kernel/drivers/pwm/core.c, branch linux-6.9.y

pwm: Fix setting period with #pwm-cells = <1> and of_pwm_single_xlate()

2024-03-29T12:50:10Z

For drivers making use of of_pwm_single_xlate() (i.e. those that don't pass a hwpwm index) and also don't pass flags, setting period was wrongly skipped. This affects the pwm-pxa and ti-sn65dsi86 drivers. Reported-by: Karel Balej Link: https://lore.kernel.org/r/D05IVTPYH35N.2CLDG6LSILRSN@matfyz.cz Fixes: 40ade0c2e794 ("pwm: Let the of_xlate callbacks accept references without period") Tested-by: Karel Balej Link: https://lore.kernel.org/r/20240329103544.545290-2-u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König

pwm: Provide pwmchip_alloc() function and a devm variant of it

2024-02-15T11:59:15Z

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

pwm: Provide an inline function to get the parent device of a given chip

2024-02-15T11:37:29Z

Currently a pwm_chip stores in its struct device *dev member a pointer to the parent device. Preparing a change that embeds a full struct device in struct pwm_chip, this accessor function should be used in all drivers directly accessing chip->dev now. This way struct pwm_chip and this new function can be changed without having to touch all drivers in the same change set. Make use of this function in the framework's core sources. Reviewed-by: Greg Kroah-Hartman Link: https://lore.kernel.org/r/cc30090d2f9762bed9854a55612144bccc910781.1707900770.git.u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König

pwm: Reorder symbols in core.c

2024-02-15T11:28:02Z

This moves the functions called by pwm consumers above the functions called by pwm providers. When character device support is added later this is hooked into the chip registration functions. As the needed callbacks are a kind of consumer and make use of the consumer functions, having this order is more natural and prevents having to add declarations for static functions. Also move the global variables for pwm tables to the respective functions to have them properly grouped. Link: https://lore.kernel.org/r/eed83de07bdfb69b5ceba0b9aed757ee612dea8f.1706182805.git.u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König

pwm: Drop duplicate check against chip->npwm in of_pwm_xlate_with_flags()

2024-02-15T11:28:02Z

args->args[0] is passed as parameter "index" to pwm_request_from_chip(). The latter function also checks for index >= npwm, so of_pwm_xlate_with_flags() doesn't need to do that. Link: https://lore.kernel.org/r/b06e445a6ed62a339add727eccb969a33d678386.1704835845.git.u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König

pwm: Let the of_xlate callbacks accept references without period

2024-02-15T11:28:02Z

With this extension of_pwm_xlate_with_flags() is suitable to replace the custom xlate function of the pwm-clps711x driver. While touching these very similar functions align their implementations. Link: https://lore.kernel.org/r/127622315d07d9d419ae8e6373c7e5be7fab7a62.1704835845.git.u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König

pwm: Drop useless member .of_pwm_n_cells of struct pwm_chip

2024-02-15T11:28:01Z

Apart from the two of_xlate implementations this member is write-only. In the of_xlate functions of_pwm_xlate_with_flags() and of_pwm_single_xlate() it's more sensible to check for args->args_count because this is what is actually used in the device tree. Acked-by: Douglas Anderson Link: https://lore.kernel.org/r/53d8c545aa8f79a920358be9e72e382b3981bdc4.1704835845.git.u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König

pwm: Fix out-of-bounds access in of_pwm_single_xlate()

2024-01-12T17:24:55Z

With args->args_count == 2 args->args[2] is not defined. Actually the flags are contained in args->args[1]. Fixes: 3ab7b6ac5d82 ("pwm: Introduce single-PWM of_xlate function") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/243908750d306e018a3d4bf2eb745d53ab50f663.1704835845.git.u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König

pwm: Reduce number of pointer dereferences in pwm_device_request()

2023-12-20T15:24:44Z

pwm->chip and pwm->chip->ops are used several times in this function. Introduce local variables for these. There is no semantical change, but with ARCH=arm, allmodconfig and gcc-13 bloat-o-meter reports a slight improvement: add/remove: 1/1 grow/shrink: 1/1 up/down: 8/-36 (-28) Function old new delta pwm_apply_state 476 480 +4 __initcall__kmod_core__307_1092_pwm_debugfs_init4 - 4 +4 __initcall__kmod_core__307_1090_pwm_debugfs_init4 4 - -4 pwm_request_from_chip 628 596 -32 Total: Before=15091, After=15063, chg -0.19% Signed-off-by: Uwe Kleine-König Signed-off-by: Thierry Reding

pwm: Make it possible to apply PWM changes in atomic context

2023-12-20T15:07:06Z

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 Reviewed-by: Uwe Kleine-König Signed-off-by: Thierry Reding