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      1 /* $NetBSD: pwm_backlight.c,v 1.10 2021/11/07 17:14:09 jmcneill Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2018 Jared McNeill <jmcneill (at) invisible.ca>
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     21  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     22  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     23  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     24  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  */
     28 
     29 #include <sys/cdefs.h>
     30 __KERNEL_RCSID(0, "$NetBSD: pwm_backlight.c,v 1.10 2021/11/07 17:14:09 jmcneill Exp $");
     31 
     32 #include <sys/param.h>
     33 #include <sys/bus.h>
     34 #include <sys/device.h>
     35 #include <sys/systm.h>
     36 #include <sys/sysctl.h>
     37 #include <sys/kmem.h>
     38 #include <sys/gpio.h>
     39 
     40 #include <dev/pwm/pwmvar.h>
     41 
     42 #include <dev/fdt/fdtvar.h>
     43 
     44 struct pwm_backlight_softc {
     45 	device_t		sc_dev;
     46 	pwm_tag_t		sc_pwm;
     47 	struct fdtbus_gpio_pin *sc_pin;
     48 
     49 	u_int			*sc_levels;
     50 	u_int			sc_nlevels;
     51 	u_int			sc_curlevel;
     52 
     53 	char			*sc_levelstr;
     54 
     55 	bool			sc_lid_state;
     56 };
     57 
     58 static int	pwm_backlight_match(device_t, cfdata_t, void *);
     59 static void	pwm_backlight_attach(device_t, device_t, void *);
     60 
     61 static void	pwm_backlight_sysctl_init(struct pwm_backlight_softc *);
     62 static void	pwm_backlight_pmf_init(struct pwm_backlight_softc *);
     63 static void	pwm_backlight_set(struct pwm_backlight_softc *, u_int, bool);
     64 static u_int	pwm_backlight_get(struct pwm_backlight_softc *);
     65 
     66 static const struct device_compatible_entry compat_data[] = {
     67 	{ .compat = "pwm-backlight" },
     68 	DEVICE_COMPAT_EOL
     69 };
     70 
     71 CFATTACH_DECL_NEW(pwmbacklight, sizeof(struct pwm_backlight_softc),
     72 	pwm_backlight_match, pwm_backlight_attach, NULL, NULL);
     73 
     74 static int
     75 pwm_backlight_match(device_t parent, cfdata_t cf, void *aux)
     76 {
     77 	struct fdt_attach_args * const faa = aux;
     78 
     79 	return of_compatible_match(faa->faa_phandle, compat_data);
     80 }
     81 
     82 static void
     83 pwm_backlight_attach(device_t parent, device_t self, void *aux)
     84 {
     85 	struct pwm_backlight_softc * const sc = device_private(self);
     86 	struct fdt_attach_args * const faa = aux;
     87 	const int phandle = faa->faa_phandle;
     88 	const u_int *levels;
     89 	u_int default_level = 0;
     90 	u_int n;
     91 	int len;
     92 
     93 	sc->sc_dev = self;
     94 	sc->sc_pwm = fdtbus_pwm_acquire(phandle, "pwms");
     95 	if (sc->sc_pwm == NULL) {
     96 		aprint_error(": couldn't acquire pwm\n");
     97 		return;
     98 	}
     99 	if (of_hasprop(phandle, "enable-gpios")) {
    100 		sc->sc_pin = fdtbus_gpio_acquire(phandle, "enable-gpios",
    101 		    GPIO_PIN_OUTPUT);
    102 		if (!sc->sc_pin) {
    103 			aprint_error(": couldn't acquire enable gpio\n");
    104 			return;
    105 		}
    106 		fdtbus_gpio_write(sc->sc_pin, 1);
    107 	}
    108 
    109 	levels = fdtbus_get_prop(phandle, "brightness-levels", &len);
    110 	if (levels != NULL) {
    111 		sc->sc_nlevels = len / 4;
    112 		sc->sc_levels = kmem_alloc(len, KM_SLEEP);
    113 		for (n = 0; n < sc->sc_nlevels; n++)
    114 			sc->sc_levels[n] = be32toh(levels[n]);
    115 	} else {
    116 		sc->sc_nlevels = 256;
    117 		sc->sc_levels = kmem_alloc(sc->sc_nlevels * 4, KM_SLEEP);
