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freebsd-dev/sys/arm/broadcom/bcm2835/bcm2835_pwm.c
Oleksandr Tymoshenko 3f9b72b641 [rpi] Add support for the second PWM channel 
Add support for the second channel to bcm2835_pwm driver. Configurable
parameters like mode, period, ratio are exposed as sysctls with postfix '2',
e.g.: dev.pwm.N.mode2, dev.pwm.N.period2, dev.pwm.N.ratio2

Second channel can be enabled in DTB by configuring pwn-2chan overlay
instead of pwm in config.txt. See [1]

[1] https://github.com/raspberrypi/firmware/blob/master/boot/overlays/README

Submitted by:	Bob Frazier
Differential Revision:	https://reviews.freebsd.org/D15769
2018-07-02 01:30:33 +00:00

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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2017 Poul-Henning Kamp <phk@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/rman.h>
#include <sys/lock.h>
#include <sys/sysctl.h>
#include <machine/bus.h>
#include <machine/resource.h>
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#include <arm/broadcom/bcm2835/bcm2835_clkman.h>
static struct ofw_compat_data compat_data[] = {
{"broadcom,bcm2835-pwm", 1},
{"brcm,bcm2835-pwm", 1},
{NULL, 0}
};
struct bcm_pwm_softc {
device_t sc_dev;
struct resource * sc_mem_res;
bus_space_tag_t sc_m_bst;
bus_space_handle_t sc_m_bsh;
device_t clkman;
uint32_t freq; /* shared between channels 1 and 2 */
uint32_t period; /* channel 1 */
uint32_t ratio;
uint32_t mode;
uint32_t period2; /* channel 2 */
uint32_t ratio2;
uint32_t mode2;
};
#define BCM_PWM_MEM_WRITE(_sc, _off, _val) \
bus_space_write_4(_sc->sc_m_bst, _sc->sc_m_bsh, _off, _val)
#define BCM_PWM_MEM_READ(_sc, _off) \
bus_space_read_4(_sc->sc_m_bst, _sc->sc_m_bsh, _off)
#define BCM_PWM_CLK_WRITE(_sc, _off, _val) \
bus_space_write_4(_sc->sc_c_bst, _sc->sc_c_bsh, _off, _val)
#define BCM_PWM_CLK_READ(_sc, _off) \
bus_space_read_4(_sc->sc_c_bst, _sc->sc_c_bsh, _off)
#define W_CTL(_sc, _val) BCM_PWM_MEM_WRITE(_sc, 0x00, _val)
#define R_CTL(_sc) BCM_PWM_MEM_READ(_sc, 0x00)
#define W_STA(_sc, _val) BCM_PWM_MEM_WRITE(_sc, 0x04, _val)
#define R_STA(_sc) BCM_PWM_MEM_READ(_sc, 0x04)
#define W_RNG(_sc, _val) BCM_PWM_MEM_WRITE(_sc, 0x10, _val)
#define R_RNG(_sc) BCM_PWM_MEM_READ(_sc, 0x10)
#define W_DAT(_sc, _val) BCM_PWM_MEM_WRITE(_sc, 0x14, _val)
#define R_DAT(_sc) BCM_PWM_MEM_READ(_sc, 0x14)
#define W_RNG2(_sc, _val) BCM_PWM_MEM_WRITE(_sc, 0x20, _val)
#define R_RNG2(_sc) BCM_PWM_MEM_READ(_sc, 0x20)
#define W_DAT2(_sc, _val) BCM_PWM_MEM_WRITE(_sc, 0x24, _val)
#define R_DAT2(_sc) BCM_PWM_MEM_READ(_sc, 0x24)
static int
bcm_pwm_reconf(struct bcm_pwm_softc *sc)
{
uint32_t u, ctlr;
/* Disable PWM */
W_CTL(sc, 0);
/* Stop PWM clock */
(void)bcm2835_clkman_set_frequency(sc->clkman, BCM_PWM_CLKSRC, 0);
ctlr = 0; /* pre-assign zero, enable bits, write to CTL at end */
if (sc->mode == 0 && sc->mode2 == 0) /* both modes are zero */
return 0; /* device is now off - return */
/* set the PWM clock frequency */
/* TODO: should I only do this if it changes and not stop it first? */
u = bcm2835_clkman_set_frequency(sc->clkman, BCM_PWM_CLKSRC, sc->freq);
if (u == 0)
return (EINVAL);
sc->freq = u;
/* control register CTL bits:
* (from BCM2835 ARM Peripherals manual, section 9.6)
*
* 15 MSEN2 chan 2 M/S enable; 0 for PWM algo, 1 for M/S transmission
* 14 unused; always reads as 0
* 13 USEF2 chan 2 use FIFO (0 uses data; 1 uses FIFO)
* 12 POLA2 chan 2 invert polarity (0 normal, 1 inverted polarity)
