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8#include <linux/clk.h>
9#include <linux/delay.h>
10#include <linux/err.h>
11#include <linux/iio/iio.h>
12#include <linux/module.h>
13#include <linux/regulator/consumer.h>
14#include <linux/spi/spi.h>
15
16#define MCP3911_REG_CHANNEL0 0x00
17#define MCP3911_REG_CHANNEL1 0x03
18#define MCP3911_REG_MOD 0x06
19#define MCP3911_REG_PHASE 0x07
20#define MCP3911_REG_GAIN 0x09
21
22#define MCP3911_REG_STATUSCOM 0x0a
23#define MCP3911_STATUSCOM_CH1_24WIDTH BIT(4)
24#define MCP3911_STATUSCOM_CH0_24WIDTH BIT(3)
25#define MCP3911_STATUSCOM_EN_OFFCAL BIT(2)
26#define MCP3911_STATUSCOM_EN_GAINCAL BIT(1)
27
28#define MCP3911_REG_CONFIG 0x0c
29#define MCP3911_CONFIG_CLKEXT BIT(1)
30#define MCP3911_CONFIG_VREFEXT BIT(2)
31
32#define MCP3911_REG_OFFCAL_CH0 0x0e
33#define MCP3911_REG_GAINCAL_CH0 0x11
34#define MCP3911_REG_OFFCAL_CH1 0x14
35#define MCP3911_REG_GAINCAL_CH1 0x17
36#define MCP3911_REG_VREFCAL 0x1a
37
38#define MCP3911_CHANNEL(x) (MCP3911_REG_CHANNEL0 + x * 3)
39#define MCP3911_OFFCAL(x) (MCP3911_REG_OFFCAL_CH0 + x * 6)
40
41
42#define MCP3911_INT_VREF_UV 1200000
43
44#define MCP3911_REG_READ(reg, id) ((((reg) << 1) | ((id) << 5) | (1 << 0)) & 0xff)
45#define MCP3911_REG_WRITE(reg, id) ((((reg) << 1) | ((id) << 5) | (0 << 0)) & 0xff)
46
47#define MCP3911_NUM_CHANNELS 2
48
49struct mcp3911 {
50 struct spi_device *spi;
51 struct mutex lock;
52 struct regulator *vref;
53 struct clk *clki;
54 u32 dev_addr;
55};
56
57static int mcp3911_read(struct mcp3911 *adc, u8 reg, u32 *val, u8 len)
58{
59 int ret;
60
61 reg = MCP3911_REG_READ(reg, adc->dev_addr);
62 ret = spi_write_then_read(adc->spi, ®, 1, val, len);
63 if (ret < 0)
64 return ret;
65
66 be32_to_cpus(val);
67 *val >>= ((4 - len) * 8);
68 dev_dbg(&adc->spi->dev, "reading 0x%x from register 0x%x\n", *val,
69 reg >> 1);
70 return ret;
71}
72
73static int mcp3911_write(struct mcp3911 *adc, u8 reg, u32 val, u8 len)
74{
75 dev_dbg(&adc->spi->dev, "writing 0x%x to register 0x%x\n", val, reg);
76
77 val <<= (3 - len) * 8;
78 cpu_to_be32s(&val);
79 val |= MCP3911_REG_WRITE(reg, adc->dev_addr);
80
81 return spi_write(adc->spi, &val, len + 1);
82}
83
84static int mcp3911_update(struct mcp3911 *adc, u8 reg, u32 mask,
85 u32 val, u8 len)
86{
87 u32 tmp;
88 int ret;
89
90 ret = mcp3911_read(adc, reg, &tmp, len);
91 if (ret)
92 return ret;
93
94 val &= mask;
95 val |= tmp & ~mask;
96 return mcp3911_write(adc, reg, val, len);
97}
98
99static int mcp3911_read_raw(struct iio_dev *indio_dev,
100 struct iio_chan_spec const *channel, int *val,
101 int *val2, long mask)
102{
103 struct mcp3911 *adc = iio_priv(indio_dev);
104 int ret = -EINVAL;
105
106 mutex_lock(&adc->lock);
107 switch (mask) {
108 case IIO_CHAN_INFO_RAW:
109 ret = mcp3911_read(adc,
110 MCP3911_CHANNEL(channel->channel), val, 3);
111 if (ret)
112 goto out;
113
114 ret = IIO_VAL_INT;
115 break;
116
