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meson_clk_pll.c revision 1.1 
      1 /* $NetBSD: meson_clk_pll.c,v 1.1 2019/01/19 20:56:03 jmcneill Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2019 Jared 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: meson_clk_pll.c,v 1.1 2019/01/19 20:56:03 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 u_int
     40 meson_clk_pll_get_rate(struct meson_clk_softc *sc,
     41     struct meson_clk_clk *clk)
     42 {
     43 	struct meson_clk_pll *pll = &clk->u.pll;
     44 	struct clk *clkp, *clkp_parent;
     45 	u_int n, m, frac;
     46 	uint64_t parent_rate, rate;
     47 	uint32_t val;
     48 
     49 	KASSERT(clk->type == MESON_CLK_PLL);
     50 
     51 	clkp = &clk->base;
     52 	clkp_parent = clk_get_parent(clkp);
     53 	if (clkp_parent == NULL)
     54 		return 0;
     55 
     56 	parent_rate = clk_get_rate(clkp_parent);
     57 	if (parent_rate == 0)
     58 		return 0;
     59 
     60 	val = CLK_READ(sc, pll->n.reg);
     61 	n = __SHIFTOUT(val, pll->n.mask);
     62 
     63 	val = CLK_READ(sc, pll->m.reg);
     64 	m = __SHIFTOUT(val, pll->m.mask);
     65 
     66 	if (pll->frac.mask) {
     67 		val = CLK_READ(sc, pll->frac.reg);
     68 		frac = __SHIFTOUT(val, pll->frac.mask);
     69 	} else {
     70 		frac = 0;
     71 	}
     72 
     73 	rate = parent_rate * m;
     74 	if (frac) {
     75 		uint64_t frac_rate = parent_rate * frac;
     76 		rate += howmany(frac_rate, __SHIFTOUT_MASK(pll->frac.mask) + 1);
     77 	}
     78 
     79 	return (u_int)howmany(rate, n);
     80 }
     81 
     82 const char *
     83 meson_clk_pll_get_parent(struct meson_clk_softc *sc,
     84     struct meson_clk_clk *clk)
     85 {
     86 	struct meson_clk_pll *pll = &clk->u.pll;
     87 
     88 	KASSERT(clk->type == MESON_CLK_PLL);
     89 
     90 	return pll->parent;
     91 }
     92