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 int ret; 51 struct regmap_config syscon_config = syscon_regmap_config; 52 53 if (!of_device_is_compatible(np, "syscon")) 54 return ERR_PTR(-EINVAL); 55 56 syscon = kzalloc(sizeof(*syscon), GFP_KERNEL); 57 if (!syscon) 58 return ERR_PTR(-ENOMEM); 59 60 base = of_iomap(np, 0); 61 if (!base) { 62 ret = -ENOMEM; 63 goto err_map; 64 } 65 66 /* Parse the device's DT node for an endianness specification */ 67 if (of_property_read_bool(np, "big-endian")) 68 syscon_config.val_format_endian = REGMAP_ENDIAN_BIG; 69 else if (of_property_read_bool(np, "little-endian")) 70 syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE; 71 72 regmap = regmap_init_mmio(NULL, base, &syscon_config); 73 if (IS_ERR(regmap)) { 74 pr_err("regmap init failed\n"); 75 ret = PTR_ERR(regmap); 76 goto err_regmap; 77 } 78 79 syscon->regmap = regmap; 80 syscon->np = np; 81 82 spin_lock(&syscon_list_slock); 83 list_add_tail(&syscon->list, &syscon_list); 84 spin_unlock(&syscon_list_slock); 85 86 return syscon; 87 88 err_regmap: 89 iounmap(base); 90 err_map: 91 kfree(syscon); 92 return ERR_PTR(ret); 93 } 94 95 struct regmap *syscon_node_to_regmap(struct device_node *np) 96 { 97 struct syscon *entry, *syscon = NULL; 98 99 spin_lock(&syscon_list_slock); 100 101 list_for_each_entry(entry, &syscon_list, list) 102 if (entry->np == np) { 103 syscon = entry; 104 break; 105 } 106 107 spin_unlock(&syscon_list_slock); 108 109 if (!syscon) 110 syscon = of_syscon_register(np); 111 112 if (IS_ERR(syscon)) 113 return ERR_CAST(syscon); 114 115 return syscon->regmap; 116 } 117 EXPORT_SYMBOL_GPL(syscon_node_to_regmap); 118 119 struct regmap *syscon_regmap_lookup_by_compatible(const char *s) 120 { 121 struct device_node *syscon_np; 122 struct regmap *regmap; 123 124 syscon_np = of_find_compatible_node(NULL, NULL, s); 125 if (!syscon_np) 126 return ERR_PTR(-ENODEV); 127 128 regmap = syscon_node_to_regmap(syscon_np); 129 of_node_put(syscon_np); 130 131 return regmap; 132 } 133 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible); 134 135 static int syscon_match_pdevname(struct device *dev, void *data) 136 { 137 return !strcmp(dev_name(dev), (const char *)data); 138 } 139 140 struct regmap *syscon_regmap_lookup_by_pdevname(const char *s) 141 { 142 struct device *dev; 143 struct syscon *syscon; 144 145 dev = driver_find_device(&syscon_driver.driver, NULL, (void *)s, 146 syscon_match_pdevname); 147 if (!dev) 148 return ERR_PTR(-EPROBE_DEFER); 149 150 syscon = dev_get_drvdata(dev); 151 152 return syscon->regmap; 153 } 154 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_pdevname); 155 156 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np, 157 const char *property) 158 { 159 struct device_node *syscon_np; 160 struct regmap *regmap; 161 162 if (property) 163 syscon_np = of_parse_phandle(np, property, 0); 164 else 165 syscon_np = np; 166 167 if (!syscon_np) 168 return ERR_PTR(-ENODEV); 169 170 regmap = syscon_node_to_regmap(syscon_np); 171 of_node_put(syscon_np); 172 173 return regmap; 174 } 175 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle); 176 177 static int syscon_probe(struct platform_device *pdev) 178 { 179 struct device *dev = &pdev->dev; 180 struct syscon_platform_data *pdata = dev_get_platdata(dev); 181 struct syscon *syscon; 182 struct resource *res; 183 void __iomem *base; 184 185 syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL); 186 if (!syscon) 187 return -ENOMEM; 188 189 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 190 if (!res) 191 return -ENOENT; 192 193 base = devm_ioremap(dev, res->start, resource_size(res)); 194 if (!base) 195 return -ENOMEM; 196 197 syscon_regmap_config.max_register = res->end - res->start - 3; 198 if (pdata) 199 syscon_regmap_config.name = pdata->label; 200 syscon->regmap = devm_regmap_init_mmio(dev, base, 201 &syscon_regmap_config); 202 if (IS_ERR(syscon->regmap)) { 203 dev_err(dev, "regmap init failed\n"); 204 return PTR_ERR(syscon->regmap); 205 } 206 207 platform_set_drvdata(pdev, syscon); 208 209 dev_dbg(dev, "regmap %pR registered\n", res); 210 211 return 0; 212 } 213 214 static const struct platform_device_id syscon_ids[] = { 215 { "syscon", }, 216 { } 217 }; 218 219 static struct platform_driver syscon_driver = { 220 .driver = { 221 .name = "syscon", 222 }, 223 .probe = syscon_probe, 224 .id_table = syscon_ids, 225 }; 226 227 static int __init syscon_init(void) 228 { 229 return platform_driver_register(&syscon_driver); 230 } 231 postcore_initcall(syscon_init); 232 233 static void __exit syscon_exit(void) 234 { 235 platform_driver_unregister(&syscon_driver); 236 } 237 module_exit(syscon_exit); 238 239 MODULE_AUTHOR("Dong Aisheng <dong.aisheng@linaro.org>"); 240 MODULE_DESCRIPTION("System Control driver"); 241 MODULE_LICENSE("GPL v2"); 242