[linux-2.6-block.git] / drivers / iio / temperature / maxim_thermocouple.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * maxim_thermocouple.c  - Support for Maxim thermocouple chips
 *
 * Copyright (C) 2016-2018 Matt Ranostay
 * Author: <matt.ranostay@konsulko.com>
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/err.h>
#include <linux/spi/spi.h>
#include <linux/iio/iio.h>
#include <linux/iio/trigger.h>
#include <linux/iio/buffer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/iio/trigger_consumer.h>

#define MAXIM_THERMOCOUPLE_DRV_NAME	"maxim_thermocouple"

enum {
	MAX6675,
	MAX31855,
};

static const struct iio_chan_spec max6675_channels[] = {
	{	/* thermocouple temperature */
		.type = IIO_TEMP,
		.info_mask_separate =
			BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
		.scan_index = 0,
		.scan_type = {
			.sign = 's',
			.realbits = 13,
			.storagebits = 16,
			.shift = 3,
			.endianness = IIO_BE,
		},
	},
	IIO_CHAN_SOFT_TIMESTAMP(1),
};

static const struct iio_chan_spec max31855_channels[] = {
	{	/* thermocouple temperature */
		.type = IIO_TEMP,
		.address = 2,
		.info_mask_separate =
			BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
		.scan_index = 0,
		.scan_type = {
			.sign = 's',
			.realbits = 14,
			.storagebits = 16,
			.shift = 2,
			.endianness = IIO_BE,
		},
	},
	{	/* cold junction temperature */
		.type = IIO_TEMP,
		.address = 0,
		.channel2 = IIO_MOD_TEMP_AMBIENT,
		.modified = 1,
		.info_mask_separate =
			BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
		.scan_index = 1,
		.scan_type = {
			.sign = 's',
			.realbits = 12,
			.storagebits = 16,
			.shift = 4,
			.endianness = IIO_BE,
		},
	},
	IIO_CHAN_SOFT_TIMESTAMP(2),
};

static const unsigned long max31855_scan_masks[] = {0x3, 0};

struct maxim_thermocouple_chip {
	const struct iio_chan_spec *channels;
	const unsigned long *scan_masks;
	u8 num_channels;
	u8 read_size;

	/* bit-check for valid input */
	u32 status_bit;
};

static const struct maxim_thermocouple_chip maxim_thermocouple_chips[] = {
	[MAX6675] = {
			.channels = max6675_channels,
			.num_channels = ARRAY_SIZE(max6675_channels),
			.read_size = 2,
			.status_bit = BIT(2),
		},
	[MAX31855] = {
			.channels = max31855_channels,
			.num_channels = ARRAY_SIZE(max31855_channels),
			.read_size = 4,
			.scan_masks = max31855_scan_masks,
			.status_bit = BIT(16),
		},
};

struct maxim_thermocouple_data {
	struct spi_device *spi;
	const struct maxim_thermocouple_chip *chip;

	u8 buffer[16] ____cacheline_aligned;
};

static int maxim_thermocouple_read(struct maxim_thermocouple_data *data,
				   struct iio_chan_spec const *chan, int *val)
{
	unsigned int storage_bytes = data->chip->read_size;
	unsigned int shift = chan->scan_type.shift + (chan->address * 8);
	__be16 buf16;
	__be32 buf32;
	int ret;

	switch (storage_bytes) {
	case 2:
		ret = spi_read(data->spi, (void *)&buf16, storage_bytes);
		*val = be16_to_cpu(buf16);
		break;
	case 4:
		ret = spi_read(data->spi, (void *)&buf32, storage_bytes);
		*val = be32_to_cpu(buf32);
		break;
	default:
		ret = -EINVAL;
	}

	if (ret)
		return ret;

	/* check to be sure this is a valid reading */
	if (*val & data->chip->status_bit)
		return -EINVAL;

	*val = sign_extend32(*val >> shift, chan->scan_type.realbits - 1);

	return 0;
}

static irqreturn_t maxim_thermocouple_trigger_handler(int irq, void *private)
{
	struct iio_poll_func *pf = private;
	struct iio_dev *indio_dev = pf->indio_dev;
	struct maxim_thermocouple_data *data = iio_priv(indio_dev);
	int ret;

	ret = spi_read(data->spi, data->buffer, data->chip->read_size);
	if (!ret) {
		iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
						   iio_get_time_ns(indio_dev));
	}

	iio_trigger_notify_done(indio_dev->trig);

