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path: root/drivers/clk/clk.c
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2014-03-28clk: Fix minor errors in of_clk_init() function commentsSylwester Nawrocki1-2/+2
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2014-03-28clk: reverse default clk provider initialization order in of_clk_init()Sylwester Nawrocki1-1/+1
This restores the default clocks registration order as parsed from devicetree, i.e. as before commit 1771b10d605d26ccee771a7fb4b08718 "clk: respect the clock dependencies in of_clk_init", for when there is no explicit parent clock dependencies between clock providers specified in the device tree. It prevents regressions (boot failure, division by 0 errors) on imx and exynos platforms. Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com> Tested-by: Fabio Estevam <fabio.estevam@freescale.com> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2014-03-25clk: support hardware-specific debugfs entriesAlex Elder1-0/+4
Add a new clk_ops->debug_init method to allow a clock hardware driver to populate the clock's debugfs directory with entries beyond those common for every clock. Signed-off-by: Alex Elder <elder@linaro.org> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2014-03-21clk: turn rate change failed warning into pr_debugSascha Hauer1-1/+1
If a rate change failed it's the opportunity of the caller to handle this. Do not spam the log with a message. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Mike Turquette <mturquette@linaro.org>
2014-03-20clk: respect the clock dependencies in of_clk_initGregory CLEMENT1-4/+79
Until now the clock providers were initialized in the order found in the device tree. This led to have the dependencies between the clocks not respected: children clocks could be initialized before their parent clocks. Instead of forcing each platform to manage its own initialization order, this patch adds this work inside the framework itself. Using the data of the device tree the of_clk_init function now delayed the initialization of a clock provider if its parent provider was not ready yet. The strict dependency check (all parents of a given clk must be initialized) was added by Boris BREZILLON Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com> Signed-off-by: Boris BREZILLON <b.brezillon@overkiz.com> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2014-02-25Merge branch 'clk-fixes' into clk-nextMike Turquette1-6/+7
2014-02-25clk: Correct handling of NULL clk in __clk_{get, put}Sylwester Nawrocki1-6/+7
Ensure clk->kref is dereferenced only when clk is not NULL. Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com> Tested-by: Sachin Kamat <sachin.kamat@linaro.org> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2014-02-25clk: return probe defer when DT clock not yet readyJean-Francois Moine1-1/+1
At probe time, a clock device may not be ready when some other device wants to use it. This patch lets the functions clk_get/devm_clk_get return a probe defer when the clock is defined in the DT but not yet available. Signed-off-by: Jean-Francois Moine <moinejf@free.fr> Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com> Tested-by: Sylwester Nawrocki <s.nawrocki@samsung.com> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2014-02-25clk: add pr_debug & kerneldoc around clk notifiersMike Turquette1-1/+4
Both the pr_err and the additional kerneldoc aim to help when debugging errors thrown from within a clock rate-change notifier callback. Reported-by: Sören Brinkmann <soren.brinkmann@xilinx.com> Acked-by: Sören Brinkmann <soren.brinkmann@xilinx.com> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2014-02-24clk: add clock-indices supportBen Dooks1-1/+19
Add a property called clock-indices to allow clock-output-names to be used where the index used to lookup a clock is not a 1:1 mapping to the array position in the clock-output-names Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2014-02-19clk: Fix notifier documentationSoren Brinkmann1-12/+3
