1 /* $NetBSD: pwm_fan.c,v 1.1 2018/07/04 23:08:06 jmcneill Exp $ */ 2 3 /*- 4 * Copyright (c) 2018 Jared McNeill <jmcneill@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 1.1 2018/07/04 23:08:06 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_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 char *compatible[] = { 59 "pwm-fan", 60 NULL 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_match_compatible(faa->faa_phandle, compatible); 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