mlx90615new.c

/*
 * mlx90615.c - Support for Melexis MLX90615 contactless IR temperature sensor
 *
 * Parts based on mlx90614 driver from:
 *        Copyright (c) 2014 Peter Meerwald <pmeerw@pmeerw.net>,
 *        Copyright (c) 2015 Essensium NV
 *        Copyright (c) 2015 Melexis
 *
 * Copyright (c) 2020 SHPI GmbH
 *
 *
 * This file is subject to the terms and conditions of version 2 of
 * the GNU General Public License.  See the file COPYING in the main
 * directory of this archive for more details.
 *
 * Driver for the Melexis MLX90615 I2C 16-bit IR thermopile sensor
 *
 * (7-bit I2C slave address 0x5b, 10 - 100KHz bus speed only!)
 *
 *
 */

#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/jiffies.h>

#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/buffer.h>
#include <linux/iio/kfifo_buf.h>
#include <linux/kthread.h>
#include <linux/sched/task.h>

#define MLX90615_OP_RAM           0x20
#define MLX90615_OP_EEPROM        0x10
 /*SCL needs to be high during Sleep,  Enter sleep mode command (SA=0x5B, Command=0xC6,PEC=0x6D) */
#define MLX90615_OP_SLEEP         0xC6
#define MLX_READ    0x1			 // read instruction
#define MLX_WRITE   0x0			 // write instruction

 /* slave adress 0x5B, do not change unless you know what youre doing!*/
#define MLX90615_ADDR           (MLX90615_OP_EEPROM | 0x00)

								 /* IIR coefficient */
#define MLX90615_CONFIG_IIR_SHIFT 12
#define MLX90615_CONFIG_IIR_MASK (0x7 << MLX90615_CONFIG_IIR_SHIFT)

/*

IIR 3 Bits

	data = data & 0x7000;
	data = data >> 12;

000	0	forbidden
001	1	100%         0.10s     1.0
010	2	50%          0.86s     0.5
011	3	33.336%      1.4s      0.33
100	4	25%          2.00s     0.25
101	5	20%          3.00s     0.20
110	6	16.666%      3.3s      0.16
111	7	14.286%      4.5s      0.14

cuts off spikes 100% means no cut off

*/

/* emissivity correction coefficient, Emissivity = dec2hex(round(16384 )) */
#define MLX90615_EMISSIVITY     (MLX90615_OP_EEPROM | 0x03)
/* configuration register */
#define MLX90615_CONFIG         (MLX90615_OP_EEPROM | 0x02)
/* raw data IR channel , Raw IR data is in sign (1 bit, the MSB) and magnitude (15 bits) format */
#define MLX90615_RAW            (MLX90615_OP_RAM | 0x05)
/* ambient temperature */
#define MLX90615_TA             (MLX90615_OP_RAM | 0x06)
/* object temperature */
#define MLX90615_TOBJ           (MLX90615_OP_RAM | 0x07)

/* time for EEPROM write/erase to complete */
#define MLX90615_TIMING_EEPROM    10
 /* time to hold SDA low for wake-up */
#define MLX90615_TIMING_WAKEUP    39
 /* time before first data after wake-up */
#define MLX90615_TIMING_STARTUP  300

/* decimal part of the Kelvin offset */
#define MLX90615_CONST_OFFSET_DEC -13657
 /* remainder of offset (273.15*50) */
#define MLX90615_CONST_OFFSET_REM 500000
/* Scale in milliKelvin (0.02 * 1000) */
#define MLX90615_CONST_SCALE 20
 /* max value for emissivity */
#define MLX90615_CONST_RAW_EMISSIVITY_MAX 16384
 /* 1/16384 ~ 0.000061035 */
#define MLX90615_CONST_EMISSIVITY_RESOLUTION 61035

