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 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 54 if (!of_device_is_compatible(np, "syscon")) 55 return ERR_PTR(-EINVAL); 56 57 syscon = kzalloc(sizeof(*syscon), GFP_KERNEL); 58 if (!syscon) 59 return ERR_PTR(-ENOMEM); 60 61 base = of_iomap(np, 0); 62 if (!base) { 63 ret = -ENOMEM; 64 goto err_map; 65 } 66 67 /* Parse the device's DT node for an endianness specification */ 68 if (of_property_read_bool(np, "big-endian")) 69 syscon_config.val_format_endian = REGMAP_ENDIAN_BIG; 70 else if (of_property_read_bool(np, "little-endian")) 71 syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE; 72 73 /* 74 * search for reg-io-width property in DT. If it is not provided, 75 * default to 4 bytes. regmap_init_mmio will return an error if values 76 * are invalid so there is no need to check them here. 77 */ 78 ret = of_property_read_u32(np, "reg-io-width", ®_io_width); 79 if (ret) 80 reg_io_width = 4; 81 82 syscon_config.reg_stride = reg_io_width; 83 syscon_config.val_bits = reg_io_width * 8; 84 85 regmap = regmap_init_mmio(NULL, base, &syscon_config); 86 if (IS_ERR(regmap)) { 87 pr_err("regmap init failed\n"); 88 ret = PTR_ERR(regmap); 89 goto err_regmap; 90 } 91 92 syscon->regmap = regmap; 93 syscon->np = np; 94 95 spin_lock(&syscon_list_slock); 96 list_add_tail(&syscon->list, &syscon_list); 97 spin_unlock(&syscon_list_slock); 98 99 return syscon; 100 101 err_regmap: 102 iounmap(base); 103 err_map: 104 kfree(syscon); 105 return ERR_PTR(ret); 106 } 107 108 struct regmap *syscon_node_to_regmap(struct device_node *np) 109 { 110 struct syscon *entry, *syscon = NULL; 111 112 spin_lock(&syscon_list_slock); 113 114 list_for_each_entry(entry, &syscon_list, list) 115 if (entry->np == np) { 116 syscon = entry; 117 break; 118 } 119 120 spin_unlock(&syscon_list_slock); 121 122 if (!syscon) 123 syscon = of_syscon_register(np); 124 125 if (IS_ERR(syscon)) 126 return ERR_CAST(syscon); 127 128 return syscon->regmap; 129 } 130 EXPORT_SYMBOL_GPL(syscon_node_to_regmap); 131 132 struct regmap *syscon_regmap_lookup_by_compatible(const char *s) 133 { 134 struct device_node *syscon_np; 135 struct regmap *regmap; 136 137 syscon_np = of_find_compatible_node(NULL, NULL, s); 138 if (!syscon_np) 139 return ERR_PTR(-ENODEV); 140 141 regmap = syscon_node_to_regmap(syscon_np); 142 of_node_put(syscon_np); 143 144 return regmap; 145 } 146 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible); 147 148 static int syscon_match_pdevname(struct device *dev, void *data) 149 { 150 return !strcmp(dev_name(dev), (const char *)data); 151 } 152 153 struct regmap *syscon_regmap_lookup_by_pdevname(const char *s) 154 { 155 struct device *dev; 156 struct syscon *syscon; 157 158 dev = driver_find_device(&syscon_driver.driver, NULL, (void *)s, 159 syscon_match_pdevname); 160 if (!dev) 161 return ERR_PTR(-EPROBE_DEFER); 162 163 syscon = dev_get_drvdata(dev); 164 165 return syscon->regmap; 166 } 167 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_pdevname); 168 169 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np, 170 const char *property) 171 { 172 struct device_node *syscon_np; 173 struct regmap *regmap; 174 175 if (property) 176 syscon_np = of_parse_phandle(np, property, 0); 177 else 178 syscon_np = np; 179 180 if (!syscon_np) 181 return ERR_PTR(-ENODEV); 182 183 regmap = syscon_node_to_regmap(syscon_np); 184 of_node_put(syscon_np); 185 186 return regmap; 187 } 188 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle); 189 190 static int syscon_probe(struct platform_device *pdev) 191 { 192 struct device *dev = &pdev->dev; 193 struct syscon_platform_data *pdata = dev_get_platdata(dev); 194 struct syscon *syscon; 195 struct resource *res; 196 void __iomem *base; 197 198 syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL); 199 if (!syscon) 200 return -ENOMEM; 201 202 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 203 if (!res) 204 return -ENOENT; 205 206 base = devm_ioremap(dev, res->start, resource_size(res)); 207 if (!base) 208 return -ENOMEM; 209 210 syscon_regmap_config.max_register = res->end - res->start - 3; 211 if (pdata) 212 syscon_regmap_config.name = pdata->label; 213 syscon->regmap = devm_regmap_init_mmio(dev, base, 214 &syscon_regmap_config); 215 if (IS_ERR(syscon->regmap)) { 216 dev_err(dev, "regmap init failed\n"); 217 return PTR_ERR(syscon->regmap); 218 } 219 220 platform_set_drvdata(pdev, syscon); 221 222 dev_dbg(dev, "regmap %pR registered\n", res); 223 224 return 0; 225 } 226 227 static const struct platform_device_id syscon_ids[] = { 228 { "syscon", }, 229 { } 230 }; 231 232 static struct platform_driver syscon_driver = { 233 .driver = { 234 .name = "syscon", 235 }, 236 .probe = syscon_probe, 237 .id_table = syscon_ids, 238 }; 239 240 static int __init syscon_init(void) 241 { 242 return platform_driver_register(&syscon_driver); 243 } 244 postcore_initcall(syscon_init); 245 246 static void __exit syscon_exit(void) 247 { 248 platform_driver_unregister(&syscon_driver); 249 } 250 module_exit(syscon_exit); 251 252 MODULE_AUTHOR("Dong Aisheng <dong.aisheng@linaro.org>"); 253 MODULE_DESCRIPTION("System Control driver"); 254 MODULE_LICENSE("GPL v2"); 255