1 /* 2 * System Control Driver 3 * 4 * Copyright (C) 2012 Freescale Semiconductor, Inc. 5 * Copyright (C) 2012 Linaro Ltd. 6 * 7 * Author: Dong Aisheng <dong.aisheng@linaro.org> 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License as published by 11 * the Free Software Foundation; either version 2 of the License, or 12 * (at your option) any later version. 13 */ 14 15 #include <linux/err.h> 16 #include <linux/hwspinlock.h> 17 #include <linux/io.h> 18 #include <linux/module.h> 19 #include <linux/list.h> 20 #include <linux/of.h> 21 #include <linux/of_address.h> 22 #include <linux/of_platform.h> 23 #include <linux/platform_data/syscon.h> 24 #include <linux/platform_device.h> 25 #include <linux/regmap.h> 26 #include <linux/mfd/syscon.h> 27 #include <linux/slab.h> 28 29 static struct platform_driver syscon_driver; 30 31 static DEFINE_SPINLOCK(syscon_list_slock); 32 static LIST_HEAD(syscon_list); 33 34 struct syscon { 35 struct device_node *np; 36 struct regmap *regmap; 37 struct list_head list; 38 }; 39 40 static const struct regmap_config syscon_regmap_config = { 41 .reg_bits = 32, 42 .val_bits = 32, 43 .reg_stride = 4, 44 }; 45 46 static struct syscon *of_syscon_register(struct device_node *np) 47 { 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 56 if (!of_device_is_compatible(np, "syscon")) 57 return ERR_PTR(-EINVAL); 58 59 syscon = kzalloc(sizeof(*syscon), GFP_KERNEL); 60 if (!syscon) 61 return ERR_PTR(-ENOMEM); 62 63 if (of_address_to_resource(np, 0, &res)) { 64 ret = -ENOMEM; 65 goto err_map; 66 } 67 68 base = ioremap(res.start, resource_size(&res)); 69 if (!base) { 70 ret = -ENOMEM; 71 goto err_map; 72 } 73 74 /* Parse the device's DT node for an endianness specification */ 75 if (of_property_read_bool(np, "big-endian")) 76 syscon_config.val_format_endian = REGMAP_ENDIAN_BIG; 77 else if (of_property_read_bool(np, "little-endian")) 78 syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE; 79 else if (of_property_read_bool(np, "native-endian")) 80 syscon_config.val_format_endian = REGMAP_ENDIAN_NATIVE; 81 82 /* 83 * search for reg-io-width property in DT. If it is not provided, 84 * default to 4 bytes. regmap_init_mmio will return an error if values 85 * are invalid so there is no need to check them here. 86 */ 87 ret = of_property_read_u32(np, "reg-io-width", ®_io_width); 88 if (ret) 89 reg_io_width = 4; 90 91 ret = of_hwspin_lock_get_id(np, 0); 92 if (ret > 0 || (IS_ENABLED(CONFIG_HWSPINLOCK) && ret == 0)) { 93 syscon_config.use_hwlock = true; 94 syscon_config.hwlock_id = ret; 95 syscon_config.hwlock_mode = HWLOCK_IRQSTATE; 96 } else if (ret < 0) { 97 switch (ret) { 98 case -ENOENT: 99 /* Ignore missing hwlock, it's optional. */ 100 break; 101 default: 102 pr_err("Failed to retrieve valid hwlock: %d\n", ret); 103 /* fall-through */ 104 case -EPROBE_DEFER: 105 goto err_regmap; 106 } 107 } 108 109 syscon_config.name = of_node_full_name(np); 110 syscon_config.reg_stride = reg_io_width; 111 syscon_config.val_bits = reg_io_width * 8; 112 syscon_config.max_register = resource_size(&res) - reg_io_width; 113 syscon_config.name = of_node_full_name(np); 114 115 regmap = regmap_init_mmio(NULL, base, &syscon_config); 116 if (IS_ERR(regmap)) { 117 pr_err("regmap init failed\n"); 118 ret = PTR_ERR(regmap); 119 goto err_regmap; 120 } 121 122 syscon->regmap = regmap; 123 syscon->np = np; 124 125 spin_lock(&syscon_list_slock); 126 list_add_tail(&syscon->list, &syscon_list); 