iio: Add Freescale MPL3115A2 pressure / temperature sensor driver
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@pmeerw.net>
Reviewed-by: Andi Shyti <andi@etezian.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
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@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;
+}
+
+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@pmeerw.net>");
+MODULE_DESCRIPTION("Freescale MPL3115 pressure/temperature driver");
+MODULE_LICENSE("GPL");