--- /dev/null
+/*
+ * mpl115.c - Support for Freescale MPL115A2 pressure/temperature sensor
+ *
+ * Copyright (c) 2014 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: shutdown pin
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/iio/iio.h>
+#include <linux/delay.h>
+
+#define MPL115_PADC 0x00 /* pressure ADC output value, MSB first, 10 bit */
+#define MPL115_TADC 0x02 /* temperature ADC output value, MSB first, 10 bit */
+#define MPL115_A0 0x04 /* 12 bit integer, 3 bit fraction */
+#define MPL115_B1 0x06 /* 2 bit integer, 13 bit fraction */
+#define MPL115_B2 0x08 /* 1 bit integer, 14 bit fraction */
+#define MPL115_C12 0x0a /* 0 bit integer, 13 bit fraction */
+#define MPL115_CONVERT 0x12 /* convert temperature and pressure */
+
+struct mpl115_data {
+ struct i2c_client *client;
+ struct mutex lock;
+ s16 a0;
+ s16 b1, b2;
+ s16 c12;
+};
+
+static int mpl115_request(struct mpl115_data *data)
+{
+ int ret = i2c_smbus_write_byte_data(data->client, MPL115_CONVERT, 0);
+ if (ret < 0)
+ return ret;
+
+ usleep_range(3000, 4000);
+
+ return 0;
+}
+
+static int mpl115_comp_pressure(struct mpl115_data *data, int *val, int *val2)
+{
+ int ret;
+ u16 padc, tadc;
+ int a1, y1, pcomp;
+ unsigned kpa;
+
+ mutex_lock(&data->lock);
+ ret = mpl115_request(data);
+ if (ret < 0)
+ goto done;
+
+ ret = i2c_smbus_read_word_swapped(data->client, MPL115_PADC);
+ if (ret < 0)
+ goto done;
+ padc = ret >> 6;
+
+ ret = i2c_smbus_read_word_swapped(data->client, MPL115_TADC);
+ if (ret < 0)
+ goto done;
+ tadc = ret >> 6;
+
+ /* see Freescale AN3785 */
+ a1 = data->b1 + ((data->c12 * tadc) >> 11);
+ y1 = (data->a0 << 10) + a1 * padc;
+
+ /* compensated pressure with 4 fractional bits */
+ pcomp = (y1 + ((data->b2 * (int) tadc) >> 1)) >> 9;
+
+ kpa = pcomp * (115 - 50) / 1023 + (50 << 4);
+ *val = kpa >> 4;
+ *val2 = (kpa & 15) * (1000000 >> 4);
+done:
+ mutex_unlock(&data->lock);
+ return ret;
+}
+
+static int mpl115_read_temp(struct mpl115_data *data)
+{
+ int ret;
+
+ mutex_lock(&data->lock);
+ ret = mpl115_request(data);
+ if (ret < 0)
+ goto done;
+ ret = i2c_smbus_read_word_swapped(data->client, MPL115_TADC);
+done:
+ mutex_unlock(&data->lock);
+ return ret;
+}
+
+static int mpl115_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct mpl115_data *data = iio_priv(indio_dev);
+ int ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_PROCESSED:
+ ret = mpl115_comp_pressure(data, val, val2);
+ if (ret < 0)
+ return ret;
+ return IIO_VAL_INT_PLUS_MICRO;
+ case IIO_CHAN_INFO_RAW:
+ /* temperature -5.35 C / LSB, 472 LSB is 25 C */
+ ret = mpl115_read_temp(data);
+ if (ret < 0)
+ return ret;
+ *val = ret >> 6;
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_OFFSET:
+ *val = 605;
+ *val2 = 750000;
+ return IIO_VAL_INT_PLUS_MICRO;
+ case IIO_CHAN_INFO_SCALE:
+ *val = -186;
+ *val2 = 915888;
+ return IIO_VAL_INT_PLUS_MICRO;
+ }
+ return -EINVAL;
+}
+
+static const struct iio_chan_spec mpl115_channels[] = {
+ {
+ .type = IIO_PRESSURE,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
+ },
+ {
+ .type = IIO_TEMP,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+ BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_SCALE),
+ },
+};
+
+static const struct iio_info mpl115_info = {
+ .read_raw = &mpl115_read_raw,
+ .driver_module = THIS_MODULE,
+};
+
+static int mpl115_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct mpl115_data *data;
+ struct iio_dev *indio_dev;
+ int ret;
+
+ 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);
+ data->client = client;
+ mutex_init(&data->lock);
+
+ i2c_set_clientdata(client, indio_dev);
+ indio_dev->info = &mpl115_info;
+ indio_dev->name = id->name;
+ indio_dev->dev.parent = &client->dev;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->channels = mpl115_channels;
+ indio_dev->num_channels = ARRAY_SIZE(mpl115_channels);
+
+ ret = i2c_smbus_read_word_swapped(data->client, MPL115_A0);
+ if (ret < 0)
+ return ret;
+ data->a0 = ret;
+ ret = i2c_smbus_read_word_swapped(data->client, MPL115_B1);
+ if (ret < 0)
+ return ret;
+ data->b1 = ret;
+ ret = i2c_smbus_read_word_swapped(data->client, MPL115_B2);
+ if (ret < 0)
+ return ret;
+ data->b2 = ret;
+ ret = i2c_smbus_read_word_swapped(data->client, MPL115_C12);
+ if (ret < 0)
+ return ret;
+ data->c12 = ret;
+
+ return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static const struct i2c_device_id mpl115_id[] = {
+ { "mpl115", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, mpl115_id);
+
+static struct i2c_driver mpl115_driver = {
+ .driver = {
+ .name = "mpl115",
+ },
+ .probe = mpl115_probe,
+ .id_table = mpl115_id,
+};
+module_i2c_driver(mpl115_driver);
+
+MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
+MODULE_DESCRIPTION("Freescale MPL115 pressure/temperature driver");
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff