summaryrefslogtreecommitdiff
path: root/include/linux/pwm.h
AgeCommit message (Collapse)Author
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-30pwm: Try to load modules during pwm_get()Hans de Goede
Add a module name string to the pwm_lookup struct and if specified try to load the module using request_module() if pwmchip_find_by_name() is unable to find the PWM chip. This is a last resort to work around drivers that can't - and can't be made to - deal with deferred probe. Signed-off-by: Hans de Goede <hdegoede@redhat.com> [thierry.reding@gmail.com: rename new macro, reword commit message] [thierry.reding@gmail.com: add comment explaining use-case] Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2017-01-04pwm: Remove .can_sleep from struct pwm_chipThierry Reding
All PWM devices have been marked as "might sleep" since v4.5, there is no longer a need to differentiate on a per-chip basis. Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2017-01-04pwm: Remove pwm_can_sleep()Thierry Reding
The last user of this function has been removed, so it is no longer needed. Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2016-09-05pwm: Unexport children before chip removalDavid Hsu
Exported pwm channels aren't removed before the pwmchip and are leaked. This results in invalid sysfs files. This fix removes all exported pwm channels before chip removal. Signed-off-by: David Hsu <davidhsu@google.com> Fixes: 76abbdde2d95 ("pwm: Add sysfs interface") Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2016-07-25Merge branch 'for-4.8/capture' into for-nextThierry Reding
2016-07-25Merge branch 'for-4.8/core' into for-nextThierry Reding
2016-07-08pwm: Remove gratuitous blank lineThierry Reding
Commit 5ec803edcb70 ("pwm: Add core infrastructure to allow atomic updates") introduced this double blank line by mistake. Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2016-07-08pwm: Add relative duty cycle manipulation helpersBoris Brezillon
The PWM framework expects PWM users to configure the duty cycle in nano- seconds, but many users want to express the duty cycle relatively to the period value (i.e. duty_cycle = 33% of the period). Add the pwm_{get,set}_relative_duty_cycle() helpers to ease this kind of conversion. Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com> Tested-by: Heiko Stuebner <heiko@sntech.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2016-07-08pwm: Add a helper to prepare a new PWM stateBoris Brezillon
The pwm_init_state() helper prepares a new state object containing the current PWM state except for the polarity and period fields which are set to the reference values (those in struct pwm_args). This is particularly useful for PWM users who want to apply a new duty- cycle expressed relatively to the reference period without changing the enable state. Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com> Tested-by: Heiko Stuebner <heiko@sntech.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2016-06-23pwm: Fix pwm_apply_args()Boris Brezillon
Commit 5ec803edcb70 ("pwm: Add core infrastructure to allow atomic updates"), implemented pwm_disable() as a wrapper around pwm_apply_state(), and then, commit ef2bf4997f7d ("pwm: Improve args checking in pwm_apply_state()") added missing checks on the ->period value in pwm_apply_state() to ensure we were not passing inappropriate values to the ->config() or ->apply() methods. The conjunction of these 2 commits led to a case where pwm_disable() was no longer succeeding, thus preventing the polarity setting done in pwm_apply_args(). Set a valid period in pwm_apply_args() to ensure polarity setting won't be rejected. Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Suggested-by: Brian Norris <briannorris@chromium.org> Fixes: 5ec803edcb70 ("pwm: Add core infrastructure to allow atomic updates") Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Brian Norris <briannorris@chromium.org> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2016-06-10pwm: Add PWM capture supportLee Jones
Supply a PWM capture callback op in order to pass back information obtained by running analysis on a PWM signal. This would normally (at least during testing) be called from the sysfs routines with a view to printing out PWM capture data which has been encoded into a string. Signed-off-by: Lee Jones <lee.jones@linaro.org> [thierry.reding@gmail.com: make capture data unsigned int for symmetry] Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2016-06-10pwm: Improve args checking in pwm_apply_state()Brian Norris