117 case IIO_CHAN_INFO_OFFSET:
118 ret = mcp3911_read(adc,
119 MCP3911_OFFCAL(channel->channel), val, 3);
120 if (ret)
121 goto out;
122
123 ret = IIO_VAL_INT;
124 break;
125
126 case IIO_CHAN_INFO_SCALE:
127 if (adc->vref) {
128 ret = regulator_get_voltage(adc->vref);
129 if (ret < 0) {
130 dev_err(indio_dev->dev.parent,
131 "failed to get vref voltage: %d\n",
132 ret);
133 goto out;
134 }
135
136 *val = ret / 1000;
137 } else {
138 *val = MCP3911_INT_VREF_UV;
139 }
140
141 *val2 = 24;
142 ret = IIO_VAL_FRACTIONAL_LOG2;
143 break;
144 }
145
146out:
147 mutex_unlock(&adc->lock);
148 return ret;
149}
150
151static int mcp3911_write_raw(struct iio_dev *indio_dev,
152 struct iio_chan_spec const *channel, int val,
153 int val2, long mask)
154{
155 struct mcp3911 *adc = iio_priv(indio_dev);
156 int ret = -EINVAL;
157
158 mutex_lock(&adc->lock);
159 switch (mask) {
160 case IIO_CHAN_INFO_OFFSET:
161 if (val2 != 0) {
162 ret = -EINVAL;
163 goto out;
164 }
165
166
167 ret = mcp3911_write(adc, MCP3911_OFFCAL(channel->channel), val,
168 3);
169 if (ret)
170 goto out;
171
172
173 ret = mcp3911_update(adc, MCP3911_REG_STATUSCOM,
174 MCP3911_STATUSCOM_EN_OFFCAL,
175 MCP3911_STATUSCOM_EN_OFFCAL, 2);
176 break;
177 }
178
179out:
180 mutex_unlock(&adc->lock);
181 return ret;
182}
183
184#define MCP3911_CHAN(idx) { \
185 .type = IIO_VOLTAGE, \
186 .indexed = 1, \
187 .channel = idx, \
188 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
189 BIT(IIO_CHAN_INFO_OFFSET) | \
190 BIT(IIO_CHAN_INFO_SCALE), \
191}
192
193static const struct iio_chan_spec mcp3911_channels[] = {
194 MCP3911_CHAN(0),
195 MCP3911_CHAN(1),
196};
197
198static const struct iio_info mcp3911_info = {
199 .read_raw = mcp3911_read_raw,
200 .write_raw = mcp3911_write_raw,
201};
202
203static int mcp3911_config(struct mcp3911 *adc, struct device_node *of_node)
204{
205 u32 configreg;
206 int ret;
207
208 of_property_read_u32(of_node, "device-addr", &adc->dev_addr);
209 if (adc->dev_addr > 3) {
210 dev_err(&adc->spi->dev,
211 "invalid device address (%i). Must be in range 0-3.\n",
212 adc->dev_addr);
213 return -EINVAL;
214 }
215 dev_dbg(&adc->spi->dev, "use device address %i\n", adc->dev_addr);
216
217 ret = mcp3911_read(adc, MCP3911_REG_CONFIG, &configreg, 2);
218 if (ret)
219 return ret;
220
221 if (adc->vref) {
222 dev_dbg(&adc->spi->dev, "use external voltage reference\n");
223 configreg |= MCP3911_CONFIG_VREFEXT;
224 } else {
225 dev_dbg(&adc->spi->dev,
226 "use internal voltage reference (1.2V)\n");
227 configreg &= ~MCP3911_CONFIG_VREFEXT;
228 }
229
230 if (adc->clki) {
231 dev_dbg(&adc->spi->dev, "use external clock as clocksource\n");
232 configreg |= MCP3911_CONFIG_CLKEXT;
233 } else {
234 dev_dbg(&adc->spi->dev,
235 "use crystal oscillator as clocksource\n");
236 configreg &= ~MCP3911_CONFIG_CLKEXT;
237 }
238
239 return mcp3911_write(adc, MCP3911_REG_CONFIG, configreg, 2);
240}
241
