1 /* 2 * Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com> 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License as published by 6 * the Free Software Foundation; either version 2 of the License, or 7 * (at your option) any later version. 8 * 9 */ 10 11 #include <linux/clk-provider.h> 12 #include <linux/clkdev.h> 13 #include <linux/clk/at91_pmc.h> 14 #include <linux/of.h> 15 #include <linux/mfd/syscon.h> 16 #include <linux/regmap.h> 17 18 #include "pmc.h" 19 20 #define MASTER_SOURCE_MAX 4 21 22 #define MASTER_PRES_MASK 0x7 23 #define MASTER_PRES_MAX MASTER_PRES_MASK 24 #define MASTER_DIV_SHIFT 8 25 #define MASTER_DIV_MASK 0x3 26 27 struct clk_master_characteristics { 28 struct clk_range output; 29 u32 divisors[4]; 30 u8 have_div3_pres; 31 }; 32 33 struct clk_master_layout { 34 u32 mask; 35 u8 pres_shift; 36 }; 37 38 #define to_clk_master(hw) container_of(hw, struct clk_master, hw) 39 40 struct clk_master { 41 struct clk_hw hw; 42 struct regmap *regmap; 43 const struct clk_master_layout *layout; 44 const struct clk_master_characteristics *characteristics; 45 }; 46 47 static inline bool clk_master_ready(struct regmap *regmap) 48 { 49 unsigned int status; 50 51 regmap_read(regmap, AT91_PMC_SR, &status); 52 53 return status & AT91_PMC_MCKRDY ? 1 : 0; 54 } 55 56 static int clk_master_prepare(struct clk_hw *hw) 57 { 58 struct clk_master *master = to_clk_master(hw); 59 60 while (!clk_master_ready(master->regmap)) 61 cpu_relax(); 62 63 return 0; 64 } 65 66 static int clk_master_is_prepared(struct clk_hw *hw) 67 { 68 struct clk_master *master = to_clk_master(hw); 69 70 return clk_master_ready(master->regmap); 71 } 72 73 static unsigned long clk_master_recalc_rate(struct clk_hw *hw, 74 unsigned long parent_rate) 75 { 76 u8 pres; 77 u8 div; 78 unsigned long rate = parent_rate; 79 struct clk_master *master = to_clk_master(hw); 80 const struct clk_master_layout *layout = master->layout; 81 const struct clk_master_characteristics *characteristics = 82 master->characteristics; 83 unsigned int mckr; 84 85 regmap_read(master->regmap, AT91_PMC_MCKR, &mckr); 86 mckr &= layout->mask; 87 88 pres = (mckr >> layout->pres_shift) & MASTER_PRES_MASK; 89 div = (mckr >> MASTER_DIV_SHIFT) & MASTER_DIV_MASK; 90 91 if (characteristics->have_div3_pres && pres == MASTER_PRES_MAX) 92 rate /= 3; 93 else 94 rate >>= pres; 95 96 rate /= characteristics->divisors[div]; 97 98 if (rate < characteristics->output.min) 99 pr_warn("master clk is underclocked"); 100 else if (rate > characteristics->output.max) 101 pr_warn("master clk is overclocked"); 102 103 return rate; 104 } 105 106 static u8 clk_master_get_parent(struct clk_hw *hw) 107 { 108 struct clk_master *master = to_clk_master(hw); 109 unsigned int mckr; 110 111 regmap_read(master->regmap, AT91_PMC_MCKR, &mckr); 112 113 return mckr & AT91_PMC_CSS; 114 } 115 116 static const struct clk_ops master_ops = { 117 .prepare = clk_master_prepare, 118 .is_prepared = clk_master_is_prepared, 119 .recalc_rate = clk_master_recalc_rate, 120 .get_parent = clk_master_get_parent, 121 }; 122 123 static struct clk * __init 124 at91_clk_register_master(struct regmap *regmap, 125 const char *name, int num_parents, 126 const char **parent_names, 127 const struct clk_master_layout *layout, 128 const struct clk_master_characteristics *characteristics) 129 { 