The patch titled
w1: feature, w1_therm.c use strong pullup and documentation
has been removed from the -mm tree. Its filename was
w1-feature-w1_thermc-use-strong-pullup-and-documentation.patch
This patch was dropped because an updated version will be merged
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: w1: feature, w1_therm.c use strong pullup and documentation
From: David Fries <david@xxxxxxxxx>
Added strong pullup to thermal sensor driver and general documentation on
the sensor.
Signed-off-by: David Fries <david@xxxxxxxxx>
Signed-off-by: Evgeniy Polyakov <johnpol@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/w1/00-INDEX | 2 +
Documentation/w1/slaves/00-INDEX | 4 ++
Documentation/w1/slaves/w1_therm | 41 +++++++++++++++++++++++++++++
drivers/w1/slaves/w1_therm.c | 15 +++++++++-
4 files changed, 60 insertions(+), 2 deletions(-)
diff -puN Documentation/w1/00-INDEX~w1-feature-w1_thermc-use-strong-pullup-and-documentation Documentation/w1/00-INDEX
--- a/Documentation/w1/00-INDEX~w1-feature-w1_thermc-use-strong-pullup-and-documentation
+++ a/Documentation/w1/00-INDEX
@@ -1,5 +1,7 @@
00-INDEX
- This file
+slaves/
+ - Drivers that provide support for specific family codes.
masters/
- Individual chips providing 1-wire busses.
w1.generic
diff -puN /dev/null Documentation/w1/slaves/00-INDEX
--- /dev/null
+++ a/Documentation/w1/slaves/00-INDEX
@@ -0,0 +1,4 @@
+00-INDEX
+ - This file
+w1_therm
+ - The Maxim/Dallas Semiconductor ds18*20 temperature sensor.
diff -puN /dev/null Documentation/w1/slaves/w1_therm
--- /dev/null
+++ a/Documentation/w1/slaves/w1_therm
@@ -0,0 +1,41 @@
+Kernel driver w1_therm
+====================
+
+Supported chips:
+ * Maxim ds18*20 based temperature sensors.
+
+Author: Evgeniy Polyakov <johnpol@xxxxxxxxxxx>
+
+
+Description
+-----------
+
+w1_therm provides basic temperature conversion for ds18*20 devices.
+supported family codes:
+W1_THERM_DS18S20 0x10
+W1_THERM_DS1822 0x22
+W1_THERM_DS18B20 0x28
+
+Support is provided through the sysfs w1_slave file. Each open and
+read sequence will initiate a temperature conversion then provide two
+lines of ASCII output. The first line contains the nine hex bytes
+read along with a calculated crc value and YES or NO if it matched.
+If the crc matched the returned values are retained. The second line
+displays the retained values along with a temperature in millidegrees
+Centigrade after t=.
+
+Parasite powered devices are limited to one slave performing a
+temperature conversion at a time. If none of the devices are parasite
+powered it would be possible to convert all the devices at the same
+time and then go back to read individual sensors. That isn't
+currently supported. The driver also doesn't support reduced
+precision (which would also reduce the conversion time).
+
+The module parameter strong_pullup can be set to 0 to disable the
+strong pullup or 1 to enable. If enabled the 5V strong pullup will be
+enabled when the conversion is taking place provided the master driver
+must support the strong pullup (or it falls back to a pullup
+resistor). The DS18b20 temperature sensor specification lists a
+maximum current draw of 1.5mA and that a 5k pullup resistor is not
+sufficient. The strong pullup is designed to provide the additional
+current required.
diff -puN drivers/w1/slaves/w1_therm.c~w1-feature-w1_thermc-use-strong-pullup-and-documentation drivers/w1/slaves/w1_therm.c
--- a/drivers/w1/slaves/w1_therm.c~w1-feature-w1_thermc-use-strong-pullup-and-documentation
+++ a/drivers/w1/slaves/w1_therm.c
@@ -37,6 +37,14 @@ MODULE_LICENSE("GPL");
MODULE_AUTHOR("Evgeniy Polyakov <johnpol@xxxxxxxxxxx>");
MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol, temperature family.");
+/* Allow the strong pullup to be disabled, but default to enabled.
+ * 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.
+ */
+static int w1_strong_pullup = 1;
+module_param_named(strong_pullup, w1_strong_pullup, int, 0);
+
static u8 bad_roms[][9] = {
{0xaa, 0x00, 0x4b, 0x46, 0xff, 0xff, 0x0c, 0x10, 0x87},
{}
@@ -192,9 +200,12 @@ static ssize_t w1_therm_read_bin(struct
int count = 0;
unsigned int tm = 750;
+ /* 750ms strong pullup (or delay) after the convert */
+ if (w1_strong_pullup)
+ w1_next_pullup(dev, tm);
w1_write_8(dev, W1_CONVERT_TEMP);
-
- msleep(tm);
+ if (!w1_strong_pullup)
+ msleep(tm);
if (!w1_reset_select_slave(sl)) {
_
Patches currently in -mm which might be from david@xxxxxxxxx are
w1-feature-w1_thermc-use-strong-pullup-and-documentation.patch
w1-be-able-to-manually-add-and-remove-slaves.patch
w1-recode-w1_slave_found-logic.patch
w1-new-module-parameter-search_count.patch
w1-document-add-remove-search_count-and-pullup.patch
w1-w1_slave_read_id-read-bug-use-device_attribute.patch
w1-w1_therm-fix-user-buffer-overflow-and-cat.patch
w1-w1_family-remove-unused-variable-need_exit.patch
w1-w1_therm-consistent-mutex-access-code-cleanup.patch
w1-w1_intc-use-first-available-master-number.patch
w1-w1c-s-printk-dev_dbg.patch
w1-w1_ioc-reset-comments-and-msleep.patch
w1-ds1wmc-msleep-for-reset.patch
w1-ds2490c-correct-print-message.patch
w1-ds2490c-add-support-for-strong-pullup.patch
w1-ds2490c-add-support-for-strong-pullup-checkpatch-fixes.patch
w1-ds2490c-ds_write_bit-grouping-error-disable-readback.patch
w1-ds2490c-disable-bit-read-and-write.patch
w1-ds2490c-simplify-and-fix-ds_touch_bit.patch
w1-ds2490c-ds_dump_status-rework.patch
w1-ds2490c-ds_reset-remove-ds_wait_status.patch
w1-ds2490c-reset-ds2490-in-init.patch
w1-ds2490c-magic-number-work.patch
w1-ds2490c-ds_write_block-remove-extra-ds_wait_status.patch
w1-documentation-w1-masters-ds2490-update.patch
w1-ds2490c-optimize-ds_set_pullup.patch
w1-ds2490c-optimize-ds_set_pullup-checkpatch-fixes.patch
--
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