1 /* 2 * Driver for the ICST307 VCO clock found in the ARM Reference designs. 3 * We wrap the custom interface from <asm/hardware/icst.h> into the generic 4 * clock framework. 5 * 6 * Copyright (C) 2012-2015 Linus Walleij 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2 as 10 * published by the Free Software Foundation. 11 * 12 * TODO: when all ARM reference designs are migrated to generic clocks, the 13 * ICST clock code from the ARM tree should probably be merged into this 14 * file. 15 */ 16 #include <linux/kernel.h> 17 #include <linux/slab.h> 18 #include <linux/export.h> 19 #include <linux/err.h> 20 #include <linux/clk-provider.h> 21 #include <linux/io.h> 22 #include <linux/regmap.h> 23 #include <linux/mfd/syscon.h> 24 25 #include "clk-icst.h" 26 27 /* Magic unlocking token used on all Versatile boards */ 28 #define VERSATILE_LOCK_VAL 0xA05F 29 30 /** 31 * struct clk_icst - ICST VCO clock wrapper 32 * @hw: corresponding clock hardware entry 33 * @vcoreg: VCO register address 34 * @lockreg: VCO lock register address 35 * @params: parameters for this ICST instance 36 * @rate: current rate 37 */ 38 struct clk_icst { 39 struct clk_hw hw; 40 struct regmap *map; 41 u32 vcoreg_off; 42 u32 lockreg_off; 43 struct icst_params *params; 44 unsigned long rate; 45 }; 46 47 #define to_icst(_hw) container_of(_hw, struct clk_icst, hw) 48 49 /** 50 * vco_get() - get ICST VCO settings from a certain ICST 51 * @icst: the ICST clock to get 52 * @vco: the VCO struct to return the value in 53 */ 54 static int vco_get(struct clk_icst *icst, struct icst_vco *vco) 55 { 56 u32 val; 57 int ret; 58 59 ret = regmap_read(icst->map, icst->vcoreg_off, &val); 60 if (ret) 61 return ret; 62 vco->v = val & 0x1ff; 63 vco->r = (val >> 9) & 0x7f; 64 vco->s = (val >> 16) & 03; 65 return 0; 66 } 67 68 /** 69 * vco_set() - commit changes to an ICST VCO 70 * @icst: the ICST clock to set 71 * @vco: the VCO struct to set the changes from 72 */ 73 static int vco_set(struct clk_icst *icst, struct icst_vco vco) 74 { 75 u32 val; 76 int ret; 77 78 ret = regmap_read(icst->map, icst->vcoreg_off, &val); 79 if (ret) 80 return ret; 81 val |= vco.v | (vco.r << 9) | (vco.s << 16); 82 83 /* This magic unlocks the VCO so it can be controlled */ 84 ret = regmap_write(icst->map, icst->lockreg_off, VERSATILE_LOCK_VAL); 85 if (ret) 86 return ret; 87 ret = regmap_write(icst->map, icst->vcoreg_off, val); 88 if (ret) 89 return ret; 90 /* This locks the VCO again */ 91 ret = regmap_write(icst->map, icst->lockreg_off, 0); 92 if (ret) 93 return ret; 94 return 0; 95 } 96 97 static unsigned long icst_recalc_rate(struct clk_hw *hw, 98 unsigned long parent_rate) 99 { 100 struct clk_icst *icst = to_icst(hw); 101 struct icst_vco vco; 102 int ret; 103 104 if (parent_rate) 105 icst->params->ref = parent_rate; 106 ret = vco_get(icst, &vco); 107 if (ret) { 108 pr_err("ICST: could not get VCO setting\n"); 109 return 0; 110 } 111 icst->rate = icst_hz(icst->params, vco); 112 return icst->rate; 113 } 114 115 static long icst_round_rate(struct clk_hw *hw, unsigned long rate, 116 unsigned long *prate) 117 { 118 struct clk_icst *icst = to_icst(hw); 119 struct icst_vco vco; 120 121 vco = icst_hz_to_vco(icst->params, rate); 122 return icst_hz(icst->params, vco); 123 } 124 125 static int icst_set_rate(struct clk_hw *hw, unsigned long rate, 126 unsigned long parent_rate) 127 { 128 struct clk_icst *icst = to_icst(hw); 129 struct icst_vco vco; 130 131 if (parent_rate) 132 icst->params->ref = parent_rate; 133 vco = icst_hz_to_vco(icst->params, rate); 134 icst->rate = icst_hz(icst->params, vco); 135 return vco_set(icst, vco); 136 } 137 138 static const struct clk_ops icst_ops = { 139 .recalc_rate = icst_recalc_rate, 140 .round_rate = icst_round_rate, 141 .set_rate = icst_set_rate, 142 }; 143 144 static struct clk *icst_clk_setup(struct device *dev, 145 const struct clk_icst_desc *desc, 146 const char *name, 147 const char *parent_name, 148 struct regmap *map) 149 { 150 struct clk *clk; 151 struct clk_icst *icst; 152 struct clk_init_data init; 153 struct icst_params *pclone; 154 155 icst = kzalloc(sizeof(struct clk_icst), GFP_KERNEL); 156 if (!icst) { 157 pr_err("could not allocate ICST clock!