Contradicting to documenation, the notifier callbacks do receive the original clock rate in struct clk_notifier_data.old_rate and the new frequency struct clk_notifier_data.new_rate, independent of the notification reason. This behavior also seems to make more sense, since callbacks can use the same code to deterimine whether clocks are scaled up or down. Something which would not even possible in the post-rate-change case if the behavior was as documented. Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2014-01-27clk: Export more clk-provider functionsStephen Boyd1-0/+7
Allow drivers to be compiled as modules by exporting more clock provider functions. Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2014-01-18CLK: ti: add init support for clock IP blocksTero Kristo1-3/+1
ti_dt_clk_init_provider() can now be used to initialize the contents of a single clock IP block. This parses all the clocks under the IP block and calls the corresponding init function for them. This patch also introduces a helper function for the TI clock drivers to get register info from DT and append the master IP info to this. Signed-off-by: Tero Kristo <t-kristo@ti.com> Acked-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2014-01-17clk: Add set_rate_and_parent() opStephen Boyd1-19/+59
Some of Qualcomm's clocks can change their parent and rate at the same time with a single register write. Add support for this hardware to the common clock framework by adding a new set_rate_and_parent() op. When the clock framework determines that both the parent and the rate are going to change during clk_set_rate() it will call the .set_rate_and_parent() op if available and fall back to calling .set_parent() followed by .set_rate() otherwise. Reviewed-by: James Hogan <james.hogan@imgtec.com> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2013-12-31Merge branch 'clk-next-unregister' into clk-nextMike Turquette1-11/+174
Conflicts: drivers/clk/clk.c
2013-12-28clk: remove CONFIG_COMMON_CLK_DEBUGMike Turquette1-1/+1
Populate ${DEBUGS_MOUNT_POINT}/clk if CONFIG_DEBUG_FS is set. This eliminates the extra (annoying) step of enabling the config option manually. Signed-off-by: Mike Turquette <mturquette@linaro.org>
2013-12-23clk: add clk accuracy retrieval supportBoris BREZILLON1-7/+93
The clock accuracy is expressed in ppb (parts per billion) and represents the possible clock drift. Say you have a clock (e.g. an oscillator) which provides a fixed clock of 20MHz with an accuracy of +- 20Hz. This accuracy expressed in ppb is 20Hz/20MHz = 1000 ppb (or 1 ppm). Clock users may need the clock accuracy information in order to choose the best clock (the one with the best accuracy) across several available clocks. This patch adds clk accuracy retrieval support for common clk framework by means of a new function called clk_get_accuracy. This function returns the given clock accuracy expressed in ppb. In order to get the clock accuracy, this implementation adds one callback called recalc_accuracy to the clk_ops structure. This callback is given the parent clock accuracy (if the clock is not a root clock) and should recalculate the given clock accuracy. This callback is optional and may be implemented if the clock is not a perfect clock (accuracy != 0 ppb). Signed-off-by: Boris BREZILLON <b.brezillon@overkiz.com> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2013-12-15clk: Fix debugfs reparenting NULL pointer dereferenceStephen Boyd1-2/+1
