 return -ERESTARTSYS;
35
36 return 0;
37 }
38
39 if (time_elapsed - LTC2497_CONVERSION_TIME_MS <= 0) {
40 /* We're in automatic mode -
41 * so the last reading is still not outdated
42 */
43 return 0;
44 }
45
46 return 1;
47 }
48
ltc2497core_read(struct ltc2497core_driverdata * ddata,u8 address,int * val)49 static int ltc2497core_read(struct ltc2497core_driverdata *ddata, u8 address, int *val)
50 {
51 int ret;
52
53 ret = ltc2497core_wait_conv(ddata);
54 if (ret < 0)
55 return ret;
56
57 if (ret || ddata->addr_prev != address) {
58 ret = ddata->result_and_measure(ddata, address, NULL);
59 if (ret < 0)
60 return ret;
61 ddata->addr_prev = address;
62
63 if (msleep_interruptible(LTC2497_CONVERSION_TIME_MS))
64 return -ERESTARTSYS;
65 }
66
67 ret = ddata->result_and_measure(ddata, address, val);
68 if (ret < 0)
69 return ret;
70
71 ddata->time_prev = ktime_get();
72
73 return ret;
74 }
75
ltc2497core_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)76 static int ltc2497core_read_raw(struct iio_dev *indio_dev,
77 struct iio_chan_spec const *chan,
78 int *val, int *val2, long mask)
79 {
80 struct ltc2497core_driverdata *ddata = iio_priv(indio_dev);
81 int ret;
82
83 switch (mask) {
84 case IIO_CHAN_INFO_RAW:
85 mutex_lock(&ddata->lock);
86 ret = ltc2497core_read(ddata, chan->address, val);
87 mutex_unlock(&ddata->lock);
88 if (ret < 0)
89 return ret;
90
91 return IIO_VAL_INT;
92
93 case IIO_CHAN_INFO_SCALE:
94 ret = regulator_get_voltage(ddata->ref);
95 if (ret < 0)
96 return ret;
97
98 *val = ret / 1000;
99 *val2 = ddata->chip_info->resolution + 1;
100
101 return IIO_VAL_FRACTIONAL_LOG2;
102
103 default:
104 return -EINVAL;
105 }
106 }
107
108 #define LTC2497_CHAN(_chan, _addr, _ds_name) { \
109 .type = IIO_VOLTAGE, \
110 .indexed = 1, \
111 .channel = (_chan), \
112 .address = (_addr | (_chan / 2) | ((_chan & 1) ? LTC2497_SIGN : 0)), \
113 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
114 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
115 .datasheet_name = (_ds_name), \
116 }
117
118 #define LTC2497_CHAN_DIFF(_chan, _addr) { \
119 .type = IIO_VOLTAGE, \
120 .indexed = 1, \
121 .channel = (_chan) * 2 + ((_addr) & LTC2497_SIGN ? 1 : 0), \
122 .channel2 = (_chan) * 2 + ((_addr) & LTC2497_SIGN ? 0 : 1),\
123 .address = (_addr | _chan), \
124 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
125 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
126 .differential = 1, \
127 }
128
129 static const struct iio_chan_spec ltc2497core_channel[] = {
130 LTC2497_CHAN(0, LTC2497_SGL, "CH0"),
131 LTC2497_CHAN(1, LTC2497_SGL, "CH1"),
132 LTC2497_CHAN(2, LTC2497_SGL, "CH2"),
133 LTC2497_CHAN(3, LTC2497_SGL, "CH3"),
134 LTC2497_CHAN(4, LTC2497_SGL, "CH4"),
135 LTC2497_CHAN(5, LTC2497_SGL, "CH5"),
136 LTC2497_CHAN(6, LTC2497_SGL, "CH6"),
137 LTC2497_CHAN(7, LTC2497_SGL, "CH7"),
138 LTC2497_CHAN(8, LTC2497_SGL, "CH8"),
139 LTC2497_CHAN(9, LTC2497_SGL, "CH9"),
140 LTC2497_CHAN(10, LTC2497_SGL, "CH10"),
141 LTC2497_CHAN(11, LTC2497_SGL, "CH11"),
142 LTC2497_CHAN(12, LTC2497_SGL, "CH12"),
143 LTC2497_CHAN(13, LTC2497_SGL, "CH13"),
144 LTC2497_CHAN(14, LTC2497_SGL, "CH14"),
145 LTC2497_CHAN(15, LTC2497_SGL, "CH15"),
