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Release 4.7 drivers/iio/pressure/mpl3115.c

/*
 * mpl3115.c - Support for Freescale MPL3115A2 pressure/temperature sensor
 *
 * Copyright (c) 2013 Peter Meerwald <pmeerw@pmeerw.net>
 *
 * 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.
 *
 * (7-bit I2C slave address 0x60)
 *
 * TODO: FIFO buffer, altimeter mode, oversampling, continuous mode,
 * interrupts, user offset correction, raw mode
 */

#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/buffer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/delay.h>


#define MPL3115_STATUS 0x00

#define MPL3115_OUT_PRESS 0x01 
/* MSB first, 20 bit */

#define MPL3115_OUT_TEMP 0x04 
/* MSB first, 12 bit */

#define MPL3115_WHO_AM_I 0x0c

#define MPL3115_CTRL_REG1 0x26


#define MPL3115_DEVICE_ID 0xc4


#define MPL3115_STATUS_PRESS_RDY BIT(2)

#define MPL3115_STATUS_TEMP_RDY BIT(1)


#define MPL3115_CTRL_RESET BIT(2) 
/* software reset */

#define MPL3115_CTRL_OST BIT(1) 
/* initiate measurement */

#define MPL3115_CTRL_ACTIVE BIT(0) 
/* continuous measurement */

#define MPL3115_CTRL_OS_258MS (BIT(5) | BIT(4)) 
/* 64x oversampling */


struct mpl3115_data {
	
struct i2c_client *client;
	
struct mutex lock;
	
u8 ctrl_reg1;
};


static int mpl3115_request(struct mpl3115_data *data) { int ret, tries = 15; /* trigger measurement */ ret = i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG1, data->ctrl_reg1 | MPL3115_CTRL_OST); if (ret < 0) return ret; while (tries-- > 0) { ret = i2c_smbus_read_byte_data(data->client, MPL3115_CTRL_REG1); if (ret < 0) return ret; /* wait for data ready, i.e. OST cleared */ if (!(ret & MPL3115_CTRL_OST)) break; msleep(20); } if (tries < 0) { dev_err(&data->client->dev, "data not ready\n"); return -EIO; } return 0; }

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static int mpl3115_read_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int *val, int *val2, long mask) { struct mpl3115_data *data = iio_priv(indio_dev); __be32 tmp = 0; int ret; switch (mask) { case IIO_CHAN_INFO_RAW: if (iio_buffer_enabled(indio_dev)) return -EBUSY; switch (chan->type) { case IIO_PRESSURE: /* in 0.25 pascal / LSB */ mutex_lock(&data->lock); ret = mpl3115_request(data); if (ret < 0) { mutex_unlock(&data->lock); return ret; } ret = i2c_smbus_read_i2c_block_data(data->client, MPL3115_OUT_PRESS, 3, (u8 *) &tmp); mutex_unlock(&data->lock); if (ret < 0) return ret; *val = be32_to_cpu(tmp) >> 12; return IIO_VAL_INT; case IIO_TEMP: /* in 0.0625 celsius / LSB */ mutex_lock(&data->lock); ret = mpl3115_request(data); if (ret < 0) { mutex_unlock(&data->lock); return ret; } ret = i2c_smbus_read_i2c_block_data(data->client, MPL3115_OUT_TEMP, 2, (u8 *) &tmp); mutex_unlock(&data->lock); if (ret < 0) return ret; *val = sign_extend32(be32_to_cpu(tmp) >> 20, 11); return IIO_VAL_INT; default: return -EINVAL; } case IIO_CHAN_INFO_SCALE: switch (chan->type) { case IIO_PRESSURE: *val = 0; *val2 = 250; /* want kilopascal */ return IIO_VAL_INT_PLUS_MICRO; case IIO_TEMP: *val = 0; *val2 = 62500; return IIO_VAL_INT_PLUS_MICRO; default: return -EINVAL; } } return -EINVAL; }

