The device lm90 can be controlled by the vdd rail. Adding the power control support to power on/off the vdd rail. And make sure that power is enabled before accessing the device. Signed-off-by: Wei Ni <wni@xxxxxxxxxx> --- drivers/hwmon/lm90.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 49 insertions(+) diff --git a/drivers/hwmon/lm90.c b/drivers/hwmon/lm90.c index cdff742..306a348 100644 --- a/drivers/hwmon/lm90.c +++ b/drivers/hwmon/lm90.c @@ -89,6 +89,7 @@ #include <linux/err.h> #include <linux/mutex.h> #include <linux/sysfs.h> +#include <linux/regulator/consumer.h> /* * Addresses to scan @@ -302,6 +303,7 @@ static const struct lm90_params lm90_params[] = { struct lm90_data { struct device *hwmon_dev; struct mutex update_lock; + struct regulator *lm90_reg; char valid; /* zero until following fields are valid */ unsigned long last_updated; /* in jiffies */ int kind; @@ -1391,6 +1393,32 @@ static void lm90_init_client(struct i2c_client *client) i2c_smbus_write_byte_data(client, LM90_REG_W_CONFIG1, config); } +static void lm90_power_control(struct i2c_client *client, bool is_enable) +{ + struct lm90_data *data = i2c_get_clientdata(client); + int ret; + + if (!data->lm90_reg) + return; + + mutex_lock(&data->update_lock); + + if (is_enable) + ret = regulator_enable(data->lm90_reg); + else + ret = regulator_disable(data->lm90_reg); + + if (ret < 0) + dev_err(&client->dev, + "Error in %s rail vdd, error %d\n", + (is_enable) ? "enabling" : "disabling", ret); + else + dev_info(&client->dev, "success in %s rail vdd\n", + (is_enable) ? "enabling" : "disabling"); + + mutex_unlock(&data->update_lock); +} + static int lm90_probe(struct i2c_client *client, const struct i2c_device_id *id) { @@ -1406,6 +1434,20 @@ static int lm90_probe(struct i2c_client *client, i2c_set_clientdata(client, data); mutex_init(&data->update_lock); + data->lm90_reg = regulator_get(&client->dev, "vdd"); + if (IS_ERR_OR_NULL(data->lm90_reg)) { + if (PTR_ERR(data->lm90_reg) == -ENODEV) + dev_info(&client->dev, + "No regulator found for vdd. Assuming vdd is always powered."); + else + dev_warn(&client->dev, + "Error [%ld] in getting the regulator handle for vdd.\n", + PTR_ERR(data->lm90_reg)); + data->lm90_reg = NULL; + } + + lm90_power_control(client, true); + /* Set the device type */ data->kind = id->driver_data; if (data->kind == adm1032) { @@ -1473,6 +1515,10 @@ exit_remove_files: lm90_remove_files(client, data); exit_restore: lm90_restore_conf(client, data); + lm90_power_control(client, false); + if (data->lm90_reg) + regulator_put(data->lm90_reg); + return err; } @@ -1483,6 +1529,9 @@ static int lm90_remove(struct i2c_client *client) hwmon_device_unregister(data->hwmon_dev); lm90_remove_files(client, data); lm90_restore_conf(client, data); + lm90_power_control(client, false); + if (data->lm90_reg) + regulator_put(data->lm90_reg); return 0; } -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html