1/*
2 * Copyright (C) 2013 Oskar Andero <oskar.andero@gmail.com>
3 * Copyright (C) 2014 Rose Technology
4 * 	   Allan Bendorff Jensen <abj@rosetechnology.dk>
5 *	   Soren Andersen <san@rosetechnology.dk>
6 *
7 * Driver for following ADC chips from Microchip Technology's:
8 * 10 Bit converter
9 * MCP3001
10 * MCP3002
11 * MCP3004
12 * MCP3008
13 * ------------
14 * 12 bit converter
15 * MCP3201
16 * MCP3202
17 * MCP3204
18 * MCP3208
19 * ------------
20 *
21 * Datasheet can be found here:
22 * http://ww1.microchip.com/downloads/en/DeviceDoc/21293C.pdf  mcp3001
23 * http://ww1.microchip.com/downloads/en/DeviceDoc/21294E.pdf  mcp3002
24 * http://ww1.microchip.com/downloads/en/DeviceDoc/21295d.pdf  mcp3004/08
25 * http://ww1.microchip.com/downloads/en/DeviceDoc/21290D.pdf  mcp3201
26 * http://ww1.microchip.com/downloads/en/DeviceDoc/21034D.pdf  mcp3202
27 * http://ww1.microchip.com/downloads/en/DeviceDoc/21298c.pdf  mcp3204/08
28 *
29 * This program is free software; you can redistribute it and/or modify
30 * it under the terms of the GNU General Public License version 2 as
31 * published by the Free Software Foundation.
32 */
33
34#include <linux/err.h>
35#include <linux/delay.h>
36#include <linux/spi/spi.h>
37#include <linux/module.h>
38#include <linux/iio/iio.h>
39#include <linux/regulator/consumer.h>
40
41enum {
42	mcp3001,
43	mcp3002,
44	mcp3004,
45	mcp3008,
46	mcp3201,
47	mcp3202,
48	mcp3204,
49	mcp3208,
50};
51
52struct mcp320x_chip_info {
53	const struct iio_chan_spec *channels;
54	unsigned int num_channels;
55	unsigned int resolution;
56};
57
58struct mcp320x {
59	struct spi_device *spi;
60	struct spi_message msg;
61	struct spi_transfer transfer[2];
62
63	struct regulator *reg;
64	struct mutex lock;
65	const struct mcp320x_chip_info *chip_info;
66
67	u8 tx_buf ____cacheline_aligned;
68	u8 rx_buf[2];
69};
70
71static int mcp320x_channel_to_tx_data(int device_index,
72			const unsigned int channel, bool differential)
73{
74	int start_bit = 1;
75
76	switch (device_index) {
77	case mcp3001:
78	case mcp3201:
79		return 0;
80	case mcp3002:
81	case mcp3202:
82		return ((start_bit << 4) | (!differential << 3) |
83							(channel << 2));
84	case mcp3004:
85	case mcp3204:
86	case mcp3008:
87	case mcp3208:
88		return ((start_bit << 6) | (!differential << 5) |
89							(channel << 2));
90	default:
91		return -EINVAL;
92	}
93}
94
95static int mcp320x_adc_conversion(struct mcp320x *adc, u8 channel,
96				  bool differential, int device_index)
97{
98	int ret;
99
100	adc->rx_buf[0] = 0;
101	adc->rx_buf[1] = 0;
102	adc->tx_buf = mcp320x_channel_to_tx_data(device_index,
103						channel, differential);
104
105	if (device_index != mcp3001 && device_index != mcp3201) {
106		ret = spi_sync(adc->spi, &adc->msg);
107		if (ret < 0)
108			return ret;
109	} else {
110		ret = spi_read(adc->spi, &adc->rx_buf, sizeof(adc->rx_buf));
111		if (ret < 0)
112			return ret;
113	}
114
115	switch (device_index) {
116	case mcp3001:
117		return (adc->rx_buf[0] << 5 | adc->rx_buf[1] >> 3);
118	case mcp3002:
119	case mcp3004:
120	case mcp3008:
121		return (adc->rx_buf[0] << 2 | adc->rx_buf[1] >> 6);
122	case mcp3201:
123		return (adc->rx_buf[0] << 7 | adc->rx_buf[1] >> 1);
124	case mcp3202:
125	case mcp3204:
126	case mcp3208:
127		return (adc->rx_buf[0] << 4 | adc->rx_buf[1] >> 4);
128	default:
129		return -EINVAL;
130	}
131}
132
133static int mcp320x_read_raw(struct iio_dev *indio_dev,
134			    struct iio_chan_spec const *channel, int *val,
135			    int *val2, long mask)
