*
* (7-bit I2C slave address 0x5a, 100KHz bus speed only!)
*
- * TODO: sleep mode, filter configuration
+ * 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>
#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 */
};
/*
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;
*val = ret;
*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;
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);
if (ret < 0)
return ret;
.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)
{
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,
projects / users / willy / linux.git / commitdiff