*
* Copyright (c) 2014 Peter Meerwald <pmeerw@pmeerw.net>
* Copyright (c) 2015 Essensium NV
+ * Copyright (c) 2015 Melexis
*
* 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
*
* (7-bit I2C slave address 0x5a, 100KHz bus speed only!)
*
- * TODO: sleep mode, configuration EEPROM
+ * To wake up from sleep mode, the SDA line must be held low while SCL is high
+ * for at least 33ms. This is achieved with an extra GPIO that can be connected
+ * directly to the SDA line. In normal operation, the GPIO is set as input and
+ * will not interfere in I2C communication. While the GPIO is driven low, the
+ * i2c adapter is locked since it cannot be used by other clients. The SCL line
+ * always has a pull-up so we do not need an extra GPIO to drive it high. If
+ * the "wakeup" GPIO is not given, power management will be disabled.
+ *
*/
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/jiffies.h>
+#include <linux/gpio/consumer.h>
+#include <linux/pm_runtime.h>
#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
#define MLX90614_OP_RAM 0x00
#define MLX90614_OP_EEPROM 0x20
#define MLX90614_TIMING_WAKEUP 34 /* time to hold SDA low for wake-up */
#define MLX90614_TIMING_STARTUP 250 /* time before first data after wake-up */
+#define MLX90614_AUTOSLEEP_DELAY 5000 /* default autosleep delay */
+
+/* Magic constants */
+#define MLX90614_CONST_OFFSET_DEC -13657 /* decimal part of the Kelvin offset */
+#define MLX90614_CONST_OFFSET_REM 500000 /* remainder of offset (273.15*50) */
+#define MLX90614_CONST_SCALE 20 /* Scale in milliKelvin (0.02 * 1000) */
+#define MLX90614_CONST_RAW_EMISSIVITY_MAX 65535 /* max value for emissivity */
+#define MLX90614_CONST_EMISSIVITY_RESOLUTION 15259 /* 1/65535 ~ 0.000015259 */
+#define MLX90614_CONST_FIR 0x7 /* Fixed value for FIR part of low pass filter */
+
struct mlx90614_data {
struct i2c_client *client;
+ struct mutex lock; /* for EEPROM access only */
+ struct gpio_desc *wakeup_gpio; /* NULL to disable sleep/wake-up */
+ unsigned long ready_timestamp; /* in jiffies */
+};
+
+/* Bandwidth values for IIR filtering */
+static const int mlx90614_iir_values[] = {77, 31, 20, 15, 723, 153, 110, 86};
+static IIO_CONST_ATTR(in_temp_object_filter_low_pass_3db_frequency_available,
+ "0.15 0.20 0.31 0.77 0.86 1.10 1.53 7.23");
+
+static struct attribute *mlx90614_attributes[] = {
+ &iio_const_attr_in_temp_object_filter_low_pass_3db_frequency_available.dev_attr.attr,
+ NULL,
};
+static const struct attribute_group mlx90614_attr_group = {
+ .attrs = mlx90614_attributes,
+};
+
+/*
+ * Erase an address and write word.
+ * The mutex must be locked before calling.
+ */
+static s32 mlx90614_write_word(const struct i2c_client *client, u8 command,
+ u16 value)
+{
+ /*
+ * Note: The mlx90614 requires a PEC on writing but does not send us a
+ * valid 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(MLX90614_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(MLX90614_TIMING_EEPROM);
+
+ return ret;
+}
+
+/*
+ * Find the IIR value inside mlx90614_iir_values array and return its position
+ * which is equivalent to the bit value in sensor register
+ */
+static inline s32 mlx90614_iir_search(const struct i2c_client *client,
+ int value)
+{
+ int i;
+ s32 ret;
+
+ for (i = 0; i < ARRAY_SIZE(mlx90614_iir_values); ++i) {
+ if (value == mlx90614_iir_values[i])
+ break;
+ }
+
+ if (i == ARRAY_SIZE(mlx90614_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, MLX90614_CONFIG);
+ if (ret < 0)
+ return ret;
+
+ ret &= ~MLX90614_CONFIG_FIR_MASK;
+ ret |= MLX90614_CONST_FIR << MLX90614_CONFIG_FIR_SHIFT;
+ ret &= ~MLX90614_CONFIG_IIR_MASK;
+ ret |= i << MLX90614_CONFIG_IIR_SHIFT;
+
+ /* Write changed values */
+ ret = mlx90614_write_word(client, MLX90614_CONFIG, ret);
+ return ret;
+}
+
+#ifdef CONFIG_PM
+/*
+ * If @startup is true, make sure MLX90614_TIMING_STARTUP ms have elapsed since
+ * the last wake-up. This is normally only needed to get a valid temperature
+ * reading. EEPROM access does not need such delay.
