Date: Fri, 5 Jun 2015 19:59:15 +0300 From: Daniel Braniss <danny@cs.huji.ac.il> To: Luiz Otavio O Souza <lists.br@gmail.com> Cc: freebsd-arm <freeBSD-arm@freebsd.org> Subject: Re: pwm for raspberry pi? Message-ID: <DC13576F-D968-492C-B6F5-0578339A021D@cs.huji.ac.il> In-Reply-To: <CAB=2f8zuMhPkwuuh-yNeMK1_iv3%2Bg3%2BXtXLZ-FyOmudBifsh0w@mail.gmail.com> References: <1FD1336E-D99F-4114-AD33-FBA1DF844E93@cs.huji.ac.il> <CAB=2f8wigyRaP9fXr6V=-%2BM9YZTE=2nzdj-AngD6m15zZFu1gQ@mail.gmail.com> <DB799EA8-3401-46F6-A4F5-79E5BE9743E2@cs.huji.ac.il> <CAB=2f8zuMhPkwuuh-yNeMK1_iv3%2Bg3%2BXtXLZ-FyOmudBifsh0w@mail.gmail.com>
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> On May 26, 2015, at 9:51 PM, Luiz Otavio O Souza <lists.br@gmail.com> = wrote: >=20 > On 26 May 2015 at 03:13, Daniel Braniss wrote: >>=20 >>> On May 26, 2015, at 1:14 AM, Luiz Otavio O Souza wrote: >>>=20 >>> On 25 May 2015 at 07:52, Daniel Braniss wrote: >>>> Hi, >>>> Now that I=E2=80=99m rapping up my spi/rfid driver (available on = demand :-), >>>> I would like to use the pwm interface to power on/off a lock, but >>>> have no idea how to go around it, so any clues would be mostly = welcomed. >>>>=20 >>>> cheers, >>>> danny >>>=20 >>> The PWM module is quite simple and has only two outputs, they can be >>> used only with recent 40 GPIO pins header (RPi-B+ or RPi2), in the >>> older models only one output was wired. >>>=20 >> I do have a B+ >>=20 >>> The bcm2835 peripherals datasheet describes the PWM module registers >>=20 >> I=E2=80=99ve read it, hence I know it=E2=80=99s possible, what I=E2=80=99= missing is how to access it via >> FreeBSD. There is a some mention for the BeagleBoneBlack, but it = seems >> broken, the FDT mentions the pins. Too many leads but not enough info >> on how to tie them up :-) >>=20 >> cheers, >> danny >=20 > There is no defined API to access PWM settings ATM, on beaglebone this > is done with sysctls: >=20 > dev.am335x_pwm.2.dutyB: 0 > dev.am335x_pwm.2.dutyA: 0 > dev.am335x_pwm.2.period: 1000 > dev.am335x_pwm.2.freq: 100000 > dev.am335x_pwm.2.clkdiv: 1 > dev.am335x_pwm.2.%parent: simplebus0 > dev.am335x_pwm.2.%pnpinfo: name=3Dpwm@48304000 compat=3Dti,am335x-pwm > dev.am335x_pwm.2.%location: > dev.am335x_pwm.2.%driver: am335x_pwm > dev.am335x_pwm.2.%desc: AM335x PWM >=20 > There are 3 PWM modules, each one with two outputs controlled by dutyA > and dutyB. >=20 > Here is the PWM code for beaglebone: > = https://svnweb.freebsd.org/base/head/sys/arm/ti/am335x/am335x_ehrpwm.c?vie= w=3Dmarkup = <https://svnweb.freebsd.org/base/head/sys/arm/ti/am335x/am335x_ehrpwm.c?vi= ew=3Dmarkup> >=20 i see these under 10.1 but nothing under 11, what am I missing? i tried with today=E2=80=99s current, and I see the modules being = compile, the .dts seems ok but no signes of am35x_pwm > At some point I think I will expose PWM settings via gpioctl (and > possibly add a gpiopwm for a software based pwm). >=20 > Regards, > Luiz
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