1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * System Control Driver 4 * 5 * Copyright (C) 2012 Freescale Semiconductor, Inc. 6 * Copyright (C) 2012 Linaro Ltd. 7 * 8 * Author: Dong Aisheng <dong.aisheng@linaro.org> 9 */ 10 11 #include <linux/clk.h> 12 #include <linux/err.h> 13 #include <linux/hwspinlock.h> 14 #include <linux/io.h> 15 #include <linux/init.h> 16 #include <linux/list.h> 17 #include <linux/of.h> 18 #include <linux/of_address.h> 19 #include <linux/of_platform.h> 20 #include <linux/platform_data/syscon.h> 21 #include <linux/platform_device.h> 22 #include <linux/regmap.h> 23 #include <linux/reset.h> 24 #include <linux/mfd/syscon.h> 25 #include <linux/slab.h> 26 27 static struct platform_driver syscon_driver; 28 29 static DEFINE_SPINLOCK(syscon_list_slock); 30 static LIST_HEAD(syscon_list); 31 32 struct syscon { 33 struct device_node *np; 34 struct regmap *regmap; 35 struct reset_control *reset; 36 struct list_head list; 37 }; 38 39 static const struct regmap_config syscon_regmap_config = { 40 .reg_bits = 32, 41 .val_bits = 32, 42 .reg_stride = 4, 43 }; 44 45 static struct syscon *of_syscon_register(struct device_node *np, bool check_res) 46 { 47 struct clk *clk; 48 struct syscon *syscon; 49 struct regmap *regmap; 50 void __iomem *base; 51 u32 reg_io_width; 52 int ret; 53 struct regmap_config syscon_config = syscon_regmap_config; 54 struct resource res; 55 struct reset_control *reset; 56 57 syscon = kzalloc(sizeof(*syscon), GFP_KERNEL); 58 if (!syscon) 59 return ERR_PTR(-ENOMEM); 60 61 if (of_address_to_resource(np, 0, &res)) { 62 ret = -ENOMEM; 63 goto err_map; 64 } 65 66 base = of_iomap(np, 0); 67 if (!base) { 68 ret = -ENOMEM; 69 goto err_map; 70 } 71 72 /* Parse the device's DT node for an endianness specification */ 73 if (of_property_read_bool(np, "big-endian")) 74 syscon_config.val_format_endian = REGMAP_ENDIAN_BIG; 75 else if (of_property_read_bool(np, "little-endian")) 76 syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE; 77 else if (of_property_read_bool(np, "native-endian")) 78 syscon_config.val_format_endian = REGMAP_ENDIAN_NATIVE; 79 80 /* 81 * search for reg-io-width property in DT. If it is not provided, 82 * default to 4 bytes. regmap_init_mmio will return an error if values 83 * are invalid so there is no need to check them here. 84 */ 85 ret = of_property_read_u32(np, "reg-io-width", ®_io_width); 86 if (ret) 87 reg_io_width = 4; 88 89 ret = of_hwspin_lock_get_id(np, 0); 90 if (ret > 0 || (IS_ENABLED(CONFIG_HWSPINLOCK) && ret == 0)) { 91 syscon_config.use_hwlock = true; 92 syscon_config.hwlock_id = ret; 93 syscon_config.hwlock_mode = HWLOCK_IRQSTATE; 94 } else if (ret < 0) { 95 switch (ret) { 96 case -ENOENT: 97 /* Ignore missing hwlock, it's optional. */ 98 break; 99 default: 100 pr_err("Failed to retrieve valid hwlock: %d\n", ret); 101 fallthrough; 102 case -EPROBE_DEFER: 103 goto err_regmap; 104 } 105 } 106 107 syscon_config.name = kasprintf(GFP_KERNEL, "%pOFn@%pa", np, &res.start); 108 syscon_config.reg_stride = reg_io_width; 109 syscon_config.val_bits = reg_io_width * 8; 110 syscon_config.max_register = resource_size(&res) - reg_io_width; 111 112 regmap = regmap_init_mmio(NULL, base, &syscon_config); 113 kfree(syscon_config.name); 114 if (IS_ERR(regmap)) { 115 pr_err("regmap init failed\n"); 116 ret = PTR_ERR(regmap); 117 goto err_regmap; 118 } 119 120 if (check_res) { 121 clk = of_clk_get(np, 0); 122 if (IS_ERR(clk)) { 123 ret = PTR_ERR(clk); 124 /* clock is optional */ 125 if (ret != -ENOENT) 126 goto err_clk; 127 } else { 128 ret = regmap_mmio_attach_clk(regmap, clk); 129 if (ret) 130 goto err_attach_clk; 131 } 132 133 reset = of_reset_control_get_optional_exclusive(np, NULL); 134 if (IS_ERR(reset)) { 135 ret = PTR_ERR(reset); 136 goto err_attach_clk; 137 } 138 139 ret = reset_control_deassert(reset); 140 if (ret) 141 goto err_reset; 142 } 143 144 syscon->regmap = regmap; 145 syscon->np = np; 146 147 spin_lock(&syscon_list_slock); 148 list_add_tail(&syscon->list, &syscon_list); 149 spin_unlock(&syscon_list_slock); 150 151 return syscon; 152 153 err_reset: 154 reset_control_put(reset); 155 err_attach_clk: 156 if (!IS_ERR(clk)) 157 clk_put(clk); 158 err_clk: 159 regmap_exit(regmap); 160 err_regmap: 161 iounmap(base); 162 err_map: 163 kfree(syscon); 164 return ERR_PTR(ret); 165 } 166 167 static struct regmap *device_node_get_regmap(struct device_node *np, 168 bool check_res) 169 { 170 struct syscon *entry, *syscon = NULL; 171 172 