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path: root/drivers/pwm/sysfs.c
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* pwm: Send a uevent on the pwmchip device upon channel sysfs (un)exportFabrice Gasnier2018-10-121-0/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch sends a uevent (KOBJ_CHANGE) on the pwmchipN device, everytime a pwmX channel has been exported/unexported via sysfs. This allows udev to implement rules on such events, like: SUBSYSTEM=="pwm*", PROGRAM="/bin/sh -c '\ chown -R root:gpio /sys/class/pwm && chmod -R 770 /sys/class/pwm;\ chown -R root:gpio /sys/devices/platform/soc/*.pwm/pwm/pwmchip* && chmod -R 770 /sys/devices/platform/soc/*.pwm/pwm/pwmchip*\ '" This is a replacement patch for commit 7e5d1fd75c3d ("pwm: Set class for exported channels in sysfs"), see [1]. basic testing: $ udevadm monitor --environment & $ echo 0 > /sys/class/pwm/pwmchip0/export KERNEL[197.321736] change /devices/.../pwm/pwmchip0 (pwm) ACTION=change DEVPATH=/devices/.../pwm/pwmchip0 EXPORT=pwm0 SEQNUM=2045 SUBSYSTEM=pwm [1] https://lkml.org/lkml/2018/9/25/713 Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com> Tested-by: Gottfried Haider <gottfried.haider@gmail.com> Tested-by: Michal Vokáč <michal.vokac@ysoft.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* Revert "pwm: Set class for exported channels in sysfs"Fabrice Gasnier2018-10-121-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit 7e5d1fd75c3dde9fc10c4472b9368089d1b81d00 ("pwm: Set class for exported channels in sysfs") as it causes regression with multiple pwm chip[1], when exporting a pwm channel (echo X > export): - ABI (Documentation/ABI/testing/sysfs-class-pwm) states pwmX should be created in /sys/class/pwm/pwmchipN/pwmX - Reverted patch causes new entry to be also created directly in /sys/class/pwm/pwmX - 1st time, exporting pwmX will create an entry in /sys/class/pwm/pwmX - class attributes are added under pwmX folder, such as export, unexport npwm, symlinks. This is wrong as it belongs to pwmchipN. It may cause bad behavior and report wrong values. - when another export happens on another pwmchip, it can't be created (e.g. -EEXIST). This is causing the issue with multiple pwmchip. Example on stm32 (stm32429i-eval) platform: $ ls /sys/class/pwm pwmchip0 pwmchip4 $ cd /sys/class/pwm/pwmchip0/ $ echo 0 > export $ ls /sys/class/pwm pwm0 pwmchip0 pwmchip4 $ cd /sys/class/pwm/pwmchip4/ $ echo 0 > export sysfs: cannot create duplicate filename '/class/pwm/pwm0' ...Exception stack follows... This is also seen on other platform [2] [1] https://lkml.org/lkml/2018/9/25/713 [2] https://lkml.org/lkml/2018/9/25/447 Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com> Tested-by: Gottfried Haider <gottfried.haider@gmail.com> Tested-by: Michal Vokáč <michal.vokac@ysoft.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* pwm: sysfs: Use put_device() instead of kfree()Arvind Yadav2018-03-281-1/+2
| | | | | | | | | Never directly free @dev after calling device_register(), even if it returned an error! Always use put_device() to give up the reference initialized. Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* pwm: Set class for exported channels in sysfsGottfried Haider2017-12-051-0/+1
| | | | | | | | | | | | | | | | | | Notifications for devices without bus or class set get dropped by dev_uevent_filter(). Adding the class to the exported child matches what the GPIO subsystem is doing. With this change exporting a channel triggers a udev event, which gives userspace a chance to fixup permissions and makes it possible for non-root users to make use of the PWM subsystem. Signed-off-by: Gottfried Haider <gottfried.haider@gmail.com> CC: Thierry Reding <thierry.reding@gmail.com> CC: H Hartley Sweeten <hsweeten@visionengravers.com> CC: linux-pwm@vger.kernel.org CC: linux-arm-kernel@lists.infradead.org CC: linux-rpi-kernel@lists.infradead.org Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* pwm: Fix device reference leakJohan Hovold2016-11-291-0/+2
| | | | | | | | | | Make sure to drop the reference to the parent device taken by class_find_device() after "unexporting" any children when deregistering a PWM chip. Fixes: 0733424c9ba9 ("pwm: Unexport children before chip removal") Signed-off-by: Johan Hovold <johan@kernel.org> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* pwm: Unexport children before chip removalDavid Hsu2016-09-051-0/+18
