The @cn is stay in @clk_notifier_list after it is freed, it cause
memory corruption.

Example, if @clk is registered(first), unregistered(first),
registered(second), unregistered(second).

The freed @cn will be used when @clk is registered(second),
and the bug will be happened when @clk is unregistered(second):

[  517.040000] clk_notif_dbg clk_notif_dbg.1: clk_notifier_unregister()
[  517.040000] Unable to handle kernel paging request at virtual address 00df3008
[  517.050000] pgd = ed858000
[  517.050000] [00df3008] *pgd=00000000
[  517.060000] Internal error: Oops: 5 [#1] PREEMPT SMP ARM
[  517.060000] Modules linked in: clk_notif_dbg(O-) [last unloaded: clk_notif_dbg]
[  517.060000] CPU: 1 PID: 499 Comm: modprobe Tainted: G           O 3.10.0-rc3-00119-ga93cb29a-dirty #85
[  517.060000] task: ee1e0180 ti: ee3e6000 task.ti: ee3e6000
[  517.060000] PC is at srcu_readers_seq_idx+0x48/0x84
[  517.060000] LR is at srcu_readers_seq_idx+0x60/0x84
[  517.060000] pc : [<c0052720>]    lr : [<c0052738>]    psr: 80070013
[  517.060000] sp : ee3e7d48  ip : 00000000  fp : ee3e7d6c
[  517.060000] r10: 00000000  r9 : ee3e6000  r8 : 00000000
[  517.060000] r7 : ed84fe4c  r6 : c068ec90  r5 : c068e430  r4 : 00000000
[  517.060000] r3 : 00df3000  r2 : 00000000  r1 : 00000002  r0 : 00000000
[  517.060000] Flags: Nzcv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
[  517.060000] Control: 18c5387d  Table: 2d85804a  DAC: 00000015
[  517.060000] Process modprobe (pid: 499, stack limit = 0xee3e6238)
[  517.060000] Stack: (0xee3e7d48 to 0xee3e8000)
....
[  517.060000] [<c0052720>] (srcu_readers_seq_idx+0x48/0x84) from [<c0052790>] (try_check_zero+0x34/0xfc)
[  517.060000] [<c0052790>] (try_check_zero+0x34/0xfc) from [<c00528b0>] (srcu_advance_batches+0x58/0x114)
[  517.060000] [<c00528b0>] (srcu_advance_batches+0x58/0x114) from [<c0052c30>] (__synchronize_srcu+0x114/0x1ac)
[  517.060000] [<c0052c30>] (__synchronize_srcu+0x114/0x1ac) from [<c0052d14>] (synchronize_srcu+0x2c/0x34)
[  517.060000] [<c0052d14>] (synchronize_srcu+0x2c/0x34) from [<c0053a08>] (srcu_notifier_chain_unregister+0x68/0x74)
[  517.060000] [<c0053a08>] (srcu_notifier_chain_unregister+0x68/0x74) from [<c0375a78>] (clk_notifier_unregister+0x7c/0xc0)
[  517.060000] [<c0375a78>] (clk_notifier_unregister+0x7c/0xc0) from [<bf008034>] (clk_notif_dbg_remove+0x34/0x9c [clk_notif_dbg])
[  517.060000] [<bf008034>] (clk_notif_dbg_remove+0x34/0x9c [clk_notif_dbg]) from [<c02bb974>] (platform_drv_remove+0x24/0x28)
[  517.060000] [<c02bb974>] (platform_drv_remove+0x24/0x28) from [<c02b9bf8>] (__device_release_driver+0x8c/0xd4)
[  517.060000] [<c02b9bf8>] (__device_release_driver+0x8c/0xd4) from [<c02ba680>] (driver_detach+0x9c/0xc4)
[  517.060000] [<c02ba680>] (driver_detach+0x9c/0xc4) from [<c02b99c4>] (bus_remove_driver+0xcc/0xfc)
[  517.060000] [<c02b99c4>] (bus_remove_driver+0xcc/0xfc) from [<c02bace4>] (driver_unregister+0x54/0x78)
[  517.060000] [<c02bace4>] (driver_unregister+0x54/0x78) from [<c02bbb44>] (platform_driver_unregister+0x1c/0x20)
[  517.060000] [<c02bbb44>] (platform_driver_unregister+0x1c/0x20) from [<bf0081f8>] (clk_notif_dbg_driver_exit+0x14/0x1c [clk_notif_dbg])
[  517.060000] [<bf0081f8>] (clk_notif_dbg_driver_exit+0x14/0x1c [clk_notif_dbg]) from [<c00835e4>] (SyS_delete_module+0x200/0x28c)
[  517.060000] [<c00835e4>] (SyS_delete_module+0x200/0x28c) from [<c000edc0>] (ret_fast_syscall+0x0/0x48)
[  517.060000] Code: e5973004 e7911102 e0833001 e2881002 (e7933101)