	return IRQ_HANDLED;
}

static int maxim_thermocouple_read_raw(struct iio_dev *indio_dev,
				       struct iio_chan_spec const *chan,
				       int *val, int *val2, long mask)
{
	struct maxim_thermocouple_data *data = iio_priv(indio_dev);
	int ret = -EINVAL;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		ret = iio_device_claim_direct_mode(indio_dev);
		if (ret)
			return ret;

		ret = maxim_thermocouple_read(data, chan, val);
		iio_device_release_direct_mode(indio_dev);

		if (!ret)
			return IIO_VAL_INT;

		break;
	case IIO_CHAN_INFO_SCALE:
		switch (chan->channel2) {
		case IIO_MOD_TEMP_AMBIENT:
			*val = 62;
			*val2 = 500000; /* 1000 * 0.0625 */
			ret = IIO_VAL_INT_PLUS_MICRO;
			break;
		default:
			*val = 250; /* 1000 * 0.25 */
			ret = IIO_VAL_INT;
		};
		break;
	}

	return ret;
}

static const struct iio_info maxim_thermocouple_info = {
	.read_raw = maxim_thermocouple_read_raw,
};

static int maxim_thermocouple_probe(struct spi_device *spi)
{
	const struct spi_device_id *id = spi_get_device_id(spi);
	struct iio_dev *indio_dev;
	struct maxim_thermocouple_data *data;
	const struct maxim_thermocouple_chip *chip =
			&maxim_thermocouple_chips[id->driver_data];
	int ret;

	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*data));
	if (!indio_dev)
		return -ENOMEM;

	indio_dev->info = &maxim_thermocouple_info;
	indio_dev->name = MAXIM_THERMOCOUPLE_DRV_NAME;
	indio_dev->channels = chip->channels;
	indio_dev->available_scan_masks = chip->scan_masks;
	indio_dev->num_channels = chip->num_channels;
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->dev.parent = &spi->dev;

	data = iio_priv(indio_dev);
	data->spi = spi;
	data->chip = chip;

	ret = iio_triggered_buffer_setup(indio_dev, NULL,
				maxim_thermocouple_trigger_handler, NULL);
	if (ret)
		return ret;

	ret = iio_device_register(indio_dev);
	if (ret)
		goto error_unreg_buffer;

	return 0;

error_unreg_buffer:
	iio_triggered_buffer_cleanup(indio_dev);

	return ret;
}

static int maxim_thermocouple_remove(struct spi_device *spi)
{
	struct iio_dev *indio_dev = spi_get_drvdata(spi);

	iio_device_unregister(indio_dev);
	iio_triggered_buffer_cleanup(indio_dev);

	return 0;
}

static const struct spi_device_id maxim_thermocouple_id[] = {
	{"max6675", MAX6675},
	{"max31855", MAX31855},
	{},
};
MODULE_DEVICE_TABLE(spi, maxim_thermocouple_id);

static struct spi_driver maxim_thermocouple_driver = {
	.driver = {
		.name	= MAXIM_THERMOCOUPLE_DRV_NAME,
	},
	.probe		= maxim_thermocouple_probe,
	.remove		= maxim_thermocouple_remove,
	.id_table	= maxim_thermocouple_id,
};
module_spi_driver(maxim_thermocouple_driver);

MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
MODULE_DESCRIPTION("Maxim thermocouple sensors");
MODULE_LICENSE("GPL");
Commit	Line	Data
d6ad8058	1	// SPDX-License-Identifier: GPL-2.0+
1f25ca11 MR	2	/*
	3	* maxim_thermocouple.c - Support for Maxim thermocouple chips
	4	*
d6ad8058 MR	5	* Copyright (C) 2016-2018 Matt Ranostay
d6ad8058 MR	6	* Author: <matt.ranostay@konsulko.com>
1f25ca11 MR	7	*/
	8
	9	#include <linux/module.h>
	10	#include <linux/init.h>
	11	#include <linux/mutex.h>
	12	#include <linux/err.h>
	13	#include <linux/spi/spi.h>
	14	#include <linux/iio/iio.h>
	15	#include <linux/iio/trigger.h>
	16	#include <linux/iio/buffer.h>
	17	#include <linux/iio/triggered_buffer.h>
	18	#include <linux/iio/trigger_consumer.h>
	19
	20	#define MAXIM_THERMOCOUPLE_DRV_NAME "maxim_thermocouple"
	21
	22	enum {
	23	MAX6675,
	24	MAX31855,
	25	};
	26
16335bcb	27	static const struct iio_chan_spec max6675_channels[] = {
1f25ca11 MR	28	{ /* thermocouple temperature */
	29	.type = IIO_TEMP,
	30	.info_mask_separate =
	31	BIT(IIO_CHAN_INFO_RAW) \| BIT(IIO_CHAN_INFO_SCALE),
	32	.scan_index = 0,
	33	.scan_type = {
	34	.sign = 's',
	35	.realbits = 13,
	36	.storagebits = 16,
	37	.shift = 3,
	38	.endianness = IIO_BE,
	39	},
	40	},
	41	IIO_CHAN_SOFT_TIMESTAMP(1),
	42	};
	43
16335bcb	44	static const struct iio_chan_spec max31855_channels[] = {
1f25ca11 MR	45	{ /* thermocouple temperature */
	46	.type = IIO_TEMP,
	47	.address = 2,
	48	.info_mask_separate =
	49	BIT(IIO_CHAN_INFO_RAW) \| BIT(IIO_CHAN_INFO_SCALE),
	50	.scan_index = 0,
	51	.scan_type = {
	52	.sign = 's',
	53	.realbits = 14,
	54	.storagebits = 16,
	55	.shift = 2,
	56	.endianness = IIO_BE,
	57	},
	58	},
	59	{ /* cold junction temperature */
	60	.type = IIO_TEMP,
	61	.address = 0,
	62	.channel2 = IIO_MOD_TEMP_AMBIENT,
	63	.modified = 1,
	64	.info_mask_separate =
	65	BIT(IIO_CHAN_INFO_RAW) \| BIT(IIO_CHAN_INFO_SCALE),
	66	.scan_index = 1,
	67	.scan_type = {
	68	.sign = 's',
	69	.realbits = 12,
	70	.storagebits = 16,
	71	.shift = 4,
	72	.endianness = IIO_BE,
	73	},
	74	},
	75	IIO_CHAN_SOFT_TIMESTAMP(2),
	76	};
	77
	78	static const unsigned long max31855_scan_masks[] = {0x3, 0};
	79
	80	struct maxim_thermocouple_chip {
	81	const struct iio_chan_spec *channels;
	82	const unsigned long *scan_masks;
	83	u8 num_channels;
	84	u8 read_size;
	85
	86	/* bit-check for valid input */
	87	u32 status_bit;
	88	};
	89
16335bcb	90	static const struct maxim_thermocouple_chip maxim_thermocouple_chips[] = {
1f25ca11 MR	91	[MAX6675] = {
	92	.channels = max6675_channels,
	93	.num_channels = ARRAY_SIZE(max6675_channels),
	94	.read_size = 2,
	95	.status_bit = BIT(2),
	96	},
	97	[MAX31855] = {
	98	.channels = max31855_channels,
	99	.num_channels = ARRAY_SIZE(max31855_channels),
	100	.read_size = 4,
	101	.scan_masks = max31855_scan_masks,
	102	.status_bit = BIT(16),
	103	},
	104	};
	105
	106	struct maxim_thermocouple_data {
	107	struct spi_device *spi;
	108	const struct maxim_thermocouple_chip *chip;
	109
	110	u8 buffer[16] ____cacheline_aligned;
	111	};
	112
	113	static int maxim_thermocouple_read(struct maxim_thermocouple_data *data,
	114	struct iio_chan_spec const chan, int val)
	115	{
	116	unsigned int storage_bytes = data->chip->read_size;
	117	unsigned int shift = chan->scan_type.shift + (chan->address * 8);
231147ee	118	__be16 buf16;
231147ee	119	__be32 buf32;
1f25ca11 MR	120	int ret;
1f25ca11 MR	121
1f25ca11 MR	122	switch (storage_bytes) {
1f25ca11 MR	123	case 2:
231147ee	124	ret = spi_read(data->spi, (void *)&buf16, storage_bytes);
231147ee	125	*val = be16_to_cpu(buf16);
1f25ca11 MR	126	break;
1f25ca11 MR	127	case 4:
231147ee	128	ret = spi_read(data->spi, (void *)&buf32, storage_bytes);
231147ee	129	*val = be32_to_cpu(buf32);
1f25ca11	130	break;
d70674ee AB	131	default:
d70674ee AB	132	ret = -EINVAL;
1f25ca11 MR	133	}
1f25ca11 MR	134
231147ee	135	if (ret)
	136	return ret;
	137
1f25ca11 MR	138	/* check to be sure this is a valid reading */