Adding clocks from a kernel module can cause a NULL pointer dereference if the parent of a clock is added after the clock is added. This happens because __clk_init() iterates over the list of orphans and reparents the orphans to the clock being registered before creating the debugfs entry for the clock. Create the debugfs entry first before reparenting the orphans. Unable to handle kernel NULL pointer dereference at virtual address 00000028 pgd = ef3e4000 [00000028] *pgd=bf810831 Internal error: Oops: 17 [#1] PREEMPT SMP ARM Modules linked in: mmcc_8960(+) CPU: 0 PID: 52 Comm: modprobe Not tainted 3.12.0-rc2-00023-g1021a28-dirty #659 task: ef319200 ti: ef3a6000 task.ti: ef3a6000 PC is at lock_rename+0x24/0xc4 LR is at debugfs_rename+0x34/0x208 pc : [<c0317238>] lr : [<c047dfe4>] psr: 00000013 sp : ef3a7b88 ip : ef3a7ba8 fp : ef3a7ba4 r10: ef3d51cc r9 : ef3bc680 r8 : ef3d5210 r7 : ef3bc640 r6 : eee287e0 r5 : eee287e0 r4 : 00000000 r3 : ef3bc640 r2 : 00000000 r1 : eee287e0 r0 : 00000000 Flags: nzcv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user Control: 10c5787d Table: af3e406a DAC: 00000015 Process modprobe (pid: 52, stack limit = 0xef3a6240) Stack: (0xef3a7b88 to 0xef3a8000) 7b80: ef3bc640 ee4047e0 00000000 eee287e0 ef3a7bec ef3a7ba8 7ba0: c047dfe4 c0317220 ef3bc680 ef3d51cc ef3a7bdc ef3a7bc0 c06e29d0 c0268784 7bc0: c08946e8 ef3d5210 00000000 ef3bc700 ef3d5290 ef3d5210 ef3bc680 ef3d51cc 7be0: ef3a7c0c ef3a7bf0 c05b9e9c c047dfbc 00000000 00000000 ef3d5210 ef3d5290 7c00: ef3a7c24 ef3a7c10 c05baebc c05b9e30 00000001 00000001 ef3a7c64 ef3a7c28 7c20: c05bb124 c05bae9c bf000cd8 ef3bc7c0 000000d0 c0ff129c bf001774 00000002 7c40: ef3bc740 ef3d5290 ef0f9a10 bf001774 bf00042c 00000061 ef3a7c8c ef3a7c68 7c60: c05bb480 c05baed8 bf001774 ef3d5290 ef0f9a10 bf001774 ef38bc10 ef0f9a00 7c80: ef3a7cac ef3a7c90 c05bb5a8 c05bb3a0 bf001774 00000062 ef0f9a10 ef38bc18 7ca0: ef3a7cec ef3a7cb0 bf00010c c05bb56c 00000000 ef38ba00 00000000 ef3d60d0 7cc0: ef3a7cdc c0fefc24 ef0f9a10 c0a091c0 bf000d24 00000000 bf0029f0 bf006000 7ce0: ef3a7cfc ef3a7cf0 c05156c0 bf000040 ef3a7d2c ef3a7d00 c0513f5c c05156a8 7d00: ef3a7d2c ef0f9a10 ef0f9a10 bf000d24 ef0f9a44 c09ca588 00000000 bf006000 7d20: ef3a7d4c ef3a7d30 c05142b8 c0513ecc ef0fd25c 00000000 bf000d24 c0514214 7d40: ef3a7d74 ef3a7d50 c0512030 c0514220 ef0050a8 ef0fd250 ef0050f8 bf000d24 7d60: ef37c100 c09ed150 ef3a7d84 ef3a7d78 c05139c8 c0511fd8 ef3a7 7d80: c051344c c05139a8 bf000864 c09ca588 ef3a7db4 bf000d24 bf002 7da0: c09ca588 00000000 ef3a7dcc ef3a7db8 c05149dc c0513360 ef3a7 7dc0: ef3a7ddc ef3a7dd0 c0515914 c0514960 ef3a7dec ef3a7de0 bf006 7de0: ef3a7e74 ef3a7df0 c0208800 bf00600c ef3a7e1c ef3a7e00 c04c5 7e00: ffffffff c09d46c4 00000000 bf0029a8 ef3a7e34 ef3a7e20 c024c 7e20: ffffffff c09d46c4 ef3a7e5c ef3a7e38 c024e2fc c024ce40 00000 7e40: ef3a7f48 bf0029b4 bf0029a8 271aeb1c ef3a7f48 bf0029a8 00000001 ef383c00 7e60: bf0029f0 00000001 ef3a7f3c ef3a7e78 c028fac4 c0208718 bf0029b4 00007fff 7e80: c028cd58 000000d2 f0065000 00000000 ef3a7ebc 00000000 00000000 bf0029b4 7ea0: 00000000 bf0029ac bf0029b4 ef3a6000 ef3a7efc c08bf128 00000000 00000000 7ec0: 00000000 00000000 00000000 00000000 6e72656b 00006c65 00000000 00000000 7ee0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 7f00: 00000000 00000000 00000000 271aeb1c ef3a7f2c 00016376 b6f38008 001d3774 7f20: 00000080 c020f968 ef3a6000 00000000 ef3a7fa4 ef3a7f40 c02904dc c028e178 7f40: c020f898 010ccfa8 f0065000 00016376 f0073f60 f0073d7d f007a1e8 00002b24 7f60: 000039e4 00000000 00000000 00000000 0000002f 00000030 00000019 00000016 7f80: 00000012 00000000 00000000 010de1b2 b6f38008 010ccfa8 00000000 ef3a7fa8 7fa0: c020f6c0 c0290434 010de1b2 b6f38008 b6f38008 00016376 001d3774 00000000 7fc0: 010de1b2 b6f38008 010ccfa8 00000080 010de1b2 bedb6f90 010de1c9 0001d8dc 7fe0: 0000000c bedb674c 0001ce30 000094c4 60000010 b6f38008 00000008 0000001d [<c0317238>] (lock_rename+0x24/0xc4) from [<c047dfe4>] (debugfs_rename+0x34/0x208) [<c047dfe4>] (debugfs_rename+0x34/0x208) from [<c05b9e9c>] (clk_debug_reparent+0x78/0xc0) [<c05baebc>] (__clk_reparent+0x2c/0x3c) from [<c05bb124>] (__clk_init+0x258/0x4c8) [<c05bb124>] (__clk_init+0x258/0x4c8) from [<c05bb480>] (_clk_register+0xec/0x1cc) [<c05bb480>] (_clk_register+0xec/0x1cc) from [<c05bb5a8>] (devm_clk_register+0x48/0x7c) [<c05bb5a8>] (devm_clk_register+0x48/0x7c) from [<bf00010c>] (msm_mmcc_8960_probe+0xd8/0x190 [mmcc_8960]) [<bf00010c>] (msm_mmcc_8960_probe+0xd8/0x190 [mmcc_8960]) from [<c05156c0>] (platform_drv_probe+0x24/0x28) [<c05156c0>] (platform_drv_probe+0x24/0x28) from [<c0513f5c>] (driver_probe_device+0x9c/0x354) [<c0513f5c>] (driver_probe_device+0x9c/0x354) from [<c05142b8>] (__driver_attach+0xa4/0xa8) [<c05142b8>] (__driver_attach+0xa4/0xa8) from [<c0512030>] (bus_for_each_dev+0x64/0x98) [<c0512030>] (bus_for_each_dev+0x64/0x98) from [<c05139c8>] (driver_attach+0x2c/0x30) [<c05139c8>] (driver_attach+0x2c/0x30) from [<c051344c>] (bus_add_driver+0xf8/0x2a8) [<c051344c>] (bus_add_driver+0xf8/0x2a8) from [<c05149dc>] (driver_register+0x88/0x104) [<c05149dc>] (driver_register+0x88/0x104) from [<c0515914>] (__platform_driver_register+0x58/0x6c) [<c0515914>] (__platform_driver_register+0x58/0x6c) from [<bf006018>] (msm_mmcc_8960_driver_init+0x18/0x24 [mmcc_8960]) [<bf006018>] (msm_mmcc_8960_driver_init+0x18/0x24 [mmcc_8960]) from [<c0208800>] (do_one_initcall+0xf4/0x1b8) [<c0208800>] (do_one_initcall+0xf4/0x1b8) from [<c028fac4>] (load_module+0x1958/0x22bc) [<c028fac4>] (load_module+0x1958/0x22bc) from [<c02904dc>] (SyS_init_module+0xb4/0x120) [<c02904dc>] (SyS_init_module+0xb4/0x120) from [<c020f6c0>] (ret_fast_syscall+0x0/0x48) Code: e1500001 e1a04000 e1a05001 0a000021 (e5903028) Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2013-12-04clk: Implement clk_unregisterSylwester Nawrocki1-3/+118
clk_unregister() is currently not implemented and it is required when a clock provider module needs to be unloaded. Normally the clock supplier module is prevented to be unloaded by taking reference on the module in clk_get(). For cases when the clock supplier module deinitializes despite the consumers of its clocks holding a reference on the module, e.g. when the driver is unbound through "unbind" sysfs attribute, there are empty clock ops added. These ops are assigned temporarily to struct clk and used until all consumers release the clock, to avoid invoking callbacks from the module which just got removed. Signed-off-by: Jiada Wang <jiada_wang@mentor.com> Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
2013-12-04clk: Add common __clk_get(), __clk_put() implementationsSylwester Nawrocki1-0/+26
This patch adds common __clk_get(), __clk_put() clkdev helpers that replace their platform specific counterparts when the common clock API is used. The owner module pointer field is added to struct clk so a reference to the clock supplier module can be taken by the clock consumers. The owner module is assigned while the clock is being registered, in functions _clk_register() and __clk_register(). Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-12-04clk: Provide not locked variant of of_clk_get_from_provider()Sylwester Nawrocki1-8/+30
Add helper functions for the of_clk_providers list locking and an unlocked variant of of_clk_get_from_provider(). These functions are intended to be used in the clkdev to avoid race condition in the device tree based clock look up in clk_get(). Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-11-28clk: clean up everything on debugfs errorAlex Elder1-1/+2
[Maybe the third time will be the charm. -Alex] If CONFIG_COMMON_CLK_DEBUG is defined, clk_debug_create_one() is called to populate a debugfs directory with a few entries that are common for all clock types. If an error happens after creating the first one debugfs_remove() is called on the clock's directory. The problem with this is that no cleanup is done on the debugfs files already created in that directory, so the directory never actually gets removed. This problem is silently ignored. Fix this by calling debugfs_remove_recursive() instead. Reset the clk->dentry field to null afterward, to ensure it can't be mistaken as a valid pointer. Signed-off-by: Alex Elder <elder@linaro.org> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2013-10-08clk: of: helper for determining number of parent clocksMike Turquette1-0/+6
Walks the "clocks" array of parent clock phandles and returns the number. Signed-off-by: Mike Turquette <mturquette@linaro.org>
2013-10-02clk: Correct lookup logic in clk_fetch_parent_index()Tomasz Figa1-4/+7