Cc: stable@kernel.org
Reported-by: NSören Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
Tested-by: NSören Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: NMike Turquette <mturquette@linaro.org>
[mturquette@linaro.org: shortened $SUBJECT]

This is primarily useful when there's a driver that doesn't claim clocks
properly, but the bootloader leaves them on. It's not expected to be used
in normal cases, but for bringup and debug it's very useful to have the
option to not gate unclaimed clocks that are still on.
Signed-off-by: NOlof Johansson <olof@lixom.net>
Signed-off-by: NMike Turquette <mturquette@linaro.org>
[mturquette@linaro.org: fixed up trivial merge issue]

The common clock api provides some helpers for clk-providers but does
not export these helpers. This hinders clk-providers to be built as modules.
This patch adds __clk_get_flags() to the list of exported symbols.
Signed-off-by: NSebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

Notifiers may return NOTIFY_(OK|DONE|STOP|BAD). The CCF uses an
inconsistent mix of checking against NOTIFY_STOP or NOTIFY_BAD.
This inconsistency leaves errors undetected in some cases:
clk_set_parent() calls __clk_speculate_rates(), which stops when it
hits a NOTIFIER_BAD (STOP is ignored), and passes this value back to the
caller.
clk_set_parent() compares this return value against NOTIFY_STOP only,
ignoring NOTIFY_BAD returns.

Use NOTIFY_STOP_MASK to detect a negative notifier return value and
document all four return value options.
Signed-off-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

Updating the clock tree topology must be protected with the spinlock
when doing clk_set_parent, otherwise we can not handle the migration
of the enable_count in a safe manner.

While issuing the .set_parent callback to make the clk-hw perform the
switch to the new parent, we can not hold the spinlock since it is must
be allowed to be slow path. This complicates error handling, but is still
possible to achieve.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Cc: Rajagopal Venkat <rajagopal.venkat@linaro.org>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

Fixup the broken feature of allowing reparent of a clk to the
orhpan list and vice verse. When operating on a single-parent
clk, the .set_parent callback for the clk hw is optional to
implement, but for a multi-parent clk it is mandatory.

Moreover improve the errorhandling by verifying the prerequisites
before triggering clk notifiers. This will prevent unnecessary
rollback with ABORT_RATE_CHANGE.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Cc: Rajagopal Venkat <rajagopal.venkat@linaro.org>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

Split __clk_reparent into three pieces, one for doing the actual
reparent for updating the clock tree topology, one for the
COMMON_CLK_DEBUG code and one for doing the rate recalculation.

This patch also makes it possible to hold the spinlock over the
update of the clock tree topology, which could not be done before
when both debugfs updates and clock rate updates was done within
the same function.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Cc: Rajagopal Venkat <rajagopal.venkat@linaro.org>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

Reentrancy into the clock framework is necessary for clock operations
that result in nested calls to the clk api.  A common example is a clock
that is prepared via an i2c transaction, such as a clock inside of a
discrete audio chip or a power management IC.  The i2c subsystem itself
will use the clk api resulting in a deadlock:

clk_prepare(audio_clk)
	i2c_transfer(..)
		clk_prepare(i2c_controller_clk)

The ability to reenter the clock framework prevents this deadlock.

