1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * mcp3422.c - driver for the Microchip mcp3421/2/3/4/5/6/7/8 chip family
4 *
5 * Copyright (C) 2013, Angelo Compagnucci
6 * Author: Angelo Compagnucci <angelo.compagnucci@gmail.com>
7 *
8 * Datasheet: http://ww1.microchip.com/downloads/en/devicedoc/22088b.pdf
9 *            https://ww1.microchip.com/downloads/en/DeviceDoc/22226a.pdf
10 *            https://ww1.microchip.com/downloads/en/DeviceDoc/22072b.pdf
11 *
12 * This driver exports the value of analog input voltage to sysfs, the
13 * voltage unit is nV.
14 */
15
16#include <linux/err.h>
17#include <linux/i2c.h>
18#include <linux/module.h>
19#include <linux/mod_devicetable.h>
20#include <linux/delay.h>
21#include <linux/sysfs.h>
22#include <asm/unaligned.h>
23
24#include <linux/iio/iio.h>
25#include <linux/iio/sysfs.h>
26
27/* Masks */
28#define MCP3422_CHANNEL_MASK	0x60
29#define MCP3422_PGA_MASK	0x03
30#define MCP3422_SRATE_MASK	0x0C
31#define MCP3422_SRATE_240	0x0
32#define MCP3422_SRATE_60	0x1
33#define MCP3422_SRATE_15	0x2
34#define MCP3422_SRATE_3	0x3
35#define MCP3422_PGA_1	0
36#define MCP3422_PGA_2	1
37#define MCP3422_PGA_4	2
38#define MCP3422_PGA_8	3
39#define MCP3422_CONT_SAMPLING	0x10
40
41#define MCP3422_CHANNEL(config)	(((config) & MCP3422_CHANNEL_MASK) >> 5)
42#define MCP3422_PGA(config)	((config) & MCP3422_PGA_MASK)
43#define MCP3422_SAMPLE_RATE(config)	(((config) & MCP3422_SRATE_MASK) >> 2)
44
45#define MCP3422_CHANNEL_VALUE(value) (((value) << 5) & MCP3422_CHANNEL_MASK)
46#define MCP3422_PGA_VALUE(value) ((value) & MCP3422_PGA_MASK)
47#define MCP3422_SAMPLE_RATE_VALUE(value) ((value << 2) & MCP3422_SRATE_MASK)
48
49#define MCP3422_CHAN(_index) \
50	{ \
51		.type = IIO_VOLTAGE, \
52		.indexed = 1, \
53		.channel = _index, \
54		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) \
55				| BIT(IIO_CHAN_INFO_SCALE), \
56		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
57	}
58
59static const int mcp3422_scales[4][4] = {
60	{ 1000000, 500000, 250000, 125000 },
61	{ 250000,  125000, 62500,  31250  },
62	{ 62500,   31250,  15625,  7812   },
63	{ 15625,   7812,   3906,   1953   } };
64
65/* Constant msleep times for data acquisitions */
66static const int mcp3422_read_times[4] = {
67	[MCP3422_SRATE_240] = 1000 / 240,
68	[MCP3422_SRATE_60] = 1000 / 60,
69	[MCP3422_SRATE_15] = 1000 / 15,
70	[MCP3422_SRATE_3] = 1000 / 3 };
71
72/* sample rates to integer conversion table */
73static const int mcp3422_sample_rates[4] = {
74	[MCP3422_SRATE_240] = 240,
75	[MCP3422_SRATE_60] = 60,
76	[MCP3422_SRATE_15] = 15,
77	[MCP3422_SRATE_3] = 3 };
78
79/* sample rates to sign extension table */
80static const int mcp3422_sign_extend[4] = {
81	[MCP3422_SRATE_240] = 11,
82	[MCP3422_SRATE_60] = 13,
83	[MCP3422_SRATE_15] = 15,
84	[MCP3422_SRATE_3] = 17 };
85
86/* Client data (each client gets its own) */
87struct mcp3422 {
