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      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 (at) 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
     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
     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 *
    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 *
    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
    146 fixedclock_put(void *priv, struct clk *clk)
    147 {
    148 }
    149 
    150 static u_int
    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