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      1 /* $NetBSD: pwm_fan.c,v 1.2 2021/01/27 03:10:21 thorpej 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_fan.c,v 1.2 2021/01/27 03:10:21 thorpej 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_fan_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 };
     52 
     53 static int	pwm_fan_match(device_t, cfdata_t, void *);
     54 static void	pwm_fan_attach(device_t, device_t, void *);
     55 
     56 static void	pwm_fan_set(struct pwm_fan_softc *, u_int);
     57 
     58 static const struct device_compatible_entry compat_data[] = {
     59 	{ .compat = "pwm-fan" },
     60 	DEVICE_COMPAT_EOL
     61 };
     62 
     63 CFATTACH_DECL_NEW(pwmfan, sizeof(struct pwm_fan_softc),
     64 	pwm_fan_match, pwm_fan_attach, NULL, NULL);
     65 
     66 static int
     67 pwm_fan_match(device_t parent, cfdata_t cf, void *aux)
     68 {
     69 	struct fdt_attach_args * const faa = aux;
     70 
     71 	return of_compatible_match(faa->faa_phandle, compat_data);
     72 }
     73 
     74 static void
     75 pwm_fan_attach(device_t parent, device_t self, void *aux)
     76 {
     77 	struct pwm_fan_softc * const sc = device_private(self);
     78 	struct fdt_attach_args * const faa = aux;
     79 	const int phandle = faa->faa_phandle;
     80 	const u_int *levels;
     81 	u_int n;
     82 	int len;
     83 
     84 	sc->sc_dev = self;
     85 	sc->sc_pwm = fdtbus_pwm_acquire(phandle, "pwms");
     86 	if (sc->sc_pwm == NULL) {
     87 		aprint_error(": couldn't acquire pwm\n");
     88 		return;
     89 	}
     90 
     91 	levels = fdtbus_get_prop(phandle, "cooling-levels", &len);
     92 	if (len < 4) {
     93 		aprint_error(": couldn't get 'cooling-levels' property\n");
     94 		return;
     95 	}
     96 	sc->sc_levels = kmem_alloc(len, KM_SLEEP);
     97 	sc->sc_nlevels = len / 4;
     98 	for (n = 0; n < sc->sc_nlevels; n++)
     99 		sc->sc_levels[n] = be32toh(levels[n]);
    100 
    101 	aprint_naive("\n");
    102 	aprint_normal(": PWM Fan");
    103 	aprint_normal(" (levels");
    104 	for (n = 0; n < sc->sc_nlevels; n++) {
    105 		aprint_normal(" %u%%", (sc->sc_levels[n] * 100) / 255);
    106 	}
    107 	aprint_normal(")\n");
    108 
    109 	/* Select the highest cooling level */
    110 	pwm_fan_set(sc, 255);
    111 }
    112 
    113 static void
    114 pwm_fan_set(struct pwm_fan_softc *sc, u_int level)
    115 {
    116 	struct pwm_config conf;
    117 
    118 	if (level > 255)
    119 		level = 255;
    120 
    121 	aprint_debug_dev(sc->sc_dev, "set duty cycle to %u%%\n", (level * 100) / 255);
    122 
    123 	pwm_disable(sc->sc_pwm);
    124 	pwm_get_config(sc->sc_pwm, &conf);
    125 	conf.duty_cycle = (conf.period * level) / 255;
    126 	pwm_set_config(sc->sc_pwm, &conf);
    127 	pwm_enable(sc->sc_pwm);
    128 }
    129