88	struct i2c_client *i2c;
89	u8 id;
90	u8 config;
91	u8 pga[4];
92	struct mutex lock;
93};
94
95static int mcp3422_update_config(struct mcp3422 *adc, u8 newconfig)
96{
97	int ret;
98
99	ret = i2c_master_send(adc->i2c, &newconfig, 1);
100	if (ret > 0) {
101		adc->config = newconfig;
102		ret = 0;
103	}
104
105	return ret;
106}
107
108static int mcp3422_read(struct mcp3422 *adc, int *value, u8 *config)
109{
110	int ret = 0;
111	u8 sample_rate = MCP3422_SAMPLE_RATE(adc->config);
112	u8 buf[4] = {0, 0, 0, 0};
113	u32 temp;
114
115	if (sample_rate == MCP3422_SRATE_3) {
116		ret = i2c_master_recv(adc->i2c, buf, 4);
117		temp = get_unaligned_be24(&buf[0]);
118		*config = buf[3];
119	} else {
120		ret = i2c_master_recv(adc->i2c, buf, 3);
121		temp = get_unaligned_be16(&buf[0]);
122		*config = buf[2];
123	}
124
125	*value = sign_extend32(temp, mcp3422_sign_extend[sample_rate]);
126
127	return ret;
128}
129
130static int mcp3422_read_channel(struct mcp3422 *adc,
131				struct iio_chan_spec const *channel, int *value)
132{
133	int ret;
134	u8 config;
135	u8 req_channel = channel->channel;
136
137	mutex_lock(&adc->lock);
138
139	if (req_channel != MCP3422_CHANNEL(adc->config)) {
140		config = adc->config;
141		config &= ~MCP3422_CHANNEL_MASK;
142		config |= MCP3422_CHANNEL_VALUE(req_channel);
143		config &= ~MCP3422_PGA_MASK;
144		config |= MCP3422_PGA_VALUE(adc->pga[req_channel]);
145		ret = mcp3422_update_config(adc, config);
146		if (ret < 0) {
147			mutex_unlock(&adc->lock);
148			return ret;
149		}
150		msleep(mcp3422_read_times[MCP3422_SAMPLE_RATE(adc->config)]);
151	}
152
153	ret = mcp3422_read(adc, value, &config);
154
155	mutex_unlock(&adc->lock);
156
157	return ret;
158}
159
160static int mcp3422_read_raw(struct iio_dev *iio,
161			struct iio_chan_spec const *channel, int *val1,
162			int *val2, long mask)
163{
164	struct mcp3422 *adc = iio_priv(iio);
165	int err;
166
167	u8 sample_rate = MCP3422_SAMPLE_RATE(adc->config);
168	u8 pga		 = MCP3422_PGA(adc->config);
169
170	switch (mask) {
171	case IIO_CHAN_INFO_RAW:
172		err = mcp3422_read_channel(adc, channel, val1);
173		if (err < 0)
174			return -EINVAL;
175		return IIO_VAL_INT;
176
177	case IIO_CHAN_INFO_SCALE:
178
179		*val1 = 0;
180		*val2 = mcp3422_scales[sample_rate][pga];
181		return IIO_VAL_INT_PLUS_NANO;
182
183	case IIO_CHAN_INFO_SAMP_FREQ:
184		*val1 = mcp3422_sample_rates[MCP3422_SAMPLE_RATE(adc->config)];
185		return IIO_VAL_INT;
186
187	default:
188		break;
189	}
190
191	return -EINVAL;
192}
193
194static int mcp3422_write_raw(struct iio_dev *iio,
195			struct iio_chan_spec const *channel, int val1,
196			int val2, long mask)
197{
198	struct mcp3422 *adc = iio_priv(iio);
199	u8 temp;
200	u8 config = adc->config;
201	u8 req_channel = channel->channel;
202	u8 sample_rate = MCP3422_SAMPLE_RATE(config);
203	u8 i;
204
205	switch (mask) {
206	case IIO_CHAN_INFO_SCALE:
