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path: root/drivers/reset/core.c
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* reset: make (de)assert report success for self-deasserting reset driversPhilipp Zabel2017-07-191-6/+25
| | | | | | | | | | | | | | | | By now there are drivers using shared reset controls and (de)assert calls on platforms with self-deasserting reset lines and thus reset drivers that do not implement .assert() and .deassert(). As long as the initial state of the reset line is deasserted, there is no reason for a reset_control_assert call to return an error for shared reset controls, or for a reset_control_deassert call to return an error for either shared or exclusive reset controls: after a call to reset_control_deassert the reset line is guaranteed to be deasserted, and after a call to reset_control_assert it is valid for the reset line to stay deasserted for shared reset controls. Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de> Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
* reset: Add APIs to manage array of resetsVivek Gautam2017-07-191-1/+210
| | | | | | | | | | | | | | | | | | Many devices may want to request a bunch of resets and control them. So it's better to manage them as an array. Add APIs to _get() an array of reset_control, reusing the _assert(), _deassert(), and _reset() APIs for single reset controls. Since reset controls already may control multiple reset lines with a single hardware bit, from the user perspective, reset control arrays are not at all different from single reset controls. Note that these APIs don't guarantee that the reset lines managed in the array are handled in any particular order. Cc: Felipe Balbi <balbi@kernel.org> Cc: Jon Hunter <jonathanh@nvidia.com> Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org> [p.zabel@pengutronix.de: changed API to hide reset control arrays behind struct reset_control] Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
* reset: use kref for reference countingPhilipp Zabel2017-06-061-8/+15
| | | | | | Use kref for reference counting and enjoy the advantages of refcount_t. Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
* reset: add exported __reset_control_get, return NULL if optionalPhilipp Zabel2017-04-041-6/+16
| | | | | | | | | | | | | | | | | Rename the internal __reset_control_get/put functions to __reset_control_get/put_internal and add an exported __reset_control_get equivalent to __of_reset_control_get that takes a struct device parameter. This avoids the confusing call to __of_reset_control_get in the non-DT case and fixes the devm_reset_control_get_optional function to return NULL if RESET_CONTROLLER is enabled but dev->of_node == NULL. Fixes: bb475230b8e5 ("reset: make optional functions really optional") Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Ramiro Oliveira <Ramiro.Oliveira@synopsys.com> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
* Merge tag 'armsoc-drivers' of ↵Linus Torvalds2017-02-231-13/+42
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc Pull ARM SoC driver updates from Arnd Bergmann: "Driver updates for ARM SoCs. A handful of driver changes this time around. The larger changes are: - Reset drivers for hi3660 and zx2967 - AHCI driver for Davinci, acked by Tejun and brought in here due to platform dependencies - Cleanups of atmel-ebi (External Bus Interface) - Tweaks for Rockchip GRF (General Register File) usage (kitchensink misc register range on the SoCs) - PM domains changes for support of two new ZTE SoCs (zx296718 and zx2967)" * tag 'armsoc-drivers' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (53 commits) soc: samsung: pmu: Add register defines for pad retention control reset: make zx2967 explicitly non-modular reset: core: fix reset_control_put soc: samsung: pm_domains: Read domain name from the new label property soc: samsung: pm_domains: Remove message about failed memory allocation soc: samsung: pm_domains: Remove unused name field soc: samsung: pm_domains: Use full names in subdomains registration log sata: ahci-da850: un-hardcode the MPY bits sata: ahci-da850: add a workaround for controller instability sata: ahci: export ahci_do_hardreset() locally sata: ahci-da850: implement a workaround for the softreset quirk sata: ahci-da850: add device tree match table sata: ahci-da850: get the sata clock using a connection id soc: samsung: pmu: Remove duplicated define for ARM_L2_OPTION register memory: atmel-ebi: Enable the SMC clock if specified soc: samsung: pmu: Remove unused and duplicated defines memory: atmel-ebi: Properly handle multiple reference to the same CS memory: atmel-ebi: Fix the test to enable generic SMC logic soc: samsung: pm_domains: Add new Exynos5433 compatible soc: samsung: pmu: Add dummy support for Exynos5433 SoC ...