/* Bandwidth values for IIR filtering */
/* IIR spikes in %  */
static const int mlx90615_iir_values[] =
{
	0, 100, 50, 33, 25, 20, 16,  14
};

static IIO_CONST_ATTR(in_temp_object_filter_low_pass_3db_frequency_available,
"1.0 0.5 0.33 0.25 0.2 0.16 0.14");

struct mlx90615_data
{
	struct i2c_client *client;
	struct mutex lock; /* for EEPROM access only */
	unsigned long ready_timestamp;
	struct task_struct *task;
	struct
	{
		u16 chan[2];
		u64 ts __aligned(8);
	} scan;
};

static const uint8_t CRC8_table[] =
{
	0x00, 0x07, 0x0E, 0x09, 0x1C, 0x1B, 0x12, 0x15, 0x38, 0x3F, 0x36, 0x31, 0x24, 0x23, 0x2A, 0x2D,
	0x70, 0x77, 0x7E, 0x79, 0x6C, 0x6B, 0x62, 0x65, 0x48, 0x4F, 0x46, 0x41, 0x54, 0x53, 0x5A, 0x5D,
	0xE0, 0xE7, 0xEE, 0xE9, 0xFC, 0xFB, 0xF2, 0xF5, 0xD8, 0xDF, 0xD6, 0xD1, 0xC4, 0xC3, 0xCA, 0xCD,
	0x90, 0x97, 0x9E, 0x99, 0x8C, 0x8B, 0x82, 0x85, 0xA8, 0xAF, 0xA6, 0xA1, 0xB4, 0xB3, 0xBA, 0xBD,
	0xC7, 0xC0, 0xC9, 0xCE, 0xDB, 0xDC, 0xD5, 0xD2, 0xFF, 0xF8, 0xF1, 0xF6, 0xE3, 0xE4, 0xED, 0xEA,
	0xB7, 0xB0, 0xB9, 0xBE, 0xAB, 0xAC, 0xA5, 0xA2, 0x8F, 0x88, 0x81, 0x86, 0x93, 0x94, 0x9D, 0x9A,
	0x27, 0x20, 0x29, 0x2E, 0x3B, 0x3C, 0x35, 0x32, 0x1F, 0x18, 0x11, 0x16, 0x03, 0x04, 0x0D, 0x0A,
	0x57, 0x50, 0x59, 0x5E, 0x4B, 0x4C, 0x45, 0x42, 0x6F, 0x68, 0x61, 0x66, 0x73, 0x74, 0x7D, 0x7A,
	0x89, 0x8E, 0x87, 0x80, 0x95, 0x92, 0x9B, 0x9C, 0xB1, 0xB6, 0xBF, 0xB8, 0xAD, 0xAA, 0xA3, 0xA4,
	0xF9, 0xFE, 0xF7, 0xF0, 0xE5, 0xE2, 0xEB, 0xEC, 0xC1, 0xC6, 0xCF, 0xC8, 0xDD, 0xDA, 0xD3, 0xD4,
	0x69, 0x6E, 0x67, 0x60, 0x75, 0x72, 0x7B, 0x7C, 0x51, 0x56, 0x5F, 0x58, 0x4D, 0x4A, 0x43, 0x44,
	0x19, 0x1E, 0x17, 0x10, 0x05, 0x02, 0x0B, 0x0C, 0x21, 0x26, 0x2F, 0x28, 0x3D, 0x3A, 0x33, 0x34,
	0x4E, 0x49, 0x40, 0x47, 0x52, 0x55, 0x5C, 0x5B, 0x76, 0x71, 0x78, 0x7F, 0x6A, 0x6D, 0x64, 0x63,
	0x3E, 0x39, 0x30, 0x37, 0x22, 0x25, 0x2C, 0x2B, 0x06, 0x01, 0x08, 0x0F, 0x1A, 0x1D, 0x14, 0x13,
	0xAE, 0xA9, 0xA0, 0xA7, 0xB2, 0xB5, 0xBC, 0xBB, 0x96, 0x91, 0x98, 0x9F, 0x8A, 0x8D, 0x84, 0x83,
	0xDE, 0xD9, 0xD0, 0xD7, 0xC2, 0xC5, 0xCC, 0xCB, 0xE6, 0xE1, 0xE8, 0xEF, 0xFA, 0xFD, 0xF4, 0xF3
};

static struct attribute *mlx90615_attributes[] =
{
	&iio_const_attr_in_temp_object_filter_low_pass_3db_frequency_available.dev_attr.attr,
	NULL,
};

static const struct attribute_group mlx90615_attr_group =
{
	.attrs = mlx90615_attributes,
};