207		if (val1 != 0)
208			return -EINVAL;
209
210		for (i = 0; i < ARRAY_SIZE(mcp3422_scales[0]); i++) {
211			if (val2 == mcp3422_scales[sample_rate][i]) {
212				adc->pga[req_channel] = i;
213
214				config &= ~MCP3422_CHANNEL_MASK;
215				config |= MCP3422_CHANNEL_VALUE(req_channel);
216				config &= ~MCP3422_PGA_MASK;
217				config |= MCP3422_PGA_VALUE(adc->pga[req_channel]);
218
219				return mcp3422_update_config(adc, config);
220			}
221		}
222		return -EINVAL;
223
224	case IIO_CHAN_INFO_SAMP_FREQ:
225		switch (val1) {
226		case 240:
227			temp = MCP3422_SRATE_240;
228			break;
229		case 60:
230			temp = MCP3422_SRATE_60;
231			break;
232		case 15:
233			temp = MCP3422_SRATE_15;
234			break;
235		case 3:
236			if (adc->id > 4)
237				return -EINVAL;
238			temp = MCP3422_SRATE_3;
239			break;
240		default:
241			return -EINVAL;
242		}
243
244		config &= ~MCP3422_CHANNEL_MASK;
245		config |= MCP3422_CHANNEL_VALUE(req_channel);
246		config &= ~MCP3422_SRATE_MASK;
247		config |= MCP3422_SAMPLE_RATE_VALUE(temp);
248
249		return mcp3422_update_config(adc, config);
250
251	default:
252		break;
253	}
254
255	return -EINVAL;
256}
257
258static int mcp3422_write_raw_get_fmt(struct iio_dev *indio_dev,
259		struct iio_chan_spec const *chan, long mask)
260{
261	switch (mask) {
262	case IIO_CHAN_INFO_SCALE:
263		return IIO_VAL_INT_PLUS_NANO;
264	case IIO_CHAN_INFO_SAMP_FREQ:
265		return IIO_VAL_INT_PLUS_MICRO;
266	default:
267		return -EINVAL;
268	}
269}
270
271static ssize_t mcp3422_show_samp_freqs(struct device *dev,
272		struct device_attribute *attr, char *buf)
273{
274	struct mcp3422 *adc = iio_priv(dev_to_iio_dev(dev));
275
276	if (adc->id > 4)
277		return sprintf(buf, "240 60 15\n");
278
279	return sprintf(buf, "240 60 15 3\n");
280}
281
282static ssize_t mcp3422_show_scales(struct device *dev,
283		struct device_attribute *attr, char *buf)
284{
285	struct mcp3422 *adc = iio_priv(dev_to_iio_dev(dev));
286	u8 sample_rate = MCP3422_SAMPLE_RATE(adc->config);
287
288	return sprintf(buf, "0.%09u 0.%09u 0.%09u 0.%09u\n",
289		mcp3422_scales[sample_rate][0],
290		mcp3422_scales[sample_rate][1],
291		mcp3422_scales[sample_rate][2],
292		mcp3422_scales[sample_rate][3]);
293}
294
295static IIO_DEVICE_ATTR(sampling_frequency_available, S_IRUGO,
296		mcp3422_show_samp_freqs, NULL, 0);
297static IIO_DEVICE_ATTR(in_voltage_scale_available, S_IRUGO,
298		mcp3422_show_scales, NULL, 0);
299
300static struct attribute *mcp3422_attributes[] = {
301	&iio_dev_attr_sampling_frequency_available.dev_attr.attr,
302	&iio_dev_attr_in_voltage_scale_available.dev_attr.attr,
303	NULL,
304};
305
306static const struct attribute_group mcp3422_attribute_group = {
307	.attrs = mcp3422_attributes,
308};
309
310static const struct iio_chan_spec mcp3421_channels[] = {
311	MCP3422_CHAN(0),
312};
313
314static const struct iio_chan_spec mcp3422_channels[] = {
315	MCP3422_CHAN(0),
