freebsd-dev/sys/arm/allwinner/aw_pwm.c
Ian Lepore 0a06f11da3 Implement the ofw_bus_get_node method in aw_pwm(4) so that ofw_pwmbus can
find its metadata for instantiating children.
2019-06-17 03:40:00 +00:00

388 lines
9.0 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2018 Emmanuel Vadot <manu@FreeBSD.org>
*
* 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 ``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 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.
*
* $FreeBSD$
*/
#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/resource.h>
#include <machine/bus.h>
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#include <dev/extres/clk/clk.h>
#include "pwmbus_if.h"
#define AW_PWM_CTRL 0x00
#define AW_PWM_CTRL_PRESCALE_MASK 0xF
#define AW_PWM_CTRL_EN (1 << 4)
#define AW_PWM_CTRL_ACTIVE_LEVEL_HIGH (1 << 5)
#define AW_PWM_CTRL_GATE (1 << 6)
#define AW_PWM_CTRL_MODE_MASK 0x80
#define AW_PWM_CTRL_PULSE_MODE (1 << 7)
#define AW_PWM_CTRL_CYCLE_MODE (0 << 7)
#define AW_PWM_CTRL_PULSE_START (1 << 8)
#define AW_PWM_CTRL_CLK_BYPASS (1 << 9)
#define AW_PWM_CTRL_PERIOD_BUSY (1 << 28)
#define AW_PWM_PERIOD 0x04
#define AW_PWM_PERIOD_TOTAL_MASK 0xFFFF
#define AW_PWM_PERIOD_TOTAL_SHIFT 16
#define AW_PWM_PERIOD_ACTIVE_MASK 0xFFFF
#define AW_PWM_PERIOD_ACTIVE_SHIFT 0
#define AW_PWM_MAX_FREQ 24000000
#define NS_PER_SEC 1000000000
static struct ofw_compat_data compat_data[] = {
{ "allwinner,sun5i-a13-pwm", 1 },
{ NULL, 0 }
};
static struct resource_spec aw_pwm_spec[] = {
{ SYS_RES_MEMORY, 0, RF_ACTIVE },
{ -1, 0 }
};
struct aw_pwm_softc {
device_t dev;
device_t busdev;
clk_t clk;
struct resource *res;
uint64_t clk_freq;
unsigned int period;
unsigned int duty;
uint32_t flags;
bool enabled;
};
static uint32_t aw_pwm_clk_prescaler[] = {
120,
180,
240,
360,
480,
0,
0,
0,
12000,
24000,
36000,
48000,
72000,
0,
0,
1,
};
#define AW_PWM_READ(sc, reg) bus_read_4((sc)->res, (reg))
#define AW_PWM_WRITE(sc, reg, val) bus_write_4((sc)->res, (reg), (val))
static int aw_pwm_probe(device_t dev);
static int aw_pwm_attach(device_t dev);
static int aw_pwm_detach(device_t dev);
static int
aw_pwm_probe(device_t dev)
{
if (!ofw_bus_status_okay(dev))
return (ENXIO);
if (!ofw_bus_search_compatible(dev, compat_data)->ocd_data)
return (ENXIO);
device_set_desc(dev, "Allwinner PWM");
return (BUS_PROBE_DEFAULT);
}
static int
aw_pwm_attach(device_t dev)
{
struct aw_pwm_softc *sc;
uint64_t clk_freq;
uint32_t reg;
phandle_t node;
int error;
sc = device_get_softc(dev);
sc->dev = dev;
error = clk_get_by_ofw_index(dev, 0, 0, &sc->clk);
if (error != 0) {
device_printf(dev, "cannot get clock\n");
goto fail;
}
error = clk_enable(sc->clk);
if (error != 0) {
device_printf(dev, "cannot enable clock\n");
goto fail;
}
error = clk_get_freq(sc->clk, &sc->clk_freq);
if (error != 0) {
device_printf(dev, "cannot get clock frequency\n");
goto fail;
}
if (bus_alloc_resources(dev, aw_pwm_spec, &sc->res) != 0) {
device_printf(dev, "cannot allocate resources for device\n");
error = ENXIO;
goto fail;
}
/* Read the configuration left by U-Boot */
reg = AW_PWM_READ(sc, AW_PWM_CTRL);
if (reg & (AW_PWM_CTRL_GATE | AW_PWM_CTRL_EN))
sc->enabled = true;
reg = AW_PWM_READ(sc, AW_PWM_CTRL);
reg &= AW_PWM_CTRL_PRESCALE_MASK;
if (reg > nitems(aw_pwm_clk_prescaler)) {
device_printf(dev, "Bad prescaler %x, cannot guess current settings\n", reg);
goto skipcfg;
}
clk_freq = sc->clk_freq / aw_pwm_clk_prescaler[reg];
reg = AW_PWM_READ(sc, AW_PWM_PERIOD);
sc->period = NS_PER_SEC /
(clk_freq / ((reg >> AW_PWM_PERIOD_TOTAL_SHIFT) & AW_PWM_PERIOD_TOTAL_MASK));
sc->duty = NS_PER_SEC /
(clk_freq / ((reg >> AW_PWM_PERIOD_ACTIVE_SHIFT) & AW_PWM_PERIOD_ACTIVE_MASK));
skipcfg:
/*
* Note that we don't check for failure to attach pwmbus -- even without
* it we can still service clients who connect via fdt xref data.