242static int mcp3911_probe(struct spi_device *spi)
243{
244 struct iio_dev *indio_dev;
245 struct mcp3911 *adc;
246 int ret;
247
248 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
249 if (!indio_dev)
250 return -ENOMEM;
251
252 adc = iio_priv(indio_dev);
253 adc->spi = spi;
254
255 adc->vref = devm_regulator_get_optional(&adc->spi->dev, "vref");
256 if (IS_ERR(adc->vref)) {
257 if (PTR_ERR(adc->vref) == -ENODEV) {
258 adc->vref = NULL;
259 } else {
260 dev_err(&adc->spi->dev,
261 "failed to get regulator (%ld)\n",
262 PTR_ERR(adc->vref));
263 return PTR_ERR(adc->vref);
264 }
265
266 } else {
267 ret = regulator_enable(adc->vref);
268 if (ret)
269 return ret;
270 }
271
272 adc->clki = devm_clk_get(&adc->spi->dev, NULL);
273 if (IS_ERR(adc->clki)) {
274 if (PTR_ERR(adc->clki) == -ENOENT) {
275 adc->clki = NULL;
276 } else {
277 dev_err(&adc->spi->dev,
278 "failed to get adc clk (%ld)\n",
279 PTR_ERR(adc->clki));
280 ret = PTR_ERR(adc->clki);
281 goto reg_disable;
282 }
283 } else {
284 ret = clk_prepare_enable(adc->clki);
285 if (ret < 0) {
286 dev_err(&adc->spi->dev,
287 "Failed to enable clki: %d\n", ret);
288 goto reg_disable;
289 }
290 }
291
292 ret = mcp3911_config(adc, spi->dev.of_node);
293 if (ret)
294 goto clk_disable;
295
296 indio_dev->name = spi_get_device_id(spi)->name;
297 indio_dev->modes = INDIO_DIRECT_MODE;
298 indio_dev->info = &mcp3911_info;
299 spi_set_drvdata(spi, indio_dev);
300
301 indio_dev->channels = mcp3911_channels;
302 indio_dev->num_channels = ARRAY_SIZE(mcp3911_channels);
303
304 mutex_init(&adc->lock);
305
306 ret = iio_device_register(indio_dev);
307 if (ret)
308 goto clk_disable;
309
310 return ret;
311
312clk_disable:
313 clk_disable_unprepare(adc->clki);
314reg_disable:
315 if (adc->vref)
316 regulator_disable(adc->vref);
317
318 return ret;
319}
320
321static int mcp3911_remove(struct spi_device *spi)
322{
323 struct iio_dev *indio_dev = spi_get_drvdata(spi);
324 struct mcp3911 *adc = iio_priv(indio_dev);
325
326 iio_device_unregister(indio_dev);
327
328 clk_disable_unprepare(adc->clki);
329 if (adc->vref)
330 regulator_disable(adc->vref);
331
332 return 0;
333}
334
335static const struct of_device_id mcp3911_dt_ids[] = {
336 { .compatible = "microchip,mcp3911" },
337 { }
338};
339MODULE_DEVICE_TABLE(of, mcp3911_dt_ids);
340
341static const struct spi_device_id mcp3911_id[] = {
342 { "mcp3911", 0 },
343 { }
344};
345MODULE_DEVICE_TABLE(spi, mcp3911_id);
346
347static struct spi_driver mcp3911_driver = {
348 .driver = {
349 .name = "mcp3911",
350 .of_match_table = mcp3911_dt_ids,
351 },
352 .probe = mcp3911_probe,
353 .remove = mcp3911_remove,
354 .id_table = mcp3911_id,
355};
356module_spi_driver(mcp3911_driver);
357
358MODULE_AUTHOR("Marcus Folkesson <marcus.folkesson@gmail.com>");
359MODULE_AUTHOR("Kent Gustavsson <kent@minoris.se>");
360MODULE_DESCRIPTION("Microchip Technology MCP3911");
361MODULE_LICENSE("GPL v2");
362
