1// SPDX-License-Identifier: GPL-2.0-or-later 2/* 3 * System Control Driver 4 * 5 * Copyright (C) 2012 Freescale Semiconductor, Inc. 6 * Copyright (C) 2012 Linaro Ltd. 7 * 8 * Author: Dong Aisheng <dong.aisheng@linaro.org> 9 */ 10 11#include <linux/clk.h> 12#include <linux/err.h> 13#include <linux/hwspinlock.h> 14#include <linux/io.h> 15#include <linux/init.h> 16#include <linux/list.h> 17#include <linux/of.h> 18#include <linux/of_address.h> 19#include <linux/of_platform.h> 20#include <linux/platform_data/syscon.h> 21#include <linux/platform_device.h> 22#include <linux/regmap.h> 23#include <linux/mfd/syscon.h> 24#include <linux/slab.h> 25 26static struct platform_driver syscon_driver; 27 28static DEFINE_SPINLOCK(syscon_list_slock); 29static LIST_HEAD(syscon_list); 30 31struct syscon { 32 struct device_node *np; 33 struct regmap *regmap; 34 struct list_head list; 35}; 36 37static const struct regmap_config syscon_regmap_config = { 38 .reg_bits = 32, 39 .val_bits = 32, 40 .reg_stride = 4, 41}; 42 43static struct syscon *of_syscon_register(struct device_node *np, bool check_clk) 44{ 45 struct clk *clk; 46 struct syscon *syscon; 47 struct regmap *regmap; 48 void __iomem *base; 49 u32 reg_io_width; 50 int ret; 51 struct regmap_config syscon_config = syscon_regmap_config; 52 struct resource res; 53 54 syscon = kzalloc(sizeof(*syscon), GFP_KERNEL); 55 if (!syscon) 56 return ERR_PTR(-ENOMEM); 57 58 if (of_address_to_resource(np, 0, &res)) { 59 ret = -ENOMEM; 60 goto err_map; 61 } 62 63 base = ioremap(res.start, resource_size(&res)); 64 if (!base) { 65 ret = -ENOMEM; 66 goto err_map; 67 } 68 69 /* Parse the device's DT node for an endianness specification */ 70 if (of_property_read_bool(np, "big-endian")) 71 syscon_config.val_format_endian = REGMAP_ENDIAN_BIG; 72 else if (of_property_read_bool(np, "little-endian")) 73 syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE; 74 else if (of_property_read_bool(np, "native-endian")) 75 syscon_config.val_format_endian = REGMAP_ENDIAN_NATIVE; 76 77 /* 78 * search for reg-io-width property in DT. If it is not provided, 79 * default to 4 bytes. regmap_init_mmio will return an error if values 80 * are invalid so there is no need to check them here. 81 */ 82 ret = of_property_read_u32(np, "reg-io-width", ®_io_width); 83 if (ret) 84 reg_io_width = 4; 85 86 ret = of_hwspin_lock_get_id(np, 0); 87 if (ret > 0 || (IS_ENABLED(CONFIG_HWSPINLOCK) && ret == 0)) { 88 syscon_config.use_hwlock = true; 89 syscon_config.hwlock_id = ret; 90 syscon_config.hwlock_mode = HWLOCK_IRQSTATE; 91 } else if (ret < 0) { 92 switch (ret) { 93 case -ENOENT: 94 /* Ignore missing hwlock, it's optional. */ 95 break; 96 default: 97 pr_err("Failed to retrieve valid hwlock: %d\n", ret); 98 fallthrough; 99 case -EPROBE_DEFER: 100 goto err_regmap; 101 } 102 } 103 104 syscon_config.name = kasprintf(GFP_KERNEL, "%pOFn@%llx", np, 105 (u64)res.start); 106 if (!syscon_config.name) { 107 ret = -ENOMEM; 108 goto err_regmap; 109 } 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; 113 114 regmap = regmap_init_mmio(NULL, base, &syscon_config); 115 kfree(syscon_config.name); 116 if (IS_ERR(regmap)) { 117 pr_err("regmap init failed\n"); 118 ret = PTR_ERR(regmap); 119 goto err_regmap; 120 } 121 122 if (check_clk) { 123 clk = of_clk_get(np, 0); 124 if (IS_ERR(clk)) { 125 ret = PTR_ERR(clk); 126 /* clock is optional */ 127 if (ret != -ENOENT) 128 goto err_clk; 129 } else { 130 ret = regmap_mmio_attach_clk(regmap, clk); 131 if (ret) 132 goto err_attach; 133 } 134 } 135 136 syscon->regmap = regmap; 137 syscon->np = np; 138 139 spin_lock(&syscon_list_slock); 140 list_add_tail(&syscon->list, &syscon_list); 141 spin_unlock(&syscon_list_slock); 142 143 return syscon; 144 145err_attach: 146 if (!IS_ERR(clk)) 147 clk_put(clk); 148err_clk: 149 regmap_exit(regmap); 150err_regmap: 151 iounmap(base); 152err_map: 153 kfree(syscon); 154 return ERR_PTR(ret); 155} 156 157static struct regmap *device_node_get_regmap(struct