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 /* fall-through */ 99 case -EPROBE_DEFER: 100 goto err_regmap; 101 } 102 } 103 104 syscon_config.name = of_node_full_name(np); 105 syscon_config.reg_stride = reg_io_width; 106 syscon_config.val_bits = reg_io_width * 8; 107 syscon_config.max_register = resource_size(&res) - reg_io_width; 108 109 regmap = regmap_init_mmio(NULL, base, &syscon_config); 110 if (IS_ERR(regmap)) { 111 pr_err("regmap init failed\n"); 112 ret = PTR_ERR(regmap); 113 goto err_regmap; 114 } 115 116 if (check_clk) { 117 clk = of_clk_get(np, 0); 118 if (IS_ERR(clk)) { 119 ret = PTR_ERR(clk); 120 /* clock is optional */ 121 if (ret != -ENOENT) 122 goto err_clk; 123 } else { 124 ret = regmap_mmio_attach_clk(regmap, clk); 125 if (ret) 126 goto err_attach; 127 } 128 } 129 130 syscon->regmap = regmap; 131 syscon->np = np; 132 133 spin_lock(&syscon_list_slock); 134 list_add_tail(&syscon->list, &syscon_list); 135 spin_unlock(&syscon_list_slock); 136 137 return syscon; 138 139 err_attach: 140 if (!IS_ERR(clk)) 141 clk_put(clk); 142 err_clk: 143 regmap_exit(regmap); 144 err_regmap: 145 iounmap(base); 146 err_map: 147 kfree(syscon); 148 return ERR_PTR(ret); 149 } 150 151 static struct regmap *device_node_get_regmap(struct device_node *np, 152 bool check_clk) 153 { 154 struct syscon *entry, *syscon = NULL; 155 156 spin_lock(&syscon_list_slock); 157 158 list_for_each_entry(entry, &syscon_list, list) 159 if (entry->np == np) { 160 syscon = entry; 161 break; 162 } 163 164 spin_unlock(&syscon_list_slock); 165 166 if (!syscon) 167 syscon = of_syscon_register(np, check_clk); 168 169 if (IS_ERR(syscon)) 170 return ERR_CAST(syscon); 171 172 return syscon->regmap; 173 } 174 175 struct regmap *device_node_to_regmap(struct device_node *np) 176 { 177 return device_node_get_regmap(np, false); 178 } 179 EXPORT_SYMBOL_GPL(device_node_to_regmap); 180 181 struct regmap *syscon_node_to_regmap(struct device_node *np) 182 { 183 if (!of_device_is_compatible(np, "syscon")) 184 return ERR_PTR(-EINVAL); 185 186 return device_node_get_regmap(np, true); 187 } 188 EXPORT_SYMBOL_GPL(syscon_node_to_regmap); 189 190 struct regmap *syscon_regmap_lookup_by_compatible(const char *s) 191 { 192 struct device_node *syscon_np; 193 struct regmap *regmap; 194 195 syscon_np = of_find_compatible_node(NULL, NULL, s); 196 if (!syscon_np) 197 return ERR_PTR(-ENODEV); 198 199 regmap = syscon_node_to_regmap(syscon_np); 200 of_node_put(syscon_np); 201 202 return regmap; 203 } 204 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible); 205 206 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np, 207 const char *property) 208 { 209 struct device_node *syscon_np; 210 struct regmap *regmap; 211 212 if (property) 213 syscon_np = of_parse_phandle(np, property, 0); 214 else 215 syscon_np = np; 216 217 if (!syscon_np) 218 return ERR_PTR(-ENODEV); 219 220 regmap = syscon_node_to_regmap(syscon_np); 221 of_node_put(syscon_np); 222 223 return regmap; 224 } 225 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle); 226 227 struct regmap *syscon_regmap_lookup_by_phandle_args(struct device_node *np, 228 const char *property, 229 int arg_count, 230 unsigned int *out_args) 231 { 232 struct device_node *syscon_np; 233 struct of_phandle_args args; 234 struct regmap *regmap; 235 unsigned int index; 236 int rc; 237 238 rc = of_parse_phandle_with_fixed_args(np, property, arg_count, 239 0, &args); 240 if (rc) 241 return ERR_PTR(rc); 242 243 syscon_np = args.np; 244 if (!syscon_np) 245 return ERR_PTR(-ENODEV); 246 247 regmap = syscon_node_to_regmap(syscon_np); 248 for (index = 0; index < arg_count; index++) 249 out_args[index] = args.args[index]; 250 of_node_put(syscon_np); 251 252 return regmap; 253 } 254 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_args); 255 256 static int syscon_probe(struct platform_device *pdev) 257 { 258 struct device *dev = &pdev->dev; 259 struct syscon_platform_data *pdata = dev_get_platdata(dev); 260 struct syscon *syscon; 261 struct regmap_config syscon_config = syscon_regmap_config; 262 struct resource *res; 263 void __iomem *base; 264 265 syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL); 266 if (!syscon) 267 return -ENOMEM; 268 269 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 270 if (!res) 271 return -ENOENT; 272 273 base = devm_ioremap(dev, res->start, resource_size(res)); 274 if (!base) 275 return -ENOMEM; 276 277 syscon_config.max_register = resource_size(res) - 4; 278 if (pdata) 279 syscon_config.name = pdata->label; 280 syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config); 281 if (IS_ERR(syscon->regmap)) { 282 dev_err(dev, "regmap init failed\n"); 283 return PTR_ERR(syscon->regmap); 284 } 285 286 platform_set_drvdata(pdev, syscon); 287 288 dev_dbg(dev, "regmap %pR registered\n", res); 289 290 return 0; 291 } 292 293 static const struct platform_device_id syscon_ids[] = { 294 { "syscon", }, 295 { } 296 }; 297 298 static struct platform_driver syscon_driver = { 299 .driver = { 300 .name = "syscon", 301 }, 302 .probe = syscon_probe, 303 .id_table = syscon_ids, 304 }; 305 306 static int __init syscon_init(void) 307 { 308 return platform_driver_register(&syscon_driver); 309 } 310 postcore_initcall(syscon_init); 311