/*
 * Erase an address and write word.
 * The mutex must be locked before calling.
 */


/*uint8_t crc8(uint8_t * data, int size)
{
	uint8_t crc = 0x00;
	int bit;
	while (size--)
	{
		crc ^= *data++;
		for (bit = 0;  bit < 8; bit++)
		{
			if (crc & 0x80)  crc = crc << 1 ^ 0x7;
			else crc <<= 1;
		}
	}
	return(crc);
}*/


uint8_t crc8citt(const uint8_t *input, int len)
{
	uint8_t data = 0, remainder = 0, i;
	for (i = 0; i < len; i++)
	{
		data = input[i] ^ remainder;
		remainder = CRC8_table[data];
	}
	return remainder;
}


static s32 mlx90615_write_word(const struct i2c_client *client, u8 command,
u16 value)
{
	/*
	 * Note: The mlx90615 requires a PEC on writing but does not send us a
	 * custom PEC on reading.  Hence, we cannot set I2C_CLIENT_PEC in
	 * i2c_client.flags.  As a workaround, we use i2c_smbus_xfer here.
	 */
	union i2c_smbus_data data;
	s32 ret;

	dev_dbg(&client->dev, "Writing 0x%x to address 0x%x", value, command);

	data.word = 0x0000;			 /* erase command */
	ret = i2c_smbus_xfer(client->adapter, client->addr,
		client->flags | I2C_CLIENT_PEC,
		I2C_SMBUS_WRITE, command,
		I2C_SMBUS_WORD_DATA, &data);
	if (ret < 0)
		return ret;

	msleep(MLX90615_TIMING_EEPROM);

	data.word = value;			 /* actual write */
	ret = i2c_smbus_xfer(client->adapter, client->addr,
		client->flags | I2C_CLIENT_PEC,
		I2C_SMBUS_WRITE, command,
		I2C_SMBUS_WORD_DATA, &data);

	msleep(MLX90615_TIMING_EEPROM);

	return ret;
}


/*
 * Find the IIR value inside mlx90615_iir_values array and return its position
 * which is equivalent to the bit value in sensor register
 */
static inline s32 mlx90615_iir_search(const struct i2c_client *client,
int value)
{
	int i;
	s32 ret;

	for (i = 1; i < ARRAY_SIZE(mlx90615_iir_values); ++i)
	{
		if (value == mlx90615_iir_values[i])
			break;
	}

	if (i == ARRAY_SIZE(mlx90615_iir_values))
		return -EINVAL;

	/*
	 * CONFIG register values must not be changed so
	 * we must read them before we actually write
	 * changes
	 */
	ret = i2c_smbus_read_word_data(client, MLX90615_CONFIG);
	if (ret < 0)
		return ret;

	/* Write changed values */
	/* ret = ret & 0x8FFF;
	 ret = ret + (i << MLX90615_CONFIG_IIR_SHIFT);     */

	ret &= ~MLX90615_CONFIG_IIR_MASK;
	ret |= i << MLX90615_CONFIG_IIR_SHIFT;

	/* Write changed values */

	ret = mlx90615_write_word(client, MLX90615_CONFIG,ret);

	return ret;
}


static int mlx90615_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *channel, int *val,
int *val2, long mask)
{
	struct mlx90615_data *data = iio_priv(indio_dev);
	u8 cmd;
	s32 ret;
	char rbuf[6]= {0};
	rbuf[0]= (data->client->addr << 1) | MLX_WRITE;
	rbuf[2]= (data->client->addr << 1) | MLX_READ;

	switch (mask)
	{
		case IIO_CHAN_INFO_RAW:	 /* 0.02K / LSB */
			switch (channel->channel2)
			{
				case IIO_MOD_TEMP_AMBIENT:
					cmd = MLX90615_TA;
					break;
				case IIO_MOD_TEMP_OBJECT:
					cmd = MLX90615_TOBJ;
					break;
				default:
					return -EINVAL;
			}

			rbuf[1] = cmd;
			ret = i2c_smbus_read_i2c_block_data(data->client, cmd, 3, &rbuf[3]);