+ * Return 0 on success, <0 on error.
+ */
+static int mlx90614_power_get(struct mlx90614_data *data, bool startup)
+{
+ unsigned long now;
+
+ if (!data->wakeup_gpio)
+ return 0;
+
+ pm_runtime_get_sync(&data->client->dev);
+
+ if (startup) {
+ now = jiffies;
+ if (time_before(now, data->ready_timestamp) &&
+ msleep_interruptible(jiffies_to_msecs(
+ data->ready_timestamp - now)) != 0) {
+ pm_runtime_put_autosuspend(&data->client->dev);
+ return -EINTR;
+ }
+ }
+
+ return 0;
+}
+
+static void mlx90614_power_put(struct mlx90614_data *data)
+{
+ if (!data->wakeup_gpio)
+ return;
+
+ pm_runtime_mark_last_busy(&data->client->dev);
+ pm_runtime_put_autosuspend(&data->client->dev);
+}
+#else
+static inline int mlx90614_power_get(struct mlx90614_data *data, bool startup)
+{
+ return 0;
+}
+
+static inline void mlx90614_power_put(struct mlx90614_data *data)
+{
+}
+#endif
+
static int mlx90614_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *channel, int *val,
int *val2, long mask)
return -EINVAL;
}
+ ret = mlx90614_power_get(data, true);
+ if (ret < 0)
+ return ret;
ret = i2c_smbus_read_word_data(data->client, cmd);
+ mlx90614_power_put(data);
+
if (ret < 0)
return ret;
+
+ /* MSB is an error flag */
+ if (ret & 0x8000)
+ return -EIO;
+
*val = ret;
return IIO_VAL_INT;
case IIO_CHAN_INFO_OFFSET:
- *val = 13657;
- *val2 = 500000;
+ *val = MLX90614_CONST_OFFSET_DEC;
+ *val2 = MLX90614_CONST_OFFSET_REM;
return IIO_VAL_INT_PLUS_MICRO;
case IIO_CHAN_INFO_SCALE:
- *val = 20;
+ *val = MLX90614_CONST_SCALE;
return IIO_VAL_INT;
+ case IIO_CHAN_INFO_CALIBEMISSIVITY: /* 1/65535 / LSB */
+ mlx90614_power_get(data, false);
+ mutex_lock(&data->lock);
+ ret = i2c_smbus_read_word_data(data->client,
+ MLX90614_EMISSIVITY);
+ mutex_unlock(&data->lock);
+ mlx90614_power_put(data);
+
+ if (ret < 0)
+ return ret;
+
+ if (ret == MLX90614_CONST_RAW_EMISSIVITY_MAX) {
+ *val = 1;
+ *val2 = 0;
+ } else {
+ *val = 0;
+ *val2 = ret * MLX90614_CONST_EMISSIVITY_RESOLUTION;
+ }
+ return IIO_VAL_INT_PLUS_NANO;
+ case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY: /* IIR setting with
+ FIR = 1024 */
+ mlx90614_power_get(data, false);
+ mutex_lock(&data->lock);
+ ret = i2c_smbus_read_word_data(data->client, MLX90614_CONFIG);
+ mutex_unlock(&data->lock);
+ mlx90614_power_put(data);
+
+ if (ret < 0)
+ return ret;
+
+ *val = mlx90614_iir_values[ret & MLX90614_CONFIG_IIR_MASK] / 100;
+ *val2 = (mlx90614_iir_values[ret & MLX90614_CONFIG_IIR_MASK] % 100) *
+ 10000;
+ return IIO_VAL_INT_PLUS_MICRO;
+ default:
+ return -EINVAL;
+ }
+}
+
+static int mlx90614_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *channel, int val,
+ int val2, long mask)
+{
+ struct mlx90614_data *data = iio_priv(indio_dev);