This function is supposed to iterate over all parents of given child clock to find the index of given parent clock in its parent list, using parent cache if possible and falling back to string compare otherwise. However currently the logic falls back to string compare in every iteration in which clock cache entry does not match given parent, due to wrong check conditions. This patch corrects the logic to continue the loop if parent cache entry is present and does not match requested parent clock. In addition, redundant checks for parent cache array presence are removed, because it is always allocated in the beginning of the function. Signed-off-by: Tomasz Figa <tomasz.figa@gmail.com> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2013-10-02clk: Use kcalloc() to allocate arraysTomasz Figa1-7/+7
Instead of calculating sizes of arrays manually, kcalloc() can be used to allocate arrays of elements with defined size. This is just a cleanup patch without any functional changes. Signed-off-by: Tomasz Figa <tomasz.figa@gmail.com> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2013-10-02clk: Add error handling to clk_fetch_parent_index()Tomasz Figa1-11/+14
There are at least two different error cases that can happen in clk_fetch_parent_index() function: - allocation failure, - parent clock lookup failure, however it returns only an u8, which is supposed to contain parent clock index. This patch modified the function to return full int instead allowing positive clock indices and negative error codes to be returned. All users of this function are adjusted as well to handle the return value correctly. Signed-off-by: Tomasz Figa <tomasz.figa@gmail.com> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2013-09-10clk: only call get_parent if there is oneAlex Elder1-1/+1
In __clk_init(), after a clock is mostly initialized, a scan is done of the orphan clocks to see if the clock being registered is the parent of any of them. This code assumes that any clock that provides a get_parent method actually has at least one parent, and that's not a valid assumption. As a result, an orphan clock with no parent can return *something* as the parent index, and that value is blindly used to dereference the orphan's parent_names[] array (which will be ZERO_SIZE_PTR or NULL). Fix this by ensuring get_parent is only called for orphans with at least one parent. Signed-off-by: Alex Elder <elder@linaro.org> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2013-09-04clk: Move symbol export to proper locationThierry Reding1-1/+1
The __clk_get_flags() symbol is exported immediately following the clk_unprepare_unused_subtree() function. This is unusual, since a symbol export typically follows body of the function that it exports. Signed-off-by: Thierry Reding <treding@nvidia.com> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2013-08-30clk: fix new_parent dereference before null checkJames Hogan1-6/+7
Commit 71472c0 (clk: add support for clock reparent on set_rate) added a dereference of the new_parent pointer in clk_reparent(), but as detected by smatch clk_reparent() later checks whether new_parent is NULL. The dereference was in order to clear the new parent's new_child pointer to avoid duplicate POST_RATE_CHANGE notifications, so clearly isn't necessary if the new parent is NULL, so move it inside the "if (new_parent)" block. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: James Hogan <james.hogan@imgtec.com> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2013-08-28clk: get matching entry under lock in of_clk_init()Alex Elder1-2/+2
Currently of_clk_init() finds a matching device node while holding the device tree spinlock. When a matching device node is found, the lock is dropped and then re-acquired in order to get a reference to the matching device id structure. Acquiring the spinlock twice is unnecessary (and it opens a vulnerable window that could conceivably lead to errors). There already exists an interface for both finding and taking a reference to a device id under lock, so use it. Signed-off-by: Alex Elder <elder@linaro.org> Reviewed-by: Christian Daudt <csd@broadcom.com> Reviewed-by: Markus Mayer <markus.mayer@linaro.org> Reviewed-by: Matt Porter <matt.porter@linaro.org> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2013-08-22clk: handle NULL struct clk gracefullyMike Turquette1-1/+7
