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Sascha Hauer 9fb27fac39 pwm: imx: Remove ipg clock and enable per clock when required
The use of the ipg clock was introduced with commit 7b27c160c6 ("pwm:
i.MX: fix clock lookup"). In the commit message it was claimed that the
ipg clock is enabled for register accesses. This is true for the
->config() callback, but not for the ->set_enable() callback. Given that
the ipg clock is not consistently enabled for all register accesses we
can assume that either it is not required at all or that the current
code does not work. Remove the ipg clock code for now so that it's no
longer in the way of refactoring the driver.

On the other hand, the i.MX 7 IP requires the peripheral clock to be
enabled before accessing its registers. Since ->config() can be called
when the PWM is disabled (in which case, the peripheral clock is also
disabled), we need to surround the imx->config() with
clk_prepare_enable(per_clk)/clk_disable_unprepare(per_clk) calls.

Note that the driver was working fine for the i.MX 7 IP so far because
the ipg and peripheral clock use the same hardware clock gate, which
guaranteed peripheral clock activation even when ->config() was called
when the PWM was disabled.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Cc: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Stefan Agner <stefan@agner.ch>
Tested-by: Stefan Agner <stefan@agner.ch>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2017-01-30 09:12:18 +01:00
arch mm: optimize PageWaiters bit use for unlock_page() 2016-12-29 11:03:15 -08:00
block ktime: Cleanup ktime_set() usage 2016-12-25 17:21:22 +01:00
certs certs: Add a secondary system keyring that can be added to dynamically 2016-04-11 22:48:09 +01:00
crypto crypto: testmgr - Use heap buffer for acomp test input 2016-12-27 17:32:11 +08:00
Documentation Documentation/unaligned-memory-access.txt: fix incorrect comparison operator 2016-12-27 13:08:42 -07:00
drivers pwm: imx: Remove ipg clock and enable per clock when required 2017-01-30 09:12:18 +01:00
firmware WHENCE: use https://linuxtv.org for LinuxTV URLs 2015-12-04 10:35:11 -02:00
fs ext4: Simplify DAX fault path 2016-12-26 20:29:25 -08:00
include Merge branch 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm 2017-01-01 12:27:05 -08:00
init mm: add PageWaiters indicating tasks are waiting for a page bit 2016-12-25 11:54:48 -08:00
ipc ipc/sem: avoid idr tree lookup for interrupted semop 2016-12-14 16:04:08 -08:00
kernel smp/hotplug: Undo tglxs brainfart 2016-12-26 17:30:24 -08:00
lib Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-12-25 14:30:04 -08:00
mm Merge branch 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm 2017-01-01 12:27:05 -08:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-12-27 16:04:37 -08:00
samples Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-12-23 16:49:12 -08:00
scripts Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2016-12-22 10:03:52 -08:00
security Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
sound ktime: Cleanup ktime_set() usage 2016-12-25 17:21:22 +01:00
tools Merge branch 'turbostat' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux 2016-12-25 14:01:28 -08:00
usr initramfs: allow again choice of the embedded initram compression algorithm 2016-12-14 16:04:08 -08:00
virt Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-12-25 14:30:04 -08:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Merge branch 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 2016-08-02 16:48:52 -04:00
.mailmap Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2016-10-15 09:26:12 -07:00
COPYING
CREDITS CREDITS: Remove outdated address information 2016-12-21 15:21:29 -08:00
Kbuild scripts/gdb: provide linux constants 2016-05-23 17:04:14 -07:00
Kconfig
MAINTAINERS Watchdog updates for v4.10 2016-12-24 11:27:45 -08:00
Makefile Linux 4.10-rc2 2017-01-01 14:31:53 -08:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

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

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

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.