There is currently a race condition in the device tree part of clk_get()
function, since the pointer returned from of_clk_get_by_name() may become
invalid before __clk_get() call. E.g. due to the clock provider driver
remove() callback being called in between of_clk_get_by_name() and
__clk_get().
Fix this by doing both the look up and __clk_get() operations with the
clock providers list mutex held. This ensures that the clock pointer
returned from __of_clk_get_from_provider() call and passed to __clk_get()
is valid, as long as the clock supplier module first removes its clock
provider instance and then does clk_unregister() on the corresponding
clocks.
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Mike Turquette <mturquette@linaro.org>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
The managed clk functions are currently only available when the generic clk
lookup framework is build. But the managed clk functions are merely wrappers
around clk_get and clk_put and do not depend on any specifics of the generic
lookup functions and there are still quite a few custom implementations of the
clk API. So make the managed functions available whenever the clk API is
implemented.
The patch also removes the custom implementation of devm_clk_get for the
coldfire platform.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
With commit 766e6a4ec6 (clk: add DT clock binding support),
compiling with OF && !COMMON_CLK is broken.
Reported-by: Alexandre Pereira da Silva <aletes.xgr@gmail.com>
Reported-by: Prashant Gaikwad <pgaikwad@nvidia.com>
Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
The commit 766e6a4 (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: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Rob Herring <rob.herring@calxeda.com>
Tested-by: Marek Vasut <marex@denx.de>
Tested-by: Lauri Hintsala <lauri.hintsala@bluegiga.com>
Signed-off-by: Mike 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: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Reviewed-by: Shawn Guo <shawn.guo@freescale.com>
Cc: Sascha Hauer <kernel@pengutronix.de>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
The common clock framework allocates clocks dynamically. Provide a
set of helpers to streamline the clkdev registration of the clock
lookups to avoid repetitive code sequences.
Reviewed-by: Viresh Kumar <viresh.kumar@st.com>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
clk_find must return as soon as it gets the correct clock. Currently it check
all clocks until it found a lookup with both dev_id and con_id matching.
If only one of them is passed, then we don't actually need to wait for both of
them to match. We can quit as soon as the requested id (dev_id or con_id)
matches.
Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Allow clk API users to simplify their cleanup paths by providing a
managed version of clk_get() and clk_put().
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
clkdev may incorrectly cause a clkdev entry with a NULL clk to return
-ENOENT. This is not the intention of this code; -ENOENT should only
be returned if the clock entry can not be found in the table. Fix
this.
Reported-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
factorise some generic infrastructure to assist looking up struct clks
for the ARM & SH architecture.
as the code is identical at 99%
put the arch specific code for allocation as example in asm/clkdev.h
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
