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 = ioremap(res.start, resource_size(&res)); 64 if (!base) { 65 ret = -ENOMEM; 66 goto err_map; 67 } 68 69 /* Parse the device's DT node for an endianness specification */ 70 if (of_property_read_bool(np, "big-endian")) 71 syscon_config.val_format_endian = REGMAP_ENDIAN_BIG; 72 else if (of_property_read_bool(np, "little-endian")) 73 syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE; 74 else if (of_property_read_bool(np, "native-endian")) 75 syscon_config.val_format_endian = REGMAP_ENDIAN_NATIVE; 76 77 /* 78 * search for reg-io-width property in DT. If it is not provided, 79 * default to 4 bytes. regmap_init_mmio will return an error if values 80 * are invalid so there is no need to check them here. 81 */ 82 ret = of_property_read_u32(np, "reg-io-width", ®_io_width); 83 if (ret) 84 reg_io_width = 4; 85 86 ret = of_hwspin_lock_get_id(np, 0); 87 if (ret > 0 || (IS_ENABLED(CONFIG_HWSPINLOCK) && ret == 0)) { 88 syscon_config.use_hwlock = true; 89 syscon_config.hwlock_id = ret; 90 syscon_config.hwlock_mode = HWLOCK_IRQSTATE; 91 } else if (ret < 0) { 92 switch (ret) { 93 case -ENOENT: 94 /* Ignore missing hwlock, it's optional. */ 95 break; 96 default: 97 pr_err("Failed to retrieve valid hwlock: %d\n", ret); 98 fallthrough; 99 case -EPROBE_DEFER: 100 goto err_regmap; 101 } 102 } 103 104 syscon_config.name = kasprintf(GFP_KERNEL, "%pOFn@%llx", np, 105 (u64)res.start); 106 syscon_config.reg_stride = reg_io_width; 107 syscon_config.val_bits = reg_io_width * 8; 108 syscon_config.max_register = resource_size(&res) - reg_io_width; 109 110 regmap = regmap_init_mmio(NULL, base, &syscon_config); 111 if (IS_ERR(regmap)) { 112 pr_err("regmap init failed\n"); 113 ret = PTR_ERR(regmap); 114 goto err_regmap; 115 } 116 117 if (check_clk) { 118 clk = of_clk_get(np, 0); 119 if (IS_ERR(clk)) { 120 ret = PTR_ERR(clk); 121 /* clock is optional */ 122 if (ret != -ENOENT) 123 goto err_clk; 124 } else { 125 ret = regmap_mmio_attach_clk(regmap, clk); 126 if (ret) 127 goto err_attach; 128 } 129 } 130 131 syscon->regmap = regmap; 132 syscon->np = np; 133 134 spin_lock(&syscon_list_slock); 135 list_add_tail(&syscon->list, &syscon_list); 136 spin_unlock(&syscon_list_slock); 137 138 return syscon; 139 140 err_attach: 141 if (!IS_ERR(clk)) 142 clk_put(clk); 143 err_clk: 144 regmap_exit(regmap); 145 err_regmap: 146 iounmap(base); 147 kfree(syscon_config.name); 148 err_map: 149 kfree(syscon); 150 return ERR_PTR(ret); 151 } 152 153 static struct regmap *device_node_get_regmap(struct device_node *np, 154 bool check_clk) 155 { 156 struct syscon *entry, *syscon = NULL; 157 158 spin_lock(&syscon_list_slock); 159 160 list_for_each_entry(entry, &syscon_list, list) 161 if (entry->np == np) { 162 syscon = entry; 163 break; 164 } 165 166 spin_unlock(&syscon_list_slock); 167 168 if (!syscon) 169 syscon = of_syscon_register(np, check_clk); 170 171 if (IS_ERR(syscon)) 172 return ERR_CAST(syscon); 173 174 return syscon->regmap; 175 } 176 177 struct regmap *device_node_to_regmap(struct device_node *np) 178 { 179 return device_node_get_regmap(np, false); 180 } 181 EXPORT_SYMBOL_GPL(device_node_to_regmap); 182 183 struct regmap *syscon_node_to_regmap(struct device_node *np) 184 { 185 if (!of_device_is_compatible(np, "syscon")) 186 return ERR_PTR(-EINVAL); 187 188 return device_node_get_regmap(np, true); 189 } 190 EXPORT_SYMBOL_GPL(syscon_node_to_regmap); 191 192 struct regmap *syscon_regmap_lookup_by_compatible(const char *s) 193 { 194 struct device_node *syscon_np; 195 struct regmap *regmap; 196 197 syscon_np = of_find_compatible_node(NULL, NULL, s); 198 if (!syscon_np) 199 return ERR_PTR(-ENODEV); 200 201 regmap = syscon_node_to_regmap(syscon_np); 202 of_node_put(syscon_np); 203 204 return regmap; 205 } 206 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible); 207 208 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np, 209 const char *property) 210 { 211 struct device_node *syscon_np; 212 struct regmap *regmap; 213 214 if (property) 215 syscon_np = of_parse_phandle(np, property, 0); 216 else 217 syscon_np = np; 218 219 if (!syscon_np) 220 return ERR_PTR(-ENODEV); 221 222 regmap = syscon_node_to_regmap(syscon_np); 223 of_node_put(syscon_np); 224 225 return regmap; 226 } 227 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle); 228 229 struct regmap *syscon_regmap_lookup_by_phandle_args(struct device_node *np, 230 const char *property, 231 int arg_count, 232 unsigned int *out_args) 233 { 234 struct device_node *syscon_np; 235 struct of_phandle_args args; 236 struct regmap *regmap; 237 unsigned int index; 238 int rc; 239 240 rc = of_parse_phandle_with_fixed_args(np, property, arg_count, 241 0, &args); 242 if (rc) 243 return ERR_PTR(rc); 244 245 syscon_np = args.np; 246 if (!syscon_np) 247 return ERR_PTR(-ENODEV); 248 249 regmap = syscon_node_to_regmap(syscon_np); 250 for (index = 0; index < arg_count; index++) 251 out_args[index] = args.args[index]; 252 of_node_put(syscon_np); 253 254 return regmap; 255 } 256 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_args); 257 258 static int syscon_probe(struct platform_device *pdev) 259 { 260 struct device *dev = &pdev->dev; 261 struct syscon_platform_data *pdata = dev_get_platdata(dev); 262 struct syscon *syscon; 263 struct regmap_config syscon_config = syscon_regmap_config; 264 struct resource *res; 265 void __iomem *base; 266 267 syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL); 268 if (!syscon) 269 return -ENOMEM; 270 271 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 272 if (!res) 273 return -ENOENT; 274 275 base = devm_ioremap(dev, res->start, resource_size(res)); 276 if (!base) 277 return -ENOMEM; 278 279 syscon_config.max_register = resource_size(res) - 4; 280 if (pdata) 281 syscon_config.name = pdata->label; 282 syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config); 283 if (IS_ERR(syscon->regmap)) { 284 dev_err(dev, "regmap init failed\n"); 285 return PTR_ERR(syscon->regmap); 286 } 287 288 platform_set_drvdata(pdev, syscon); 289 290 dev_dbg(dev, "regmap %pR registered\n", res); 291 292 return 0; 293 } 294 295 static const struct platform_device_id syscon_ids[] = { 296 { "syscon", }, 297 { } 298 }; 299 300 static struct platform_driver syscon_driver = { 301 .driver = { 302 .name = "syscon", 303 }, 304 .probe = syscon_probe, 305 .id_table = syscon_ids, 306 }; 307 308 static int __init syscon_init(void) 309 { 310 return platform_driver_register(&syscon_driver); 311 } 312 postcore_initcall(syscon_init); 313