+ s32 ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_CALIBEMISSIVITY: /* 1/65535 / LSB */
+ if (val < 0 || val2 < 0 || val > 1 || (val == 1 && val2 != 0))
+ return -EINVAL;
+ val = val * MLX90614_CONST_RAW_EMISSIVITY_MAX +
+ val2 / MLX90614_CONST_EMISSIVITY_RESOLUTION;
+
+ mlx90614_power_get(data, false);
+ mutex_lock(&data->lock);
+ ret = mlx90614_write_word(data->client, MLX90614_EMISSIVITY,
+ val);
+ mutex_unlock(&data->lock);
+ mlx90614_power_put(data);
+
+ return ret;
+ case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY: /* IIR Filter setting */
+ if (val < 0 || val2 < 0)
+ return -EINVAL;
+
+ mlx90614_power_get(data, false);
+ mutex_lock(&data->lock);
+ ret = mlx90614_iir_search(data->client,
+ val * 100 + val2 / 10000);
+ mutex_unlock(&data->lock);
+ mlx90614_power_put(data);
+
+ return ret;
+ default:
+ return -EINVAL;
+ }
+}
+
+static int mlx90614_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;
}
.type = IIO_TEMP,
.modified = 1,
.channel2 = IIO_MOD_TEMP_OBJECT,
- .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+ .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),
},
.modified = 1,
.channel = 1,
.channel2 = IIO_MOD_TEMP_OBJECT,
- .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+ .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),
},
static const struct iio_info mlx90614_info = {
.read_raw = mlx90614_read_raw,
+ .write_raw = mlx90614_write_raw,
+ .write_raw_get_fmt = mlx90614_write_raw_get_fmt,
+ .attrs = &mlx90614_attr_group,
.driver_module = THIS_MODULE,
};
+#ifdef CONFIG_PM
+static int mlx90614_sleep(struct mlx90614_data *data)
+{
+ s32 ret;
+
+ if (!data->wakeup_gpio) {
+ dev_dbg(&data->client->dev, "Sleep disabled");
+ return -ENOSYS;
+ }
+
+ dev_dbg(&data->client->dev, "Requesting sleep");
+
+ mutex_lock(&data->lock);
+ ret = i2c_smbus_xfer(data->client->adapter, data->client->addr,
+ data->client->flags | I2C_CLIENT_PEC,
+ I2C_SMBUS_WRITE, MLX90614_OP_SLEEP,
+ I2C_SMBUS_BYTE, NULL);
+ mutex_unlock(&data->lock);
+
+ return ret;
+}
+
+static int mlx90614_wakeup(struct mlx90614_data *data)
+{
+ if (!data->wakeup_gpio) {
+ dev_dbg(&data->client->dev, "Wake-up disabled");
+ return -ENOSYS;
+ }
+
+ dev_dbg(&data->client->dev, "Requesting wake-up");
+
+ i2c_lock_adapter(data->client->adapter);
+ gpiod_direction_output(data->wakeup_gpio, 0);
+ msleep(MLX90614_TIMING_WAKEUP);
+ gpiod_direction_input(data->wakeup_gpio);
+ i2c_unlock_adapter(data->client->adapter);
+
+ data->ready_timestamp = jiffies +
+ msecs_to_jiffies(MLX90614_TIMING_STARTUP);
+
+ /*
+ * Quirk: the i2c controller may get confused right after the
+ * wake-up signal has been sent. As a workaround, do a dummy read.
+ * If the read fails, the controller will probably be reset so that
+ * further reads will work.
