Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 58 insertions, 0 deletions

diff --git a/Documentation/hwmon/ads7828 b/Documentation/hwmon/ads7828
new file mode 100644
index 000000000..f6e263e0f
--- /dev/null
+++ b/Documentation/hwmon/ads7828
@@ -0,0 +1,58 @@
+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.