1 /* $NetBSD: fixedclock.c,v 1.6 2021/01/27 03:10:21 thorpej 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 1.6 2021/01/27 03:10:21 thorpej 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, int, 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 const struct device_compatible_entry compat_data[] = {
78 { .compat = "fixed-clock" },
79 DEVICE_COMPAT_EOL
80 };
81
82 static int
fixedclock_match(device_t parent,cfdata_t cf,void * aux)83 fixedclock_match(device_t parent, cfdata_t cf, void *aux)
84 {
85 const struct fdt_attach_args *faa = aux;
86
87 return of_compatible_match(faa->faa_phandle, compat_data);
88 }
89
90 static void
fixedclock_attach(device_t parent,device_t self,void * aux)91 fixedclock_attach(device_t parent, device_t self, void *aux)
92 {
93 struct fixedclock_softc * const sc = device_private(self);
94 const struct fdt_attach_args *faa = aux;
95 const int phandle = faa->faa_phandle;
96 const char *clkname;
97
98 clkname = fdtbus_get_string(phandle, "clock-output-names");
99 if (!clkname)
100 clkname = faa->faa_name;
101
102 sc->sc_dev = self;
103 sc->sc_phandle = phandle;
104 sc->sc_clkdom.name = device_xname(self);
105 sc->sc_clkdom.funcs = &fixedclock_clk_funcs;
106 sc->sc_clkdom.priv = sc;
107 if (of_getprop_uint32(phandle, "clock-frequency",
108 &sc->sc_clk.rate) != 0) {
109 aprint_error(": couldn't determine frequency\n");
110 return;
111 }
112 sc->sc_clk.base.domain = &sc->sc_clkdom;
113 sc->sc_clk.base.name = kmem_asprintf("%s", clkname);
114 clk_attach(&sc->sc_clk.base);
115
116 aprint_naive("\n");
117 aprint_normal(": %u Hz fixed clock (%s)\n", sc->sc_clk.rate, clkname);
118
119 fdtbus_register_clock_controller(self, phandle, &fixedclock_fdt_funcs);
120 }
121
122 static struct clk *
fixedclock_decode(device_t dev,int cc_phandle,const void * data,size_t len)123 fixedclock_decode(device_t dev, int cc_phandle, const void *data, size_t len)
124 {
125 struct fixedclock_softc * const sc = device_private(dev);
126
127 /* #clock-cells for a fixed clock is always 0 */
128 if (len != 0)
129 return NULL;
130
131 return &sc->sc_clk.base;
132 }
133
134 static struct clk *
fixedclock_get(void * priv,const char * name)135 fixedclock_get(void *priv, const char *name)
136 {
137 struct fixedclock_softc * const sc = priv;
138
139 if (strcmp(name, sc->sc_clk.base.name) != 0)
140 return NULL;
141
142 return &sc->sc_clk.base;
143 }
144
145 static void
fixedclock_put(void * priv,struct clk * clk)146 fixedclock_put(void *priv, struct clk *clk)
147 {
148 }
149
150 static u_int
fixedclock_get_rate(void * priv,struct clk * clk)151 fixedclock_get_rate(void *priv, struct clk *clk)
152 {
153 struct fixedclock_clk *fclk = (struct fixedclock_clk *)clk;
154
155 return fclk->rate;
156 }
157