146 LTC2497_CHAN_DIFF(0, LTC2497_DIFF),
147 LTC2497_CHAN_DIFF(1, LTC2497_DIFF),
148 LTC2497_CHAN_DIFF(2, LTC2497_DIFF),
149 LTC2497_CHAN_DIFF(3, LTC2497_DIFF),
150 LTC2497_CHAN_DIFF(4, LTC2497_DIFF),
151 LTC2497_CHAN_DIFF(5, LTC2497_DIFF),
152 LTC2497_CHAN_DIFF(6, LTC2497_DIFF),
153 LTC2497_CHAN_DIFF(7, LTC2497_DIFF),
154 LTC2497_CHAN_DIFF(0, LTC2497_DIFF | LTC2497_SIGN),
155 LTC2497_CHAN_DIFF(1, LTC2497_DIFF | LTC2497_SIGN),
156 LTC2497_CHAN_DIFF(2, LTC2497_DIFF | LTC2497_SIGN),
157 LTC2497_CHAN_DIFF(3, LTC2497_DIFF | LTC2497_SIGN),
158 LTC2497_CHAN_DIFF(4, LTC2497_DIFF | LTC2497_SIGN),
159 LTC2497_CHAN_DIFF(5, LTC2497_DIFF | LTC2497_SIGN),
160 LTC2497_CHAN_DIFF(6, LTC2497_DIFF | LTC2497_SIGN),
161 LTC2497_CHAN_DIFF(7, LTC2497_DIFF | LTC2497_SIGN),
162 };
163
164 static const struct iio_info ltc2497core_info = {
165 .read_raw = ltc2497core_read_raw,
166 };
167
ltc2497core_probe(struct device * dev,struct iio_dev * indio_dev)168 int ltc2497core_probe(struct device *dev, struct iio_dev *indio_dev)
169 {
170 struct ltc2497core_driverdata *ddata = iio_priv(indio_dev);
171 int ret;
172
173 /*
174 * Keep using dev_name() for the iio_dev's name on some of the parts,
175 * since updating it would result in a ABI breakage.
176 */
177 if (ddata->chip_info->name)
178 indio_dev->name = ddata->chip_info->name;
179 else
180 indio_dev->name = dev_name(dev);
181
182 indio_dev->info = <c2497core_info;
183 indio_dev->modes = INDIO_DIRECT_MODE;
184 indio_dev->channels = ltc2497core_channel;
185 indio_dev->num_channels = ARRAY_SIZE(ltc2497core_channel);
186
187 ret = ddata->result_and_measure(ddata, LTC2497_CONFIG_DEFAULT, NULL);
188 if (ret < 0)
189 return ret;
190
191 ddata->ref = devm_regulator_get(dev, "vref");
192 if (IS_ERR(ddata->ref))
193 return dev_err_probe(dev, PTR_ERR(ddata->ref),
194 "Failed to get vref regulator\n");
195
196 ret = regulator_enable(ddata->ref);
197 if (ret < 0) {
198 dev_err(dev, "Failed to enable vref regulator: %pe\n",
199 ERR_PTR(ret));
200 return ret;
201 }
202
203 if (dev->platform_data) {
204 struct iio_map *plat_data;
205
206 plat_data = (struct iio_map *)dev->platform_data;
207
208 ret = iio_map_array_register(indio_dev, plat_data);
209 if (ret) {
210 dev_err(&indio_dev->dev, "iio map err: %d\n", ret);
211 goto err_regulator_disable;
212 }
213 }
214
215 ddata->addr_prev = LTC2497_CONFIG_DEFAULT;
216 ddata->time_prev = ktime_get();
217
218 mutex_init(&ddata->lock);
219
220 ret = iio_device_register(indio_dev);
221 if (ret < 0)
222 goto err_array_unregister;
223
224 return 0;
225
226 err_array_unregister:
227 iio_map_array_unregister(indio_dev);
228
229 err_regulator_disable:
230 regulator_disable(ddata->ref);
231
232 return ret;
233 }
234 EXPORT_SYMBOL_NS(ltc2497core_probe, LTC2497);
235
ltc2497core_remove(struct iio_dev * indio_dev)236 void ltc2497core_remove(struct iio_dev *indio_dev)
237 {
238 struct ltc2497core_driverdata *ddata = iio_priv(indio_dev);
239
240 iio_device_unregister(indio_dev);
241
242 iio_map_array_unregister(indio_dev);
243
244 regulator_disable(ddata->ref);
245 }
246 EXPORT_SYMBOL_NS(ltc2497core_remove, LTC2497);
247
248 MODULE_DESCRIPTION("common code for LTC2496/LTC2497 drivers");
249 MODULE_LICENSE("GPL v2");
250