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authorBreno Leitao <leitao@debian.org>2026-08-05 07:52:36 -0700
committerTejun Heo <tj@kernel.org>2026-08-10 11:47:20 -1000
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tree39f5b258386e1127d253d293194e9a2991bf3c34 /Documentation/hwmon/tmp421.rst
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workqueue: skip the node_nr_active update for non-unbound workqueuesgrafted
apply_wqattrs_commit() updates node_nr_active->max unconditionally. wq->node_nr_active[] is only allocated for unbound workqueues, so guard the call before per-cpu workqueues start using this path. No functional change: only unbound workqueues reach apply_wqattrs_*() today. Signed-off-by: Breno Leitao <leitao@debian.org> Signed-off-by: Tejun Heo <tj@kernel.org>
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+Kernel driver tmp421
+====================
+
+Supported chips:
+
+ * Texas Instruments TMP421
+
+ Prefix: 'tmp421'
+
+ Addresses scanned: I2C 0x2a, 0x4c, 0x4d, 0x4e and 0x4f
+
+ Datasheet: http://focus.ti.com/docs/prod/folders/print/tmp421.html
+
+ * Texas Instruments TMP422
+
+ Prefix: 'tmp422'
+
+ Addresses scanned: I2C 0x4c, 0x4d, 0x4e and 0x4f
+
+ Datasheet: http://focus.ti.com/docs/prod/folders/print/tmp421.html
+
+ * Texas Instruments TMP423
+
+ Prefix: 'tmp423'
+
+ Addresses scanned: I2C 0x4c and 0x4d
+
+ Datasheet: http://focus.ti.com/docs/prod/folders/print/tmp421.html
+
+ * Texas Instruments TMP441
+
+ Prefix: 'tmp441'
+
+ Addresses scanned: I2C 0x2a, 0x4c, 0x4d, 0x4e and 0x4f
+
+ Datasheet: https://www.ti.com/product/tmp441
+
+ * Texas Instruments TMP442
+
+ Prefix: 'tmp442'
+
+ Addresses scanned: I2C 0x4c and 0x4d
+
+ Datasheet: https://www.ti.com/product/tmp442
+
+Authors:
+
+ Andre Prendel <andre.prendel@gmx.de>
+
+Description
+-----------
+
+This driver implements support for Texas Instruments TMP421, TMP422,
+TMP423, TMP441, and TMP442 temperature sensor chips. These chips
+implement one local and up to one (TMP421, TMP441), up to two (TMP422,
+TMP442) or up to three (TMP423) remote sensors. Temperature is measured
+in degrees Celsius. The chips are wired over I2C/SMBus and specified
+over a temperature range of -40 to +125 degrees Celsius. Resolution
+for both the local and remote channels is 0.0625 degree C.
+
+The chips support only temperature measurement. The driver exports
+the temperature values via the following sysfs files:
+
+**temp[1-4]_input**
+
+**temp[2-4]_fault**
+
+Each sensor can be individually disabled via Devicetree or from sysfs
+via:
+
+**temp[1-4]_enable**
+
+If labels were specified in Devicetree, additional sysfs files will
+be present:
+
+**temp[1-4]_label**