			/* MSB is an error flag */
			if (crc8citt( (uint8_t *)rbuf, 5)  != rbuf[5])

			{
				printk(KERN_INFO "MLX90615: value: %04x PEC error %02x",(rbuf[4]<<8 | rbuf[3]),rbuf[5]);
				return -2;
			}

			if (rbuf[4] & 0x80)
			{
				return -EIO;
			}

			*val = (rbuf[4]<<8 | rbuf[3]);

			return IIO_VAL_INT;
		case IIO_CHAN_INFO_OFFSET:
			*val = MLX90615_CONST_OFFSET_DEC;
			*val2 = MLX90615_CONST_OFFSET_REM;
			return IIO_VAL_INT_PLUS_MICRO;
		case IIO_CHAN_INFO_SCALE:
			*val = MLX90615_CONST_SCALE;
			return IIO_VAL_INT;
				 /* 1/16384 / LSB */
		case IIO_CHAN_INFO_CALIBEMISSIVITY:

			mutex_lock(&data->lock);
			ret = i2c_smbus_read_word_data(data->client,
				MLX90615_EMISSIVITY);
			mutex_unlock(&data->lock);

			if (ret < 0)
				return ret;

			if (ret == MLX90615_CONST_RAW_EMISSIVITY_MAX)
			{
				*val = 1;
				*val2 = 0;
			}
			else
			{
				*val = 0;
				*val2 = ret * MLX90615_CONST_EMISSIVITY_RESOLUTION;
			}
			return IIO_VAL_INT_PLUS_NANO;
		case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
			mutex_lock(&data->lock);
			ret = i2c_smbus_read_word_data(data->client, MLX90615_CONFIG);
			mutex_unlock(&data->lock);

			if (ret < 0)
				return ret;

			*val = mlx90615_iir_values[(ret & MLX90615_CONFIG_IIR_MASK) >> MLX90615_CONFIG_IIR_SHIFT ] / 100;
			*val2 = (mlx90615_iir_values[(ret & MLX90615_CONFIG_IIR_MASK) >> MLX90615_CONFIG_IIR_SHIFT ] % 100) *
				10000;
			return IIO_VAL_INT_PLUS_MICRO;

		default:
			return -EINVAL;
	}
}


static int mlx90615_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *channel, int val,
int val2, long mask)
{
	struct mlx90615_data *data = iio_priv(indio_dev);
	s32 ret;

	switch (mask)
	{
		/* 1/16384 / LSB */
		case IIO_CHAN_INFO_CALIBEMISSIVITY:
			if (val < 0 || val2 < 0 || val > 1 || (val == 1 && val2 != 0))
				return -EINVAL;
			val = val * MLX90615_CONST_RAW_EMISSIVITY_MAX +
		              val2 / MLX90615_CONST_EMISSIVITY_RESOLUTION;

			mutex_lock(&data->lock);
			ret = mlx90615_write_word(data->client, MLX90615_EMISSIVITY,
				val);
			mutex_unlock(&data->lock);

			return ret;
		/* IIR Filter setting */
		case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
			if ((val < 0) | (val > 1))
				return -EINVAL;

			mutex_lock(&data->lock);
			ret = mlx90615_iir_search(data->client,
				val * 100 + val2 / 10000);
			/* write IIR */
			mutex_unlock(&data->lock);

			return ret;
		default:
			return -EINVAL;
	}
}


static int mlx90615_work_buffer(struct iio_dev *indio_dev)
{
	struct mlx90615_data *data = iio_priv(indio_dev);
	int ret, i = 0;
	s64 time;
	char rbuf[6]= {0};
        rbuf[0]= (data->client->addr << 1) | MLX_WRITE;
        rbuf[2]= (data->client->addr << 1) | MLX_READ;


	time = iio_get_time_ns(indio_dev);

