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Paweł Anikiel 59dad726de ASoC: ssm2602: Add workaround for playback distortions 
[ Upstream commit f63550e2b1 ]

Apply a workaround for what appears to be a hardware quirk.

The problem seems to happen when enabling "whole chip power" (bit D7
register R6) for the very first time after the chip receives power. If
either "output" (D4) or "DAC" (D3) aren't powered on at that time,
playback becomes very distorted later on.

This happens on the Google Chameleon v3, as well as on a ZYBO Z7-10:
https://ez.analog.com/audio/f/q-a/543726/solved-ssm2603-right-output-offset-issue/480229
I suspect this happens only when using an external MCLK signal (which
is the case for both of these boards).

Here are some experiments run on a Google Chameleon v3. These were run
in userspace using a wrapper around the i2cset utility:
ssmset() {
        i2cset -y 0 0x1a $(($1*2)) $2
}

For each of the following sequences, we apply power to the ssm2603
chip, set the configuration registers R0-R5 and R7-R8, run the selected
sequence, and check for distortions on playback.

  ssmset 0x09 0x01 # core
  ssmset 0x06 0x07 # chip, out, dac
  OK

  ssmset 0x09 0x01 # core
  ssmset 0x06 0x87 # out, dac
  ssmset 0x06 0x07 # chip
  OK

  (disable MCLK)
  ssmset 0x09 0x01 # core
  ssmset 0x06 0x1f # chip
  ssmset 0x06 0x07 # out, dac
  (enable MCLK)
  OK

  ssmset 0x09 0x01 # core
  ssmset 0x06 0x1f # chip
  ssmset 0x06 0x07 # out, dac
  NOT OK

  ssmset 0x06 0x1f # chip
  ssmset 0x09 0x01 # core
  ssmset 0x06 0x07 # out, dac
  NOT OK

  ssmset 0x09 0x01 # core
  ssmset 0x06 0x0f # chip, out
  ssmset 0x06 0x07 # dac
  NOT OK

  ssmset 0x09 0x01 # core
  ssmset 0x06 0x17 # chip, dac
  ssmset 0x06 0x07 # out
  NOT OK

For each of the following sequences, we apply power to the ssm2603
chip, run the selected sequence, issue a reset with R15, configure
R0-R5 and R7-R8, run one of the NOT OK sequences from above, and check
for distortions.

  ssmset 0x09 0x01 # core
  ssmset 0x06 0x07 # chip, out, dac
  OK

  (disable MCLK)
  ssmset 0x09 0x01 # core
  ssmset 0x06 0x07 # chip, out, dac
  (enable MCLK after reset)
  NOT OK

  ssmset 0x09 0x01 # core
  ssmset 0x06 0x17 # chip, dac
  NOT OK

  ssmset 0x09 0x01 # core
  ssmset 0x06 0x0f # chip, out
  NOT OK

  ssmset 0x06 0x07 # chip, out, dac
  NOT OK

Signed-off-by: Paweł Anikiel <pan@semihalf.com
Link: https://lore.kernel.org/r/20230508113037.137627-8-pan@semihalf.com
Signed-off-by: Mark Brown <broonie@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2023-06-09 10:34:10 +02:00
arch um: harddog: fix modular build 2023-06-09 10:34:10 +02:00
block block: fix bio-cache for passthru IO 2023-06-05 09:26:21 +02:00
certs certs: Fix build error when PKCS#11 URI contains semicolon 2023-02-09 11:28:11 +01:00
crypto crypto: testmgr - fix RNG performance in fuzz tests 2023-05-24 17:32:53 +01:00
Documentation ASoC: dt-bindings: Adjust #sound-dai-cells on TI's single-DAI codecs 2023-06-09 10:34:10 +02:00
drivers nvme-pci: add quirk for missing secondary temperature thresholds 2023-06-09 10:34:09 +02:00
fs gfs2: Don't deref jdesc in evict 2023-06-09 10:34:08 +02:00
include tcp: fix mishandling when the sack compression is deferred. 2023-06-09 10:34:05 +02:00
init gcc: disable '-Warray-bounds' for gcc-13 too 2023-04-26 14:28:43 +02:00
io_uring io_uring/rsrc: use nospec'ed indexes 2023-05-11 23:03:24 +09:00
ipc ipc: fix memory leak in init_mqueue_fs() 2022-12-31 13:32:01 +01:00
kernel x86/pci/xen: populate MSI sysfs entries 2023-05-30 14:03:22 +01:00
lib debugobjects: Don't wake up kswapd from fill_pool() 2023-05-30 14:03:20 +01:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm mm: fix zswap writeback race condition 2023-05-24 17:32:51 +01:00
net xfrm: Check if_id in inbound policy/secpath match 2023-06-09 10:34:10 +02:00
rust rust: kernel: Mark rust_fmt_argument as extern "C" 2023-04-26 14:28:38 +02:00
samples samples/bpf: Fix fout leak in hbm's run_bpf_prog 2023-05-24 17:32:38 +01:00
scripts recordmcount: Fix memory leaks in the uwrite function 2023-05-24 17:32:41 +01:00
security selinux: ensure av_permissions.h is built when needed 2023-05-11 23:03:06 +09:00
sound ASoC: ssm2602: Add workaround for playback distortions 2023-06-09 10:34:10 +02:00
tools perf ftrace latency: Remove unnecessary "--" from --use-nsec option 2023-06-09 10:34:02 +02:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt KVM: Fix vcpu_array[0] races 2023-05-24 17:32:50 +01:00
.clang-format inet: ping: use hlist_nulls rcu iterator during lookup 2022-12-01 12:42:46 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore Kbuild: add Rust support 2022-09-28 09:02:20 +02:00
.mailmap 9 hotfixes. 6 for MM, 3 for other areas. Four of these patches address 2022-12-10 17:10:52 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Remove Michal Marek from Kbuild maintainers 2022-11-16 14:53:00 +09:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS platform/x86: Move existing HP drivers to a new hp subdir 2023-05-24 17:32:42 +01:00
Makefile Linux 6.1.32 2023-06-05 09:26:22 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.