On 08/07/2013 03:03 PM, Guenter Roeck wrote: > On 08/06/2013 11:52 PM, Wei Ni wrote: >> 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 <w...@nvidia.com> >> --- >> drivers/hwmon/lm90.c | 52 >> ++++++++++++++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 52 insertions(+) >> >> diff --git a/drivers/hwmon/lm90.c b/drivers/hwmon/lm90.c >> index cdff742..eeb0115 100644 >> --- a/drivers/hwmon/lm90.c >> +++ b/drivers/hwmon/lm90.c >> @@ -89,6 +89,8 @@ >> #include <linux/err.h> >> #include <linux/mutex.h> >> #include <linux/sysfs.h> >> +#include <linux/delay.h> >> +#include <linux/regulator/consumer.h> >> >> /* >> * Addresses to scan >> @@ -179,6 +181,8 @@ enum chips { lm90, adm1032, lm99, lm86, max6657, >> max6659, adt7461, max6680, >> #define LM90_HAVE_TEMP3 (1 << 6) /* 3rd temperature sensor >> */ >> #define LM90_HAVE_BROKEN_ALERT (1 << 7) /* Broken alert >> */ >> >> +#define POWER_ON_DELAY 20 /*ms*/ >> + >> /* >> * Driver data (common to all clients) >> */ >> @@ -302,6 +306,7 @@ 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 +1396,48 @@ static void lm90_init_client(struct i2c_client >> *client) >> i2c_smbus_write_byte_data(client, LM90_REG_W_CONFIG1, config); >> } >> >> +static int lm90_power_control(struct i2c_client *client, bool is_enable) >> +{ >> + struct lm90_data *data = i2c_get_clientdata(client); >> + int ret; >> + >> + mutex_lock(&data->update_lock); >> + >> + if (!data->lm90_reg) { >> + 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; >> + mutex_unlock(&data->update_lock); >> + return -ENODEV; > > I don't think it is acceptable to have the driver fail on pretty much all PCs.
Yes, you are right, I didn't consider it carefully, I will fix it. I think it's better to move these codes to the probe() directly. > > Also, I dislike that - even if the calling code doesn't fail - the above > message would be displayed on unload as well. > > In general, the 'unload' flag seems unnecessary. You could just call > > if (data->lm90_reg) > regulator_disable(); > > in the remove function. In addition to that, shouldn't you call > regulator_put() on exit ? Oh, sorry, I miss the regulator_put(), I will fix it. > Also, I am missing error handling in the probe function; if something else > fails, > the regulator is neither disabled nor released. It looks this patch have many problems, I will fix them. Thanks for your comments. > > Guenter > >> + } >> + } >> + if (is_enable) { >> + ret = regulator_enable(data->lm90_reg); >> + msleep(POWER_ON_DELAY); >> + } 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); >> + >> + return ret; >> +} >> + >> static int lm90_probe(struct i2c_client *client, >> const struct i2c_device_id *id) >> { >> @@ -1406,6 +1453,10 @@ static int lm90_probe(struct i2c_client *client, >> i2c_set_clientdata(client, data); >> mutex_init(&data->update_lock); >> >> + err = lm90_power_control(client, true); >> + if (err < 0) >> + return err; >> + >> /* Set the device type */ >> data->kind = id->driver_data; >> if (data->kind == adm1032) { >> @@ -1483,6 +1534,7 @@ 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); >> >> return 0; >> } >> > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/