*/
node = ofw_bus_get_node(dev);
OF_device_register_xref(OF_xref_from_node(node), dev);
sc->busdev = device_add_child(dev, "pwmbus", -1);
return (bus_generic_attach(dev));
fail:
aw_pwm_detach(dev);
return (error);
}
static int
aw_pwm_detach(device_t dev)
{
struct aw_pwm_softc *sc;
int error;
sc = device_get_softc(dev);
if ((error = bus_generic_detach(sc->dev)) != 0) {
device_printf(sc->dev, "cannot detach child devices\n");
return (error);
}
if (sc->busdev != NULL)
device_delete_child(dev, sc->busdev);
if (sc->res != NULL)
bus_release_resources(dev, aw_pwm_spec, &sc->res);
return (0);
}
static phandle_t
aw_pwm_get_node(device_t bus, device_t dev)
{
/*
* Share our controller node with our pwmbus child; it instantiates
* devices by walking the children contained within our node.
*/
return ofw_bus_get_node(bus);
}
static int
aw_pwm_channel_count(device_t dev, u_int *nchannel)
{
*nchannel = 1;
return (0);
}
static int
aw_pwm_channel_config(device_t dev, u_int channel, u_int period, u_int duty)
{
struct aw_pwm_softc *sc;
uint64_t period_freq, duty_freq;
uint64_t clk_rate, div;
uint32_t reg;
int prescaler;
int i;
sc = device_get_softc(dev);
period_freq = NS_PER_SEC / period;
if (period_freq > AW_PWM_MAX_FREQ)
return (EINVAL);
duty_freq = NS_PER_SEC / duty;
if (duty_freq < period_freq) {
device_printf(sc->dev, "duty < period\n");
return (EINVAL);
}
/* First test without prescaler */
clk_rate = AW_PWM_MAX_FREQ;
prescaler = AW_PWM_CTRL_PRESCALE_MASK;
div = AW_PWM_MAX_FREQ / period_freq;
if ((div - 1) > AW_PWM_PERIOD_TOTAL_MASK) {
/* Test all prescaler */
for (i = 0; i < nitems(aw_pwm_clk_prescaler); i++) {
if (aw_pwm_clk_prescaler[i] == 0)
continue;
div = (AW_PWM_MAX_FREQ * aw_pwm_clk_prescaler[i]) / period_freq;
if ((div - 1) < AW_PWM_PERIOD_TOTAL_MASK ) {
prescaler = i;
clk_rate = AW_PWM_MAX_FREQ / aw_pwm_clk_prescaler[i];
break;
}
}
if (prescaler == AW_PWM_CTRL_PRESCALE_MASK)
return (EINVAL);
}
reg = AW_PWM_READ(sc, AW_PWM_CTRL);
if (reg & AW_PWM_CTRL_PERIOD_BUSY) {
device_printf(sc->dev, "pwm busy\n");
return (EBUSY);
}
/* Write the prescalar */
reg &= ~AW_PWM_CTRL_PRESCALE_MASK;
reg |= prescaler;
AW_PWM_WRITE(sc, AW_PWM_CTRL, reg);
/* Write the total/active cycles */
reg = ((clk_rate / period_freq) << AW_PWM_PERIOD_TOTAL_SHIFT) |
((clk_rate / duty_freq) << AW_PWM_PERIOD_ACTIVE_SHIFT);
AW_PWM_WRITE(sc, AW_PWM_PERIOD, reg);
sc->period = period;
sc->duty = duty;
return (0);
}
static int
aw_pwm_channel_get_config(device_t dev, u_int channel, u_int *period, u_int *duty)
{
struct aw_pwm_softc *sc;
sc = device_get_softc(dev);
*period = sc->period;
*duty = sc->duty;
return (0);
}
static int
aw_pwm_channel_enable(device_t dev, u_int channel, bool enable)
{
struct aw_pwm_softc *sc;
uint32_t reg;
sc = device_get_softc(dev);
if (enable && sc->enabled)
return (0);
reg = AW_PWM_READ(sc, AW_PWM_CTRL);
if (enable)
reg |= AW_PWM_CTRL_GATE | AW_PWM_CTRL_EN;
else
reg &= ~(AW_PWM_CTRL_GATE | AW_PWM_CTRL_EN);
AW_PWM_WRITE(sc, AW_PWM_CTRL, reg);
sc->enabled = enable;
return (0);
}
static int
aw_pwm_channel_is_enabled(device_t dev, u_int channel, bool *enabled)
{
struct aw_pwm_softc *sc;
sc = device_get_softc(dev);
*enabled = sc->enabled;
return (0);
}
static device_method_t aw_pwm_methods[] = {
/* Device interface */
DEVMETHOD(device_probe, aw_pwm_probe),
DEVMETHOD(device_attach, aw_pwm_attach),
DEVMETHOD(device_detach, aw_pwm_detach),
/* ofw_bus interface */
DEVMETHOD(ofw_bus_get_node, aw_pwm_get_node),
/* pwmbus interface */
DEVMETHOD(pwmbus_channel_count, aw_pwm_channel_count),
DEVMETHOD(pwmbus_channel_config, aw_pwm_channel_config),
DEVMETHOD(pwmbus_channel_get_config, aw_pwm_channel_get_config),
DEVMETHOD(pwmbus_channel_enable, aw_pwm_channel_enable),
DEVMETHOD(pwmbus_channel_is_enabled, aw_pwm_channel_is_enabled),
DEVMETHOD_END
};
static driver_t aw_pwm_driver = {
"pwm",
aw_pwm_methods,
sizeof(struct aw_pwm_softc),
};
static devclass_t aw_pwm_devclass;
DRIVER_MODULE(aw_pwm, simplebus, aw_pwm_driver, aw_pwm_devclass, 0, 0);
MODULE_VERSION(aw_pwm, 1);
SIMPLEBUS_PNP_INFO(compat_data);