    118 		for (n = 0; n < sc->sc_nlevels; n++)
    119 			sc->sc_levels[n] = n;
    120 		default_level = 200;
    121 	}
    122 
    123 	aprint_naive("\n");
    124 	aprint_normal(": PWM Backlight");
    125 	if (sc->sc_nlevels > 1) {
    126 		aprint_normal(", %u-%u (%u steps)",
    127 		    sc->sc_levels[0], sc->sc_levels[sc->sc_nlevels - 1],
    128 		    sc->sc_nlevels);
    129 	}
    130 	aprint_normal("\n");
    131 
    132 	sc->sc_lid_state = true;
    133 
    134 	of_getprop_uint32(phandle, "default-brightness-level", &default_level);
    135 	if (default_level != 0) {
    136 		/* set the default level now */
    137 		pwm_backlight_set(sc, default_level, true);
    138 	}
    139 
    140 	sc->sc_curlevel = pwm_backlight_get(sc);
    141 
    142 	pwm_backlight_sysctl_init(sc);
    143 	pwm_backlight_pmf_init(sc);
    144 }
    145 
    146 static void
    147 pwm_backlight_set(struct pwm_backlight_softc *sc, u_int index, bool set_cur)
    148 {
    149 	struct pwm_config conf;
    150 
    151 	if (index >= sc->sc_nlevels)
    152 		return;
    153 
    154 	KASSERT(sc->sc_levels[sc->sc_nlevels - 1] != 0);
    155 	aprint_debug_dev(sc->sc_dev, "set duty cycle to %u%%\n",
    156 	    (100 * sc->sc_levels[index]) / sc->sc_levels[sc->sc_nlevels - 1]);
    157 
    158 	pwm_disable(sc->sc_pwm);
    159 	pwm_get_config(sc->sc_pwm, &conf);
    160 	conf.duty_cycle = (conf.period * sc->sc_levels[index]) / sc->sc_levels[sc->sc_nlevels - 1];
    161 	pwm_set_config(sc->sc_pwm, &conf);
    162 	pwm_enable(sc->sc_pwm);
    163 
    164 	if (set_cur)
    165 		sc->sc_curlevel = index;
    166 }
    167 
    168 static u_int
    169 pwm_backlight_get(struct pwm_backlight_softc *sc)
    170 {
    171 	struct pwm_config conf;
    172 	u_int raw_val, n;
    173 
    174 	pwm_get_config(sc->sc_pwm, &conf);
    175 
    176 	raw_val = (conf.duty_cycle * sc->sc_levels[sc->sc_nlevels - 1]) / conf.period;
    177 
    178 	/* Return the closest setting to the raw value */
    179 	for (n = 0; n < sc->sc_nlevels; n++) {
    180 		if (raw_val <= sc->sc_levels[n])
    181 			break;
    182 	}
    183 	return n;
    184 }
    185 
    186 static int
    187 pwm_backlight_sysctl_helper(SYSCTLFN_ARGS)
    188 {
    189 	struct pwm_backlight_softc * const sc = rnode->sysctl_data;
    190 	struct sysctlnode node;
    191 	int error;
    192 	u_int level, n;
    193 
    194 	node = *rnode;
    195 	node.sysctl_data = &level;
    196 
    197 	n = pwm_backlight_get(sc);
    198 	level = sc->sc_levels[n];
    199 
    200 	error = sysctl_lookup(SYSCTLFN_CALL(&node));
    201 	if (error || newp == NULL)
    202 		return error;
    203 
    204 	for (n = 0; n < sc->sc_nlevels; n++) {
    205 		if (sc->sc_levels[n] == level) {
    206 			pwm_backlight_set(sc, n, true);
    207 			return 0;
    208 		}
    209 	}
    210 
    211 	return EINVAL;
    212 }
    213 
    214 static void
    215 pwm_backlight_sysctl_init(struct pwm_backlight_softc *sc)
    216 {
    217 	const struct sysctlnode *node, *pwmnode;
    218 	struct sysctllog *log = NULL;
    219 	int error;
    220 	u_int n;
    221 
    222 	sc->sc_levelstr = kmem_zalloc(strlen("XXXXX ") * sc->sc_nlevels, KM_SLEEP);
    223 	for (n = 0; n < sc->sc_nlevels; n++) {
    224 		char buf[7];
    225 		snprintf(buf, sizeof(buf), n ? " %u" : "%u", sc->sc_levels[n]);
    226 		strcat(sc->sc_levelstr, buf);
    227 	}
    228 
    229 	error = sysctl_createv(&log, 0, NULL, &node,
    230 	    CTLFLAG_PERMANENT, CTLTYPE_NODE, "hw", NULL,
    231 	    NULL, 0, NULL, 0, CTL_HW, CTL_EOL);
    232 	if (error)
