Linux-libre 4.2-gnu

1 files changed, 350 insertions, 5 deletions

diff --git a/drivers/iio/temperature/mlx90614.c b/drivers/iio/temperature/mlx90614.c
index a112fc9ab..7a2b639ea 100644
--- a/drivers/iio/temperature/mlx90614.c
+++ b/drivers/iio/temperature/mlx90614.c
@@ -12,12 +12,24 @@
  *
  * (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.
+ *
+ * TODO: filter configuration
  */
 
 #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>
 
@@ -51,10 +63,101 @@
 #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 */
+
 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 */
 };
 
+/*
+ * 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;
+}
+
+#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)
@@ -85,18 +188,85 @@ static int mlx90614_read_raw(struct iio_dev *indio_dev,
 			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;
+		*val = -13657;
 		*val2 = 500000;
 		return IIO_VAL_INT_PLUS_MICRO;
 	case IIO_CHAN_INFO_SCALE:
 		*val = 20;
 		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 == 65535) {
+			*val = 1;
+			*val2 = 0;
+		} else {
+			*val = 0;
+			*val2 = ret * 15259; /* 1/65535 ~ 0.000015259 */
+		}
+		return IIO_VAL_INT_PLUS_NANO;
+	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 * 65535 + val2 / 15259; /* 1/65535 ~ 0.000015259 */
+
+		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;
+	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;
 	default:
 		return -EINVAL;
 	}
@@ -115,7 +285,8 @@ static const struct iio_chan_spec mlx90614_channels[] = {
 		.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),
 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) |
 		    BIT(IIO_CHAN_INFO_SCALE),
 	},
@@ -125,7 +296,8 @@ static const struct iio_chan_spec mlx90614_channels[] = {
 		.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),
 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) |
 		    BIT(IIO_CHAN_INFO_SCALE),
 	},
@@ -133,9 +305,103 @@ static const struct iio_chan_spec mlx90614_channels[] = {
 
 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,
 	.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)
 {
@@ -166,6 +432,10 @@ static int mlx90614_probe(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;
@@ -188,12 +458,30 @@ static int mlx90614_probe(struct i2c_client *client,
 		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;
 }
@@ -204,10 +492,67 @@ static const struct i2c_device_id mlx90614_id[] = {
 };
 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,