/* $NetBSD: pwm_backlight.c,v 1.10 2021/11/07 17:14:09 jmcneill Exp $ */

/*-
* Copyright (c) 2018 Jared McNeill <[email protected]>
* 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 ``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.
*/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: pwm_backlight.c,v 1.10 2021/11/07 17:14:09 jmcneill Exp $");

#include <sys/param.h>
#include <sys/bus.h>
#include <sys/device.h>
#include <sys/systm.h>
#include <sys/sysctl.h>
#include <sys/kmem.h>
#include <sys/gpio.h>

#include <dev/pwm/pwmvar.h>

#include <dev/fdt/fdtvar.h>

struct pwm_backlight_softc {
       device_t                sc_dev;
       pwm_tag_t               sc_pwm;
       struct fdtbus_gpio_pin *sc_pin;

       u_int                   *sc_levels;
       u_int                   sc_nlevels;
       u_int                   sc_curlevel;

       char                    *sc_levelstr;

       bool                    sc_lid_state;
};

static int      pwm_backlight_match(device_t, cfdata_t, void *);
static void     pwm_backlight_attach(device_t, device_t, void *);

static void     pwm_backlight_sysctl_init(struct pwm_backlight_softc *);
static void     pwm_backlight_pmf_init(struct pwm_backlight_softc *);
static void     pwm_backlight_set(struct pwm_backlight_softc *, u_int, bool);
static u_int    pwm_backlight_get(struct pwm_backlight_softc *);

static const struct device_compatible_entry compat_data[] = {
       { .compat = "pwm-backlight" },
       DEVICE_COMPAT_EOL
};

CFATTACH_DECL_NEW(pwmbacklight, sizeof(struct pwm_backlight_softc),
       pwm_backlight_match, pwm_backlight_attach, NULL, NULL);

static int
pwm_backlight_match(device_t parent, cfdata_t cf, void *aux)
{
       struct fdt_attach_args * const faa = aux;

       return of_compatible_match(faa->faa_phandle, compat_data);
}

static void
pwm_backlight_attach(device_t parent, device_t self, void *aux)
{
       struct pwm_backlight_softc * const sc = device_private(self);
       struct fdt_attach_args * const faa = aux;
       const int phandle = faa->faa_phandle;
       const u_int *levels;
       u_int default_level = 0;
       u_int n;
       int len;

       sc->sc_dev = self;
       sc->sc_pwm = fdtbus_pwm_acquire(phandle, "pwms");
       if (sc->sc_pwm == NULL) {
               aprint_error(": couldn't acquire pwm\n");
               return;
       }
       if (of_hasprop(phandle, "enable-gpios")) {
               sc->sc_pin = fdtbus_gpio_acquire(phandle, "enable-gpios",
                   GPIO_PIN_OUTPUT);
               if (!sc->sc_pin) {
                       aprint_error(": couldn't acquire enable gpio\n");
                       return;
               }
               fdtbus_gpio_write(sc->sc_pin, 1);
       }

       levels = fdtbus_get_prop(phandle, "brightness-levels", &len);
       if (levels != NULL) {
               sc->sc_nlevels = len / 4;
               sc->sc_levels = kmem_alloc(len, KM_SLEEP);
               for (n = 0; n < sc->sc_nlevels; n++)
                       sc->sc_levels[n] = be32toh(levels[n]);
       } else {
               sc->sc_nlevels = 256;
               sc->sc_levels = kmem_alloc(sc->sc_nlevels * 4, KM_SLEEP);
               for (n = 0; n < sc->sc_nlevels; n++)
                       sc->sc_levels[n] = n;
               default_level = 200;
       }

       aprint_naive("\n");
       aprint_normal(": PWM Backlight");
       if (sc->sc_nlevels > 1) {
               aprint_normal(", %u-%u (%u steps)",
                   sc->sc_levels[0], sc->sc_levels[sc->sc_nlevels - 1],
                   sc->sc_nlevels);
       }
       aprint_normal("\n");

       sc->sc_lid_state = true;

       of_getprop_uint32(phandle, "default-brightness-level", &default_level);
       if (default_level != 0) {
               /* set the default level now */
               pwm_backlight_set(sc, default_level, true);
       }

       sc->sc_curlevel = pwm_backlight_get(sc);

       pwm_backlight_sysctl_init(sc);
       pwm_backlight_pmf_init(sc);
}

static void
pwm_backlight_set(struct pwm_backlight_softc *sc, u_int index, bool set_cur)
{
       struct pwm_config conf;

       if (index >= sc->sc_nlevels)
               return;

       KASSERT(sc->sc_levels[sc->sc_nlevels - 1] != 0);
       aprint_debug_dev(sc->sc_dev, "set duty cycle to %u%%\n",
           (100 * sc->sc_levels[index]) / sc->sc_levels[sc->sc_nlevels - 1]);

       pwm_disable(sc->sc_pwm);
       pwm_get_config(sc->sc_pwm, &conf);
       conf.duty_cycle = (conf.period * sc->sc_levels[index]) / sc->sc_levels[sc->sc_nlevels - 1];
       pwm_set_config(sc->sc_pwm, &conf);
       pwm_enable(sc->sc_pwm);

       if (set_cur)
               sc->sc_curlevel = index;
}

static u_int
pwm_backlight_get(struct pwm_backlight_softc *sc)
{
       struct pwm_config conf;
       u_int raw_val, n;

       pwm_get_config(sc->sc_pwm, &conf);

       raw_val = (conf.duty_cycle * sc->sc_levels[sc->sc_nlevels - 1]) / conf.period;