\n"); 158 return ERR_PTR(-ENOMEM); 159 } 160 161 pclone = kmemdup(desc->params, sizeof(*pclone), GFP_KERNEL); 162 if (!pclone) { 163 kfree(icst); 164 pr_err("could not clone ICST params\n"); 165 return ERR_PTR(-ENOMEM); 166 } 167 168 init.name = name; 169 init.ops = &icst_ops; 170 init.flags = CLK_IS_ROOT; 171 init.parent_names = (parent_name ? &parent_name : NULL); 172 init.num_parents = (parent_name ? 1 : 0); 173 icst->map = map; 174 icst->hw.init = &init; 175 icst->params = pclone; 176 icst->vcoreg_off = desc->vco_offset; 177 icst->lockreg_off = desc->lock_offset; 178 179 clk = clk_register(dev, &icst->hw); 180 if (IS_ERR(clk)) { 181 kfree(pclone); 182 kfree(icst); 183 } 184 185 return clk; 186 } 187 188 struct clk *icst_clk_register(struct device *dev, 189 const struct clk_icst_desc *desc, 190 const char *name, 191 const char *parent_name, 192 void __iomem *base) 193 { 194 struct regmap_config icst_regmap_conf = { 195 .reg_bits = 32, 196 .val_bits = 32, 197 .reg_stride = 4, 198 }; 199 struct regmap *map; 200 201 map = regmap_init_mmio(dev, base, &icst_regmap_conf); 202 if (IS_ERR(map)) { 203 pr_err("could not initialize ICST regmap\n"); 204 return ERR_CAST(map); 205 } 206 return icst_clk_setup(dev, desc, name, parent_name, map); 207 } 208 EXPORT_SYMBOL_GPL(icst_clk_register); 209 210 #ifdef CONFIG_OF 211 /* 212 * In a device tree, an memory-mapped ICST clock appear as a child 213 * of a syscon node. Assume this and probe it only as a child of a 214 * syscon. 215 */ 216 217 static const struct icst_params icst525_params = { 218 .vco_max = ICST525_VCO_MAX_5V, 219 .vco_min = ICST525_VCO_MIN, 220 .vd_min = 8, 221 .vd_max = 263, 222 .rd_min = 3, 223 .rd_max = 65, 224 .s2div = icst525_s2div, 225 .idx2s = icst525_idx2s, 226 }; 227 228 static const struct icst_params icst307_params = { 229 .vco_max = ICST307_VCO_MAX, 230 .vco_min = ICST307_VCO_MIN, 231 .vd_min = 4 + 8, 232 .vd_max = 511 + 8, 233 .rd_min = 1 + 2, 234 .rd_max = 127 + 2, 235 .s2div = icst307_s2div, 236 .idx2s = icst307_idx2s, 237 }; 238 239 static void __init of_syscon_icst_setup(struct device_node *np) 240 { 241 struct device_node *parent; 242 struct regmap *map; 243 struct clk_icst_desc icst_desc; 244 const char *name = np->name; 245 const char *parent_name; 246 struct clk *regclk; 247 248 /* We do not release this reference, we are using it perpetually */ 249 parent = of_get_parent(np); 250 if (!parent) { 251 pr_err("no parent node for syscon ICST clock\n"); 252 return; 253 } 254 map = syscon_node_to_regmap(parent); 255 if (IS_ERR(map)) { 256 pr_err("no regmap for syscon ICST clock parent\n"); 257 return; 258 } 259 260 if (of_property_read_u32(np, "vco-offset", &icst_desc.vco_offset)) { 261 pr_err("no VCO register offset for ICST clock\n"); 262 return; 263 } 264 if (of_property_read_u32(np, "lock-offset", &icst_desc.lock_offset)) { 265 pr_err("no lock register offset for ICST clock\n"); 266 return; 267 } 268 269 if (of_device_is_compatible(np, "arm,syscon-icst525")) 270 icst_desc.params = &icst525_params; 271 else if (of_device_is_compatible(np, "arm,syscon-icst307")) 272 icst_desc.params = &icst307_params; 273 else { 274 pr_err("unknown ICST clock %s\n", name); 275 return; 276 } 277 278 /* Parent clock name is not the same as node parent */ 279 parent_name = of_clk_get_parent_name(np, 0); 280 281 regclk = icst_clk_setup(NULL, &icst_desc, name, parent_name, map); 282 if (IS_ERR(regclk)) { 283 pr_err("error setting up syscon ICST clock %s\n", name); 284 return; 285 } 286 of_clk_add_provider(np, of_clk_src_simple_get, regclk); 287 pr_debug("registered syscon ICST clock %s\n", name); 288 } 289 290 CLK_OF_DECLARE(arm_syscon_icst525_clk, 291 "arm,syscon-icst525", of_syscon_icst_setup); 292 CLK_OF_DECLARE(arm_syscon_icst307_clk, 293 "arm,syscon-icst307", of_syscon_icst_setup); 294 295 #endif 296