At some point changes to clk_set_rate and clk_set_parent introduced a bug whereby NULL struct clk pointers were treated as an error. This is in violation of the API in include/linux/clk.h. Reintroduce graceful handling of NULL clk's by bailing from clk_set_rate and clk_set_parent with return codes of zero. Signed-off-by: Mike Turquette <mturquette@linaro.org>
2013-08-19clk: clk-mux: implement remuxing on set_rateJames Hogan1-0/+49
Implement clk-mux remuxing if the CLK_SET_RATE_NO_REPARENT flag isn't set. This implements determine_rate for clk-mux to propagate to each parent and to choose the best one (like clk-divider this chooses the parent which provides the fastest rate <= the requested rate). The determine_rate op is implemented as a core helper function so that it can be easily used by more complex clocks which incorporate muxes. Signed-off-by: James Hogan <james.hogan@imgtec.com> Reviewed-by: Stephen Boyd <sboyd@codeaurora.org> Cc: Mike Turquette <mturquette@linaro.org> Cc: linux-arm-kernel@lists.infradead.org Signed-off-by: Mike Turquette <mturquette@linaro.org>
2013-08-19clk: add support for clock reparent on set_rateJames Hogan1-46/+96
Add core support to allow clock implementations to select the best parent clock when rounding a rate, e.g. the one which can provide the closest clock rate to that requested. This is by way of adding a new clock op, determine_rate(), which is like round_rate() but has an extra parameter to allow the clock implementation to optionally select a different parent clock. The core then takes care of reparenting the clock when setting the rate. The parent change takes place with the help of some new private data members. struct clk::new_parent specifies a clock's new parent (NULL indicates no change), and struct clk::new_child specifies a clock's new child (whose new_parent member points back to it). The purpose of these are to allow correct walking of the future tree for notifications prior to actually reparenting any clocks, specifically to skip child clocks who are being reparented to another clock (they will be notified via the new parent), and to include any new child clock. These pointers are set by clk_calc_subtree(), and the new_child pointer gets cleared when a child is actually reparented to avoid duplicate POST_RATE_CHANGE notifications. Each place where round_rate() is called, determine_rate() is checked first and called in preference. This restructures a few of the call sites to simplify the logic into if/else blocks. Signed-off-by: James Hogan <james.hogan@imgtec.com> Reviewed-by: Stephen Boyd <sboyd@codeaurora.org> Cc: Mike Turquette <mturquette@linaro.org> Cc: linux-arm-kernel@lists.infradead.org Signed-off-by: Mike Turquette <mturquette@linaro.org>
2013-08-19clk: move some parent related functions upwardsJames Hogan1-104/+104
Move some parent related functions up in clk.c so they can be used by the modifications in the following patch which enables clock reparenting during set_rate. No other changes are made so this patch makes no functional difference in isolation. This is separate from the following patch primarily to ease readability of that patch. Signed-off-by: James Hogan <james.hogan@imgtec.com> Reviewed-by: Stephen Boyd <sboyd@codeaurora.org> Cc: Mike Turquette <mturquette@linaro.org> Cc: linux-arm-kernel@lists.infradead.org Signed-off-by: Mike Turquette <mturquette@linaro.org>
2013-08-19clk: abstract parent cacheJames Hogan1-7/+14
Abstract access to the clock parent cache by defining clk_get_parent_by_index(clk, index). This allows access to parent clocks from clock drivers. Signed-off-by: James Hogan <james.hogan@imgtec.com> Reviewed-by: Stephen Boyd <sboyd@codeaurora.org> Cc: Mike Turquette <mturquette@linaro.org> Cc: linux-arm-kernel@lists.infradead.org Signed-off-by: Mike Turquette <mturquette@linaro.org>
