1/* $NetBSD: fixedfactorclock.c,v 1.4 2021/01/27 03:10:21 thorpej Exp $ */
2
3/*-
4 * Copyright (c) 2017 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: fixedfactorclock.c,v 1.4 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	fixedfactorclock_match(device_t, cfdata_t, void *);
43static void	fixedfactorclock_attach(device_t, device_t, void *);
44
45static struct clk *fixedfactorclock_decode(device_t, int, const void *, size_t);
46
47static const struct fdtbus_clock_controller_func fixedfactorclock_fdt_funcs = {
48	.decode = fixedfactorclock_decode
49};
50
51static struct clk *fixedfactorclock_get(void *, const char *);
52static void	fixedfactorclock_put(void *, struct clk *);
53static u_int	fixedfactorclock_get_rate(void *, struct clk *);
54
55static const struct clk_funcs fixedfactorclock_clk_funcs = {
56	.get = fixedfactorclock_get,
57	.put = fixedfactorclock_put,
58	.get_rate = fixedfactorclock_get_rate,
59};
60
61struct fixedfactorclock_clk {
62	struct clk	base;
63
64	u_int		div;
65	u_int		mult;
66};
67
68struct fixedfactorclock_softc {
69	device_t	sc_dev;
70	int		sc_phandle;
71
72	struct clk_domain sc_clkdom;
73	struct fixedfactorclock_clk sc_clk;
74};
75
76CFATTACH_DECL_NEW(ffclock, sizeof(struct fixedfactorclock_softc),
77    fixedfactorclock_match, fixedfactorclock_attach, NULL, NULL);
78
79static const struct device_compatible_entry compat_data[] = {
80	{ .compat = "fixed-factor-clock" },
81	DEVICE_COMPAT_EOL
82};
83
84static int
85fixedfactorclock_match(device_t parent, cfdata_t cf, void *aux)
86{
87	const struct fdt_attach_args *faa = aux;
88
89	return of_compatible_match(faa->faa_phandle, compat_data);
90}
91
92static void
93fixedfactorclock_attach(device_t parent, device_t self, void *aux)
94{
95	struct fixedfactorclock_softc * const sc = device_private(self);
96	const struct fdt_attach_args *faa = aux;
97	const int phandle = faa->faa_phandle;
98	const char *name;
99
100	sc->sc_dev = self;
101	sc->sc_phandle = phandle;
102	sc->sc_clkdom.name = device_xname(self);
103	sc->sc_clkdom.funcs = &fixedfactorclock_clk_funcs;
104	sc->sc_clkdom.priv = sc;
105
106	of_getprop_uint32(phandle, "clock-div", &sc->sc_clk.div);
107	of_getprop_uint32(phandle, "clock-mult", &sc->sc_clk.mult);
108
109	if (sc->sc_clk.div == 0 || sc->sc_clk.mult == 0) {
110		aprint_error(": invalid properties\n");
111		return;
112	}
113
114	name = fdtbus_get_string(phandle, "clock-output-names");
115	if (name == NULL)
116		name = faa->faa_name;
117
118	sc->sc_clk.base.domain = &sc->sc_clkdom;
119	sc->sc_clk.base.name = name;
120	clk_attach(&sc->sc_clk.base);
121
122	aprint_naive("\n");
123	aprint_normal(": x%u /%u fixed-factor clock\n",
124	    sc->sc_clk.mult, sc->sc_clk.div);
125
126	fdtbus_register_clock_controller(self, phandle,
127	    &fixedfactorclock_fdt_funcs);
128}
129
130static struct clk *
131fixedfactorclock_decode(device_t dev, int cc_phandle, const void *data,
132			size_t len)
133{
134	struct fixedfactorclock_softc * const sc = device_private(dev);
135
136	/* #clock-cells for a fixed factor clock is always 0 */
137	if (len != 0)
138		return NULL;
139
140	return &sc->sc_clk.base;
141}
142
143static struct clk *
144fixedfactorclock_get(void *priv, const char *name)
145{
146	struct fixedfactorclock_softc * const sc = priv;
147
148	if (strcmp(name, sc->sc_clk.base.name) != 0)
149		return NULL;
150
151	return &sc->sc_clk.base;
152}
153
154static void
155fixedfactorclock_put(void *priv, struct clk *clk)
156{
157}
158
159static u_int
160fixedfactorclock_get_rate(void *priv, struct clk *clk)
161{
162	struct fixedfactorclock_softc * const sc = priv;
163	struct fixedfactorclock_clk *fclk = (struct fixedfactorclock_clk *)clk;
164	struct clk *clkp_parent;
165
166	clkp_parent = fdtbus_clock_get_index(sc->sc_phandle, 0);
167	if (clkp_parent == NULL)
168		return 0;
169
170	return (clk_get_rate(clkp_parent) * fclk->mult) / fclk->div;
171}
172