* 11 SBIT2 chan 2 'Silence' bit (when not transmitting data)
* 10 RPTL2 chan 2 FIFO repeat last data (1 repeats, 0 interrupts)
* 9 MODE2 chan 2 PWM/Serializer mode (0 PWM, 1 Serializer)
* 8 PWEN2 chan 2 enable (0 disable, 1 enable)
* 7 MSEN1 chan 1 M/S enable; 0 for PWM algo, 1 for M/S transmission
* 6 CLRF1 chan 1 clear FIFO (set 1 to clear; always reads as 0)
* 5 USEF1 chan 1 use FIFO (0 uses data; 1 uses FIFO)
* 4 POLA1 chan 1 invert polarity (0 normal, 1 inverted polarity)
* 3 SBIT1 chan 1 'Silence' bit (when not transmitting data)
* 2 RTPL1 chan 1 FIFO repeat last data (1 repeats, 0 interrupts)
* 1 MODE1 chan 1 PWM/Serializer mode (0 PWM, 1 Serializer)
* 0 PWMEN1 chan 1 enable (0 disable, 1 enable)
*
* Notes on M/S enable: when this bit is '1', a simple M/S ratio is used. In short,
* the value of 'ratio' is the number of 'on' bits, and the total length of the data is
* defined by 'period'. So if 'ratio' is 2500 and 'period' is 10000, then the output
* remains 'on' for 2500 clocks, and goes 'off' for the remaining 7500 clocks.
* When the M/S enable is '0', a more complicated algorithm effectively 'dithers' the
* pulses in order to obtain the desired ratio. For details, see section 9.3 of the
* BCM2835 ARM Peripherals manual.
*/
if (sc->mode != 0) {
/* Config PWM Channel 1 */
W_RNG(sc, sc->period);
if (sc->ratio > sc->period)
sc->ratio = sc->period;
W_DAT(sc, sc->ratio);
/* Start PWM Channel 1 */
if (sc->mode == 1)
ctlr |= 0x81; /* chan 1 enable + chan 1 M/S enable */
else
ctlr |= 0x1; /* chan 1 enable */
}
if (sc->mode2 != 0) {
/* Config PWM Channel 2 */
W_RNG2(sc, sc->period2);
if (sc->ratio2 > sc->period2)
sc->ratio2 = sc->period2;
W_DAT2(sc, sc->ratio2);
/* Start PWM Channel 2 */
if (sc->mode2 == 1)
ctlr |= 0x8100; /* chan 2 enable + chan 2 M/S enable */
else
ctlr |= 0x100; /* chan 2 enable */
}
/* write CTL register with updated value */
W_CTL(sc, ctlr);
return (0);
}
static int
bcm_pwm_pwm_freq_proc(SYSCTL_HANDLER_ARGS)
{
struct bcm_pwm_softc *sc;
uint32_t r;
int error;
sc = (struct bcm_pwm_softc *)arg1;
if (sc->mode == 1)
r = sc->freq / sc->period;
else
r = 0;
error = sysctl_handle_int(oidp, &r, sizeof(r), req);
return (error);
}
static int
bcm_pwm_mode_proc(SYSCTL_HANDLER_ARGS)
{
struct bcm_pwm_softc *sc;
uint32_t r;
int error;
sc = (struct bcm_pwm_softc *)arg1;
r = sc->mode;
error = sysctl_handle_int(oidp, &r, sizeof(r), req);
if (error != 0 || req->newptr == NULL)
return (error);
if (r > 2)
return (EINVAL);
sc->mode = r;
return (bcm_pwm_reconf(sc));
}
static int
bcm_pwm_freq_proc(SYSCTL_HANDLER_ARGS)
{
struct bcm_pwm_softc *sc;
uint32_t r;
int error;
sc = (struct bcm_pwm_softc *)arg1;
r = sc->freq;
error = sysctl_handle_int(oidp, &r, sizeof(r), req);
if (error != 0 || req->newptr == NULL)
return (error);
if (r > 125000000)
return (EINVAL);
sc->freq = r;
return (bcm_pwm_reconf(sc));
}
static int
bcm_pwm_period_proc(SYSCTL_HANDLER_ARGS)
{
struct bcm_pwm_softc *sc;
int error;
sc = (struct bcm_pwm_softc *)arg1;
error = sysctl_handle_int(oidp, &sc->period, sizeof(sc->period), req);
if (error != 0 || req->newptr == NULL)
return (error);
return (bcm_pwm_reconf(sc));
}
static int
bcm_pwm_ratio_proc(SYSCTL_HANDLER_ARGS)
{
struct bcm_pwm_softc *sc;
uint32_t r;
int error;
sc = (struct bcm_pwm_softc *)arg1;
r = sc->ratio;
error = sysctl_handle_int(oidp, &r, sizeof(r), req);
if (error != 0 || req->newptr == NULL)
return (error);
if (r > sc->period) // XXX >= ?
