diff options
Diffstat (limited to 'drivers/w1/slaves/w1_therm.c')
| -rw-r--r-- | drivers/w1/slaves/w1_therm.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/drivers/w1/slaves/w1_therm.c b/drivers/w1/slaves/w1_therm.c index 5ef583d520f..c1a702f8c80 100644 --- a/drivers/w1/slaves/w1_therm.c +++ b/drivers/w1/slaves/w1_therm.c @@ -41,6 +41,14 @@ MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol, temperature famil * If it was disabled a parasite powered device might not get the require * current to do a temperature conversion. If it is enabled parasite powered * devices have a better chance of getting the current required. + * In case the parasite power-detection is not working (seems to be the case + * for some DS18S20) the strong pullup can also be forced, regardless of the + * power state of the devices. + * + * Summary of options: + * - strong_pullup = 0 Disable strong pullup completely + * - strong_pullup = 1 Enable automatic strong pullup detection + * - strong_pullup = 2 Force strong pullup */ static int w1_strong_pullup = 1; module_param_named(strong_pullup, w1_strong_pullup, int, 0); @@ -197,7 +205,8 @@ static ssize_t w1_therm_read(struct device *device, continue; /* 750ms strong pullup (or delay) after the convert */ - if (!external_power && w1_strong_pullup) + if (w1_strong_pullup == 2 || + (!external_power && w1_strong_pullup)) w1_next_pullup(dev, tm); w1_write_8(dev, W1_CONVERT_TEMP); |