The commit 766e6a4e (clk: add DT clock binding support) plugs device
tree clk lookup of_clk_get_by_name into clk_get, and fall on non-DT
lookup clk_get_sys if DT lookup fails.

The return check on of_clk_get_by_name takes (clk != NULL) as a
successful DT lookup.  But it's not the case.  For any system that
does not define clk lookup in device tree, ERR_PTR(-ENOENT) will be
returned, and consequently, all the client drivers calling clk_get
in their probe functions will fail to probe with error code -ENOENT
returned.

Fix the issue by checking of_clk_get_by_name return with !IS_ERR(clk),
and update of_clk_get and of_clk_get_by_name for !CONFIG_OF build
correspondingly.
Signed-off-by: NShawn Guo <shawn.guo@linaro.org>
Acked-by: NRob Herring <rob.herring@calxeda.com>
Tested-by: NMarek Vasut <marex@denx.de>
Tested-by: NLauri Hintsala <lauri.hintsala@bluegiga.com>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

Based on work 1st by Ben Herrenschmidt and Jeremy Kerr, then by Grant
Likely, this patch adds support to clk_get to allow drivers to retrieve
clock data from the device tree.

Platforms scan for clocks in DT with of_clk_init and a match table, and
the register a provider through of_clk_add_provider. The provider's
clk_src_get function will be called when a device references the
provider's OF node for a clock reference.

v6 (Rob Herring):
    - Return error values instead of NULL to match clock framework
      expectations

v5 (Rob Herring):
    - Move from drivers/of into common clock subsystem
    - Squashed "dt/clock: add a simple provider get function" and
      "dt/clock: add function to get parent clock name"
    - Rebase to 3.4-rc1
    - Drop CONFIG_OF_CLOCK and just use CONFIG_OF
    - Add missing EXPORT_SYMBOL to various functions
    - s/clock-output-name/clock-output-names/
    - Define that fixed-clock binding is a single output

v4 (Rob Herring):
    - Rework for common clk subsystem
    - Add of_clk_get_parent_name function

v3: - Clarified documentation

v2: - fixed errant ';' causing compile error
    - Editorial fixes from Shawn Guo
    - merged in adding lookup to clkdev
    - changed property names to match established convention. After
      working with the binding a bit it really made more sense to follow the
      lead of 'reg', 'gpios' and 'interrupts' by making the input simply
      'clocks' & 'clock-names' instead of 'clock-input-*', and to only use
      clock-output* for the producer nodes. (Sorry Shawn, this will mean
      you need to change some code, but it should be trivial)
    - Add ability to inherit clocks from parent nodes by using an empty
      'clock-ranges' property.  Useful for busses.  I could use some feedback
      on the new property name, 'clock-ranges' doesn't feel right to me.
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>
Signed-off-by: NRob Herring <rob.herring@calxeda.com>
Reviewed-by: NShawn Guo <shawn.guo@freescale.com>
Cc: Sascha Hauer <kernel@pengutronix.de>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

Remove trailing whitespace from 2 lines.
Signed-off-by: NRob Herring <rob.herring@calxeda.com>

The comment is inaccurate (it actually ends the CONFIG_COMMON_CLK
section, there's no else) and given that we've just got a single level
of ifdef isn't really needed anyway.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

Allow clk API users to simplify their cleanup paths by providing a
managed version of clk_get() and clk_put().
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The common clock framework defines a common struct clk useful across
most platforms as well as an implementation of the clk api that drivers
can use safely for managing clocks.

The net result is consolidation of many different struct clk definitions
and platform-specific clock framework implementations.

This patch introduces the common struct clk, struct clk_ops and an
implementation of the well-known clock api in include/clk/clk.h.
Platforms may define their own hardware-specific clock structure and
their own clock operation callbacks, so long as it wraps an instance of
struct clk_hw.

See Documentation/clk.txt for more details.

This patch is based on the work of Jeremy Kerr, which in turn was based
on the work of Ben Herrenschmidt.
Signed-off-by: NMike Turquette <mturquette@linaro.org>
Signed-off-by: NMike Turquette <mturquette@ti.com>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Tested-by: NAndrew Lunn <andrew@lunn.ch>
Reviewed-by: Rob Herring <rob.herring <at> calxeda.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Jeremy Kerr <jeremy.kerr@canonical.com>
Cc: Arnd Bergman <arnd.bergmann@linaro.org>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Shawn Guo <shawn.guo@freescale.com>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Richard Zhao <richard.zhao@linaro.org>
Cc: Saravana Kannan <skannan@codeaurora.org>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Linus Walleij <linus.walleij@stericsson.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Amit Kucheria <amit.kucheria@linaro.org>
Cc: Deepak Saxena <dsaxena@linaro.org>
Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>

It's for migrating to generic clk framework API.

The helper functions  help cases clk_enable/clk_disable is used
in non-atomic context.
For example, Call clk_enable in probe and clk_disable in remove.
Signed-off-by: NRichard Zhao <richard.zhao@linaro.org>
Signed-off-by: NSascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: NShawn Guo <shawn.guo@linaro.org>
Cc: Russell King <linux@arm.linux.org.uk>
Acked-by: NMarek Vasut <marek.vasut@gmail.com>

As discussed previously, there's the need on some platforms to run some
parts of clk_enable() in contexts which can schedule.  The solution
which was agreed upon was to provide clk_prepare() and clk_unprepare()
to contain this parts, while clk_enable() and clk_disable() perform
the atomic part.

This patch provides a common definition for clk_prepare() and
clk_unprepare() in linux/clk.h, and provides an upgrade path for
existing implementation and drivers: drivers can start using
clk_prepare() and clk_unprepare() once this patch is merged without
having to wait for platform support.  Platforms can then start to
provide these additional functions.

Eventually, HAVE_CLK_PREPARE will be removed from the kernel, and
everyone will have to provide these new APIs.
Acked-by: NSaravana Kannan <skannan@codeaurora.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This can be used for other arm platforms too as discussed
on the linux-arm-kernel list.

Also check the return value with IS_ERR and return PTR_ERR
as suggested by Russell King.
Signed-off-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This adds clk_get_sys to get a clock without the associated struct
device.
Signed-off-by: NSascha Hauer <s.hauer@pengutronix.de>

clk_get and clk_put may not be used from within interrupt context.  Change
comment to this function.
Signed-off-by: NAlex Raimondi <raimondi@miromico.ch>
Signed-off-by: NHaavard Skinnemoen <haavard.skinnemoen@atmel.com>
Acked-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

include/linux/clk.h is betraying its ARM origins.
Signed-off-by: NTodd Poynor <tpoynor@mvista.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This is needs to be visible to other architectures using the AMBA
bus and peripherals.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

It seems that clk_use() and clk_unuse() are additional complexity
which isn't required anymore.  Remove them from the clock framework
to avoid the additional confusion which they cause, and update all
ARM machine types except for OMAP.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

It seems that there's some confusion over how the clock source
framework should be used.  Add some additional comments to explain
the ambiguous areas.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

clk_get() comments can be confusing.  Add extra explaination of
the dev and id parameters to ensure correct usage.
Signed-off-by: NRussell King <rmk@arm.linux.org.uk>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!