Other use cases exist such as allowing .set_rate callbacks to call
clk_set_parent to achieve the best rate, or to save power in certain
configurations.  Yet another example is performing pinctrl operations
from a clk_ops callback.  Calls into the pinctrl subsystem may call
clk_{un}prepare on an unrelated clock.  Allowing for nested calls to
reenter the clock framework enables both of these use cases.

Reentrancy is implemented by two global pointers that track the owner
currently holding a global lock.  One pointer tracks the owner during
sleepable, mutex-protected operations and the other one tracks the owner
during non-interruptible, spinlock-protected operations.

When the clk framework is entered we try to hold the global lock.  If it
is held we compare the current task against the current owner; a match
implies a nested call and we reenter.  If the values do not match then
we block on the lock until it is released.
Signed-off-by: NMike Turquette <mturquette@linaro.org>
Cc: Rajagopal Venkat <rajagopal.venkat@linaro.org>
Cc: David Brown <davidb@codeaurora.org>
Tested-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Reviewed-by: NUlf Hansson <ulf.hansson@linaro.org>

Create locking helpers for the global mutex and global spinlock.  The
definitions of these helpers will be expanded upon in the next patch
which introduces reentrancy into the locking scheme.
Signed-off-by: NMike Turquette <mturquette@linaro.org>
Cc: Rajagopal Venkat <rajagopal.venkat@linaro.org>
Cc: David Brown <davidb@codeaurora.org>
Tested-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Reviewed-by: NUlf Hansson <ulf.hansson@linaro.org>

Return type of function clk_propagate_rate_change is a pointer.
But 0 was being returned. Change it to NULL.
Silences the following warning:
drivers/clk/clk.c:977:24: warning: Using plain integer as NULL pointer
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Reviewed-by: NPankaj Jangra <jangra.pankaj9@gmail.com>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

An unprepare_unused callback is introduced due to the same reasons to
why the disable_unused callback was added.

During the clk_disable_unused sequence, those clk_hw that needs specific
treatment with regards to being unprepared, shall implement the
unprepare_unused callback.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

The unused ungated fast clocks are already being disabled from
clk_disable_unused at late init. This patch extend this sequence
to the slow unused prepared clocks to be unprepared.

Unless the optional .is_prepared callback is implemented by a
clk_hw the clk_disable_unused sequence will not unprepare any
unused clocks, since it will fall back to use the software
prepare counter.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NMike Turquette <mturquette@linaro.org>
[mturquette@linaro.org: fixed hlist accessors per b67bfe0d]

To reflect whether a clk_hw is prepared the clk_hw may implement
the optional is_prepared callback. If not implemented we fall back
to use the software prepare counter.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

I'm not sure why, but the hlist for each entry iterators were conceived

        list_for_each_entry(pos, head, member)

The hlist ones were greedy and wanted an extra parameter:

        hlist_for_each_entry(tpos, pos, head, member)

Why did they need an extra pos parameter? I'm not quite sure. Not only
they don't really need it, it also prevents the iterator from looking
exactly like the list iterator, which is unfortunate.

Besides the semantic patch, there was some manual work required:

 - Fix up the actual hlist iterators in linux/list.h
 - Fix up the declaration of other iterators based on the hlist ones.
 - A very small amount of places were using the 'node' parameter, this
 was modified to use 'obj->member' instead.
 - Coccinelle didn't handle the hlist_for_each_entry_safe iterator
 properly, so those had to be fixed up manually.