316	MCP3422_CHAN(1),
317};
318
319static const struct iio_chan_spec mcp3424_channels[] = {
320	MCP3422_CHAN(0),
321	MCP3422_CHAN(1),
322	MCP3422_CHAN(2),
323	MCP3422_CHAN(3),
324};
325
326static const struct iio_info mcp3422_info = {
327	.read_raw = mcp3422_read_raw,
328	.write_raw = mcp3422_write_raw,
329	.write_raw_get_fmt = mcp3422_write_raw_get_fmt,
330	.attrs = &mcp3422_attribute_group,
331};
332
333static int mcp3422_probe(struct i2c_client *client)
334{
335	const struct i2c_device_id *id = i2c_client_get_device_id(client);
336	struct iio_dev *indio_dev;
337	struct mcp3422 *adc;
338	int err;
339	u8 config;
340
341	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
342		return -EOPNOTSUPP;
343
344	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*adc));
345	if (!indio_dev)
346		return -ENOMEM;
347
348	adc = iio_priv(indio_dev);
349	adc->i2c = client;
350	adc->id = (u8)(id->driver_data);
351
352	mutex_init(&adc->lock);
353
354	indio_dev->name = dev_name(&client->dev);
355	indio_dev->modes = INDIO_DIRECT_MODE;
356	indio_dev->info = &mcp3422_info;
357
358	switch (adc->id) {
359	case 1:
360	case 5:
361		indio_dev->channels = mcp3421_channels;
362		indio_dev->num_channels = ARRAY_SIZE(mcp3421_channels);
363		break;
364	case 2:
365	case 3:
366	case 6:
367	case 7:
368		indio_dev->channels = mcp3422_channels;
369		indio_dev->num_channels = ARRAY_SIZE(mcp3422_channels);
370		break;
371	case 4:
372	case 8:
373		indio_dev->channels = mcp3424_channels;
374		indio_dev->num_channels = ARRAY_SIZE(mcp3424_channels);
375		break;
376	}
377
378	/* meaningful default configuration */
379	config = (MCP3422_CONT_SAMPLING
380		| MCP3422_CHANNEL_VALUE(0)
381		| MCP3422_PGA_VALUE(MCP3422_PGA_1)
382		| MCP3422_SAMPLE_RATE_VALUE(MCP3422_SRATE_240));
383	err = mcp3422_update_config(adc, config);
384	if (err < 0)
385		return err;
386
387	err = devm_iio_device_register(&client->dev, indio_dev);
388	if (err < 0)
389		return err;
390
391	i2c_set_clientdata(client, indio_dev);
392
393	return 0;
394}
395
396static const struct i2c_device_id mcp3422_id[] = {
397	{ "mcp3421", 1 },
398	{ "mcp3422", 2 },
399	{ "mcp3423", 3 },
400	{ "mcp3424", 4 },
401	{ "mcp3425", 5 },
402	{ "mcp3426", 6 },
403	{ "mcp3427", 7 },
404	{ "mcp3428", 8 },
405	{ }
406};
407MODULE_DEVICE_TABLE(i2c, mcp3422_id);
408
409static const struct of_device_id mcp3422_of_match[] = {
410	{ .compatible = "mcp3422" },
411	{ }
412};
413MODULE_DEVICE_TABLE(of, mcp3422_of_match);
414
415static struct i2c_driver mcp3422_driver = {
416	.driver = {
417		.name = "mcp3422",
418		.of_match_table = mcp3422_of_match,
419	},
420	.probe = mcp3422_probe,
421	.id_table = mcp3422_id,
422};
423module_i2c_driver(mcp3422_driver);
424
425MODULE_AUTHOR("Angelo Compagnucci <angelo.compagnucci@gmail.com>");
426MODULE_DESCRIPTION("Microchip mcp3421/2/3/4/5/6/7/8 driver");
427MODULE_LICENSE("GPL v2");
428