return (EINVAL);
sc->ratio = r;
W_DAT(sc, sc->ratio);
return (0);
}
static int
bcm_pwm_pwm_freq2_proc(SYSCTL_HANDLER_ARGS)
{
struct bcm_pwm_softc *sc;
uint32_t r;
int error;
sc = (struct bcm_pwm_softc *)arg1;
if (sc->mode2 == 1)
r = sc->freq / sc->period2;
else
r = 0;
error = sysctl_handle_int(oidp, &r, sizeof(r), req);
return (error);
}
static int
bcm_pwm_mode2_proc(SYSCTL_HANDLER_ARGS)
{
struct bcm_pwm_softc *sc;
uint32_t r;
int error;
sc = (struct bcm_pwm_softc *)arg1;
r = sc->mode2;
error = sysctl_handle_int(oidp, &r, sizeof(r), req);
if (error != 0 || req->newptr == NULL)
return (error);
if (r > 2)
return (EINVAL);
sc->mode2 = r;
return (bcm_pwm_reconf(sc));
}
static int
bcm_pwm_period2_proc(SYSCTL_HANDLER_ARGS)
{
struct bcm_pwm_softc *sc;
int error;
sc = (struct bcm_pwm_softc *)arg1;
error = sysctl_handle_int(oidp, &sc->period2, sizeof(sc->period2), req);
if (error != 0 || req->newptr == NULL)
return (error);
return (bcm_pwm_reconf(sc));
}
static int
bcm_pwm_ratio2_proc(SYSCTL_HANDLER_ARGS)
{
struct bcm_pwm_softc *sc;
uint32_t r;
int error;
sc = (struct bcm_pwm_softc *)arg1;
r = sc->ratio2;
error = sysctl_handle_int(oidp, &r, sizeof(r), req);
if (error != 0 || req->newptr == NULL)
return (error);
if (r > sc->period2) // XXX >= ?
return (EINVAL);
sc->ratio2 = r;
W_DAT(sc, sc->ratio2);
return (0);
}
static int
bcm_pwm_reg_proc(SYSCTL_HANDLER_ARGS)
{
struct bcm_pwm_softc *sc;
uint32_t reg;
int error;
sc = (struct bcm_pwm_softc *)arg1;
reg = BCM_PWM_MEM_READ(sc, arg2 & 0xff);
error = sysctl_handle_int(oidp, &reg, sizeof(reg), req);
if (error != 0 || req->newptr == NULL)
return (error);
BCM_PWM_MEM_WRITE(sc, arg2, reg);
return (0);
}
static void
bcm_pwm_sysctl_init(struct bcm_pwm_softc *sc)
{
struct sysctl_ctx_list *ctx;
struct sysctl_oid *tree_node;
struct sysctl_oid_list *tree;
/*
* Add system sysctl tree/handlers.