    233 		goto failed;
    234 
    235 	error = sysctl_createv(&log, 0, &node, &pwmnode,
    236 	    0, CTLTYPE_NODE, device_xname(sc->sc_dev), NULL,
    237 	    NULL, 0, NULL, 0, CTL_CREATE, CTL_EOL);
    238 	if (error)
    239 		goto failed;
    240 
    241 	error = sysctl_createv(&log, 0, &pwmnode, NULL,
    242 	    0, CTLTYPE_STRING, "levels", NULL,
    243 	    NULL, 0, sc->sc_levelstr, 0,
    244 	    CTL_CREATE, CTL_EOL);
    245 	if (error)
    246 		goto failed;
    247 
    248 	error = sysctl_createv(&log, 0, &pwmnode, NULL,
    249 	    CTLFLAG_READWRITE, CTLTYPE_INT, "level", NULL,
    250 	    pwm_backlight_sysctl_helper, 0, (void *)sc, 0,
    251 	    CTL_CREATE, CTL_EOL);
    252 	if (error)
    253 		goto failed;
    254 
    255 	return;
    256 
    257 failed:
    258 	aprint_error_dev(sc->sc_dev, "couldn't create sysctl nodes: %d\n", error);
    259 	sysctl_teardown(&log);
    260 }
    261 
    262 static void
    263 pwm_backlight_enable(struct pwm_backlight_softc *sc, int enable)
    264 {
    265 	if (sc->sc_pin)
    266 		fdtbus_gpio_write(sc->sc_pin, enable);
    267 	else
    268 		pwm_backlight_set(sc, enable ? sc->sc_curlevel : 0, false);
    269 }
    270 
    271 static void
    272 pwm_backlight_display_on(device_t dev)
    273 {
    274 	struct pwm_backlight_softc * const sc = device_private(dev);
    275 
    276 	if (sc->sc_lid_state)
    277 		pwm_backlight_enable(sc, 1);
    278 }
    279 
    280 static void
    281 pwm_backlight_display_off(device_t dev)
    282 {
    283 	struct pwm_backlight_softc * const sc = device_private(dev);
    284 
    285 	pwm_backlight_enable(sc, 0);
    286 }
    287 
    288 static void
    289 pwm_backlight_chassis_lid_open(device_t dev)
    290 {
    291 	struct pwm_backlight_softc * const sc = device_private(dev);
    292 
    293 	sc->sc_lid_state = true;
    294 
    295 	pwm_backlight_enable(sc, 1);
    296 }
    297 
    298 static void
    299 pwm_backlight_chassis_lid_close(device_t dev)
    300 {
    301 	struct pwm_backlight_softc * const sc = device_private(dev);
    302 
    303 	sc->sc_lid_state = false;
    304 
    305 	pwm_backlight_enable(sc, 0);
    306 }
    307 
    308 static void
    309 pwm_backlight_display_brightness_up(device_t dev)
    310 {
    311 	struct pwm_backlight_softc * const sc = device_private(dev);
    312 	u_int n;
    313 
    314 	n = pwm_backlight_get(sc);
    315 	if (n < sc->sc_nlevels - 1)
    316 		pwm_backlight_set(sc, n + 1, true);
    317 }
    318 
    319 static void
    320 pwm_backlight_display_brightness_down(device_t dev)
    321 {
    322 	struct pwm_backlight_softc * const sc = device_private(dev);
    323 	u_int n;
    324 
    325 	n = pwm_backlight_get(sc);
    326 	if (n > 0)
    327 		pwm_backlight_set(sc, n - 1, true);
    328 }
    329 
    330 static void
    331 pwm_backlight_pmf_init(struct pwm_backlight_softc *sc)
    332 {
    333 	pmf_event_register(sc->sc_dev, PMFE_DISPLAY_ON,
    334 	    pwm_backlight_display_on, true);
    335 	pmf_event_register(sc->sc_dev, PMFE_DISPLAY_OFF,
    336 	    pwm_backlight_display_off, true);
    337 	pmf_event_register(sc->sc_dev, PMFE_CHASSIS_LID_OPEN,
    338 	    pwm_backlight_chassis_lid_open, true);
    339 	pmf_event_register(sc->sc_dev, PMFE_CHASSIS_LID_CLOSE,
    340 	    pwm_backlight_chassis_lid_close, true);
    341 	pmf_event_register(sc->sc_dev, PMFE_DISPLAY_BRIGHTNESS_UP,
    342 	    pwm_backlight_display_brightness_up, true);
    343 	pmf_event_register(sc->sc_dev, PMFE_DISPLAY_BRIGHTNESS_DOWN,
    344 	    pwm_backlight_display_brightness_down, true);
    345 }
    346