2013-07-26clk: fix typosPeter Meerwald1-6/+7
Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2013-07-03Merge tag 'clk-for-linus-3.11' of git://git.linaro.org/people/mturquette/linuxLinus Torvalds1-51/+49
Pull clock framework updates from Mike Turquette: "The common clock framework changes for 3.11 include new clock drivers across several different platforms and architectures, fixes to existing drivers, a MAINTAINERS file fix and improvements to the basic clock types that allow them to be of use to more platforms than before. Only a few fixes to the core framework are included with most all of the changes landing in the various clock drivers themselves." * tag 'clk-for-linus-3.11' of git://git.linaro.org/people/mturquette/linux: (55 commits) clk: tegra: fix ifdef for tegra_periph_reset_assert inline clk: tegra: provide tegra_periph_reset_assert alternative clk: exynos4: Fix clock aliases for cpufreq related clocks clk: samsung: Add MUX_FA macro to pass flag and alias clk: add support for Rockchip gate clocks clk: vexpress: Make the clock drivers directly available for arm64 clk: vexpress: Use full node name to identify individual clocks clk: tegra: T114: add DFLL DVCO reset control clk: tegra: T114: add DFLL source clocks clk: tegra: T114: add FCPU clock shaper programming, needed by the DFLL clk: gate: add CLK_GATE_HIWORD_MASK clk: divider: add CLK_DIVIDER_HIWORD_MASK flag clk: mux: add CLK_MUX_HIWORD_MASK clk: Always notify whole subtree when reparenting MAINTAINERS: make drivers/clk entry match subdirs clk: honor CLK_GET_RATE_NOCACHE in clk_set_rate clk: use clk_get_rate() for debugfs clk: tegra: Use override bits when needed clk: tegra: override bits for Tegra30 PLLM clk: tegra: override bits for Tegra114 PLLM ...
2013-06-16clk: Always notify whole subtree when reparentingSoren Brinkmann1-2/+1
A clock's notifier count only reflects notifiers which are registered directly for that clock. A reparent operation though affects the whole subtree because of a potential rate change. When issuing the pre rate change notifications only the notifier count for the clock to be changed is considered and notifiers for subclocks may never be called. Resulting in clocks in the subtree which have registered notifiers, may receive a POST_- or ABORT_RATE_CHANGE notification, without a PRE_RATE_CHANGE_NOTIFICATION. Therefore always traverse the whole subtree when issueing pre rate change notifications during a reparent operation. Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2013-06-12clk: honor CLK_GET_RATE_NOCACHE in clk_set_ratePeter De Schrijver1-1/+1
clk_set_rate() uses clk->rate directly. This causes problems if the clock is marked as CLK_GET_RATE_NOCACHE. Hence call clk_get_rate() to get the current rate. Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2013-06-12clk: use clk_get_rate() for debugfsPeter De Schrijver1-2/+2
debugfs uses the rate field directly. However this ignores the CLK_GET_RATE_NOCACHE flag. Call clk_get_rate() instead. Tested-by: Mark Zhang <markz@nvidia.com> Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2013-06-07clk: remove notifier from list before freeing itLai Jiangshan1-0/+1
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-ga93cb29-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: Sören Brinkmann <soren.brinkmann@xilinx.com> Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Tested-by: Sören Brinkmann <soren.brinkmann@xilinx.com> Signed-off-by: Mike Turquette <mturquette@linaro.org> [mturquette@linaro.org: shortened $SUBJECT]
2013-05-29clk: Disable unused clocks after deferred probing is doneSaravana Kannan1-1/+1
With deferred probing, late_initcall() is too soon to declare a clock as unused. Wait for deferred probing to finish before declaring a clock as unused. Since deferred probing is done in late_initcall(), do the unused check to late_initcall_sync. Signed-off-by: Saravana Kannan <skannan@codeaurora.org> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2013-05-29clk: Fix race condition between clk_set_parent and clk_enable()Saravana Kannan1-45/+44