It seems like in the process of refactoring pwm_config() to utilize the newly-introduced pwm_apply_state() API, some args/bounds checking was dropped. In particular, I noted that we are now allowing invalid period selections, e.g.: # echo 1 > /sys/class/pwm/pwmchip0/export # cat /sys/class/pwm/pwmchip0/pwm1/period 100 # echo 101 > /sys/class/pwm/pwmchip0/pwm1/duty_cycle [... driver may or may not reject the value, or trigger some logic bug ...] It's better to see: # echo 1 > /sys/class/pwm/pwmchip0/export # cat /sys/class/pwm/pwmchip0/pwm1/period 100 # echo 101 > /sys/class/pwm/pwmchip0/pwm1/duty_cycle -bash: echo: write error: Invalid argument This patch reintroduces some bounds checks in both pwm_config() (for its signed parameters; we don't want to convert negative values into large unsigned values) and in pwm_apply_state() (which fix the above described behavior, as well as other potential API misuses). Fixes: 5ec803edcb70 ("pwm: Add core infrastructure to allow atomic updates") Signed-off-by: Brian Norris <briannorris@chromium.org> Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2016-05-17pwm: Add core infrastructure to allow atomic updatesBoris Brezillon
Add an ->apply() method to the pwm_ops struct to allow PWM drivers to implement atomic updates. This method is preferred over the ->enable(), ->disable() and ->config() methods if available. Add the pwm_apply_state() function to the PWM user API. Note that the pwm_apply_state() does not guarantee the atomicity of the update operation, it all depends on the availability and implementation of the ->apply() method. pwm_enable/disable/set_polarity/config() are now implemented as wrappers around the pwm_apply_state() function. pwm_adjust_config() is allowing smooth handover between the bootloader and the kernel. This function tries to adapt the current PWM state to the PWM arguments coming from a PWM lookup table or a DT definition without changing the duty_cycle/period proportion. Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com> [thierry.reding@gmail.com: fix a couple of typos] Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2016-05-17pwm: Add hardware readout infrastructureBoris Brezillon
Add a ->get_state() function to the pwm_ops struct to let PWM drivers initialize the PWM state attached to a PWM device. Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2016-05-17pwm: Move the enabled/disabled info into pwm_stateBoris Brezillon
Prepare the transition to PWM atomic update by moving the enabled and disabled state into the pwm_state struct. This way we can easily update the whole PWM state by copying the new state in the ->state field. Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2016-05-17pwm: Introduce the pwm_state conceptBoris Brezillon
The PWM state, represented by its period, duty_cycle and polarity is currently directly stored in the PWM device. Declare a pwm_state structure embedding those field so that we can later use this struct to atomically update all the PWM parameters at once. All pwm_get_xxx() helpers are now implemented as wrappers around pwm_get_state(). Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2016-05-17pwm: Keep PWM state in sync with hardware stateBoris Brezillon
Before the introduction of pwm_args, the core was resetting the PWM period and polarity states to the reference values (those provided through the DT, a PWM lookup table or hardcoded in the driver). Now that all PWM users are correctly using pwm_args to configure their PWM device, we can safely remove the pwm_apply_args() call in pwm_get() and of_pwm_get(). We can also get rid of the pwm_set_period() call in pwm_apply_args(), because PWM users are now directly using pargs->period instead of pwm_get_period(). By doing that we avoid messing with the current PWM period. The only remaining bit in pwm_apply_args() is the initial polarity setting, and it should go away when all PWM users have been patched to use the atomic API (with this API the polarity will be set along with other PWM arguments when configuring the PWM). Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2016-05-17pwm: Get rid of pwm->lockBoris BREZILLON
PWM devices are not protected against concurrent accesses. The lock in struct pwm_device might let PWM users think it is, but it's actually only protecting the enabled state. Removing this lock should be fine as long as all PWM users are aware that accesses to the PWM device have to be serialized, which seems to be the case for all of them except the sysfs interface. Patch the sysfs code by adding a lock to the pwm_export struct and making sure it's taken for all relevant accesses to the exported PWM device. Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2016-05-03pwm: Introduce the pwm_args conceptBoris Brezillon