	/*
	 * Single register reads: bulk_read will not work with ina226/219
	 * as there is no auto-increment of the register pointer.
	 */

	if (test_bit(0, indio_dev->active_scan_mask))
	{
		rbuf[1] = MLX90615_TA;
		ret = i2c_smbus_read_i2c_block_data(data->client, MLX90615_TA, 3, &rbuf[3]);
		/* MSB is an error flag */
		if (crc8citt((uint8_t *)rbuf, 5)  != rbuf[5])
		{
			printk(KERN_INFO "MLX90615: value: %04x PEC error %02x",(rbuf[4]<<8 | rbuf[3]),rbuf[5]);
			return -2;
		}
		if (rbuf[4] & 0x80)   { return -EIO;}
		data->scan.chan[0] = (rbuf[4]<<8 | rbuf[3]);
		i++;
	}

	if (test_bit(1, indio_dev->active_scan_mask))
	{

		rbuf[1] = MLX90615_TOBJ;
		ret = i2c_smbus_read_i2c_block_data(data->client, MLX90615_TOBJ, 3, &rbuf[3]);
		/* MSB is an error flag */
		if (crc8citt((uint8_t *)rbuf, 5)  != rbuf[5])
		{
			printk(KERN_INFO "MLX90615: value: %04x PEC error %02x",(rbuf[4]<<8 | rbuf[3]),rbuf[5]);
			return -2;
		}
		if (rbuf[4] & 0x80)   { return -EIO;}
		data->scan.chan[i] = (rbuf[4]<<8 | rbuf[3]);

	}

	iio_push_to_buffers_with_timestamp(indio_dev, &data->scan, time);

	return 0;
};

static int mlx90615_capture_thread(void *data)
{
	struct iio_dev *indio_dev = data;
	int sampling_ms = 100;
	int ret, slept_ms=0;
	//struct timespec64 next, now, delta;
	//s64 delay_us;

	//ktime_get_ts64(&next);

	do
	{

		if (slept_ms == 0)
		{
			ret = mlx90615_work_buffer(indio_dev);
			if (ret >= 0)
			{
				slept_ms = msleep_interruptible(sampling_ms);
			}
		}
		else {slept_ms = msleep_interruptible(slept_ms);}

		//ktime_get_ts64(&now);

		/*
		 * Advance the timestamp for the next poll by one sampling
		 * interval, and sleep for the remainder (next - now)
		 * In case "next" has already passed, the interval is added
		 * multiple times, i.e. samples are dropped.
		 */
		/* do {
			timespec64_add_ns(&next, 1000 * sampling_us);
			delta = timespec64_sub(next, now);
			delay_us = div_s64(timespec64_to_ns(&delta), 1000);
		} while (delay_us <= 0);

		usleep_range(delay_us, (delay_us * 3) >> 1);
				*/

	} while (!kthread_should_stop());

	return 0;
}


static int mlx90615_buffer_enable(struct iio_dev *indio_dev)
{
	struct mlx90615_data *data = iio_priv(indio_dev);
	unsigned int sampling_ms = 100;
	struct task_struct *task;

	dev_info(&indio_dev->dev, "Enabling buffer w/ scan_mask %02x, freq = %d\n",
		(unsigned int)(*indio_dev->active_scan_mask),
		1000 / sampling_ms);

	task = kthread_create(mlx90615_capture_thread, (void *)indio_dev,
		"%s:%d-%ums", indio_dev->name, indio_dev->id,
		sampling_ms);
	if (IS_ERR(task))
		return PTR_ERR(task);

	get_task_struct(task);
	wake_up_process(task);
	data->task = task;