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static irqreturn_t mpl3115_trigger_handler(int irq, void *p) { struct iio_poll_func *pf = p; struct iio_dev *indio_dev = pf->indio_dev; struct mpl3115_data *data = iio_priv(indio_dev); u8 buffer[16]; /* 32-bit channel + 16-bit channel + padding + ts */ int ret, pos = 0; mutex_lock(&data->lock); ret = mpl3115_request(data); if (ret < 0) { mutex_unlock(&data->lock); goto done; } memset(buffer, 0, sizeof(buffer)); if (test_bit(0, indio_dev->active_scan_mask)) { ret = i2c_smbus_read_i2c_block_data(data->client, MPL3115_OUT_PRESS, 3, &buffer[pos]); if (ret < 0) { mutex_unlock(&data->lock); goto done; } pos += 4; } if (test_bit(1, indio_dev->active_scan_mask)) { ret = i2c_smbus_read_i2c_block_data(data->client, MPL3115_OUT_TEMP, 2, &buffer[pos]); if (ret < 0) { mutex_unlock(&data->lock); goto done; } } mutex_unlock(&data->lock); iio_push_to_buffers_with_timestamp(indio_dev, buffer, iio_get_time_ns()); done: iio_trigger_notify_done(indio_dev->trig); return IRQ_HANDLED; }

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static const struct iio_chan_spec mpl3115_channels[] = { { .type = IIO_PRESSURE, .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), BIT(IIO_CHAN_INFO_SCALE), .scan_index = 0, .scan_type = { .sign = 'u', .realbits = 20, .storagebits = 32, .shift = 12, .endianness = IIO_BE, } }, { .type = IIO_TEMP, .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 struct iio_info mpl3115_info = { .read_raw = &mpl3115_read_raw, .driver_module = THIS_MODULE, };
static int mpl3115_probe(struct i2c_client *client, const struct i2c_device_id *id) { struct mpl3115_data *data; struct iio_dev *indio_dev; int ret; ret = i2c_smbus_read_byte_data(client, MPL3115_WHO_AM_I); if (ret < 0) return ret; if (ret != MPL3115_DEVICE_ID) return -ENODEV; indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); if (!indio_dev) return -ENOMEM; data = iio_priv(indio_dev); data->client = client; mutex_init(&data->lock); i2c_set_clientdata(client, indio_dev); indio_dev->info = &mpl3115_info; indio_dev->name = id->name; indio_dev->dev.parent = &client->dev; indio_dev->modes = INDIO_DIRECT_MODE; indio_dev->channels = mpl3115_channels; indio_dev->num_channels = ARRAY_SIZE(mpl3115_channels); /* software reset, I2C transfer is aborted (fails) */ i2c_smbus_write_byte_data(client, MPL3115_CTRL_REG1, MPL3115_CTRL_RESET); msleep(50); data->ctrl_reg1 = MPL3115_CTRL_OS_258MS; ret = i2c_smbus_write_byte_data(client, MPL3115_CTRL_REG1, data->ctrl_reg1); if (ret < 0) return ret; ret = iio_triggered_buffer_setup(indio_dev, NULL, mpl3115_trigger_handler, NULL); if (ret < 0) return ret; ret = iio_device_register(indio_dev); if (ret < 0) goto buffer_cleanup; return 0; buffer_cleanup: iio_triggered_buffer_cleanup(indio_dev); return ret; }

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static int mpl3115_standby(struct mpl3115_data *data) { return i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG1, data->ctrl_reg1 & ~MPL3115_CTRL_ACTIVE); }

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static int mpl3115_remove(struct i2c_client *client) { struct iio_dev *indio_dev = i2c_get_clientdata(client); iio_device_unregister(indio_dev); iio_triggered_buffer_cleanup(indio_dev); mpl3115_standby(iio_priv(indio_dev)); return 0; }

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#ifdef CONFIG_PM_SLEEP
static int mpl3115_suspend(struct device *dev) { return mpl3115_standby(iio_priv(i2c_get_clientdata( to_i2c_client(dev)))); }

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static int mpl3115_resume(struct device *dev) { struct mpl3115_data *data = iio_priv(i2c_get_clientdata( to_i2c_client(dev))); return i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG1, data->ctrl_reg1); }

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static SIMPLE_DEV_PM_OPS(mpl3115_pm_ops, mpl3115_suspend, mpl3115_resume); #define MPL3115_PM_OPS (&mpl3115_pm_ops) #else #define MPL3115_PM_OPS NULL #endif static const struct i2c_device_id mpl3115_id[] = { { "mpl3115", 0 }, { } }; MODULE_DEVICE_TABLE(i2c, mpl3115_id); static struct i2c_driver mpl3115_driver = { .driver = { .name = "mpl3115", .pm = MPL3115_PM_OPS, }, .probe = mpl3115_probe, .remove = mpl3115_remove, .id_table = mpl3115_id, }; module_i2c_driver(mpl3115_driver); MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>"); MODULE_DESCRIPTION("Freescale MPL3115 pressure/temperature driver"); MODULE_LICENSE("GPL");

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