       /* Return the closest setting to the raw value */
       for (n = 0; n < sc->sc_nlevels; n++) {
               if (raw_val <= sc->sc_levels[n])
                       break;
       }
       return n;
}

static int
pwm_backlight_sysctl_helper(SYSCTLFN_ARGS)
{
       struct pwm_backlight_softc * const sc = rnode->sysctl_data;
       struct sysctlnode node;
       int error;
       u_int level, n;

       node = *rnode;
       node.sysctl_data = &level;

       n = pwm_backlight_get(sc);
       level = sc->sc_levels[n];

       error = sysctl_lookup(SYSCTLFN_CALL(&node));
       if (error || newp == NULL)
               return error;

       for (n = 0; n < sc->sc_nlevels; n++) {
               if (sc->sc_levels[n] == level) {
                       pwm_backlight_set(sc, n, true);
                       return 0;
               }
       }

       return EINVAL;
}

static void
pwm_backlight_sysctl_init(struct pwm_backlight_softc *sc)
{
       const struct sysctlnode *node, *pwmnode;
       struct sysctllog *log = NULL;
       int error;
       u_int n;

       sc->sc_levelstr = kmem_zalloc(strlen("XXXXX ") * sc->sc_nlevels, KM_SLEEP);
       for (n = 0; n < sc->sc_nlevels; n++) {
               char buf[7];
               snprintf(buf, sizeof(buf), n ? " %u" : "%u", sc->sc_levels[n]);
               strcat(sc->sc_levelstr, buf);
       }

       error = sysctl_createv(&log, 0, NULL, &node,
           CTLFLAG_PERMANENT, CTLTYPE_NODE, "hw", NULL,
           NULL, 0, NULL, 0, CTL_HW, CTL_EOL);
       if (error)
               goto failed;

       error = sysctl_createv(&log, 0, &node, &pwmnode,
           0, CTLTYPE_NODE, device_xname(sc->sc_dev), NULL,
           NULL, 0, NULL, 0, CTL_CREATE, CTL_EOL);
       if (error)
               goto failed;

       error = sysctl_createv(&log, 0, &pwmnode, NULL,
           0, CTLTYPE_STRING, "levels", NULL,
           NULL, 0, sc->sc_levelstr, 0,
           CTL_CREATE, CTL_EOL);
       if (error)
               goto failed;

       error = sysctl_createv(&log, 0, &pwmnode, NULL,
           CTLFLAG_READWRITE, CTLTYPE_INT, "level", NULL,
           pwm_backlight_sysctl_helper, 0, (void *)sc, 0,
           CTL_CREATE, CTL_EOL);
       if (error)
               goto failed;

       return;

failed:
       aprint_error_dev(sc->sc_dev, "couldn't create sysctl nodes: %d\n", error);
       sysctl_teardown(&log);
}

static void
pwm_backlight_enable(struct pwm_backlight_softc *sc, int enable)
{
       if (sc->sc_pin)
               fdtbus_gpio_write(sc->sc_pin, enable);
       else
               pwm_backlight_set(sc, enable ? sc->sc_curlevel : 0, false);
}

static void
pwm_backlight_display_on(device_t dev)
{
       struct pwm_backlight_softc * const sc = device_private(dev);

       if (sc->sc_lid_state)
               pwm_backlight_enable(sc, 1);
}

static void
pwm_backlight_display_off(device_t dev)
{
       struct pwm_backlight_softc * const sc = device_private(dev);

       pwm_backlight_enable(sc, 0);
}

static void
pwm_backlight_chassis_lid_open(device_t dev)
{
       struct pwm_backlight_softc * const sc = device_private(dev);

       sc->sc_lid_state = true;

       pwm_backlight_enable(sc, 1);
}

static void
pwm_backlight_chassis_lid_close(device_t dev)
{
       struct pwm_backlight_softc * const sc = device_private(dev);

       sc->sc_lid_state = false;

       pwm_backlight_enable(sc, 0);
}

static void
pwm_backlight_display_brightness_up(device_t dev)
{
       struct pwm_backlight_softc * const sc = device_private(dev);
       u_int n;

       n = pwm_backlight_get(sc);
       if (n < sc->sc_nlevels - 1)
               pwm_backlight_set(sc, n + 1, true);
}

static void
pwm_backlight_display_brightness_down(device_t dev)
{
       struct pwm_backlight_softc * const sc = device_private(dev);
       u_int n;

       n = pwm_backlight_get(sc);
       if (n > 0)
               pwm_backlight_set(sc, n - 1, true);
}

static void
pwm_backlight_pmf_init(struct pwm_backlight_softc *sc)
{
       pmf_event_register(sc->sc_dev, PMFE_DISPLAY_ON,
           pwm_backlight_display_on, true);
       pmf_event_register(sc->sc_dev, PMFE_DISPLAY_OFF,
           pwm_backlight_display_off, true);
       pmf_event_register(sc->sc_dev, PMFE_CHASSIS_LID_OPEN,
           pwm_backlight_chassis_lid_open, true);
       pmf_event_register(sc->sc_dev, PMFE_CHASSIS_LID_CLOSE,
           pwm_backlight_chassis_lid_close, true);
       pmf_event_register(sc->sc_dev, PMFE_DISPLAY_BRIGHTNESS_UP,
           pwm_backlight_display_brightness_up, true);
       pmf_event_register(sc->sc_dev, PMFE_DISPLAY_BRIGHTNESS_DOWN,
           pwm_backlight_display_brightness_down, true);
}

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