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* pwm: Provide pwmchip_alloc() function and a devm variant of itUwe Kleine-König2024-02-151-5/+6
| | | | | | | | | | | | | | | | | | | | This function allocates a struct pwm_chip and driver data. Compared to the status quo the split into pwm_chip and driver data is new, otherwise it doesn't change anything relevant (yet). The intention is that after all drivers are switched to use this allocation function, its possible to add a struct device to struct pwm_chip to properly track the latter's lifetime without touching all drivers again. Proper lifetime tracking is a necessary precondition to introduce character device support for PWMs (that implements atomic setting and doesn't suffer from the sysfs overhead of the /sys/class/pwm userspace support). The new function pwmchip_priv() (obviously?) only works for chips allocated with pwmchip_alloc(). Link: https://lore.kernel.org/r/9577d6053a5a52536057dc8654ff567181c2da82.1707900770.git.u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
* pwm: Make it possible to apply PWM changes in atomic contextSean Young2023-12-201-0/+9
| | | | | | | | | | | | | | | Some PWM devices require sleeping, for example if the pwm device is connected over I2C. However, many PWM devices could be used from atomic context, e.g. memory mapped PWM. This is useful for, for example, the pwm-ir-tx driver which requires precise timing. Sleeping causes havoc with the generated IR signal. Since not all PWM devices can support atomic context, we also add a pwm_might_sleep() function to check if is not supported. Signed-off-by: Sean Young <sean@mess.org> Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* pwm: Rename pwm_apply_state() to pwm_apply_might_sleep()Sean Young2023-12-201-4/+4
| | | | | | | | | | | | | | | | | | | | | In order to introduce a pwm api which can be used from atomic context, we will need two functions for applying pwm changes: int pwm_apply_might_sleep(struct pwm *, struct pwm_state *); int pwm_apply_atomic(struct pwm *, struct pwm_state *); This commit just deals with renaming pwm_apply_state(), a following commit will introduce the pwm_apply_atomic() function. Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Acked-by: Guenter Roeck <linux@roeck-us.net> Acked-by: Mark Brown <broonie@kernel.org> Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> # for input Acked-by: Hans de Goede <hdegoede@redhat.com> Acked-by: Jani Nikula <jani.nikula@intel.com> Acked-by: Lee Jones <lee@kernel.org> Signed-off-by: Sean Young <sean@mess.org> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* pwm: Adapt sysfs API documentation to realityUwe Kleine-König2023-10-101-3/+3
| | | | | | | | | | | Most low-level PWM drivers support duty_cycle == period, and so does the sysfs API. Also polarity can be changed for enabled PWMs since commit 39100ceea79f ("pwm: Switch to the atomic API"). Reported-by: Jens Gehrlein <J.Gehrlein@eckelmann.de> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Link: https://lore.kernel.org/r/20230911154454.675057-1-u.kleine-koenig@pengutronix.de
* pwm: Delete deprecated functions pwm_request() and pwm_free()Uwe Kleine-König2023-04-131-8/+5
| | | | | | | | | | | Since commit 5a7fbe452ad9 ("backlight: pwm_bl: Drop support for legacy PWM probing") the last user of pwm_request() and pwm_free() is gone. So remove these functions that were deprecated over 10 years ago in commit 8138d2ddbcca ("pwm: Add table-based lookup for static mappings"). Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> [thierry.reding@gmail.com: clean up a bit after removal] Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* pwm: core: Get rid of unused devm_of_pwm_get()Andy Shevchenko2022-09-191-2/+1
| | | | | | | | | | | | | The devm_of_pwm_get() has recently lost its single user, drop the dead API as well. Note, the new code should use either plain pwm_get() or managed devm_pwm_get() or devm_fwnode_pwm_get() APIs. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Link: https://lore.kernel.org/r/20220826172642.16404-2-andriy.shevchenko@linux.intel.com Signed-off-by: Guenter Roeck <linux@roeck-us.net>
* pwm: Document that the pinstate of a disabled PWM isn't reliableUwe Kleine-König2022-05-201-0/+6
| | | | | | | | | | | | | | | | | Some (most?) drivers emit the inactive state when the PWM is disabled. However there are exceptions, so document that a consumer better doesn't depend on this behaviour. Some known exceptions: - imx27 emits 0 independent of the configured polarity - mxs just drives the output to the last emitted state. - iqs620a makes the output tristated on disable, so an external pull-down would be required. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Acked-by: Alexander Stein <alexander.stein@ew.tq-group.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* pwm: core: Remove unused devm_pwm_put()Andy Shevchenko2021-06-301-1/+2
| | | | | | | | | | | There are no users and seems no will come of the devm_pwm_put(). Remove the function. While at it, slightly update documentation. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* pwm: core: Support new usage_power setting in PWM stateClemens Gruber2021-06-041-0/+4
| | | | | | | | | | | If usage_power is set, the PWM driver is only required to maintain the power output but has more freedom regarding signal form. If supported, the signal can be optimized, for example to improve EMI by phase shifting individual channels. Signed-off-by: Clemens Gruber <clemens.gruber@pqgruber.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* pwm: Reword docs about pwm_apply_state()Uwe Kleine-König2021-04-261-5/+5
| | | | | | | | | | | | | | | | | | The main issue is that the current documentation talks about the non-existent function pwm_get_last_applied_state. (This was right in the context of https://lore.kernel.org/linux-pwm/20210406073036.26857-1-u.kleine-koenig@pengutronix.de/ but was then missed to adapt when this patch was reduced to a documentation update.) While at is also clarify "last applied PWM state" to "PWM state that was passed to the last invocation of pwm_apply_state()" to better distinguish to the last actually implemented state and reword to drop a word repetition. Fixes: 1a7a6e8072ea ("pwm: Clarify which state pwm_get_state() returns") Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* pwm: Clarify which state pwm_get_state() returnsUwe Kleine-König2021-04-091-1/+5
| | | | | | | | | | | | | Given that lowlevel drivers usually cannot implement exactly what a consumer requests with pwm_apply_state() there is some rounding involved. pwm_get_state() returns the setting that was requested most recently by the consumer (opposed to what was actually implemented in hardware in reply to the last request). Clarify this in the function kerneldoc. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
* docs: driver-api: add a series of orphaned documentsMauro Carvalho Chehab2019-07-151-0/+165
There are lots of documents under Documentation/*.txt and a few other orphan documents elsehwere that belong to the driver-API book. Move them to their right place. Reviewed-by: Cornelia Huck <cohuck@redhat.com> # vfio-related parts Acked-by: Logan Gunthorpe <logang@deltatee.com> # switchtec Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
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