| | | | | | | | | | 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>
* Merge branch 'for-4.8/capture' into for-nextThierry Reding2016-07-251-0/+17
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| * pwm: sysfs: Add PWM capture supportLee Jones2016-06-101-0/+17
| | | | | | | | | | | | | | | | | | | | | | | | Allow a user to read PWM capture results from sysfs. To start a capture and read the result, simply read the file: $ cat $PWMCHIP/capture The output format is "<period> <duty cycle>". Signed-off-by: Lee Jones <lee.jones@linaro.org> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* | pwm: sysfs: Get return value from pwm_apply_state()Ryo Kodama2016-06-101-1/+1
|/ | | | | | | | | | | This patch adds to check the return value from pwm_apply_state() used in enable_store(). The error of enable_store() doesn't work if the return value doesn't received. Signed-off-by: Ryo Kodama <ryo.kodama.vz@renesas.com> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> Fixes: 39100ceea79f ("pwm: Switch to the atomic API") Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* pwm: Switch to the atomic APIBoris Brezillon2016-05-171-11/+37
| | | | | | | | Replace legacy pwm_get/set_xxx() and pwm_config/enable/disable() calls by pwm_get/apply_state(). Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* pwm: Get rid of pwm->lockBoris BREZILLON2016-05-171-4/+20
| | | | | | | | | | | | | | | 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>
* pwm: sysfs: Make use of the DEVICE_ATTR_[RW][WO] macro'sOlliver Schinagl2015-11-101-36/+36
| | | | | | | | | | | | | For the npwm property the PWM sysfs interface already made use of the DEVICE_ATTR_RO macro. This patch expands this to the other sysfs properties so that the code base is concise and makes use of this helpful macro. This has the advantage of slightly reducing the code size, improving readability and no longer using magic values for permissions. Signed-off-by: Olliver Schinagl <oliver@schinagl.nl> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* pwm: sysfs: Remove unnecessary temporary variableOlliver Schinagl2015-11-101-2/+1
| | | | | | | | Use the result of pwm_is_enabled() directly instead of storing it in a temporary variable. Signed-off-by: Olliver Schinagl <oliver@schinagl.nl> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* pwm: sysfs: Remove unnecessary paddingThierry Reding2015-07-271-3/+3
| | | | | | | | Padding initializers so that assignment operators align is bound to lead to inconsistencies or churn. Single spaces around the assignment is just fine. Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* pwm: sysfs: Properly convert from enum to stringThierry Reding2015-07-271-2/+12
| | | | | | | | | The current code will check for polarity in a boolean way. While it is correct that polarity is either normal or inversed, make it more obvious that it's an enumeration by using a switch statement and explicit matches on the enumeration values. Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* pwm: Make use of pwm_get_xxx() helpers where appropriateBoris Brezillon2015-07-201-5/+6
| | | | | | | | | Use the pwm_get_xxx() helpers instead of directly accessing the fields in struct pwm_device. This will allow us to smoothly move to the atomic update approach. Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* pwm: Add the pwm_is_enabled() helperBoris Brezillon2015-07-201-1/+1
| | | | | | | | | | 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>
* pwm: sysfs: Convert to use ATTRIBUTE_GROUPS macroAxel Lin2013-12-041-10/+2
| | | | | | | Use new ATTRIBUTE_GROUPS macro to reduce the number of lines of code. Signed-off-by: Axel Lin <axel.lin@ingics.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* pwm: convert class code to use dev_groupsGreg Kroah-Hartman2013-07-291-9/+12
| | | | | | | | | The dev_attrs field of struct class is going away soon, dev_groups should be used instead. This converts the PWM class code to use the correct field. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* pwm: Add sysfs interfaceH Hartley Sweeten2013-06-211-0/+352
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>
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