1 /* $NetBSD: meson_clk_mux.c,v 1.2 2019/02/25 19:30:17 jmcneill Exp $ */
2
3 /*-
4 * Copyright (c) 2017-2019 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: meson_clk_mux.c,v 1.2 2019/02/25 19:30:17 jmcneill Exp $");
31
32 #include <sys/param.h>
33 #include <sys/bus.h>
34
35 #include <dev/clk/clk_backend.h>
36
37 #include <arm/amlogic/meson_clk.h>
38
39 const char *
meson_clk_mux_get_parent(struct meson_clk_softc * sc,struct meson_clk_clk * clk)40 meson_clk_mux_get_parent(struct meson_clk_softc *sc, struct meson_clk_clk *clk)
41 {
42 struct meson_clk_mux *mux = &clk->u.mux;
43 uint32_t val;
44 u_int sel;
45
46 KASSERT(clk->type == MESON_CLK_MUX);
47
48 CLK_LOCK(sc);
49 val = CLK_READ(sc, mux->reg);
50 CLK_UNLOCK(sc);
51
52 sel = __SHIFTOUT(val, mux->sel);
53 if (sel >= mux->nparents)
54 return NULL;
55
56 return mux->parents[sel];
57 }
58