The semantic patch which is mostly the work of Peter Senna Tschudin is here:

@@
iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host;

type T;
expression a,c,d,e;
identifier b;
statement S;
@@

-T b;
    <+... when != b
(
hlist_for_each_entry(a,
- b,
c, d) S
|
hlist_for_each_entry_continue(a,
- b,
c) S
|
hlist_for_each_entry_from(a,
- b,
c) S
|
hlist_for_each_entry_rcu(a,
- b,
c, d) S
|
hlist_for_each_entry_rcu_bh(a,
- b,
c, d) S
|
hlist_for_each_entry_continue_rcu_bh(a,
- b,
c) S
|
for_each_busy_worker(a, c,
- b,
d) S
|
ax25_uid_for_each(a,
- b,
c) S
|
ax25_for_each(a,
- b,
c) S
|
inet_bind_bucket_for_each(a,
- b,
c) S
|
sctp_for_each_hentry(a,
- b,
c) S
|
sk_for_each(a,
- b,
c) S
|
sk_for_each_rcu(a,
- b,
c) S
|
sk_for_each_from
-(a, b)
+(a)
S
+ sk_for_each_from(a) S
|
sk_for_each_safe(a,
- b,
c, d) S
|
sk_for_each_bound(a,
- b,
c) S
|
hlist_for_each_entry_safe(a,
- b,
c, d, e) S
|
hlist_for_each_entry_continue_rcu(a,
- b,
c) S
|
nr_neigh_for_each(a,
- b,
c) S
|
nr_neigh_for_each_safe(a,
- b,
c, d) S
|
nr_node_for_each(a,
- b,
c) S
|
nr_node_for_each_safe(a,
- b,
c, d) S
|
- for_each_gfn_sp(a, c, d, b) S
+ for_each_gfn_sp(a, c, d) S
|
- for_each_gfn_indirect_valid_sp(a, c, d, b) S
+ for_each_gfn_indirect_valid_sp(a, c, d) S
|
for_each_host(a,
- b,
c) S
|
for_each_host_safe(a,
- b,
c, d) S
|
for_each_mesh_entry(a,
- b,
c, d) S
)
    ...+>

[akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c]
[akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c]
[akpm@linux-foundation.org: checkpatch fixes]
[akpm@linux-foundation.org: fix warnings]
[akpm@linux-foudnation.org: redo intrusive kvm changes]
Tested-by: NPeter Senna Tschudin <peter.senna@gmail.com>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: NSasha Levin <sasha.levin@oracle.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Modify of_clk_init function so that it will determine which
driver to initialize based on device tree instead of each driver
registering to it.

Based on a similar patch for drivers/irqchip by Thomas Petazzoni and
drivers/clocksource by Stephen Warren.
Signed-off-by: NPrashant Gaikwad <pgaikwad@nvidia.com>
Tested-by: NTony Prisk <linux@prisktech.co.nz>
Tested-by: NPawel Moll <pawel.moll@arm.com>
Tested-by: NRob Herring <rob.herring@calxeda.com>
Tested-by: NJosh Cartwright <josh.cartwright@ni.com>
Reviewed-by: NJosh Cartwright <josh.cartwright@ni.com>
Acked-by: NMaxime Ripard <maxime.ripard@anandra.org>
Signed-off-by: NMike Turquette <mturquette@linaro.org>
[mturquette@linaro.org: merge conflict from missing CLKSRC_OF_TABLES()]
Signed-off-by: NMike Turquette <mturquette@linaro.org>

On non-out case 'return ret;' is equivalent to 'return 0;' as the ret
variable is initialized at 0 and never changed.
Signed-off-by: NNestor Ovroy <novroy@riseup.net>

Clock information is dumped in JSON format which is easy
for machines to parse.

Each clock is represented as an object which has same name as
clock and following properties
	- enable_count
	- prepare_count
	- rate

Output is verified using online JSON editor.
Signed-off-by: NPrashant Gaikwad <pgaikwad@nvidia.com>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

Adds debug file "clk_summary" in /sys/kernel/debug/clk dir.
It helps to view all the clock registered in human-readable format.

