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/io.h> 17 #include <linux/module.h> 18 #include <linux/list.h> 19 #include <linux/of.h> 20 #include <linux/of_address.h> 21 #include <linux/of_platform.h> 22 #include <linux/platform_data/syscon.h> 23 #include <linux/platform_device.h> 24 #include <linux/regmap.h> 25 #include <linux/mfd/syscon.h> 26 #include <linux/slab.h> 27 28 static struct platform_driver syscon_driver; 29 30 static DEFINE_SPINLOCK(syscon_list_slock); 31 static LIST_HEAD(syscon_list); 32 33 struct syscon { 34 struct device_node *np; 35 struct regmap *regmap; 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) 46 { 47 struct syscon *syscon; 48 struct regmap *regmap; 49 void __iomem *base; 50 u32 reg_io_width; 51 int ret; 52 struct regmap_config syscon_config = syscon_regmap_config; 53 struct resource res; 54 55 if (!of_device_is_compatible(np, "syscon")) 56 return ERR_PTR(-EINVAL); 57 58 syscon = kzalloc(sizeof(*syscon), GFP_KERNEL); 59 if (!syscon) 60 return ERR_PTR(-ENOMEM); 61 62 if (of_address_to_resource(np, 0, &res)) { 63 ret = -ENOMEM; 64 goto err_map; 65 } 66 67 base = ioremap(res.start, resource_size(&res)); 68 if (!base) { 69 ret = -ENOMEM; 70 goto err_map; 71 } 72 73 /* Parse the device's DT node for an endianness specification */ 74 if (of_property_read_bool(np, "big-endian")) 75 syscon_config.val_format_endian = REGMAP_ENDIAN_BIG; 76 else if (of_property_read_bool(np, "little-endian")) 77 syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE; 78 else if (of_property_read_bool(np, "native-endian")) 79 syscon_config.val_format_endian = REGMAP_ENDIAN_NATIVE; 80 81 /* 82 * search for reg-io-width property in DT. If it is not provided, 83 * default to 4 bytes. regmap_init_mmio will return an error if values 84 * are invalid so there is no need to check them here. 85 */ 86 ret = of_property_read_u32(np, "reg-io-width", ®_io_width); 87 if (ret) 88 reg_io_width = 4; 89 90 syscon_config.reg_stride = reg_io_width; 91 syscon_config.val_bits = reg_io_width * 8; 92 syscon_config.max_register = resource_size(&res) - reg_io_width; 93 94 regmap = regmap_init_mmio(NULL, base, &syscon_config); 95 if (IS_ERR(regmap)) { 96 pr_err("regmap init failed\n"); 97 ret = PTR_ERR(regmap); 98 goto err_regmap; 99 } 100 101 syscon->regmap = regmap; 102 syscon->np = np; 103 104 spin_lock(&syscon_list_slock); 105 list_add_tail(&syscon->list, &syscon_list); 106 spin_unlock(&syscon_list_slock); 107 108 return syscon; 109 110 err_regmap: 111 iounmap(base); 112 err_map: 113 kfree(syscon); 114 return ERR_PTR(ret); 115 } 116 117 struct regmap *syscon_node_to_regmap(struct device_node *np) 118 { 119 struct syscon *entry, *syscon = NULL; 120 121 spin_lock(&syscon_list_slock); 122 123 list_for_each_entry(entry, &syscon_list, list) 124 if (entry->np == np) { 125 syscon = entry; 126 break; 127 } 128 129 spin_unlock(&syscon_list_slock); 130 131 if (!syscon) 132 syscon = of_syscon_register(np); 133 134 if (IS_ERR(syscon)) 135 return ERR_CAST(syscon); 136 137 return syscon->regmap; 138 } 139 EXPORT_SYMBOL_GPL(syscon_node_to_regmap); 140 141 struct regmap *syscon_regmap_lookup_by_compatible(const char *s) 142 { 143 struct device_node *syscon_np; 144 struct regmap *regmap; 145 146 syscon_np = of_find_compatible_node(NULL, NULL, s); 147 if (!syscon_np) 148 return ERR_PTR(-ENODEV); 149 150 regmap = syscon_node_to_regmap(syscon_np); 151 of_node_put(syscon_np); 152 153 return regmap; 154 } 155 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible); 156 157 static int syscon_match_pdevname(struct device *dev, void *data) 158 { 159 return !strcmp(dev_name(dev), (const char *)data); 160 } 161 162 struct regmap *syscon_regmap_lookup_by_pdevname(const char *s) 163 { 164 struct device *dev; 165 struct syscon *syscon; 166 167 dev = driver_find_device(&syscon_driver.driver, NULL, (void *)s, 168 syscon_match_pdevname); 169 if (!dev) 170 return ERR_PTR(-EPROBE_DEFER); 171 172 syscon = dev_get_drvdata(dev); 173 174 return syscon->regmap; 175 } 176 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_pdevname); 177 178 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np, 179 const char *property) 180 { 181 struct device_node *syscon_np; 182 struct regmap *regmap; 183 184 if (property) 185 syscon_np = of_parse_phandle(np, property, 0); 186 else 187 syscon_np = np; 188 189 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_phandle); 198 199 static int syscon_probe(struct platform_device *pdev) 200 { 201 struct device *dev = &pdev->dev; 202 struct syscon_platform_data *pdata = dev_get_platdata(dev); 203 struct syscon *syscon; 204 struct regmap_config syscon_config = syscon_regmap_config; 205 struct resource *res; 206 void __iomem *base; 207 208 syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL); 209 if (!syscon) 210 return -ENOMEM; 211 212 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 213 if (!res) 214 return -ENOENT; 215 216 base = devm_ioremap(dev, res->start, resource_size(res)); 217 if (!base) 218 return -ENOMEM; 219 220 syscon_config.max_register = res->end - res->start - 3; 221 if (pdata) 222 syscon_config.name = pdata->label; 223 syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config); 224 if (IS_ERR(syscon->regmap)) { 225 dev_err(dev, "regmap init failed\n"); 226 return PTR_ERR(syscon->regmap); 227 } 228 229 platform_set_drvdata(pdev, syscon); 230 231 dev_dbg(dev, "regmap %pR registered\n", res); 232 233 return 0; 234 } 235 236 static const struct platform_device_id syscon_ids[] = { 237 { "syscon", }, 238 { } 239 }; 240 241 static struct platform_driver syscon_driver = { 242 .driver = { 243 .name = "syscon", 244 }, 245 .probe = syscon_probe, 246 .id_table = syscon_ids, 247 }; 248 249 static int __init syscon_init(void) 250 { 251 return platform_driver_register(&syscon_driver); 252 } 253 postcore_initcall(syscon_init); 254 255 static void __exit syscon_exit(void) 256 { 257 platform_driver_unregister(&syscon_driver); 258 } 259 module_exit(syscon_exit); 260 261 MODULE_AUTHOR("Dong Aisheng <dong.aisheng@linaro.org>"); 262 MODULE_DESCRIPTION("System Control driver"); 263 MODULE_LICENSE("GPL v2"); 264