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sunxi_ccu_div.c revision 1.1.4.2 
      1 /* $NetBSD: sunxi_ccu_div.c,v 1.1.4.2 2017/07/18 19:13:08 snj Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2017 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: sunxi_ccu_div.c,v 1.1.4.2 2017/07/18 19:13:08 snj Exp $");
     31 
     32 #include <sys/param.h>
     33 #include <sys/bus.h>
     34 
     35 #include <dev/clk/clk_backend.h>
     36 
     37 #include <arm/sunxi/sunxi_ccu.h>
     38 
     39 u_int
     40 sunxi_ccu_div_get_rate(struct sunxi_ccu_softc *sc,
     41     struct sunxi_ccu_clk *clk)
     42 {
     43 	struct sunxi_ccu_div *div = &clk->u.div;
     44 	struct clk *clkp, *clkp_parent;
     45 	u_int rate, ratio;
     46 	uint32_t val;
     47 
     48 	KASSERT(clk->type == SUNXI_CCU_DIV);
     49 
     50 	clkp = &clk->base;
     51 	clkp_parent = clk_get_parent(clkp);
     52 	if (clkp_parent == NULL)
     53 		return 0;
     54 
     55 	rate = clk_get_rate(clkp_parent);
     56 	if (rate == 0)
     57 		return 0;
     58 
     59 	val = CCU_READ(sc, div->reg);
     60 	ratio = __SHIFTOUT(val, div->div);
     61 	if ((div->flags & SUNXI_CCU_DIV_ZERO_IS_ONE) != 0 && ratio == 0)
     62 		ratio = 1;
     63 	if (div->flags & SUNXI_CCU_DIV_POWER_OF_TWO)
     64 		ratio = 1 << ratio;
     65 	else
     66 		ratio++;
     67 
     68 	return rate / ratio;
     69 }
     70 
     71 int
     72 sunxi_ccu_div_set_rate(struct sunxi_ccu_softc *sc,
     73     struct sunxi_ccu_clk *clk, u_int new_rate)
     74 {
     75 	return EINVAL;
     76 }
     77 
     78 int
     79 sunxi_ccu_div_set_parent(struct sunxi_ccu_softc *sc,
     80     struct sunxi_ccu_clk *clk, const char *name)
     81 {
     82 	struct sunxi_ccu_div *div = &clk->u.div;
     83 	uint32_t val;
     84 	u_int index;
     85 
     86 	KASSERT(clk->type == SUNXI_CCU_DIV);
     87 
     88 	if (div->sel == 0)
     89 		return ENODEV;
     90 
     91 	for (index = 0; index < div->nparents; index++) {
     92 		if (div->parents[index] != NULL &&
     93 		    strcmp(div->parents[index], name) == 0)
     94 			break;
     95 	}
     96 	if (index == div->nparents)
     97 		return EINVAL;
     98 
     99 	val = CCU_READ(sc, div->reg);
    100 	val &= ~div->sel;
    101 	val |= __SHIFTIN(index, div->sel);
    102 	CCU_WRITE(sc, div->reg, val);
    103 
    104 	return 0;
    105 }
    106 
    107 const char *
    108 sunxi_ccu_div_get_parent(struct sunxi_ccu_softc *sc,
    109     struct sunxi_ccu_clk *clk)
    110 {
    111 	struct sunxi_ccu_div *div = &clk->u.div;
    112 	u_int index;
    113 	uint32_t val;
    114 
    115 	KASSERT(clk->type == SUNXI_CCU_DIV);
    116 
    117 	if (div->sel == 0)
    118 		return div->parents[0];
    119 
    120 	val = CCU_READ(sc, div->reg);
    121 	index = __SHIFTOUT(val, div->sel);
    122 
    123 	return div->parents[index];
    124 }
    125