Currently the PWM core mixes the current PWM state with the per-platform reference config (specified through the PWM lookup table, DT definition or directly hardcoded in PWM drivers). Create a struct pwm_args to store this reference configuration, so that PWM users can differentiate between the current and reference configurations. Patch all places where pwm->args should be initialized. We keep the pwm_set_polarity/period() calls until all PWM users are patched to use pwm_args instead of pwm_get_period/polarity(). Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com> [thierry.reding@gmail.com: reword kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2015-11-10pwm: Set enable state properly on failed call to enableJonathan Richardson
The pwm_enable() function didn't clear the enabled bit if a call to the driver's ->enable() callback returned an error. The result was that the state of the PWM core was wrong. Clearing the bit when enable returns an error ensures the state is properly set. Tested-by: Jonathan Richardson <jonathar@broadcom.com> Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by: Jonathan Richardson <jonathar@broadcom.com> [thierry.reding@gmail.com: add missing kerneldoc for the lock] Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2015-08-17pwm: Clean up kerneldocThierry Reding
Clean up kerneldoc in preparation for including the PWM documentation in DocBook. Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2015-08-17pwm: Remove useless whitespaceThierry Reding
Remove useless tabs used for padding in structure definitions as well as some blank lines. Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2015-07-20pwm: Add pwm_get_polarity() helper functionBoris Brezillon
Some drivers are directly accessing the ->polarity field in pwm_device. Add a helper to retrieve the current polarity so that we can easily move this field elsewhere (required to support atomic update). Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2015-07-20pwm: Constify PWM device where possibleBoris Brezillon
The PWM argument is not modified in PWM property accessors, make it a const argument so that the accessors can be used from sysfs. Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2015-07-20pwm: Add the pwm_is_enabled() helperBoris Brezillon
Some PWM drivers are testing the PWMF_ENABLED flag. Create a helper function to hide the logic behind enabled test. This will allow us to smoothly move from the current approach to an atomic PWM update approach. Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2015-06-12pwm: Add pwmchip_add_with_polarity() APITim Kryger
Add a new function to register a PWM chip with channels that have their initial polarity as specified by an additional parameter. This benefits drivers of controllers that by default operate with inversed polarity by removing the need to modify the polarity during initialization. Signed-off-by: Tim Kryger <tim.kryger@gmail.com> Signed-off-by: Jonathan Richardson <jonathar@broadcom.com> [thierry.reding@gmail.com: export pwmchip_add_with_polarity()] Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2015-05-06pwm: Add support to remove registered consumer lookup tablesShobhit Kumar
In case some drivers are unloading, they can remove lookup tables which they had registered during their load time to avoid redundant entries if loaded again. CC: Samuel Ortiz <sameo@linux.intel.com> Cc: Linus Walleij <linus.walleij@linaro.org> Cc: Alexandre Courbot <gnurou@gmail.com> Cc: Thierry Reding <thierry.reding@gmail.com> Signed-off-by: Shobhit Kumar <shobhit.kumar@intel.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2014-05-21pwm: modify PWM_LOOKUP to initialize all struct pwm_lookup membersAlexandre Belloni
Now that PWM_LOOKUP is not used anymore, modify it to initialize all the members of struct pwm_lookup. Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2014-05-21pwm: add period and polarity to struct pwm_lookupAlexandre Belloni
Add period and polarity members to struct pwm_lookup so that platforms using the lookup table can be treated the same way as those using the device tree. Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2014-02-10pwm: Remove obsolete HAVE_PWM Kconfig symbolSascha Hauer
