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