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w1: w1_therm: Add force-pullup option for "broken" sensors

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Signed-off-by: Michael Arndt <michael@scriptkiller.de>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Michael Arndt
2013-02-17 20:51:20 +01:00
committed by Greg Kroah-Hartman
parent 9c95bb6f25
commit 29e5507ae4
2 changed files with 20 additions and 4 deletions
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11
drivers/w1/slaves/w1_therm.c
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@@ -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);