Differential D26252 Diff 77105 sys/dev/pwm/pwm_backlight.c

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sys/dev/pwm/pwm_backlight.c

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				/*-
				* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
				*
				* Copyright (c) 2020 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 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.
				*
				* $FreeBSD$
				*/

				#include <sys/cdefs.h>
				__FBSDID("$FreeBSD$");


				#include <sys/param.h>
				#include <sys/systm.h>
				#include <sys/bio.h>
				#include <sys/bus.h>
				#include <sys/conf.h>
				#include <sys/endian.h>
				#include <sys/fcntl.h>
				#include <sys/ioccom.h>
				#include <sys/kernel.h>
				#include <sys/kthread.h>
				#include <sys/lock.h>
				#include <sys/malloc.h>
				#include <sys/module.h>
				#include <sys/mutex.h>
				#include <sys/priv.h>
				#include <sys/slicer.h>
				#include <sys/sysctl.h>
				#include <sys/time.h>

				#include <dev/ofw/ofw_bus.h>
				#include <dev/ofw/ofw_bus_subr.h>

				#include <dev/extres/regulator/regulator.h>

				#include <dev/backlight/backlight.h>

				#include <dev/pwm/ofw_pwm.h>

				#include "backlight_if.h"
				#include "pwmbus_if.h"

				struct pwm_backlight_softc {
				device_t pwmdev;
				struct cdev *cdev;

				pwm_channel_t channel;
				uint32_t *levels;
				ssize_t nlevels;
				int default_level;
				ssize_t current_level;

				regulator_t power_supply;
				uint64_t period;
				uint64_t duty;
				bool enabled;
				};

				static int pwm_backlight_find_level_per_percent(struct pwm_backlight_softc *sc, int percent);

				static struct ofw_compat_data compat_data[] = {
				{ "pwm-backlight", 1 },
				{ NULL, 0 }
				};

				static int
				pwm_backlight_probe(device_t dev)
				{

				if (!ofw_bus_search_compatible(dev, compat_data)->ocd_data)
				return (ENXIO);

				device_set_desc(dev, "PWM Backlight");
				return (BUS_PROBE_DEFAULT);
				}

				static int
				pwm_backlight_attach(device_t dev)
				{
				struct pwm_backlight_softc *sc;
				phandle_t node;
				int rv;

				sc = device_get_softc(dev);
				node = ofw_bus_get_node(dev);

				rv = pwm_get_by_ofw_propidx(dev, node, "pwms", 0, &sc->channel);
				if (rv != 0) {
				device_printf(dev, "Cannot map pwm channel %d\n", rv);
				return (ENXIO);
				}

				if (regulator_get_by_ofw_property(dev, 0, "power-supply",
				&sc->power_supply) != 0) {
				device_printf(dev, "No power-supply property\n");
				return (ENXIO);
				}

				if (OF_hasprop(node, "brightness-levels")) {
				sc->nlevels = OF_getencprop_alloc(node, "brightness-levels",
				(void **)&sc->levels);
				if (sc->nlevels <= 0) {
				device_printf(dev, "Cannot parse brightness levels\n");
				return (ENXIO);
				}
				sc->nlevels /= sizeof(uint32_t);

				if (OF_getencprop(node, "default-brightness-level",
				&sc->default_level, sizeof(uint32_t)) <= 0) {
				device_printf(dev, "No default-brightness-level while brightness-levels is specified\n");
				return (ENXIO);
				} else {
				if (sc->default_level > sc->nlevels) {
				device_printf(dev, "default-brightness-level isn't present in brightness-levels range\n");
				return (ENXIO);
				}
				sc->channel->duty = sc->channel->period * sc->levels[sc->default_level] / 100;
				}

				if (bootverbose) {
				device_printf(dev, "Number of levels: %zd\n", sc->nlevels);
				device_printf(dev, "Configured period time: %lu\n", sc->channel->period);
				device_printf(dev, "Default duty cycle: %lu\n", sc->channel->duty);
				}
				} else {
				/* Get the current backlight level */
				PWMBUS_CHANNEL_GET_CONFIG(sc->channel->dev,
				sc->channel->channel,
				(unsigned int *)&sc->channel->period,
				(unsigned int *)&sc->channel->duty);
				if (sc->channel->duty > sc->channel->period)
				sc->channel->duty = sc->channel->period;
				if (bootverbose) {
				device_printf(dev, "Configured period time: %lu\n", sc->channel->period);
				device_printf(dev, "Default duty cycle: %lu\n", sc->channel->duty);
				}
				}