Without this patch, the following race condition is possible. * clk-A has two parents - clk-X and clk-Y. * All three are disabled and clk-X is current parent. * Thread A: clk_set_parent(clk-A, clk-Y). * Thread A: <snip execution flow> * Thread A: Grabs enable lock. * Thread A: Sees enable count of clk-A is 0, so doesn't enable clk-Y. * Thread A: Updates clk-A SW parent to clk-Y * Thread A: Releases enable lock. * Thread B: clk_enable(clk-A). * Thread B: clk_enable() enables clk-Y, then enabled clk-A and returns. clk-A is now enabled in software, but not clocking in hardware since the hardware parent is still clk-X. The only way to avoid race conditions between clk_set_parent() and clk_enable/disable() is to ensure that clk_enable/disable() calls don't require changes to hardware enable state between changes to software clock topology and hardware clock topology. The options to achieve the above are: 1. Grab the enable lock before changing software/hardware topology and release it afterwards. 2. Keep the clock enabled for the duration of software/hardware topology change so that any additional enable/disable calls don't try to change the hardware state. Once the topology change is complete, the clock can be put back in its original enable state. Option (1) is not an acceptable solution since the set_parent() ops might need to sleep. Therefore, this patch implements option (2). This patch doesn't violate any API semantics. clk_disable() doesn't guarantee that the clock is actually disabled. So, no clients of a clock can assume that a clock is disabled after their last call to clk_disable(). So, enabling the clock during a parent change is not a violation of any API semantics. This also has the nice side effect of simplifying the error handling code. Signed-off-by: Saravana Kannan <skannan@codeaurora.org> Acked-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Mike Turquette <mturquette@linaro.org> [mturquette@linaro.org: fixed up whitespace issue]
2013-04-28clk: add clk_ignore_unused option to keep boot clocks onOlof Johansson1-0/+13
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: Olof Johansson <olof@lixom.net> Signed-off-by: Mike Turquette <mturquette@linaro.org> [mturquette@linaro.org: fixed up trivial merge issue]
2013-04-16clk: export __clk_get_flags for modular clock providersSebastian Hesselbarth1-0/+1
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: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2013-04-11clk: Properly handle notifier return valuesSoren Brinkmann1-5/+5
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: Soren Brinkmann <soren.brinkmann@xilinx.com> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2013-04-09clk: Fixup locking issues for clk_set_parentUlf Hansson1-15/+52
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: Ulf Hansson <ulf.hansson@linaro.org> Cc: Rajagopal Venkat <rajagopal.venkat@linaro.org> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2013-04-09clk: Fixup errorhandling for clk_set_parentUlf Hansson1-20/+36
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: Ulf Hansson <ulf.hansson@linaro.org> Cc: Rajagopal Venkat <rajagopal.venkat@linaro.org> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2013-04-09clk: Restructure code for __clk_reparentUlf Hansson1-28/+42
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: Ulf Hansson <ulf.hansson@linaro.org> Cc: Rajagopal Venkat <rajagopal.venkat@linaro.org> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2013-04-02clk: allow reentrant calls into the clk frameworkMike Turquette1-2/+42
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: Mike Turquette <mturquette@linaro.org> Cc: Rajagopal Venkat <rajagopal.venkat@linaro.org> Cc: David Brown <davidb@codeaurora.org> Tested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
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