*/
ctx = device_get_sysctl_ctx(sc->sc_dev);
tree_node = device_get_sysctl_tree(sc->sc_dev);
tree = SYSCTL_CHILDREN(tree_node);
if (bootverbose) {
#define RR(x,y) \
SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, y, \
CTLFLAG_RW | CTLTYPE_UINT, sc, 0x##x, \
bcm_pwm_reg_proc, "IU", "Register 0x" #x " " y);
RR(24, "DAT2")
RR(20, "RNG2")
RR(18, "FIF1")
RR(14, "DAT1")
RR(10, "RNG1")
RR(08, "DMAC")
RR(04, "STA")
RR(00, "CTL")
#undef RR
}
SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "pwm_freq",
CTLFLAG_RD | CTLTYPE_UINT, sc, 0,
bcm_pwm_pwm_freq_proc, "IU", "PWM frequency ch 1 (Hz)");
SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "period",
CTLFLAG_RW | CTLTYPE_UINT, sc, 0,
bcm_pwm_period_proc, "IU", "PWM period ch 1 (#clocks)");
SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "ratio",
CTLFLAG_RW | CTLTYPE_UINT, sc, 0,
bcm_pwm_ratio_proc, "IU", "PWM ratio ch 1 (0...period)");
SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "freq",
CTLFLAG_RW | CTLTYPE_UINT, sc, 0,
bcm_pwm_freq_proc, "IU", "PWM clock (Hz)");
SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "mode",
CTLFLAG_RW | CTLTYPE_UINT, sc, 0,
bcm_pwm_mode_proc, "IU", "PWM mode ch 1 (0=off, 1=pwm, 2=dither)");
SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "pwm_freq2",
CTLFLAG_RD | CTLTYPE_UINT, sc, 0,
bcm_pwm_pwm_freq2_proc, "IU", "PWM frequency ch 2 (Hz)");
SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "period2",
CTLFLAG_RW | CTLTYPE_UINT, sc, 0,
bcm_pwm_period2_proc, "IU", "PWM period ch 2 (#clocks)");
SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "ratio2",
CTLFLAG_RW | CTLTYPE_UINT, sc, 0,
bcm_pwm_ratio2_proc, "IU", "PWM ratio ch 2 (0...period)");
SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "mode2",
CTLFLAG_RW | CTLTYPE_UINT, sc, 0,
bcm_pwm_mode2_proc, "IU", "PWM mode ch 2 (0=off, 1=pwm, 2=dither)");
}
static int
bcm_pwm_probe(device_t dev)
{
if (!ofw_bus_status_okay(dev))
return (ENXIO);
if (ofw_bus_search_compatible(dev, compat_data)->ocd_data == 0)
return (ENXIO);
device_set_desc(dev, "BCM2708/2835 PWM controller");
return (BUS_PROBE_DEFAULT);
}
static int
bcm_pwm_attach(device_t dev)
{
struct bcm_pwm_softc *sc;
int rid;
if (device_get_unit(dev) != 0) {
device_printf(dev, "only one PWM controller supported\n");
return (ENXIO);
}
sc = device_get_softc(dev);
sc->sc_dev = dev;
sc->clkman = devclass_get_device(devclass_find("bcm2835_clkman"), 0);
if (sc->clkman == NULL) {
device_printf(dev, "cannot find Clock Manager\n");
return (ENXIO);
}
rid = 0;
sc->sc_mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
RF_ACTIVE);
if (!sc->sc_mem_res) {
device_printf(dev, "cannot allocate memory window\n");
return (ENXIO);
}
sc->sc_m_bst = rman_get_bustag(sc->sc_mem_res);
sc->sc_m_bsh = rman_get_bushandle(sc->sc_mem_res);
/* Add sysctl nodes. */
bcm_pwm_sysctl_init(sc);
sc->freq = 125000000; /* 125 Mhz */
sc->period = 10000; /* 12.5 khz */
sc->ratio = 2500; /* 25% */
sc->period2 = 10000; /* 12.5 khz */
sc->ratio2 = 2500; /* 25% */
return (bus_generic_attach(dev));
}
static int
bcm_pwm_detach(device_t dev)
{
struct bcm_pwm_softc *sc;
bus_generic_detach(dev);
sc = device_get_softc(dev);
sc->mode = 0;
sc->mode2 = 0;
(void)bcm_pwm_reconf(sc);
if (sc->sc_mem_res)
bus_release_resource(dev, SYS_RES_MEMORY, 0, sc->sc_mem_res);
return (0);
}
static phandle_t
bcm_pwm_get_node(device_t bus, device_t dev)
{
return (ofw_bus_get_node(bus));
}
static device_method_t bcm_pwm_methods[] = {
/* Device interface */
DEVMETHOD(device_probe, bcm_pwm_probe),
DEVMETHOD(device_attach, bcm_pwm_attach),
DEVMETHOD(device_detach, bcm_pwm_detach),
DEVMETHOD(ofw_bus_get_node, bcm_pwm_get_node),
DEVMETHOD_END
};
static devclass_t bcm_pwm_devclass;
static driver_t bcm_pwm_driver = {
"pwm",
bcm_pwm_methods,
sizeof(struct bcm_pwm_softc),
};
DRIVER_MODULE(bcm2835_pwm, simplebus, bcm_pwm_driver, bcm_pwm_devclass, 0, 0);
MODULE_DEPEND(bcm2835_pwm, bcm2835_clkman, 1, 1, 1);
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