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authorYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 12:17:53 -0700
committerYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 15:44:42 -0700
commit9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch)
tree1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/Documentation/hwmon/ads7828
parent98260f3884f4a202f9ca5eabed40b1354c489b29 (diff)
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
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+Kernel driver ads7828
+=====================
+
+Supported chips:
+ * Texas Instruments/Burr-Brown ADS7828
+ Prefix: 'ads7828'
+ Datasheet: Publicly available at the Texas Instruments website:
+ http://focus.ti.com/lit/ds/symlink/ads7828.pdf
+
+ * Texas Instruments ADS7830
+ Prefix: 'ads7830'
+ Datasheet: Publicly available at the Texas Instruments website:
+ http://focus.ti.com/lit/ds/symlink/ads7830.pdf
+
+Authors:
+ Steve Hardy <shardy@redhat.com>
+ Vivien Didelot <vivien.didelot@savoirfairelinux.com>
+ Guillaume Roguez <guillaume.roguez@savoirfairelinux.com>
+
+Platform data
+-------------
+
+The ads7828 driver accepts an optional ads7828_platform_data structure (defined
+in include/linux/platform_data/ads7828.h). The structure fields are:
+
+* diff_input: (bool) Differential operation
+ set to true for differential mode, false for default single ended mode.
+
+* ext_vref: (bool) External reference
+ set to true if it operates with an external reference, false for default
+ internal reference.
+
+* vref_mv: (unsigned int) Voltage reference
+ if using an external reference, set this to the reference voltage in mV,
+ otherwise it will default to the internal value (2500mV). This value will be
+ bounded with limits accepted by the chip, described in the datasheet.
+
+ If no structure is provided, the configuration defaults to single ended
+ operation and internal voltage reference (2.5V).
+
+Description
+-----------
+
+This driver implements support for the Texas Instruments ADS7828 and ADS7830.
+
+The ADS7828 device is a 12-bit 8-channel A/D converter, while the ADS7830 does
+8-bit sampling.
+
+It can operate in single ended mode (8 +ve inputs) or in differential mode,
+where 4 differential pairs can be measured.
+
+The chip also has the facility to use an external voltage reference. This
+may be required if your hardware supplies the ADS7828 from a 5V supply, see
+the datasheet for more details.
+
+There is no reliable way to identify this chip, so the driver will not scan
+some addresses to try to auto-detect it. That means that you will have to
+statically declare the device in the platform support code.