	return 0;
}


static int mlx90615_buffer_disable(struct iio_dev *indio_dev)
{
	struct mlx90615_data *data = iio_priv(indio_dev);
	dev_info(&indio_dev->dev, "Disabling buffer for MLX90615\n");

	if (data->task)
	{
		kthread_stop(data->task);
		put_task_struct(data->task);
		data->task = NULL;
	}

	return 0;
}


static const struct iio_buffer_setup_ops mlx90615_setup_ops =
{
	.postenable = &mlx90615_buffer_enable,
	.predisable = &mlx90615_buffer_disable,
};

static int mlx90615_write_raw_get_fmt(struct iio_dev *indio_dev,
struct iio_chan_spec const *channel,
long mask)
{
	switch (mask)
	{
		case IIO_CHAN_INFO_CALIBEMISSIVITY:
			return IIO_VAL_INT_PLUS_NANO;
		case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
			return IIO_VAL_INT_PLUS_MICRO;
		default:
			return -EINVAL;
	}
}


static const struct iio_chan_spec mlx90615_channels[] =
{
	{
		.type = IIO_TEMP,
		.modified = 1,
		.indexed = 1,
		.channel2 = IIO_MOD_TEMP_AMBIENT,
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) |
		BIT(IIO_CHAN_INFO_SCALE),
		.scan_index = 0,
		.scan_type =
		{
			.sign = 'u',
			.realbits = 16,
			.storagebits = 16,
			.shift = 0,
			.endianness = IIO_LE,
		},
	},
	{
		.type = IIO_TEMP,
		.modified = 1,
		.indexed = 1,
		.channel2 = IIO_MOD_TEMP_OBJECT,
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
		BIT(IIO_CHAN_INFO_CALIBEMISSIVITY) |
		BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY),
		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) |
		BIT(IIO_CHAN_INFO_SCALE),
		.scan_index = 1,
		.scan_type =
		{
			.sign = 'u',
			.realbits = 16,
			.storagebits = 16,
			.shift = 0,
			.endianness = IIO_LE,
		},

	},
	IIO_CHAN_SOFT_TIMESTAMP(2),
};

static const struct iio_info mlx90615_info =
{
	.read_raw = mlx90615_read_raw,
	.write_raw = mlx90615_write_raw,
	.write_raw_get_fmt = mlx90615_write_raw_get_fmt,
	.attrs = &mlx90615_attr_group,

};

static int mlx90615_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
	struct iio_dev *indio_dev;
	struct mlx90615_data *data;
	struct iio_buffer *buffer;

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
		return -ENODEV;

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

	data = iio_priv(indio_dev);
	i2c_set_clientdata(client, indio_dev);
	data->client = client;

	indio_dev->dev.parent = &client->dev;
	indio_dev->name = id->name;
	indio_dev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_SOFTWARE;
	indio_dev->info = &mlx90615_info;
	indio_dev->channels = mlx90615_channels;
	indio_dev->num_channels = ARRAY_SIZE(mlx90615_channels);

	indio_dev->setup_ops = &mlx90615_setup_ops;

	buffer = devm_iio_kfifo_allocate(&indio_dev->dev);
	if (!buffer)
		return -ENOMEM;

	iio_device_attach_buffer(indio_dev, buffer);

	return iio_device_register(indio_dev);
}


static int mlx90615_remove(struct i2c_client *client)
{
	struct iio_dev *indio_dev = i2c_get_clientdata(client);

	iio_device_unregister(indio_dev);

	return 0;
}


static const struct i2c_device_id mlx90615_id[] =
{
	{ "mlx90615", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, mlx90615_id);

static struct i2c_driver mlx90615_driver =
{
	.driver =
	{
		.name   = "mlx90615",
	},
	.probe = mlx90615_probe,
	.remove = mlx90615_remove,
	.id_table = mlx90615_id,
};
module_i2c_driver(mlx90615_driver);

MODULE_AUTHOR("LH <lh@shpi.de>");
MODULE_DESCRIPTION("Melexis MLX90615 contactless IR temperature sensor driver");
MODULE_LICENSE("GPL");