136{
137	struct mcp320x *adc = iio_priv(indio_dev);
138	int ret = -EINVAL;
139	int device_index = 0;
140
141	mutex_lock(&adc->lock);
142
143	device_index = spi_get_device_id(adc->spi)->driver_data;
144
145	switch (mask) {
146	case IIO_CHAN_INFO_RAW:
147		ret = mcp320x_adc_conversion(adc, channel->address,
148			channel->differential, device_index);
149
150		if (ret < 0)
151			goto out;
152
153		*val = ret;
154		ret = IIO_VAL_INT;
155		break;
156
157	case IIO_CHAN_INFO_SCALE:
158		ret = regulator_get_voltage(adc->reg);
159		if (ret < 0)
160			goto out;
161
162		/* convert regulator output voltage to mV */
163		*val = ret / 1000;
164		*val2 = adc->chip_info->resolution;
165		ret = IIO_VAL_FRACTIONAL_LOG2;
166		break;
167	}
168
169out:
170	mutex_unlock(&adc->lock);
171
172	return ret;
173}
174
175#define MCP320X_VOLTAGE_CHANNEL(num)				\
176	{							\
177		.type = IIO_VOLTAGE,				\
178		.indexed = 1,					\
179		.channel = (num),				\
180		.address = (num),				\
181		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
182		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
183	}
184
185#define MCP320X_VOLTAGE_CHANNEL_DIFF(num)			\
186	{							\
187		.type = IIO_VOLTAGE,				\
188		.indexed = 1,					\
189		.channel = (num * 2),				\
190		.channel2 = (num * 2 + 1),			\
191		.address = (num * 2),				\
192		.differential = 1,				\
193		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
194		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
195	}
196
197static const struct iio_chan_spec mcp3201_channels[] = {
198	MCP320X_VOLTAGE_CHANNEL_DIFF(0),
199};
200
201static const struct iio_chan_spec mcp3202_channels[] = {
202	MCP320X_VOLTAGE_CHANNEL(0),
203	MCP320X_VOLTAGE_CHANNEL(1),
204	MCP320X_VOLTAGE_CHANNEL_DIFF(0),
205};
206
207static const struct iio_chan_spec mcp3204_channels[] = {
208	MCP320X_VOLTAGE_CHANNEL(0),
209	MCP320X_VOLTAGE_CHANNEL(1),
210	MCP320X_VOLTAGE_CHANNEL(2),
211	MCP320X_VOLTAGE_CHANNEL(3),
212	MCP320X_VOLTAGE_CHANNEL_DIFF(0),
213	MCP320X_VOLTAGE_CHANNEL_DIFF(1),
214};
215
216static const struct iio_chan_spec mcp3208_channels[] = {
217	MCP320X_VOLTAGE_CHANNEL(0),
218	MCP320X_VOLTAGE_CHANNEL(1),
219	MCP320X_VOLTAGE_CHANNEL(2),
220	MCP320X_VOLTAGE_CHANNEL(3),
221	MCP320X_VOLTAGE_CHANNEL(4),
222	MCP320X_VOLTAGE_CHANNEL(5),
223	MCP320X_VOLTAGE_CHANNEL(6),
224	MCP320X_VOLTAGE_CHANNEL(7),
225	MCP320X_VOLTAGE_CHANNEL_DIFF(0),
226	MCP320X_VOLTAGE_CHANNEL_DIFF(1),
227	MCP320X_VOLTAGE_CHANNEL_DIFF(2),
228	MCP320X_VOLTAGE_CHANNEL_DIFF(3),
229};
230
231static const struct iio_info mcp320x_info = {
232	.read_raw = mcp320x_read_raw,
233	.driver_module = THIS_MODULE,
234};
235
236static const struct mcp320x_chip_info mcp320x_chip_infos[] = {
237	[mcp3001] = {
238		.channels = mcp3201_channels,
239		.num_channels = ARRAY_SIZE(mcp3201_channels),
240		.resolution = 10
241	},
242	[mcp3002] = {
243		.channels = mcp3202_channels,
244		.num_channels = ARRAY_SIZE(mcp3202_channels),
245		.resolution = 10
246	},
247	[mcp3004] = {
248		.channels = mcp3204_channels,
249		.num_channels = ARRAY_SIZE(mcp3204_channels),
250		.resolution = 10
251	},
252	[mcp3008] = {
253		.channels = mcp3208_channels,
254		.num_channels = ARRAY_SIZE(mcp3208_channels),
255		.resolution = 10
256	},
257	[mcp3201] = {
258		.channels = mcp3201_channels,
259		.num_channels = ARRAY_SIZE(mcp3201_channels),
260		.resolution = 12
261	},
262	[mcp3202] = {
263		.channels = mcp3202_channels,
264		.num_channels = ARRAY_SIZE(mcp3202_channels),
265		.resolution = 12