Before we had the PWM framework we used to have a barebone PWM api. The HAVE_PWM Kconfig symbol used to be selected by the PWM drivers to specify the PWM API is present in the kernel. Since the last legacy driver is gone the HAVE_PWM symbol can go aswell. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com> Cc: Eric Miao <eric.y.miao@gmail.com> Cc: Haojian Zhuang <haojian.zhuang@gmail.com> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Cc: Thierry Reding <thierry.reding@gmail.com> Cc: linux-pwm@vger.kernel.orig Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2013-06-21pwm: Add sysfs interfaceH Hartley Sweeten
Add a simple sysfs interface to the generic PWM framework. /sys/class/pwm/ `-- pwmchipN/ for each PWM chip |-- export (w/o) ask the kernel to export a PWM channel |-- npwm (r/o) number of PWM channels in this PWM chip |-- pwmX/ for each exported PWM channel | |-- duty_cycle (r/w) duty cycle (in nanoseconds) | |-- enable (r/w) enable/disable PWM | |-- period (r/w) period (in nanoseconds) | `-- polarity (r/w) polarity of PWM (normal/inversed) `-- unexport (w/o) return a PWM channel to the kernel Based on work by Lars Poeschel. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Lars Poeschel <poeschel@lemonage.de> Cc: Ryan Mallon <rmallon@gmail.com> Cc: Rob Landley <rob@landley.net> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2013-02-26Merge tag 'for-3.9-rc1' of git://gitorious.org/linux-pwm/linux-pwmLinus Torvalds
Pull PWM changes from Thierry Reding: "A new driver has been added to support the PWM mode of the timer counter blocks found on Atmel AT91 SoCs. The VT8500 driver now supports changing the PWM signal polarity and the TI drivers (EHRPWM and ECAP) gained suspend and resume functionality. User drivers can now query the core for whether access to a PWM device will sleep (if the PWM chip is on a slow bus such as I2C or SPI). The pwm-backlight driver now handles the backlight BL_CORE_FBBLANK state in addition to the FB layer's blanking states. To round things off, a few fixes and cleanups are also included" * tag 'for-3.9-rc1' of git://gitorious.org/linux-pwm/linux-pwm: pwm: twl: Use to_twl() instead of container_of() pwm: tegra: assume CONFIG_OF pwm_backlight: Validate dft_brightness in main probe function pwm: Export pwm_{set,get}_chip_data() pwm: Make Kconfig entries more consistent pwm: Add can_sleep property to drivers pwm: Add pwm_can_sleep() as exported API to users pwm-backlight: handle BL_CORE_FBBLANK state pwm: pwm-tiecap: Low power sleep support pwm: pwm-tiehrpwm: Low power sleep support pwm: pwm-tiehrpwm: Update the clock handling of pwm-tiehrpwm driver pwm: vt8500: Add polarity support pwm: vt8500: Register write busy test performed incorrectly pwm: atmel: add Timer Counter Block PWM driver
2013-02-01pwm: Add devm_of_pwm_get() as exported API for usersPeter Ujfalusi
When booted with DT users can use devm version of of_pwm_get() to benefit from automatic resource release. Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com> Acked-by: Thierry Reding <thierry.reding@avionic-design.de> Signed-off-by: Bryan Wu <cooloney@gmail.com>
2013-02-01pwm: core: Rename of_pwm_request() to of_pwm_get() and export itPeter Ujfalusi
Allow client driver to use of_pwm_get() to get the PWM they need. This is needed for drivers which handle more than one PWM separately, like leds-pwm driver, which have: pwmleds { compatible = "pwm-leds"; kpad { label = "omap4::keypad"; pwms = <&twl_pwm 0 7812500>; max-brightness = <127>; }; charging { label = "omap4:green:chrg"; pwms = <&twl_pwmled 0 7812500>; max-brightness = <255>; }; }; in the dts files. Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com> Acked-by: Thierry Reding <thierry.reding@avionic-design.de> Signed-off-by: Bryan Wu <cooloney@gmail.com>
2013-02-01pwm: Correct parameter name in header for *pwm_get() functionsPeter Ujfalusi
To synchronize the header file definition and the actual code. In the code the consumer parameter is named as con_id, change the header file and replace consumer -> con_id in the parameter list. Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com> Ackedy-by: Thierry Reding <thierry.reding@avionic-design.de> Signed-off-by: Bryan Wu <cooloney@gmail.com>
2013-01-30pwm: Add pwm_can_sleep() as exported API to usersFlorian Vaussard
Calls to some external PWM chips can sleep. To help users, add pwm_can_sleep() API. Cc: Thierry Reding <thierry.reding@avionic-design.de> Cc: Peter Ujfalusi <peter.ujfalusi@ti.com> Signed-off-by: Florian Vaussard <florian.vaussard@epfl.ch> Reviewed-by: Peter Ujfalusi <peter.ujfalusi@ti.com> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2012-11-22pwm: Device tree support for PWM polarityPhilip, Avinash
