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 79 /* 80 * search for reg-io-width property in DT. If it is not provided, 81 * default to 4 bytes. regmap_init_mmio will return an error if values 82 * are invalid so there is no need to check them here. 83 */ 84 ret = of_property_read_u32(np, "reg-io-width", ®_io_width); 85 if (ret) 86 reg_io_width = 4; 87 88 syscon_config.reg_stride = reg_io_width; 89 syscon_config.val_bits = reg_io_width * 8; 90 syscon_config.max_register = resource_size(&res) - reg_io_width; 91 92 regmap = regmap_init_mmio(NULL, base, &syscon_config); 93 if (IS_ERR(regmap)) { 94 pr_err("regmap init failed\n"); 95 ret = PTR_ERR(regmap); 96 goto err_regmap; 97 } 98 99 syscon->regmap = regmap; 100 syscon->np = np; 101 102 spin_lock(&syscon_list_slock); 103 list_add_tail(&syscon->list, &syscon_list); 104 spin_unlock(&syscon_list_slock); 105 106 return syscon; 107 108 err_regmap: 109 iounmap(base); 110 err_map: 111 kfree(syscon); 112 return ERR_PTR(ret); 113 } 114 115 struct regmap *syscon_node_to_regmap(struct device_node *np) 116 { 117 struct syscon *entry, *syscon = NULL; 118 119 spin_lock(&syscon_list_slock); 120 121 list_for_each_entry(entry, &syscon_list, list) 122 if (entry->np == np) { 123 syscon = entry; 124 break; 125 } 126 127 spin_unlock(&syscon_list_slock); 128 129 if (!syscon) 130 syscon = of_syscon_register(np); 131 132 if (IS_ERR(syscon)) 133 return ERR_CAST(syscon); 134 135 return syscon->regmap; 136 } 137 EXPORT_SYMBOL_GPL(syscon_node_to_regmap); 138 139 struct regmap *syscon_regmap_lookup_by_compatible(const char *s) 140 { 141 struct device_node *syscon_np; 142 struct regmap *regmap; 143 144 syscon_np = of_find_compatible_node(NULL, NULL, s); 145 if (!syscon_np) 146 return ERR_PTR(-ENODEV); 147 148 regmap = syscon_node_to_regmap(syscon_np); 149 of_node_put(syscon_np); 150 151 return regmap; 152 } 153 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible); 154 155 static int syscon_match_pdevname(struct device *dev, void *data) 156 { 157 return !strcmp(dev_name(dev), (const char *)data); 158 } 159 160 struct regmap *syscon_regmap_lookup_by_pdevname(const char *s) 161 { 162 struct device *dev; 163 struct syscon *syscon; 164 165 dev = driver_find_device(&syscon_driver.driver, NULL, (void *)s, 166 syscon_match_pdevname); 167 if (!dev) 168 return ERR_PTR(-EPROBE_DEFER); 169 170 syscon = dev_get_drvdata(dev); 171 172 return syscon->regmap; 173 } 174 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_pdevname); 175 176 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np, 177 const char *property) 178 { 179 struct device_node *syscon_np; 180 struct regmap *regmap; 181 182 if (property) 183 syscon_np = of_parse_phandle(np, property, 0); 184 else 185 syscon_np = np; 186 187 if (!syscon_np) 188 return ERR_PTR(-ENODEV); 189 190 regmap = syscon_node_to_regmap(syscon_np); 191 of_node_put(syscon_np); 192 193 return regmap; 194 } 195 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle); 196 197 static int syscon_probe(struct platform_device *pdev) 198 { 199 struct device *dev = &pdev->dev; 200 struct syscon_platform_data *pdata = dev_get_platdata(dev); 201 struct syscon *syscon; 202 struct regmap_config syscon_config = syscon_regmap_config; 203 struct resource *res; 204 void __iomem *base; 205 206 syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL); 207 if (!syscon) 208 return -ENOMEM; 209 210 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 211 if (!res) 212 return -ENOENT; 213 214 base = devm_ioremap(dev, res->start, resource_size(res)); 215 if (!base) 216 return -ENOMEM; 217 218 syscon_config.max_register = res->end - res->start - 3; 219 if (pdata) 220 syscon_config.name = pdata->label; 221 syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config); 222 if (IS_ERR(syscon->regmap)) { 223 dev_err(dev, "regmap init failed\n"); 224 return PTR_ERR(syscon->regmap); 225 } 226 227 platform_set_drvdata(pdev, syscon); 228 229 dev_dbg(dev, "regmap %pR registered\n", res); 230 231 return 0; 232 } 233 234 static const struct platform_device_id syscon_ids[] = { 235 { "syscon", }, 236 { } 237 }; 238 239 static struct platform_driver syscon_driver = { 240 .driver = { 241 .name = "syscon", 242 }, 243 .probe = syscon_probe, 244 .id_table = syscon_ids, 245 }; 246 247 static int __init syscon_init(void) 248 { 249 return platform_driver_register(&syscon_driver); 250 } 251 postcore_initcall(syscon_init); 252 253 static void __exit syscon_exit(void) 254 { 255 platform_driver_unregister(&syscon_driver); 256 } 257 module_exit(syscon_exit); 258 259 MODULE_AUTHOR("Dong Aisheng <dong.aisheng@linaro.org>"); 260 MODULE_DESCRIPTION("System Control driver"); 261 MODULE_LICENSE("GPL v2"); 262