I2C-controlled MEMS sensor with 20-bit pressure measurement (pascal) and 12-bit temperature measurement driver only exposes basic functionality, see TODO remarks datasheet: http://cache.freescale.com/files/sensors/doc/data_sheet/MPL3115A2.pdf v2: * store 20-bit value in 32-bit buffer element (instead of 24-bit) * zero buffer to prevent kernel data leak to userspace * fix mutex unlock in trigger handler (thanks Andi Shyti) Signed-off-by: Peter Meerwald <pmeerw@xxxxxxxxxx> Cc: Andi Shyti <andi@xxxxxxxxxxx> --- drivers/iio/pressure/Kconfig | 12 ++ drivers/iio/pressure/Makefile | 1 + drivers/iio/pressure/mpl3115.c | 329 +++++++++++++++++++++++++++++++++++++++++ 3 files changed, 342 insertions(+) create mode 100644 drivers/iio/pressure/mpl3115.c diff --git a/drivers/iio/pressure/Kconfig b/drivers/iio/pressure/Kconfig index 4f2e0f9..a8b9cae 100644 --- a/drivers/iio/pressure/Kconfig +++ b/drivers/iio/pressure/Kconfig @@ -5,6 +5,18 @@ menu "Pressure sensors" +config MPL3115 + tristate "Freescale MPL3115A2 pressure sensor driver" + depends on I2C + select IIO_BUFFER + select IIO_TRIGGERED_BUFFER + help + Say yes here to build support for the Freescale MPL3115A2 + pressure sensor / altimeter. + + To compile this driver as a module, choose M here: the module + will be called mpl3115. + config IIO_ST_PRESS tristate "STMicroelectronics pressure sensor Driver" depends on (I2C || SPI_MASTER) && SYSFS diff --git a/drivers/iio/pressure/Makefile b/drivers/iio/pressure/Makefile index be71464..42bb9fc 100644 --- a/drivers/iio/pressure/Makefile +++ b/drivers/iio/pressure/Makefile @@ -3,6 +3,7 @@ # # When adding new entries keep the list in alphabetical order +obj-$(CONFIG_MPL3115) += mpl3115.o obj-$(CONFIG_IIO_ST_PRESS) += st_pressure.o st_pressure-y := st_pressure_core.o st_pressure-$(CONFIG_IIO_BUFFER) += st_pressure_buffer.o diff --git a/drivers/iio/pressure/mpl3115.c b/drivers/iio/pressure/mpl3115.c new file mode 100644 index 0000000..ac8c8ab --- /dev/null +++ b/drivers/iio/pressure/mpl3115.c @@ -0,0 +1,329 @@ +/* + * mpl3115.c - Support for Freescale MPL3115A2 pressure/temperature sensor + * + * Copyright (c) 2013 Peter Meerwald <pmeerw@xxxxxxxxxx> + * + * 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; +} + +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); + s32 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 = sign_extend32(be32_to_cpu(tmp) >> 12, 23); + 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, 15); + 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; +} + +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; +} + +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 = 's', + .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; +} + +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); +} + +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; +} + +#ifdef CONFIG_PM_SLEEP +static int mpl3115_suspend(struct device *dev) +{ + return mpl3115_standby(iio_priv(i2c_get_clientdata( + to_i2c_client(dev)))); +} + +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); +} + +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@xxxxxxxxxx>"); +MODULE_DESCRIPTION("Freescale MPL3115 pressure/temperature driver"); +MODULE_LICENSE("GPL"); -- 1.8.4.3 -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
