fixedclock.c revision 1.6 
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
42static int	fixedclock_match(device_t, cfdata_t, void *);
43static void	fixedclock_attach(device_t, device_t, void *);
44
45static struct clk *fixedclock_decode(device_t, int, const void *, size_t);
46
47static const struct fdtbus_clock_controller_func fixedclock_fdt_funcs = {
48	.decode = fixedclock_decode
49};
50
51static struct clk *fixedclock_get(void *, const char *);
52static void	fixedclock_put(void *, struct clk *);
53static u_int	fixedclock_get_rate(void *, struct clk *);
54
55static const struct clk_funcs fixedclock_clk_funcs = {
56	.get = fixedclock_get,
57	.put = fixedclock_put,
58	.get_rate = fixedclock_get_rate,
59};
60
61struct fixedclock_clk {
62	struct clk	base;
63	u_int		rate;
64};
65
66struct 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
74CFATTACH_DECL_NEW(fclock, sizeof(struct fixedclock_softc),
75    fixedclock_match, fixedclock_attach, NULL, NULL);
76
77static const struct device_compatible_entry compat_data[] = {
78	{ .compat = "fixed-clock" },
79	DEVICE_COMPAT_EOL
80};
81
82static int
83fixedclock_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
90static void
91fixedclock_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
122static struct clk *
123fixedclock_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
134static struct clk *
135fixedclock_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
145static void
146fixedclock_put(void *priv, struct clk *clk)
147{
148}
149
150static u_int
151fixedclock_get_rate(void *priv, struct clk *clk)
152{
153	struct fixedclock_clk *fclk = (struct fixedclock_clk *)clk;
154
155	return fclk->rate;
156}
157