130 struct clk_master *master; 131 struct clk *clk = NULL; 132 struct clk_init_data init; 133 134 if (!name || !num_parents || !parent_names) 135 return ERR_PTR(-EINVAL); 136 137 master = kzalloc(sizeof(*master), GFP_KERNEL); 138 if (!master) 139 return ERR_PTR(-ENOMEM); 140 141 init.name = name; 142 init.ops = &master_ops; 143 init.parent_names = parent_names; 144 init.num_parents = num_parents; 145 init.flags = 0; 146 147 master->hw.init = &init; 148 master->layout = layout; 149 master->characteristics = characteristics; 150 master->regmap = regmap; 151 152 clk = clk_register(NULL, &master->hw); 153 if (IS_ERR(clk)) { 154 kfree(master); 155 } 156 157 return clk; 158 } 159 160 161 static const struct clk_master_layout at91rm9200_master_layout = { 162 .mask = 0x31F, 163 .pres_shift = 2, 164 }; 165 166 static const struct clk_master_layout at91sam9x5_master_layout = { 167 .mask = 0x373, 168 .pres_shift = 4, 169 }; 170 171 172 static struct clk_master_characteristics * __init 173 of_at91_clk_master_get_characteristics(struct device_node *np) 174 { 175 struct clk_master_characteristics *characteristics; 176 177 characteristics = kzalloc(sizeof(*characteristics), GFP_KERNEL); 178 if (!characteristics) 179 return NULL; 180 181 if (of_at91_get_clk_range(np, "atmel,clk-output-range", &characteristics->output)) 182 goto out_free_characteristics; 183 184 of_property_read_u32_array(np, "atmel,clk-divisors", 185 characteristics->divisors, 4); 186 187 characteristics->have_div3_pres = 188 of_property_read_bool(np, "atmel,master-clk-have-div3-pres"); 189 190 return characteristics; 191 192 out_free_characteristics: 193 kfree(characteristics); 194 return NULL; 195 } 196 197 static void __init 198 of_at91_clk_master_setup(struct device_node *np, 199 const struct clk_master_layout *layout) 200 { 201 struct clk *clk; 202 unsigned int num_parents; 203 const char *parent_names[MASTER_SOURCE_MAX]; 204 const char *name = np->name; 205 struct clk_master_characteristics *characteristics; 206 struct regmap *regmap; 207 208 num_parents = of_clk_get_parent_count(np); 209 if (num_parents == 0 || num_parents > MASTER_SOURCE_MAX) 210 return; 211 212 of_clk_parent_fill(np, parent_names, num_parents); 213 214 of_property_read_string(np, "clock-output-names", &name); 215 216 characteristics = of_at91_clk_master_get_characteristics(np); 217 if (!characteristics) 218 return; 219 220 regmap = syscon_node_to_regmap(of_get_parent(np)); 221 if (IS_ERR(regmap)) 222 return; 223 224 clk = at91_clk_register_master(regmap, name, num_parents, 225 parent_names, layout, 226 characteristics); 227 if (IS_ERR(clk)) 228 goto out_free_characteristics; 229 230 of_clk_add_provider(np, of_clk_src_simple_get, clk); 231 return; 232 233 out_free_characteristics: 234 kfree(characteristics); 235 } 236 237 static void __init of_at91rm9200_clk_master_setup(struct device_node *np) 238 { 239 of_at91_clk_master_setup(np, &at91rm9200_master_layout); 240 } 241 CLK_OF_DECLARE(at91rm9200_clk_master, "atmel,at91rm9200-clk-master", 242 of_at91rm9200_clk_master_setup); 243 244 static void __init of_at91sam9x5_clk_master_setup(struct device_node *np) 245 { 246 of_at91_clk_master_setup(np, &at91sam9x5_master_layout); 247 } 248 CLK_OF_DECLARE(at91sam9x5_clk_master, "atmel,at91sam9x5-clk-master", 249 of_at91sam9x5_clk_master_setup); 250