1 /* $NetBSD: fixedclock.c,v 1.2 2017/04/21 19:18:05 jmcneill Exp $ */ 2 3 /*- 4 * Copyright (c) 2017 Jared D. 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: fixedclock.c,v 1.2 2017/04/21 19:18:05 jmcneill Exp $"); 31 32 #include <sys/param.h> 33 #include <sys/systm.h> 34 #include <sys/device.h> 35 #include <sys/kmem.h> 36 #include <sys/bus.h> 37 38 #include <dev/clk/clk_backend.h> 39 40 #include <dev/fdt/fdtvar.h> 41 42 static int fixedclock_match(device_t, cfdata_t, void *); 43 static void fixedclock_attach(device_t, device_t, void *); 44 45 static struct clk *fixedclock_decode(device_t, const void *, size_t); 46 47 static const struct fdtbus_clock_controller_func fixedclock_fdt_funcs = { 48 .decode = fixedclock_decode 49 }; 50 51 static struct clk *fixedclock_get(void *, const char *); 52 static void fixedclock_put(void *, struct clk *); 53 static u_int fixedclock_get_rate(void *, struct clk *); 54 55 static const struct clk_funcs fixedclock_clk_funcs = { 56 .get = fixedclock_get, 57 .put = fixedclock_put, 58 .get_rate = fixedclock_get_rate, 59 }; 60 61 struct fixedclock_clk { 62 struct clk base; 63 u_int rate; 64 }; 65 66 struct fixedclock_softc { 67 device_t sc_dev; 68 int sc_phandle; 69 70 struct clk_domain sc_clkdom; 71 struct fixedclock_clk sc_clk; 72 }; 73 74 CFATTACH_DECL_NEW(fclock, sizeof(struct fixedclock_softc), 75 fixedclock_match, fixedclock_attach, NULL, NULL); 76 77 static int 78 fixedclock_match(device_t parent, cfdata_t cf, void *aux) 79 { 80 const char * const compatible[] = { "fixed-clock", NULL }; 81 const struct fdt_attach_args *faa = aux; 82 83 return of_match_compatible(faa->faa_phandle, compatible); 84 } 85 86 static void 87 fixedclock_attach(device_t parent, device_t self, void *aux) 88 { 89 struct fixedclock_softc * const sc = device_private(self); 90 const struct fdt_attach_args *faa = aux; 91 const int phandle = faa->faa_phandle; 92 93 sc->sc_dev = self; 94 sc->sc_phandle = phandle; 95 sc->sc_clkdom.funcs = &fixedclock_clk_funcs; 96 sc->sc_clkdom.priv = sc; 97 if (of_getprop_uint32(phandle, "clock-frequency", 98 &sc->sc_clk.rate) != 0) { 99 aprint_error(": couldn't determine frequency\n"); 100 return; 101 } 102 sc->sc_clk.base.domain = &sc->sc_clkdom; 103 sc->sc_clk.base.name = kmem_asprintf("%s", faa->faa_name); 104 105 aprint_naive("\n"); 106 aprint_normal(": %u Hz fixed clock\n", sc->sc_clk.rate); 107 108 fdtbus_register_clock_controller(self, phandle, &fixedclock_fdt_funcs); 109 } 110 111 static struct clk * 112 fixedclock_decode(device_t dev, const void *data, size_t len) 113 { 114 struct fixedclock_softc * const sc = device_private(dev); 115 116 /* #clock-cells for a fixed clock is always 0 */ 117 if (len != 0) 118 return NULL; 119 120 return &sc->sc_clk.base; 121 } 122 123 static struct clk * 124 fixedclock_get(void *priv, const char *name) 125 { 126 struct fixedclock_softc * const sc = priv; 127 128 if (strcmp(name, sc->sc_clk.base.name) != 0) 129 return NULL; 130 131 return &sc->sc_clk.base; 132 } 133 134 static void 135 fixedclock_put(void *priv, struct clk *clk) 136 { 137 } 138 139 static u_int 140 fixedclock_get_rate(void *priv, struct clk *clk) 141 { 142 struct fixedclock_clk *fclk = (struct fixedclock_clk *)clk; 143 144 return fclk->rate; 145 } 146