	139	if (*val & data->chip->status_bit)
	140	return -EINVAL;
	141
	142	val = sign_extend32(val >> shift, chan->scan_type.realbits - 1);
	143
	144	return 0;
	145	}
	146
	147	static irqreturn_t maxim_thermocouple_trigger_handler(int irq, void *private)
	148	{
	149	struct iio_poll_func *pf = private;
	150	struct iio_dev *indio_dev = pf->indio_dev;
	151	struct maxim_thermocouple_data *data = iio_priv(indio_dev);
	152	int ret;
	153
	154	ret = spi_read(data->spi, data->buffer, data->chip->read_size);
	155	if (!ret) {
	156	iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
	157	iio_get_time_ns(indio_dev));
	158	}
	159
	160	iio_trigger_notify_done(indio_dev->trig);
	161
	162	return IRQ_HANDLED;
	163	}
	164
	165	static int maxim_thermocouple_read_raw(struct iio_dev *indio_dev,
	166	struct iio_chan_spec const *chan,
	167	int val, int val2, long mask)
	168	{
	169	struct maxim_thermocouple_data *data = iio_priv(indio_dev);
	170	int ret = -EINVAL;
	171
	172	switch (mask) {
	173	case IIO_CHAN_INFO_RAW:
	174	ret = iio_device_claim_direct_mode(indio_dev);
	175	if (ret)
	176	return ret;
	177
	178	ret = maxim_thermocouple_read(data, chan, val);
	179	iio_device_release_direct_mode(indio_dev);
	180
	181	if (!ret)
	182	return IIO_VAL_INT;
	183
	184	break;
	185	case IIO_CHAN_INFO_SCALE:
	186	switch (chan->channel2) {
	187	case IIO_MOD_TEMP_AMBIENT:
	188	*val = 62;
	189	val2 = 500000; / 1000 * 0.0625 */
	190	ret = IIO_VAL_INT_PLUS_MICRO;
	191	break;
	192	default:
	193	val = 250; / 1000 * 0.25 */
	194	ret = IIO_VAL_INT;
	195	};
	196	break;
	197	}
	198
	199	return ret;
	200	}
	201
202	static const struct iio_info maxim_thermocouple_info = {
1f25ca11 MR	203	.read_raw = maxim_thermocouple_read_raw,
	204	};
	205
	206	static int maxim_thermocouple_probe(struct spi_device *spi)
	207	{
	208	const struct spi_device_id *id = spi_get_device_id(spi);
	209	struct iio_dev *indio_dev;
	210	struct maxim_thermocouple_data *data;
	211	const struct maxim_thermocouple_chip *chip =
	212	&maxim_thermocouple_chips[id->driver_data];
	213	int ret;
	214
	215	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*data));
	216	if (!indio_dev)
	217	return -ENOMEM;
	218
	219	indio_dev->info = &maxim_thermocouple_info;
	220	indio_dev->name = MAXIM_THERMOCOUPLE_DRV_NAME;
	221	indio_dev->channels = chip->channels;
	222	indio_dev->available_scan_masks = chip->scan_masks;
	223	indio_dev->num_channels = chip->num_channels;
	224	indio_dev->modes = INDIO_DIRECT_MODE;
74e2419b	225	indio_dev->dev.parent = &spi->dev;
1f25ca11 MR	226
	227	data = iio_priv(indio_dev);
	228	data->spi = spi;
	229	data->chip = chip;
	230
	231	ret = iio_triggered_buffer_setup(indio_dev, NULL,
	232	maxim_thermocouple_trigger_handler, NULL);
	233	if (ret)
	234	return ret;
	235
	236	ret = iio_device_register(indio_dev);
	237	if (ret)
	238	goto error_unreg_buffer;
	239
	240	return 0;
	241
	242	error_unreg_buffer:
	243	iio_triggered_buffer_cleanup(indio_dev);
	244
	245	return ret;
	246	}
	247
	248	static int maxim_thermocouple_remove(struct spi_device *spi)
	249	{
	250	struct iio_dev *indio_dev = spi_get_drvdata(spi);
	251
	252	iio_device_unregister(indio_dev);
	253	iio_triggered_buffer_cleanup(indio_dev);
	254
	255	return 0;
	256	}
	257
	258	static const struct spi_device_id maxim_thermocouple_id[] = {
	259	{"max6675", MAX6675},
	260	{"max31855", MAX31855},
	261	{},
	262	};
	263	MODULE_DEVICE_TABLE(spi, maxim_thermocouple_id);
	264
	265	static struct spi_driver maxim_thermocouple_driver = {
	266	.driver = {
	267	.name = MAXIM_THERMOCOUPLE_DRV_NAME,
	268	},
	269	.probe = maxim_thermocouple_probe,
	270	.remove = maxim_thermocouple_remove,
	271	.id_table = maxim_thermocouple_id,
	272	};
	273	module_spi_driver(maxim_thermocouple_driver);
	274
d6ad8058	275	MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
1f25ca11 MR	276	MODULE_DESCRIPTION("Maxim thermocouple sensors");
1f25ca11 MR	277	MODULE_LICENSE("GPL");