1 /* $NetBSD: sunxi_ccu_fractional.c,v 1.6 2019/11/23 21:30:41 jmcneill 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_fractional.c,v 1.6 2019/11/23 21:30:41 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/sunxi/sunxi_ccu.h> 38 39 int 40 sunxi_ccu_fractional_enable(struct sunxi_ccu_softc *sc, 41 struct sunxi_ccu_clk *clk, int enable) 42 { 43 struct sunxi_ccu_fractional *fractional = &clk->u.fractional; 44 uint32_t val; 45 46 KASSERT(clk->type == SUNXI_CCU_FRACTIONAL); 47 48 if (!fractional->enable) 49 return enable ? 0 : EINVAL; 50 51 val = CCU_READ(sc, fractional->reg); 52 if (enable) 53 val |= fractional->enable; 54 else 55 val &= ~fractional->enable; 56 CCU_WRITE(sc, fractional->reg, val); 57 58 return 0; 59 } 60 61 u_int 62 sunxi_ccu_fractional_get_rate(struct sunxi_ccu_softc *sc, 63 struct sunxi_ccu_clk *clk) 64 { 65 struct sunxi_ccu_fractional *fractional = &clk->u.fractional; 66 struct clk *clkp, *clkp_parent; 67 u_int rate, m; 68 uint32_t val; 69 70 KASSERT(clk->type == SUNXI_CCU_FRACTIONAL); 71 72 clkp = &clk->base; 73 clkp_parent = clk_get_parent(clkp); 74 if (clkp_parent == NULL) 75 return 0; 76 77 rate = clk_get_rate(clkp_parent); 78 if (rate == 0) 79 return 0; 80 81 val = CCU_READ(sc, fractional->reg); 82 83 if (fractional->prediv != 0) { 84 rate = rate / (__SHIFTOUT(val, fractional->prediv) + 1); 85 } else if (fractional->prediv_val > 0) { 86 rate = rate / fractional->prediv_val; 87 } 88 89 if (fractional->enable && !(val & fractional->enable)) 90 return 0; 91 92 if ((val & fractional->div_en) == 0) { 93 int sel = __SHIFTOUT(val, fractional->frac_sel); 94 return fractional->frac[sel]; 95 } 96 m = __SHIFTOUT(val, fractional->m); 97 98 if (fractional->flags & SUNXI_CCU_FRACTIONAL_PLUSONE) 99 m++; 100 101 return rate * m; 102 } 103 104 int 105 sunxi_ccu_fractional_set_rate(struct sunxi_ccu_softc *sc, 106 struct sunxi_ccu_clk *clk, u_int new_rate) 107 { 108 struct sunxi_ccu_fractional *fractional = &clk->u.fractional; 109 struct clk *clkp, *clkp_parent; 110 u_int parent_rate, best_rate, best_m; 111 u_int m, rate; 112 int best_diff; 113 uint32_t val; 114 int i; 115 116 clkp = &clk->base; 117 clkp_parent = clk_get_parent(clkp); 118 if (clkp_parent == NULL) 119 return ENXIO; 120 121 parent_rate = clk_get_rate(clkp_parent); 122 if (parent_rate == 0) 123 return (new_rate == 0) ? 0 : ERANGE; 124 125 val = CCU_READ(sc, fractional->reg); 126 127 if (fractional->prediv != 0) { 128 if (fractional->prediv_val > 0) { 129 val &= ~fractional->prediv; 130 val |= __SHIFTIN(fractional->prediv_val - 1, 131 fractional->prediv); 132 } 133 parent_rate = parent_rate / (__SHIFTOUT(val, fractional->prediv) + 1); 134 } else if (fractional->prediv_val > 0) { 135 parent_rate = parent_rate / fractional->prediv_val; 136 } 137 138 for (i = 0; i < __arraycount(fractional->frac); i++) { 139 if (fractional->frac[i] == new_rate) { 140 val &= ~fractional->prediv; 141 val &= ~fractional->div_en; 142 val &= ~fractional->frac_sel; 143 val |= __SHIFTIN(i, fractional->frac_sel); 144 if (fractional->flags & SUNXI_CCU_FRACTIONAL_SET_ENABLE) 145 val |= fractional->enable; 146 CCU_WRITE(sc, fractional->reg, val); 147 return 0; 148 } 149 } 150 val |= fractional->div_en; 151 152 best_rate = 0; 153 best_diff = INT_MAX; 154 155 for (m = fractional->m_min; m <= fractional->m_max; m++) { 156 rate = parent_rate * m; 157 const int diff = abs(new_rate - rate); 158 if (diff < best_diff) { 159 best_diff = diff; 160 best_rate = rate; 161 best_m = m; 162 if (diff == 0) 163 break; 164 } 165 } 166 167 if (best_rate == 0) 168 return ERANGE; 169 170 if (fractional->flags & SUNXI_CCU_FRACTIONAL_PLUSONE) 171 best_m--; 172 173 val &= ~fractional->m; 174 val |= __SHIFTIN(best_m, fractional->m); 175 if (fractional->flags & SUNXI_CCU_FRACTIONAL_SET_ENABLE) 176 val |= fractional->enable; 177 CCU_WRITE(sc, fractional->reg, val); 178 179 180 return 0; 181 } 182 183 u_int 184 sunxi_ccu_fractional_round_rate(struct sunxi_ccu_softc *sc, 185 struct sunxi_ccu_clk *clk, u_int try_rate) 186 { 187 struct sunxi_ccu_fractional *fractional = &clk->u.fractional; 188 struct clk *clkp, *clkp_parent; 189 u_int parent_rate, best_rate; 190 u_int m, rate; 191 int best_diff; 192 uint32_t val; 193 int i; 194 195 clkp = &clk->base; 196 clkp_parent = clk_get_parent(clkp); 197 if (clkp_parent == NULL) 198 return 0; 199 200 parent_rate = clk_get_rate(clkp_parent); 201 if (parent_rate == 0) 202 return 0; 203 204 val = CCU_READ(sc, fractional->reg); 205 206 if (fractional->prediv_val > 0) { 207 parent_rate = parent_rate / fractional->prediv_val; 208 } else if (fractional->prediv != 0) { 209 val = CCU_READ(sc, fractional->reg); 210 parent_rate = parent_rate / (__SHIFTOUT(val, fractional->prediv) + 1); 211 } 212 213 for (i = 0; i < __arraycount(fractional->frac); i++) { 214 if (fractional->frac[i] == try_rate) { 215 return try_rate; 216 } 217 } 218 219 best_rate = 0; 220 best_diff = INT_MAX; 221 222 for (m = fractional->m_min; m <= fractional->m_max; m++) { 223 rate = parent_rate * m; 224 const int diff = abs(try_rate - rate); 225 if (diff < best_diff) { 226 best_diff = diff; 227 best_rate = rate; 228 if (diff == 0) 229 break; 230 } 231 } 232 233 return best_rate; 234 } 235 236 const char * 237 sunxi_ccu_fractional_get_parent(struct sunxi_ccu_softc *sc, 238 struct sunxi_ccu_clk *clk) 239 { 240 struct sunxi_ccu_fractional *fractional = &clk->u.fractional; 241 242 KASSERT(clk->type == SUNXI_CCU_FRACTIONAL); 243 244 return fractional->parent; 245 } 246
Indexes created Tue Sep 30 20:09:53 GMT 2025