For example:
   clock                        enable_cnt  prepare_cnt  rate
---------------------------------------------------------------------
 i2s0_sync                      0           0            24000000
 spdif_in_sync                  0           0            24000000
    spdif_mux                   0           0            24000000
       spdif                    0           0            24000000
          spdif_doubler         0           0            48000000
             spdif_div          0           0            48000000
                spdif_2x        0           0            48000000
 clk_32k                        2           2            32768
    blink_override              1           1            32768
       blink                    1           1            32768
 clk_m                          2           2            12000000
    clk_out_3_mux               0           0            12000000
       clk_out_3                0           0            12000000
    pll_ref                     3           3            12000000
       pll_e_mux                0           0            12000000
          pll_e                 0           0            100000000
             cml0               0           0            100000000
             cml1               0           0            100000000
             pciex              0           0            100000000
       pll_d2                   0           0            1000000
          pll_d2_out0           0           0            500000
       pll_d                    0           0            1000000
          pll_d_out0            0           0            500000
             dsib_mux           0           0            500000
                dsib            0           0            500000
             dsia               0           0            500000
Signed-off-by: NPrashant Gaikwad <pgaikwad@nvidia.com>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

This fixes the following error when building for arm-imx:
> ERROR: "__clk_get_name" [drivers/staging/imx-drm/ipu-v3/imx-ipu-v3.ko] undefined!
> make[1]: *** [__modpost] Error 1
> make: *** [modules] Error 2

There are valid usecases to get the name of a clock, be it for debugging
purposes or to register a children of a clock like done in this IPU driver.
Therefore exporting __clk_get_name() and make it available for others makes
sense.
Reported-by: NPeter Robinson <pbrobinson@gmail.com>
CC: Sascha Hauer <s.hauer@pengutronix.de>
CC: Mike Turquette <mturquette@linaro.org>
Signed-off-by: NNiels de Vos <ndevos@redhat.com>
Signed-off-by: NMike Turquette <mturquette@linaro.org>
[mturquette@linaro.org: removal of inline made redundant by 65800b2c]

The helper functions that access the opaque struct clk should
not be marked inline since they are contained in clk.c, but expected
to be used by other compilation units. This causes compile errors
under gcc-4.7

In file included from arch/arm/mach-omap2/clockdomain.c:25:0:
arch/arm/mach-omap2/clockdomain.c: In function ‘clkdm_clk_disable’:
include/linux/clk-provider.h:338:12: error: inlining failed in call to always_inline ‘__clk_get_enable_count’: function body not available
arch/arm/mach-omap2/clockdomain.c:1001:28: error: called from here
make[1]: *** [arch/arm/mach-omap2/clockdomain.o] Error 1
make: *** [arch/arm/mach-omap2] Error 2
Signed-off-by: NRuss Dill <Russ.Dill@ti.com>
Signed-off-by: NMike Turquette <mturquette@linaro.org>
[mturquette@linaro.org: removed fixes made redundant by commit 93532c8a]
[mturquette@linaro.org: improved $SUBJECT]

Some gate clocks have special needs which must be handled during the
disable-unused clocks sequence.  These needs might be driven by software
due to the fact that we're disabling a clock outside of the normal
clk_disable path and a clk's enable_count will not be accurate.  On the
other hand a specific hardware programming sequence might need to be
followed for this corner case.

This change is needed for the upcoming OMAP port to the common clock
framework.  Specifically, it is undesirable to treat the disable-unused
path identically to the normal clk_disable path since other software
layers are involved.  In this case OMAP's clockdomain code throws WARNs
and bails early due to the clock's enable_count being set to zero.  A
custom callback mitigates this problem nicely.

Cc: Paul Walmsley <paul@pwsan.com>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

When a clock, C is initialised any orphan clocks listing C as
a possible parent are reparented to it regardless of the
parent requested by the orphan's get_parent() operation.

This means that multiplexers registered before their parents
are reparented to the first parent subsequently declared,
regardless of the selection made by the hardware registers.

For example:
	static const char *sel[] = { "srcA", "srcB", "dummy", "srcC" };

	child = clk_register_mux(NULL, "child",  sel, ARRAY_SIZE(sel), ...);
	clk_register_fixed(NULL, "dummy", ...);
	clk_register_fixed(NULL, "srcA", ...);
	clk_register_fixed(NULL, "srcB", ...);
	clk_register_fixed(NULL, "srcC", ...);

Causes child's parent to always be "dummy".