device_node *np, 158 bool check_clk) 159{ 160 struct syscon *entry, *syscon = NULL; 161 162 spin_lock(&syscon_list_slock); 163 164 list_for_each_entry(entry, &syscon_list, list) 165 if (entry->np == np) { 166 syscon = entry; 167 break; 168 } 169 170 spin_unlock(&syscon_list_slock); 171 172 if (!syscon) 173 syscon = of_syscon_register(np, check_clk); 174 175 if (IS_ERR(syscon)) 176 return ERR_CAST(syscon); 177 178 return syscon->regmap; 179} 180 181struct regmap *device_node_to_regmap(struct device_node *np) 182{ 183 return device_node_get_regmap(np, false); 184} 185EXPORT_SYMBOL_GPL(device_node_to_regmap); 186 187struct regmap *syscon_node_to_regmap(struct device_node *np) 188{ 189 if (!of_device_is_compatible(np, "syscon")) 190 return ERR_PTR(-EINVAL); 191 192 return device_node_get_regmap(np, true); 193} 194EXPORT_SYMBOL_GPL(syscon_node_to_regmap); 195 196struct regmap *syscon_regmap_lookup_by_compatible(const char *s) 197{ 198 struct device_node *syscon_np; 199 struct regmap *regmap; 200 201 syscon_np = of_find_compatible_node(NULL, NULL, s); 202 if (!syscon_np) 203 return ERR_PTR(-ENODEV); 204 205 regmap = syscon_node_to_regmap(syscon_np); 206 of_node_put(syscon_np); 207 208 return regmap; 209} 210EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible); 211 212struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np, 213 const char *property) 214{ 215 struct device_node *syscon_np; 216 struct regmap *regmap; 217 218 if (property) 219 syscon_np = of_parse_phandle(np, property, 0); 220 else 221 syscon_np = np; 222 223 if (!syscon_np) 224 return ERR_PTR(-ENODEV); 225 226 regmap = syscon_node_to_regmap(syscon_np); 227 of_node_put(syscon_np); 228 229 return regmap; 230} 231EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle); 232 233struct regmap *syscon_regmap_lookup_by_phandle_args(struct device_node *np, 234 const char *property, 235 int arg_count, 236 unsigned int *out_args) 237{ 238 struct device_node *syscon_np; 239 struct of_phandle_args args; 240 struct regmap *regmap; 241 unsigned int index; 242 int rc; 243 244 rc = of_parse_phandle_with_fixed_args(np, property, arg_count, 245 0, &args); 246 if (rc) 247 return ERR_PTR(rc); 248 249 syscon_np = args.np; 250 if (!syscon_np) 251 return ERR_PTR(-ENODEV); 252 253 regmap = syscon_node_to_regmap(syscon_np); 254 for (index = 0; index < arg_count; index++) 255 out_args[index] = args.args[index]; 256 of_node_put(syscon_np); 257 258 return regmap; 259} 260EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_args); 261 262static int syscon_probe(struct platform_device *pdev) 263{ 264 struct device *dev = &pdev->dev; 265 struct syscon_platform_data *pdata = dev_get_platdata(dev); 266 struct syscon *syscon; 267 struct regmap_config syscon_config = syscon_regmap_config; 268 struct resource *res; 269 void __iomem *base; 270 271 syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL); 272 if (!syscon) 273 return -ENOMEM; 274 275 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 276 if (!res) 277 return -ENOENT; 278 279 base = devm_ioremap(dev, res->start, resource_size(res)); 280 if (!base) 281 return -ENOMEM; 282 283 syscon_config.max_register = resource_size(res) - 4; 284 if (pdata) 285 syscon_config.name = pdata->label; 286 syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config); 287 if (IS_ERR(syscon->regmap)) { 288 dev_err(dev, "regmap init failed\n"); 289 return PTR_ERR(syscon->regmap); 290 } 291 292 platform_set_drvdata(pdev, syscon); 293 294 dev_dbg(dev, "regmap %pR registered\n", res); 295 296 return 0; 297} 298 299static const struct platform_device_id syscon_ids[] = { 300 { "syscon", }, 301 { } 302}; 303 304static struct platform_driver syscon_driver = { 305 .driver = { 306 .name = "syscon", 307 }, 308 .probe = syscon_probe, 309 .id_table = syscon_ids, 310}; 311 312static int __init syscon_init(void) 313{ 314 return platform_driver_register(&syscon_driver); 315} 316postcore_initcall(syscon_init); 317