266	},
267	[mcp3204] = {
268		.channels = mcp3204_channels,
269		.num_channels = ARRAY_SIZE(mcp3204_channels),
270		.resolution = 12
271	},
272	[mcp3208] = {
273		.channels = mcp3208_channels,
274		.num_channels = ARRAY_SIZE(mcp3208_channels),
275		.resolution = 12
276	},
277};
278
279static int mcp320x_probe(struct spi_device *spi)
280{
281	struct iio_dev *indio_dev;
282	struct mcp320x *adc;
283	const struct mcp320x_chip_info *chip_info;
284	int ret;
285
286	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
287	if (!indio_dev)
288		return -ENOMEM;
289
290	adc = iio_priv(indio_dev);
291	adc->spi = spi;
292
293	indio_dev->dev.parent = &spi->dev;
294	indio_dev->name = spi_get_device_id(spi)->name;
295	indio_dev->modes = INDIO_DIRECT_MODE;
296	indio_dev->info = &mcp320x_info;
297
298	chip_info = &mcp320x_chip_infos[spi_get_device_id(spi)->driver_data];
299	indio_dev->channels = chip_info->channels;
300	indio_dev->num_channels = chip_info->num_channels;
301
302	adc->transfer[0].tx_buf = &adc->tx_buf;
303	adc->transfer[0].len = sizeof(adc->tx_buf);
304	adc->transfer[1].rx_buf = adc->rx_buf;
305	adc->transfer[1].len = sizeof(adc->rx_buf);
306
307	spi_message_init_with_transfers(&adc->msg, adc->transfer,
308					ARRAY_SIZE(adc->transfer));
309
310	adc->reg = devm_regulator_get(&spi->dev, "vref");
311	if (IS_ERR(adc->reg))
312		return PTR_ERR(adc->reg);
313
314	ret = regulator_enable(adc->reg);
315	if (ret < 0)
316		return ret;
317
318	mutex_init(&adc->lock);
319
320	ret = iio_device_register(indio_dev);
321	if (ret < 0)
322		goto reg_disable;
323
324	return 0;
325
326reg_disable:
327	regulator_disable(adc->reg);
328
329	return ret;
330}
331
332static int mcp320x_remove(struct spi_device *spi)
333{
334	struct iio_dev *indio_dev = spi_get_drvdata(spi);
335	struct mcp320x *adc = iio_priv(indio_dev);
336
337	iio_device_unregister(indio_dev);
338	regulator_disable(adc->reg);
339
340	return 0;
341}
342
343#if defined(CONFIG_OF)
344static const struct of_device_id mcp320x_dt_ids[] = {
345	{
346		.compatible = "mcp3001",
347		.data = &mcp320x_chip_infos[mcp3001],
348	}, {
349		.compatible = "mcp3002",
350		.data = &mcp320x_chip_infos[mcp3002],
351	}, {
352		.compatible = "mcp3004",
353		.data = &mcp320x_chip_infos[mcp3004],
354	}, {
355		.compatible = "mcp3008",
356		.data = &mcp320x_chip_infos[mcp3008],
357	}, {
358		.compatible = "mcp3201",
359		.data = &mcp320x_chip_infos[mcp3201],
360	}, {
361		.compatible = "mcp3202",
362		.data = &mcp320x_chip_infos[mcp3202],
363	}, {
364		.compatible = "mcp3204",
365		.data = &mcp320x_chip_infos[mcp3204],
366	}, {
367		.compatible = "mcp3208",
368		.data = &mcp320x_chip_infos[mcp3208],
369	}, {
370	}
371};
372MODULE_DEVICE_TABLE(of, mcp320x_dt_ids);
373#endif
374
375static const struct spi_device_id mcp320x_id[] = {
376	{ "mcp3001", mcp3001 },
377	{ "mcp3002", mcp3002 },
378	{ "mcp3004", mcp3004 },
379	{ "mcp3008", mcp3008 },
380	{ "mcp3201", mcp3201 },
381	{ "mcp3202", mcp3202 },
382	{ "mcp3204", mcp3204 },
383	{ "mcp3208", mcp3208 },
384	{ }
385};
386MODULE_DEVICE_TABLE(spi, mcp320x_id);
387
388static struct spi_driver mcp320x_driver = {
389	.driver = {
390		.name = "mcp320x",
391		.owner = THIS_MODULE,
392	},
393	.probe = mcp320x_probe,
394	.remove = mcp320x_remove,
395	.id_table = mcp320x_id,
396};
397module_spi_driver(mcp320x_driver);
398
399MODULE_AUTHOR("Oskar Andero <oskar.andero@gmail.com>");
400MODULE_DESCRIPTION("Microchip Technology MCP3x01/02/04/08");
401MODULE_LICENSE("GPL v2");
402