Add support for encoding PWM properties in bit encoded form with of_pwm_xlate_with_flags() function support. Platforms require platform specific PWM properties has to populate in 3rd cell of the pwm-specifier and PWM driver should also set .of_xlate support with this function. Currently PWM property polarity encoded in bit position 0 of the third cell in pwm-specifier. Signed-off-by: Philip, Avinash <avinashphilip@ti.com> Acked-by: Grant Likely <grant.likely@secretlab.ca> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2012-09-20pwm: Fix compilation error when CONFIG_PWM is not definedTushar Behera
Add dummy implemention of public symbols for compilation-safe inclusion of include/linux/pwm.h file when CONFIG_PWM is not defined. Reported-by: Sachin Kamat <sachin.kamat@linaro.org> Signed-off-by: Tushar Behera <tushar.behera@linaro.org> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2012-09-10pwm: add devm_pwm_get() and devm_pwm_put()Alexandre Courbot
Add resource managed variants of pwm_get() and pwm_put() for convenience. Code is largely inspired by the equivalent devm functions of the regulator framework. Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2012-09-10pwm: Add support for configuring the PWM polarityPhilip, Avinash
Some hardware supports inverting the polarity of the PWM signal. This commit adds support to the PWM framework to allow users of the PWM API to configure the polarity. Note that in order to reduce complexity, changing the polarity of a PWM signal is only allowed while the PWM is disabled. A practical example where this can prove useful is to simulate inversion of the duty cycle. While inversion of polarity and duty cycle are not exactly the same, the differences for most use-cases are negligible. Signed-off-by: Philip, Avinash <avinashphilip@ti.com> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2012-06-15pwm: Add device tree supportThierry Reding
This patch adds helpers to support device tree bindings for the generic PWM API. Device tree binding documentation for PWM controllers is also provided. Acked-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2012-06-15pwm: Add table-based lookup for static mappingsThierry Reding
In order to get rid of the global namespace for PWM devices, this commit provides an alternative method, similar to that of the regulator or clock frameworks, for registering a static mapping for PWM devices. This works by providing a table with a provider/consumer map in the board setup code. With the new pwm_get() and pwm_put() functions available, usage of pwm_request() and pwm_free() becomes deprecated. Reviewed-by: Shawn Guo <shawn.guo@linaro.org> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2012-06-15pwm: Add debugfs interfaceThierry Reding
This commit adds a debugfs interface that can be used to list the current internal state of the PWM devices registered with the PWM framework. Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2012-06-15pwm: Allow chips to support multiple PWMsThierry Reding
Many PWM controllers provide access to more than a single PWM output and may even share some resource among them. Allowing a PWM chip to provide multiple PWM devices enables better sharing of those resources. As a side-effect this change allows easy integration with the device tree where a given PWM can be looked up based on the PWM chip's phandle and a corresponding index. This commit modifies the PWM core to support multiple PWMs per struct pwm_chip. It achieves this in a similar way to how gpiolib works, by allowing PWM ranges to be requested dynamically (pwm_chip.base == -1) or starting at a given offset (pwm_chip.base >= 0). A chip specifies how many PWMs it controls using the npwm member. Each of the functions in the pwm_ops structure gets an additional argument that specified the PWM number (it can be converted to a per-chip index by subtracting the chip's base). The total maximum number of PWM devices is currently fixed to 1024 while the data is actually stored in a radix tree, thus saving resources if not all of them are used. Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [eric@eukrea.com: fix error handling in pwmchip_add] Signed-off-by: Eric BĂ©nard <eric@eukrea.com> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2012-06-15pwm: Add PWM framework supportSascha Hauer
This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2009-03-30trivial: PWM: fix of #endif commentMark Vels
Signed-off-by: Mark Vels <mark.vels@team-embedded.nl> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2008-05-19[ARM] pxa: Add bare bones PWM APIRussell King
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>