Hi Thierry, It's been a while since I submitted this version but no feedback so far on it. I re-done it as you suggested. Do you have any thoughts on this version?
Thank you, Claudiu beznea On 22.05.2018 15:07, Claudiu Beznea wrote: > Hi, > > Please give feedback on these patches which extends the PWM framework in > order to support multiple PWM modes of operations. This series is a rework > of [1] and [2]. > > The current patch series add the following PWM modes: > - PWM mode normal > - PWM mode complementary > - PWM mode push-pull > > Normal mode - for PWM channels with one output; output waveforms looks like > this: > __ __ __ __ > PWM __| |__| |__| |__| |__ > <--T--> > > Where T is the signal period > > Since PWMs with more than one output per channel could be used as one > output PWM the normal mode is the default mode for all PWMs (if not > specified otherwise). > > Complementary mode - for PWM channels with two outputs; output waveforms > for a PWM channel in complementary mode looks line this: > __ __ __ __ > PWMH1 __| |__| |__| |__| |__ > __ __ __ __ __ > PWML1 |__| |__| |__| |__| > <--T--> > > Where T is the signal period. > > Push-pull mode - for PWM channels with two outputs; output waveforms for a > PWM channel in push-pull mode with normal polarity looks like this: > __ __ > PWMH __| |________| |________ > __ __ > PWML ________| |________| |__ > <--T--> > > If polarity is inversed: > __ ________ ________ > PWMH |__| |__| > ________ ________ __ > PWML |__| |__| > <--T--> > > Where T is the signal period. > > The PWM working modes are per PWM channel registered as PWM's capabilities. > The driver registers itself to PWM core a get_caps() function, in > struct pwm_ops, that will be used by PWM core to retrieve PWM capabilities. > If this function is not registered in driver's probe, a default function > will be used to retrieve PWM capabilities. Currently, the default > capabilities includes only PWM normal mode. > > PWM state has been updated to keep PWM mode. PWM mode could be configured > via sysfs or via DT. pwm_apply_state() will do the preliminary validation > for PWM mode to be applied. > > In sysfs, user could get PWM modes by reading mode file of PWM device: > root@sama5d2-xplained:/sys/class/pwm/pwmchip0/pwm2# ls -l > total 0 > -r--r--r-- 1 root root 4096 Oct 9 09:07 capture > lrwxrwxrwx 1 root root 0 Oct 9 09:07 device -> ../../pwmchip0 > -rw-r--r-- 1 root root 4096 Oct 9 08:42 duty_cycle > -rw-r--r-- 1 root root 4096 Oct 9 08:44 enable > --w------- 1 root root 4096 Oct 9 09:07 export > -rw-r--r-- 1 root root 4096 Oct 9 08:43 mode > -r--r--r-- 1 root root 4096 Oct 9 09:07 npwm > -rw-r--r-- 1 root root 4096 Oct 9 08:42 period > -rw-r--r-- 1 root root 4096 Oct 9 08:44 polarity > drwxr-xr-x 2 root root 0 Oct 9 09:07 power > lrwxrwxrwx 1 root root 0 Oct 9 09:07 subsystem -> > ../../../../../../../../class/pwm > -rw-r--r-- 1 root root 4096 Oct 9 08:42 uevent > --w------- 1 root root 4096 Oct 9 09:07 unexport > root@sama5d2-xplained:/sys/class/pwm/pwmchip0/pwm2# cat mode > normal complementary [push-pull] > > The mode enclosed in bracket is the currently active mode. > > The mode could be set, via sysfs, by writing to mode file one of the modes > displayed at read: > root@sama5d2-xplained:/sys/class/pwm/pwmchip0/pwm2# echo normal > mode > root@sama5d2-xplained:/sys/class/pwm/pwmchip0/pwm2# cat mode > [normal] complementary push-pull > > The PWM push-pull mode could be usefull in applications like half bridge > converters. > > This series also add PWM modes support for Atmel/Microchip SoCs. > > Thank you, > Claudiu Beznea > > [1] https://www.spinics.net/lists/arm-kernel/msg580275.html > [2] https://lkml.org/lkml/2018/1/12/359 > > Changes in v5: > - solved kbuild errors by removing dummy functions for case where > CONFIG_PWM is not defined; adopted this approach since the removed > function are used only only when CONFIG_PWM is defined (in PWM core > and few drivers from drivers/pwm/ directory) > > Changes in v4: > - removed changes related to pwm_config() as per maintainer proposals > - added pwm_mode_get_valid() to retrieve a valid PWM mode fror PWM device > instead of using BIT(ffs(caps.mode) - 1) and changed drivers to use > pwm_mode_get_valid() instead of pwm_get_caps() + BIT(ffs(caps.mode) - 1) > (patches 2, 3, 4 from this series) > - renamed PWM_MODE() macro in PWMC_MODE() to avoid conflicts with > pwm-sun4i.c driver ('C' stands for capability) > - removed pwm_caps_valid() function > - renamed PWM_DTMODE_COMPLEMENTARY and PWM_DTMODE_PUSH_PULL macros in > PWM_MODE_COMPLEMENTARY and PWM_MODE_PUSH_PULL > > Changes in v3: > - removed changes related to only one of_xlate function for all PWM drivers > - switch to PWM capabilities per PWM channel nor per PWM chip > - squash documentation and bindings patches as requeted by reviewer > - introduced PWM_MODE(name) macro and used a bit enum for pwm modes > - related to DT bindings, used flags cell also for PWM modes > - updated of_xlate specific functions with "state->mode = mode;" > instructions to avoid pwm_apply_state() failures > - use available modes for PWM channel in pwm_config() by first calling > pwm_get_caps() to get caps.modes > - use loops through available modes in mode_store()/mode_show() and also in > of_pwm_xlate_with_flags() instead of "if else" instructions; in this way, > the addition of a new mode is independent of this code sections > - use DTLI=1, DTHI=0 register settings to obtain push-pull mode waveforms > for Atmel/Microchip PWM controller. > > Changes in v2: > - remove of_xlate and of_pwm_n_cells and use generic functions to pharse DT > inputs; this is done in patches 1, 2, 3, 4, 5, 6, 7 of this series; this > will > make easy the addition of PWM mode support from DT > - add PWM mode normal > - register PWM modes as capabilities of PWM chips at driver probe and, in case > driver doesn't provide these capabilities use default ones > - change the way PWM mode is pharsed via DT by using a new input for pwms > binding property > > > Claudiu Beznea (9): > pwm: extend PWM framework with PWM modes > pwm: clps711x: populate PWM mode in of_xlate function > pwm: cros-ec: populate PWM mode in of_xlate function > pwm: pxa: populate PWM mode in of_xlate function > pwm: add PWM modes > pwm: atmel: add pwm capabilities > pwm: add push-pull mode support > pwm: add documentation for pwm push-pull mode > pwm: atmel: add push-pull mode support > > Documentation/devicetree/bindings/pwm/pwm.txt | 11 ++- > Documentation/pwm.txt | 42 ++++++++- > drivers/pwm/core.c | 125 > +++++++++++++++++++++++++- > drivers/pwm/pwm-atmel.c | 118 +++++++++++++++++------- > drivers/pwm/pwm-clps711x.c | 10 ++- > drivers/pwm/pwm-cros-ec.c | 1 + > drivers/pwm/pwm-pxa.c | 1 + > drivers/pwm/sysfs.c | 61 +++++++++++++ > include/dt-bindings/pwm/pwm.h | 2 + > include/linux/pwm.h | 64 +++++++++++++ > 10 files changed, 395 insertions(+), 40 deletions(-) >
