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Filename Latest commit message Latest commit date
Ian Abbott 279dd75cec staging: comedi: dt2815: fix writing hi byte of analog output
commit ed87d33ddbcd9a1c3b5ae87995da34e6f51a862c upstream.

The DT2815 analog output command is 16 bits wide, consisting of the
12-bit sample value in bits 15 to 4, the channel number in bits 3 to 1,
and a voltage or current selector in bit 0.  Both bytes of the 16-bit
command need to be written in turn to a single 8-bit data register.
However, the driver currently only writes the low 8-bits.  It is broken
and appears to have always been broken.

Electronic copies of the DT2815 User's Manual seem impossible to find
online, but looking at the source code, a best guess for the sequence
the driver intended to use to write the analog output command is as
follows:

1. Wait for the status register to read 0x00.
2. Write the low byte of the command to the data register.
3. Wait for the status register to read 0x80.
4. Write the high byte of the command to the data register.

Step 4 is missing from the driver.  Add step 4 to (hopefully) fix the
driver.

Also add a "FIXME" comment about setting bit 0 of the low byte of the
command.  Supposedly, it is used to choose between voltage output and
current output, but the current driver always sets it to 1.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200406142015.126982-1-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-04-29 16:33:20 +02:00
arch powerpc/setup_64: Set cache-line-size based on cache-block-size 2020-04-29 16:33:20 +02:00
block block, bfq: invoke flush_idle_tree after reparent_active_queues in pd_offline 2020-04-23 10:36:26 +02:00
certs
crypto crypto: rng - Fix a refcounting bug in crypto_rng_reset() 2020-04-17 10:50:16 +02:00
Documentation USB: hub: Revert commit bd0e6c9614 ("usb: hub: try old enumeration scheme first for high speed devices") 2020-04-29 16:33:14 +02:00
drivers staging: comedi: dt2815: fix writing hi byte of analog output 2020-04-29 16:33:20 +02:00
fs cifs: fix uninitialised lease_key in open_shroot() 2020-04-29 16:33:19 +02:00
include mac80211: populate debugfs only after cfg80211 init 2020-04-29 16:33:18 +02:00
init kbuild: remove header compile test 2020-03-05 16:43:47 +01:00
ipc ipc/util.c: sysvipc_find_ipc() should increase position index 2020-04-29 16:33:00 +02:00
kernel audit: check the length of userspace generated audit records 2020-04-29 16:33:18 +02:00
lib lib/raid6/test: fix build on distros whose /bin/sh is not bash 2020-04-29 16:33:00 +02:00
LICENSES
mm mm/ksm: fix NULL pointer dereference when KSM zero page is enabled 2020-04-29 16:33:15 +02:00
net SUNRPC: Fix backchannel RPC soft lockups 2020-04-29 16:33:18 +02:00
samples vmalloc: fix remap_vmalloc_range() bounds checks 2020-04-29 16:33:14 +02:00
scripts kconfig: qconf: Fix a few alignment issues 2020-04-29 16:33:00 +02:00
security KEYS: Avoid false positive ENOMEM error on key read 2020-04-29 16:33:11 +02:00
sound ASoC: dapm: fixup dapm kcontrol widget 2020-04-29 16:33:18 +02:00
tools tools/vm: fix cross-compile build 2020-04-29 16:33:15 +02:00
usr initramfs: restore default compression behavior 2020-04-08 09:08:38 +02:00
virt KVM: Check for a bad hva before dropping into the ghc slow path 2020-03-05 16:43:48 +01:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore Modules updates for v5.4 2019-09-22 10:34:46 -07:00
.mailmap ARM: SoC fixes 2019-11-10 13:41:59 -08:00
COPYING
CREDITS MAINTAINERS: Remove Simon as Renesas SoC Co-Maintainer 2019-10-10 08:12:51 -07:00
Kbuild
Kconfig
MAINTAINERS MAINTAINERS: Update drm/i915 bug filing URL 2020-02-28 17:22:19 +01:00
Makefile Linux 5.4.35 2020-04-23 10:36:46 +02:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.