| * reset: core: fix reset_control_putHeiner Kallweit2017-02-011-1/+1
| | | | | | | | | | | | | | | | | | | | Commit "reset: make optional functions really optional" missed to adjust one check in reset_control_put, causing a NULL pointer access for optional resets. Fixes: bb475230b8e5 "reset: make optional functions really optional" Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
| * reset: make optional functions really optionalRamiro Oliveira2017-01-201-10/+39
| | | | | | | | | | | | | | | | | | | | | | | | The *_get_optional_* functions weren't really optional so this patch makes them really optional. These *_get_optional_* functions will now return NULL instead of an error if no matching reset phandle is found in the DT, and all the reset_control_* functions now accept NULL rstc pointers. Signed-off-by: Ramiro Oliveira <Ramiro.Oliveira@synopsys.com> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
| * reset: Change shared flag from int to boolRamiro Oliveira2017-01-201-4/+4
| | | | | | | | | | | | | | | | Since the new parameter being added is going to be a bool this patch changes the shared flag from int to bool to match the new parameter. Signed-off-by: Ramiro Oliveira <Ramiro.Oliveira@synopsys.com> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
* | reset: fix shared reset triggered_count decrement on errorJerome Brunet2017-02-171-1/+1
|/ | | | | | | | | | | | | | | | | | | For a shared reset, when the reset is successful, the triggered_count is incremented when trying to call the reset callback, so that another device sharing the same reset line won't trigger it again. If the reset has not been triggered successfully, the trigger_count should be decremented. The code does the opposite, and decrements the trigger_count on success. As a consequence, another device sharing the reset will be able to trigger it again. Fixed be removing negation in from of the error code of the reset function. Fixes: 7da33a37b48f ("reset: allow using reset_control_reset with shared reset") Signed-off-by: Jerome Brunet <jbrunet@baylibre.com> Acked-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
* reset: allow using reset_control_reset with shared resetMartin Blumenstingl2016-11-141-6/+37
| | | | | | | | | | | | | | | | | | | | | Some SoCs (for example Amlogic GXBB) implement a reset controller which only supports a reset pulse (triggered via reset_control_reset). At the same time multiple devices (in case of the Amlogic GXBB SoC both USB PHYs) are sharing the same reset line. This patch allows using reset_control_reset also for shared resets. There are limitations though: reset_control_reset can only be used if reset_control_assert was not used yet. reset_control_assert can only be used if reset_control_reset was not used yet. For shared resets the reset is only triggered once for the lifetime of the reset_control instance (the reset can be triggered again if all consumers of that specific reset_control are gone, as the reset framework will free the reset_control instance in that case). Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
* reset: warn on invalid input to reset_control_reset/assert/deassert/statusPhilipp Zabel2016-08-241-1/+11
| | | | | | | Instead of potentially crashing, dump a backtrace and return -EINVAL if rstc is NULL or an error code. Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
* reset: add devm_reset_controller_register APIMasahiro Yamada2016-05-301-0/+37
| | | | | | | | | | | Add a device managed API for reset_controller_register(). This helps in reducing code in .remove callbacks and sometimes dropping .remove callbacks entirely. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Laxman Dewangan <ldewangan@nvidia.com> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
* reset: Add support for shared reset controlsHans de Goede2016-03-301-11/+48
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In some SoCs some hw-blocks share a reset control. Add support for this setup by adding new: reset_control_get_shared() devm_reset_control_get_shared() devm_reset_control_get_shared_by_index() methods to get a reset_control. Note that this patch omits adding of_ variants, if these are needed later they can be easily added. This patch also changes the behavior of the existing exclusive reset_control_get() variants, if these are now called more then once for the same reset_control they will return -EBUSY. To catch existing drivers triggering this error (there should not be any) a WARN_ON(1) is added in this path. When a reset_control is shared, the behavior of reset_control_assert / deassert is changed, for shared reset_controls these will work like the clock-enable/disable and regulator-on/off functions. They will keep a deassert_count, and only (re-)assert the reset after reset_control_assert has been called as many times as reset_control_deassert was called. Calling reset_control_assert without first calling reset_control_deassert is not allowed on a shared reset control. Calling reset_control_reset is also not allowed on a shared reset control. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
* reset: Share struct reset_control between reset_control_get callsHans de Goede2016-03-301-21/+63
| | | | | | | | | | | | Now that struct reset_control no longer stores the device pointer for the device calling reset_control_get we can share a single struct reset_control when multiple calls to reset_control_get are made for the same reset line (same id / index). This is a preparation patch for adding support for shared reset lines. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
* reset: Make [of_]reset_control_get[_foo] functions wrappersHans de Goede2016-03-301-67/+17