+ */
+ i2c_smbus_read_word_data(data->client, MLX90614_CONFIG);
+
+ return 0;
+}
+
+/* Return wake-up GPIO or NULL if sleep functionality should be disabled. */
+static struct gpio_desc *mlx90614_probe_wakeup(struct i2c_client *client)
+{
+ struct gpio_desc *gpio;
+
+ if (!i2c_check_functionality(client->adapter,
+ I2C_FUNC_SMBUS_WRITE_BYTE)) {
+ dev_info(&client->dev,
+ "i2c adapter does not support SMBUS_WRITE_BYTE, sleep disabled");
+ return NULL;
+ }
+
+ gpio = devm_gpiod_get_optional(&client->dev, "wakeup", GPIOD_IN);
+
+ if (IS_ERR(gpio)) {
+ dev_warn(&client->dev,
+ "gpio acquisition failed with error %ld, sleep disabled",
+ PTR_ERR(gpio));
+ return NULL;
+ } else if (!gpio) {
+ dev_info(&client->dev,
+ "wakeup-gpio not found, sleep disabled");
+ }
+
+ return gpio;
+}
+#else
+static inline int mlx90614_sleep(struct mlx90614_data *data)
+{
+ return -ENOSYS;
+}
+static inline int mlx90614_wakeup(struct mlx90614_data *data)
+{
+ return -ENOSYS;
+}
+static inline struct gpio_desc *mlx90614_probe_wakeup(struct i2c_client *client)
+{
+ return NULL;
+}
+#endif
+
/* Return 0 for single sensor, 1 for dual sensor, <0 on error. */
static int mlx90614_probe_num_ir_sensors(struct i2c_client *client)
{
data = iio_priv(indio_dev);
i2c_set_clientdata(client, indio_dev);
data->client = client;
+ mutex_init(&data->lock);
+ data->wakeup_gpio = mlx90614_probe_wakeup(client);
+
+ mlx90614_wakeup(data);
indio_dev->dev.parent = &client->dev;
indio_dev->name = id->name;
return ret;
}
+ if (data->wakeup_gpio) {
+ pm_runtime_set_autosuspend_delay(&client->dev,
+ MLX90614_AUTOSLEEP_DELAY);
+ pm_runtime_use_autosuspend(&client->dev);
+ pm_runtime_set_active(&client->dev);
+ pm_runtime_enable(&client->dev);
+ }
+
return iio_device_register(indio_dev);
}
static int mlx90614_remove(struct i2c_client *client)
{
- iio_device_unregister(i2c_get_clientdata(client));
+ struct iio_dev *indio_dev = i2c_get_clientdata(client);
+ struct mlx90614_data *data = iio_priv(indio_dev);
+
+ iio_device_unregister(indio_dev);
+
+ if (data->wakeup_gpio) {
+ pm_runtime_disable(&client->dev);
+ if (!pm_runtime_status_suspended(&client->dev))
+ mlx90614_sleep(data);
+ pm_runtime_set_suspended(&client->dev);
+ }
return 0;
}
};
MODULE_DEVICE_TABLE(i2c, mlx90614_id);
+#ifdef CONFIG_PM_SLEEP
+static int mlx90614_pm_suspend(struct device *dev)
+{
+ struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+ struct mlx90614_data *data = iio_priv(indio_dev);
+
+ if (data->wakeup_gpio && pm_runtime_active(dev))
+ return mlx90614_sleep(data);
+
+ return 0;
+}
+
+static int mlx90614_pm_resume(struct device *dev)
+{
+ struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+ struct mlx90614_data *data = iio_priv(indio_dev);
+ int err;
+
+ if (data->wakeup_gpio) {
+ err = mlx90614_wakeup(data);
+ if (err < 0)
+ return err;
+
+ pm_runtime_disable(dev);
+ pm_runtime_set_active(dev);
+ pm_runtime_enable(dev);
+ }
+
+ return 0;
+}
+#endif
+
+#ifdef CONFIG_PM
+static int mlx90614_pm_runtime_suspend(struct device *dev)
+{
+ struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+ struct mlx90614_data *data = iio_priv(indio_dev);
+
+ return mlx90614_sleep(data);
+}
+
+static int mlx90614_pm_runtime_resume(struct device *dev)
+{
+ struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+ struct mlx90614_data *data = iio_priv(indio_dev);
+
+ return mlx90614_wakeup(data);
+}
+#endif
+
+static const struct dev_pm_ops mlx90614_pm_ops = {
+ SET_SYSTEM_SLEEP_PM_OPS(mlx90614_pm_suspend, mlx90614_pm_resume)
+ SET_RUNTIME_PM_OPS(mlx90614_pm_runtime_suspend,
+ mlx90614_pm_runtime_resume, NULL)
+};
+
static struct i2c_driver mlx90614_driver = {
.driver = {
.name = "mlx90614",
- .owner = THIS_MODULE,
+ .pm = &mlx90614_pm_ops,
},
.probe = mlx90614_probe,
.remove = mlx90614_remove,
MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
MODULE_AUTHOR("Vianney le Clément de Saint-Marcq <vianney.leclement@essensium.com>");
+MODULE_AUTHOR("Crt Mori <cmo@melexis.com>");
MODULE_DESCRIPTION("Melexis MLX90614 contactless IR temperature sensor driver");
MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff