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meson_clk_mpll.c revision 1.1.2.2 
      1 /* $NetBSD: meson_clk_mpll.c,v 1.1.2.2 2019/01/26 21:59:59 pgoyette 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_mpll.c,v 1.1.2.2 2019/01/26 21:59:59 pgoyette 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 #define	SDM_DEN		0x4000
     40 
     41 u_int
     42 meson_clk_mpll_get_rate(struct meson_clk_softc *sc,
     43     struct meson_clk_clk *clk)
     44 {
     45 	struct meson_clk_mpll *mpll = &clk->u.mpll;
     46 	struct clk *clkp, *clkp_parent;
     47 	uint64_t parent_rate, sdm, n2;
     48 	uint32_t val;
     49 
     50 	KASSERT(clk->type == MESON_CLK_MPLL);
     51 
     52 	clkp = &clk->base;
     53 	clkp_parent = clk_get_parent(clkp);
     54 	if (clkp_parent == NULL)
     55 		return 0;
     56 
     57 	parent_rate = clk_get_rate(clkp_parent);
     58 	if (parent_rate == 0)
     59 		return 0;
     60 
     61 	val = CLK_READ(sc, mpll->sdm.reg);
     62 	sdm = __SHIFTOUT(val, mpll->sdm.mask);
     63 
     64 	val = CLK_READ(sc, mpll->n2.reg);
     65 	n2 = __SHIFTOUT(val, mpll->n2.mask);
     66 
     67 	const uint64_t div = (SDM_DEN * n2) + sdm;
     68 	if (div == 0)
     69 		return 0;
     70 
     71 	return (u_int)howmany(parent_rate * SDM_DEN, div);
     72 }
     73 
     74 const char *
     75 meson_clk_mpll_get_parent(struct meson_clk_softc *sc,
     76     struct meson_clk_clk *clk)
     77 {
     78 	struct meson_clk_mpll *mpll = &clk->u.mpll;
     79 
     80 	KASSERT(clk->type == MESON_CLK_MPLL);
     81 
     82 	return mpll->parent;
     83 }
     84