spin_lock(&syscon_list_slock); 173 174 list_for_each_entry(entry, &syscon_list, list) 175 if (entry->np == np) { 176 syscon = entry; 177 break; 178 } 179 180 spin_unlock(&syscon_list_slock); 181 182 if (!syscon) 183 syscon = of_syscon_register(np, check_res); 184 185 if (IS_ERR(syscon)) 186 return ERR_CAST(syscon); 187 188 return syscon->regmap; 189 } 190 191 struct regmap *device_node_to_regmap(struct device_node *np) 192 { 193 return device_node_get_regmap(np, false); 194 } 195 EXPORT_SYMBOL_GPL(device_node_to_regmap); 196 197 struct regmap *syscon_node_to_regmap(struct device_node *np) 198 { 199 if (!of_device_is_compatible(np, "syscon")) 200 return ERR_PTR(-EINVAL); 201 202 return device_node_get_regmap(np, true); 203 } 204 EXPORT_SYMBOL_GPL(syscon_node_to_regmap); 205 206 struct regmap *syscon_regmap_lookup_by_compatible(const char *s) 207 { 208 struct device_node *syscon_np; 209 struct regmap *regmap; 210 211 syscon_np = of_find_compatible_node(NULL, NULL, s); 212 if (!syscon_np) 213 return ERR_PTR(-ENODEV); 214 215 regmap = syscon_node_to_regmap(syscon_np); 216 of_node_put(syscon_np); 217 218 return regmap; 219 } 220 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible); 221 222 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np, 223 const char *property) 224 { 225 struct device_node *syscon_np; 226 struct regmap *regmap; 227 228 if (property) 229 syscon_np = of_parse_phandle(np, property, 0); 230 else 231 syscon_np = np; 232 233 if (!syscon_np) 234 return ERR_PTR(-ENODEV); 235 236 regmap = syscon_node_to_regmap(syscon_np); 237 of_node_put(syscon_np); 238 239 return regmap; 240 } 241 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle); 242 243 struct regmap *syscon_regmap_lookup_by_phandle_args(struct device_node *np, 244 const char *property, 245 int arg_count, 246 unsigned int *out_args) 247 { 248 struct device_node *syscon_np; 249 struct of_phandle_args args; 250 struct regmap *regmap; 251 unsigned int index; 252 int rc; 253 254 rc = of_parse_phandle_with_fixed_args(np, property, arg_count, 255 0, &args); 256 if (rc) 257 return ERR_PTR(rc); 258 259 syscon_np = args.np; 260 if (!syscon_np) 261 return ERR_PTR(-ENODEV); 262 263 regmap = syscon_node_to_regmap(syscon_np); 264 for (index = 0; index < arg_count; index++) 265 out_args[index] = args.args[index]; 266 of_node_put(syscon_np); 267 268 return regmap; 269 } 270 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_args); 271 272 /* 273 * It behaves the same as syscon_regmap_lookup_by_phandle() except where 274 * there is no regmap phandle. In this case, instead of returning -ENODEV, 275 * the function returns NULL. 276 */ 277 struct regmap *syscon_regmap_lookup_by_phandle_optional(struct device_node *np, 278 const char *property) 279 { 280 struct regmap *regmap; 281 282 regmap = syscon_regmap_lookup_by_phandle(np, property); 283 if (IS_ERR(regmap) && PTR_ERR(regmap) == -ENODEV) 284 return NULL; 285 286 return regmap; 287 } 288 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_optional); 289 290 static int syscon_probe(struct platform_device *pdev) 291 { 292 struct device *dev = &pdev->dev; 293 struct syscon_platform_data *pdata = dev_get_platdata(dev); 294 struct syscon *syscon; 295 struct regmap_config syscon_config = syscon_regmap_config; 296 struct resource *res; 297 void __iomem *base; 298 299 syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL); 300 if (!syscon) 301 return -ENOMEM; 302 303 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 304 if (!res) 305 return -ENOENT; 306 307 base = devm_ioremap(dev, res->start, resource_size(res)); 308 if (!base) 309 return -ENOMEM; 310 311 syscon_config.max_register = resource_size(res) - 4; 312 if (pdata) 313 syscon_config.name = pdata->label; 314 syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config); 315 if (IS_ERR(syscon->regmap)) { 316 dev_err(dev, "regmap init failed\n"); 317 return PTR_ERR(syscon->regmap); 318 } 319 320 platform_set_drvdata(pdev, syscon); 321 322 dev_dbg(dev, "regmap %pR registered\n", res); 323 324 return 0; 325 } 326 327 static const struct platform_device_id syscon_ids[] = { 328 { "syscon", }, 329 { } 330 }; 331 332 static struct platform_driver syscon_driver = { 333 .driver = { 334 .name = "syscon", 335 }, 336 .probe = syscon_probe, 337 .id_table = syscon_ids, 338 }; 339 340 static int __init syscon_init(void) 341 { 342 return platform_driver_register(&syscon_driver); 343 } 344 postcore_initcall(syscon_init); 345