To fix this, when an orphanned clock has a get_parent() operation,
only reparent to the clock indicated by get_parent().
Signed-off-by: NMartin Fuzzey <mfuzzey@parkeon.com>
Signed-off-by: NMike Turquette <mturquette@linaro.org>
[mturquette@linaro.org: improve $SUBJECT]

Some clock drivers can be simplified if devres takes care of
unregistering any registered clocks along error paths. Introduce
devm_clk_register() so that clock drivers get unregistration for
free along with simplified error paths.
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

Some of the helper functions return negative error codes if
passed a NULL clock. This can lead to confusing behavior when the
expected return value is unsigned. Fix up these accessors so that
they return unsigned values (or bool in the case of is_enabled).
This way we can't interpret NULL clocks as having valid and
interesting values.
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

For those SoCs that have hundreds of clock outputs, their clock
DT bindings could reasonably define #clock-cells as 1 and require
the client device specify the index of the clock it consumes in the
cell of its "clocks" phandle.

Add a generic of_clk_src_onecell_get() function for this purpose.
Signed-off-by: NShawn Guo <shawn.guo@linaro.org>
Reviewed-by: NRob Herring <rob.herring@calxeda.com>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

By using CLK_GET_RATE_NOCACHE flag, we tell the clk_get_rate API to
issue the hw for an updated clock rate. This can be used for a clock
which rate may be updated without a client necessary modifying it.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

clk_get() returns -ENOENT on error and some careless caller might
dereference it without error checking:

In mxc_rnga_remove():

        struct clk *clk = clk_get(&pdev->dev, "rng");

	// ...

        clk_disable(clk);

Since it's insane to audit the lots of existing and future clk users,
let's add a check in the callee to avoid kernel panic and warn about
any buggy user.

Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Viresh Kumar <viresh.kumar@st.com>
Cc: viresh kumar <viresh.linux@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.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>

caching parent clocks makes sense only when a clock has more
than one parent (mux clocks).
Avoid doing this for every other clock.
Signed-off-by: NRajendra Nayak <rnayak@ti.com>
[mturquette@linaro.org: removed extra parentheses]
Signed-off-by: NMike Turquette <mturquette@linaro.org>

The below commit introduced a bug in __clk_set_parent()
which could cause it to *skip* the parent validation
which makes sure the parent passed to the api is a valid
one.

    commit 7975059d
    Author: Rajendra Nayak <rnayak@ti.com>
    Date:   Wed Jun 6 14:41:31 2012 +0530

        clk: Allow late cache allocation for clk->parents

This was identified by the following compiler warning..

    drivers/clk/clk.c: In function '__clk_set_parent':
    drivers/clk/clk.c:1083:5: warning: 'i' may be used uninitialized in this function [-Wuninitialized]

.. as reported by Marc Kleine-Budde.

There were various options discussed on how to fix this, one
being initing 'i' to clk->num_parents, but the below approach
was found to be more appropriate as it also makes the 'parent
validation' code simpler to read.
Reported-by: NMarc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: NRajendra Nayak <rnayak@ti.com>
Signed-off-by: NMike Turquette <mturquette@linaro.org>
Cc: stable@kernel.org

clk_change_rate() is accessing parent's rate without checking
if the parent exists at all. In case of root clocks this will
cause NULL pointer dereference.

This patch follows what clk_calc_new_rates() does in such
situation.
Signed-off-by: NPawel Moll <pawel.moll@arm.com>
Signed-off-by: NMike Turquette <mturquette@linaro.org>
Cc: stable@kernel.org

Parent clocks for muxes are cached in clk->parents to
avoid frequent lookups, however the cache allocation happens
only during clock registeration and later clk_set_parent()
assumes a cache space available and allocated.

This is not entirely true for platforms which do early clock
registerations wherein the cache allocation using kzalloc
could fail during clock registeration.

Allow cache allocation to happen later as part of clk_set_parent()
to help such cases and avoid crashes assuming a cache being
available.