				regulator_enable(sc->power_supply);
				sc->channel->enabled = true;
				PWMBUS_CHANNEL_CONFIG(sc->channel->dev, sc->channel->channel,
				sc->channel->period, sc->channel->duty);
				PWMBUS_CHANNEL_ENABLE(sc->channel->dev, sc->channel->channel,
				sc->channel->enabled);

				sc->current_level = pwm_backlight_find_level_per_percent(sc,
				sc->channel->period / sc->channel->duty);
				sc->cdev = backlight_register("pwm_backlight", dev);
				if (sc->cdev == NULL)
				device_printf(dev, "Cannot register as a backlight\n");

				return (0);
				}

				static int
				pwm_backlight_detach(device_t dev)
				{
				struct pwm_backlight_softc *sc;

				sc = device_get_softc(dev);
				if (sc->nlevels > 0)
				OF_prop_free(sc->levels);
				regulator_disable(sc->power_supply);
				backlight_destroy(sc->cdev);
				return (0);
				}

				static int
				pwm_backlight_find_level_per_percent(struct pwm_backlight_softc *sc, int percent)
				{
				int i;
				int diff;

				if (percent < 0 \|\| percent > 100)
				return (-1);

				for (i = 0, diff = 0; i < sc->nlevels; i++) {
				if (sc->levels[i] == percent)
				return (i);
				else if (sc->levels[i] < percent)
				diff = percent - sc->levels[i];
				else {
				if (diff < abs((percent - sc->levels[i])))
				return (i - 1);
				else
				return (i);
				}
				}

				return (-1);
				}

				static int
				pwm_backlight_update_status(device_t dev, struct backlight_props *props)
				{
				struct pwm_backlight_softc *sc;
				int reg_status;
				int error;

				sc = device_get_softc(dev);

				if (sc->nlevels != 0) {
				error = pwm_backlight_find_level_per_percent(sc,
				props->brightness);
				if (error < 0)
				return (ERANGE);
				sc->current_level = error;
				sc->channel->duty = sc->channel->period *
				sc->levels[sc->current_level] / 100;
				} else {
				if (props->brightness > 100 \|\| props->brightness < 0)
				return (ERANGE);
				sc->channel->duty = sc->channel->period *
				props->brightness / 100;
				}
				sc->channel->enabled = true;
				PWMBUS_CHANNEL_CONFIG(sc->channel->dev, sc->channel->channel,
				sc->channel->period, sc->channel->duty);
				PWMBUS_CHANNEL_ENABLE(sc->channel->dev, sc->channel->channel,
				sc->channel->enabled);
				error = regulator_status(sc->power_supply, &reg_status);
				if (error != 0)
				device_printf(dev,
				"Cannot get power-supply status: %d\n", error);
				else {
				if (props->brightness > 0) {
				if (reg_status != REGULATOR_STATUS_ENABLED)
				regulator_enable(sc->power_supply);
				} else {
				if (reg_status == REGULATOR_STATUS_ENABLED)
				regulator_disable(sc->power_supply);
				}
				}

				return (0);
				}

				static int
				pwm_backlight_get_status(device_t dev, struct backlight_props *props)
				{
				struct pwm_backlight_softc *sc;
				int i;

				sc = device_get_softc(dev);

				if (sc->nlevels != 0) {
				props->brightness = sc->levels[sc->current_level];
				props->nlevels = sc->nlevels;
				for (i = 0; i < sc->nlevels; i++)
				props->levels[i] = sc->levels[i];
				} else {
				props->brightness = sc->channel->duty * 100 / sc->channel->period;
				props->nlevels = 0;
				}
				return (0);
				}

				static int
				pwm_backlight_get_info(device_t dev, struct backlight_info *info)
				{

				info->type = BACKLIGHT_TYPE_PANEL;
				strlcpy(info->name, "pwm-backlight", BACKLIGHTMAXNAMELENGTH);
				return (0);
				}

				static device_method_t pwm_backlight_methods[] = {
				/* device_if */
				DEVMETHOD(device_probe, pwm_backlight_probe),
				DEVMETHOD(device_attach, pwm_backlight_attach),
				DEVMETHOD(device_detach, pwm_backlight_detach),

				/* backlight interface */
				DEVMETHOD(backlight_update_status, pwm_backlight_update_status),
				DEVMETHOD(backlight_get_status, pwm_backlight_get_status),
				DEVMETHOD(backlight_get_info, pwm_backlight_get_info),
				DEVMETHOD_END
				};

				driver_t pwm_backlight_driver = {
				"pwm_backlight",
				pwm_backlight_methods,
				sizeof(struct pwm_backlight_softc),
				};
				devclass_t pwm_backlight_devclass;

				DRIVER_MODULE(pwm_backlight, simplebus, pwm_backlight_driver,
				pwm_backlight_devclass, 0, 0);
				OFWBUS_PNP_INFO(compat_data);