127 spin_unlock(&syscon_list_slock); 128 129 return syscon; 130 131 err_regmap: 132 iounmap(base); 133 err_map: 134 kfree(syscon); 135 return ERR_PTR(ret); 136 } 137 138 struct regmap *syscon_node_to_regmap(struct device_node *np) 139 { 140 struct syscon *entry, *syscon = NULL; 141 142 spin_lock(&syscon_list_slock); 143 144 list_for_each_entry(entry, &syscon_list, list) 145 if (entry->np == np) { 146 syscon = entry; 147 break; 148 } 149 150 spin_unlock(&syscon_list_slock); 151 152 if (!syscon) 153 syscon = of_syscon_register(np); 154 155 if (IS_ERR(syscon)) 156 return ERR_CAST(syscon); 157 158 return syscon->regmap; 159 } 160 EXPORT_SYMBOL_GPL(syscon_node_to_regmap); 161 162 struct regmap *syscon_regmap_lookup_by_compatible(const char *s) 163 { 164 struct device_node *syscon_np; 165 struct regmap *regmap; 166 167 syscon_np = of_find_compatible_node(NULL, NULL, s); 168 if (!syscon_np) 169 return ERR_PTR(-ENODEV); 170 171 regmap = syscon_node_to_regmap(syscon_np); 172 of_node_put(syscon_np); 173 174 return regmap; 175 } 176 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible); 177 178 static int syscon_match_pdevname(struct device *dev, void *data) 179 { 180 return !strcmp(dev_name(dev), (const char *)data); 181 } 182 183 struct regmap *syscon_regmap_lookup_by_pdevname(const char *s) 184 { 185 struct device *dev; 186 struct syscon *syscon; 187 188 dev = driver_find_device(&syscon_driver.driver, NULL, (void *)s, 189 syscon_match_pdevname); 190 if (!dev) 191 return ERR_PTR(-EPROBE_DEFER); 192 193 syscon = dev_get_drvdata(dev); 194 195 return syscon->regmap; 196 } 197 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_pdevname); 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 static int syscon_probe(struct platform_device *pdev) 221 { 222 struct device *dev = &pdev->dev; 223 struct syscon_platform_data *pdata = dev_get_platdata(dev); 224 struct syscon *syscon; 225 struct regmap_config syscon_config = syscon_regmap_config; 226 struct resource *res; 227 void __iomem *base; 228 229 syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL); 230 if (!syscon) 231 return -ENOMEM; 232 233 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 234 if (!res) 235 return -ENOENT; 236 237 base = devm_ioremap(dev, res->start, resource_size(res)); 238 if (!base) 239 return -ENOMEM; 240 241 syscon_config.max_register = res->end - res->start - 3; 242 if (pdata) 243 syscon_config.name = pdata->label; 244 syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config); 245 if (IS_ERR(syscon->regmap)) { 246 dev_err(dev, "regmap init failed\n"); 247 return PTR_ERR(syscon->regmap); 248 } 249 250 platform_set_drvdata(pdev, syscon); 251 252 dev_dbg(dev, "regmap %pR registered\n", res); 253 254 return 0; 255 } 256 257 static const struct platform_device_id syscon_ids[] = { 258 { "syscon", }, 259 { } 260 }; 261 262 static struct platform_driver syscon_driver = { 263 .driver = { 264 .name = "syscon", 265 }, 266 .probe = syscon_probe, 267 .id_table = syscon_ids, 268 }; 269 270 static int __init syscon_init(void) 271 { 272 return platform_driver_register(&syscon_driver); 273 } 274 postcore_initcall(syscon_init); 275 276 static void __exit syscon_exit(void) 277 { 278 platform_driver_unregister(&syscon_driver); 279 } 280 module_exit(syscon_exit); 281 282 MODULE_AUTHOR("Dong Aisheng <dong.aisheng@linaro.org>"); 283 MODULE_DESCRIPTION("System Control driver"); 284 MODULE_LICENSE("GPL v2"); 285