| | | | | | | | | | | | | With both the regular, _by_index and _optional variants we already have quite a few variants of [of_]reset_control_get[_foo], the upcoming addition of shared reset lines support makes this worse. This commit changes all the variants into wrappers around common core functions. For completeness sake this commit also adds a new devm_get_reset_control_by_index wrapper. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
* reset: Move DT cell size check to the coreMaxime Ripard2016-01-251-3/+5
| | | | | | | | | | | | The core currently doesn't check that the DT cell size matches what the driver declares, which means that every xlate function needs to duplicate that check. Make sure that of_reset_control_get checks for this to avoid duplication and errors. Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
* reset: remove unnecessary local variable initialization from ↵Philipp Zabel2016-01-251-1/+1
| | | | | | | | | of_reset_control_get_by_index There is no need to initialize rstc, as it is unconditionally assigned the return value of a kzalloc call before use. Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
* reset: remove unused device pointer from struct reset_controlPhilipp Zabel2015-11-181-8/+1
| | | | | | | | Commit 0c5b2b915a58 ("reset: Mark function as static and remove unused function in core.c") removed the only user of the device pointer in struct reset_control. As it is now unused, remove it. Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
* reset: use ENOTSUPP instead of ENOSYSPhilipp Zabel2015-11-161-4/+4
| | | | | | | | ENOSYS is reserved to report invalid syscalls to userspace. Consistently return ENOTSUPP to indicate that the driver doesn't support the functionality or the reset framework is not enabled at all. Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
* reset: Fix of_reset_control_get() for consistent return valuesAlban Bedel2015-11-161-1/+4
| | | | | | | | | | | | | | | | When of_reset_control_get() is called without connection ID it returns -ENOENT when the 'resets' property doesn't exists or is an empty entry. However when a connection ID is given it returns -EINVAL when the 'resets' property doesn't exists or the requested name can't be found. This is because the error code returned by of_property_match_string() is just passed down as an index to of_parse_phandle_with_args(), which then returns -EINVAL. To get a consistent return value with both code paths we must return -ENOENT when of_property_match_string() fails. Signed-off-by: Alban Bedel <albeu@free.fr> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
* reset: add of_reset_control_get_by_index()Vince Hsu2015-11-161-11/+29
| | | | | | | | | | | Add of_reset_control_get_by_index() to allow the drivers to get reset device without knowing its name. Signed-off-by: Vince Hsu <vinceh@nvidia.com> [jonathanh@nvidia.com: Updated stub function to return -ENOTSUPP instead of -ENOSYS which should only be used for system calls.] Signed-off-by: Jon Hunter <jonathanh@nvidia.com> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
* reset: add reset_control_status helper functionDinh Nguyen2014-10-201-0/+15
| | | | | | | | | There are cases where a system will want to read a reset status bit before doing any other toggling. Add a reset_control_status helper function to the reset controller API. Signed-off-by: Dinh Nguyen <dinguyen@opensource.altera.com> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
* reset: Add of_reset_control_getMaxime Ripard2014-02-031-9/+30
| | | | | | | | | | | In some cases, you might need to deassert from reset an hardware block that doesn't associated to a struct device (CPUs, timers, etc.). Add a small helper to retrieve the reset controller from the device tree without the need to pass a struct device. Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
* reset: Mark function as static and remove unused function in core.cRashika Kheria2014-02-031-29/+1
| | | | | | | | | | | | | | | Mark function of_reset_simple_xlate() as static in core.c because it is not used outside this file. Also, remove functions devm_reset_control_put() and devm_reset_control_match() because they are unused. This eliminates the following warnings in core.c: drivers/reset/core.c:46:5: warning: no previous prototype for ‘of_reset_simple_xlate’ [-Wmissing-prototypes] drivers/reset/core.c:262:6: warning: no previous prototype for ‘devm_reset_control_put’ [-Wmissing-prototypes] Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
* reset: allow drivers to request probe deferralPhilipp Zabel2014-02-031-1/+1
| | | | | | | | | | If the requested reset controller is not yet available, have reset_control_get and device_reset return -EPROBE_DEFER so the driver can decide to request probe deferral. Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de> Acked-by: Shawn Guo <shawn.guo@linaro.org> Reviewed-by: Stephen Warren <swarren@nvidia.com>
* reset: NULL deref on allocation failureDan Carpenter2013-04-121-1/+1
| | | | | | | "rstc" is NULL here and we should use "rcdev" instead of "rstc->rcdev". Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
* reset: Add reset controller APIPhilipp Zabel2013-04-121-0/+297
This adds a simple API for devices to request being reset by separate reset controller hardware and implements the reset signal device tree binding. Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de> Reviewed-by: Stephen Warren <swarren@nvidia.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> Reviewed-by: Marek Vasut <marex@denx.de> Reviewed-by: Pavel Machek <pavel@ucw.cz>
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