While here also replace existing kmalloc() with kzalloc()
in the file.
Signed-off-by: NRajendra Nayak <rnayak@ti.com>
Signed-off-by: NMike Turquette <mturquette@linaro.org>
Cc: stable@kernel.org

The clk_set_rate() code shouldn't check the clock's enable count when
validating CLK_SET_RATE_GATE flag since the enable count could change after
the validation. Similar to clk_set_parent(), it should instead check the
prepare count. The prepare count should go to zero only when the end user
expects the clock to not be enabled in the future. Since the code already
grabs the prepare count before validation, it's not possible for prepare
count to change after validation and by association not possible for a well
behaving end user to enable the clock while the set rate is in progress.
Signed-off-by: NSaravana Kannan <skannan@codeaurora.org>
Reviewed-by: NRichard Zhao <richard.zhao@freescale.com>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

While there's no actual implementation behind it having the call to use
in drivers makes them feel neater from a driver author point of view. An
actual implementation can wait for someone who needs to use the function
in a real system.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
[mturquette@linaro.org: void return type instead of int -EINVAL]
Signed-off-by: NMike Turquette <mturquette@linaro.org>

Exposing this option generates confusion and incorrect behavior for
single-image builds across platforms.  Enable this behavior permanently.
Signed-off-by: NMike Turquette <mturquette@linaro.org>
Acked-by: NSaravana Kannan <skannan@codeaurora.org>

Patch 'clk: always pass parent_rate into .round_rate' made a subtle
change to the semantics of .round_rate.  It is now expected for the
parent's rate to always be passed in, simplifying the implemenation of
various .round_rate callback definitions.

However the patch also introduced a bug in clk_calc_new_rates whereby a
clock without the CLK_SET_RATE_PARENT flag set could still propagate a
rate change up to a parent clock if the the .round_rate callback
modified the &best_parent_rate value in any way.

This patch fixes the issue at the framework level (in
clk_calc_new_rates) by specifically handling the case where the
CLK_SET_RATE_PARENT flag is not set.
Signed-off-by: NMike Turquette <mturquette@linaro.org>
Acked-by: NSascha Hauer <s.hauer@pengutronix.de>

This is well documented but isn't implemented. clk_set_rate() must check if
flags have CLK_SET_RATE_GATE bit set and is enabled too.
Signed-off-by: NViresh Kumar <viresh.kumar@st.com>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

Create a struct clk_init_data to hold all data that needs to be passed from
the platfrom specific driver to the common clock framework during clock
registration. Add a pointer to this struct inside clk_hw.

This has several advantages:
* Completely hides struct clk from many clock platform drivers and static
  clock initialization code that don't care for static initialization of
  the struct clks.
* For platforms that want to do complete static initialization, it removed
  the need to directly mess with the struct clk's fields while still
  allowing to statically allocate struct clk. This keeps the code more
  future proof even if they include clk-private.h.
* Simplifies the generic clk_register() function and allows adding optional
  fields in the future without modifying the function signature.
* Simplifies the static initialization of clocks on all platforms by
  removing the need for forward delcarations or convoluted macros.
Signed-off-by: NSaravana Kannan <skannan@codeaurora.org>
[mturquette@linaro.org: kept DEFINE_CLK_* macros and __clk_init]
Signed-off-by: NMike Turquette <mturquette@linaro.org>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Jeremy Kerr <jeremy.kerr@canonical.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
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: Jamie Iles <jamie@jamieiles.com>
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>

if (!clk->ops->round_rate && (clk->flags & CLK_SET_RATE_PARENT)) is true, then
we don't need to set clk->new_rate here, as we will call clk_calc_subtree()
afterwards and it also sets clk->new_rate.
Signed-off-by: NViresh Kumar <viresh.kumar@st.com>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

Need to propagate round_rate call for the clk that has no .round_rate
operation but with flag CLK_SET_RATE_PARENT set.

For example, clk_mux is a clk with no .round_rate operation.  However,
it could likely be in a clk_set_rate propagation path, saying it has
parent clk who has .round_rate and .set_rate operations.
Signed-off-by: NShawn Guo <shawn.guo@linaro.org>
Signed-off-by: NMike Turquette <mturquette@linaro.org>