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 26 static struct platform_driver syscon_driver; 27 28 static DEFINE_SPINLOCK(syscon_list_slock); 29 static LIST_HEAD(syscon_list); 30 31 struct syscon { 32 struct device_node *np; 33 struct regmap *regmap; 34 struct list_head list; 35 }; 36 37 static const struct regmap_config syscon_regmap_config = { 38 .reg_bits = 32, 39 .val_bits = 32, 40 .reg_stride = 4, 41 }; 42 43 static struct syscon *of_syscon_register(struct device_node *np) 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 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 if (of_address_to_resource(np, 0, &res)) { 62 ret = -ENOMEM; 63 goto err_map; 64 } 65 66 base = ioremap(res.start, resource_size(&res)); 67 if (!base) { 68 ret = -ENOMEM; 69 goto err_map; 70 } 71 72 /* Parse the device's DT node for an endianness specification */ 73 if (of_property_read_bool(np, "big-endian")) 74 syscon_config.val_format_endian = REGMAP_ENDIAN_BIG; 75 else if (of_property_read_bool(np, "little-endian")) 76 syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE; 77 else if (of_property_read_bool(np, "native-endian")) 78 syscon_config.val_format_endian = REGMAP_ENDIAN_NATIVE; 79 80 /* 81 * search for reg-io-width property in DT. If it is not provided, 82 * default to 4 bytes. regmap_init_mmio will return an error if values 83 * are invalid so there is no need to check them here. 84 */ 85 ret = of_property_read_u32(np, "reg-io-width", ®_io_width); 86 if (ret) 87 reg_io_width = 4; 88 89 ret = of_hwspin_lock_get_id(np, 0); 90 if (ret > 0 || (IS_ENABLED(CONFIG_HWSPINLOCK) && ret == 0)) { 91 syscon_config.use_hwlock = true; 92 syscon_config.hwlock_id = ret; 93 syscon_config.hwlock_mode = HWLOCK_IRQSTATE; 94 } else if (ret < 0) { 95 switch (ret) { 96 case -ENOENT: 97 /* Ignore missing hwlock, it's optional. */ 98 break; 99 default: 100 pr_err("Failed to retrieve valid hwlock: %d\n", ret); 101 /* fall-through */ 102 case -EPROBE_DEFER: 103 goto err_regmap; 104 } 105 } 106 107 syscon_config.name = of_node_full_name(np); 108 syscon_config.reg_stride = reg_io_width; 109 syscon_config.val_bits = reg_io_width * 8; 110 syscon_config.max_register = resource_size(&res) - reg_io_width; 111 syscon_config.name = of_node_full_name(np); 112 113 regmap = regmap_init_mmio(NULL, base, &syscon_config); 114 if (IS_ERR(regmap)) { 115 pr_err("regmap init failed\n"); 116 ret = PTR_ERR(regmap); 117 goto err_regmap; 118 } 119 120 clk = of_clk_get(np, 0); 121 if (IS_ERR(clk)) { 122 ret = PTR_ERR(clk); 123 /* clock is optional */ 124 if (ret != -ENOENT) 125 goto err_clk; 126 } else { 127 ret = regmap_mmio_attach_clk(regmap, clk); 128 if (ret) 129 goto err_attach; 130 } 131 132 syscon->regmap = regmap; 133 syscon->np = np; 134 135 spin_lock(&syscon_list_slock); 136 list_add_tail(&syscon->list, &syscon_list); 137 spin_unlock(&syscon_list_slock); 138 139 return syscon; 140 141 err_attach: 142 if (!IS_ERR(clk)) 143 clk_put(clk); 144 err_clk: 145 regmap_exit(regmap); 146 err_regmap: 147 iounmap(base); 148 err_map: 149 kfree(syscon); 150 return ERR_PTR(ret); 151 } 152 153 struct regmap *syscon_node_to_regmap(struct device_node *np) 154 { 155 struct syscon *entry, *syscon = NULL; 156 157 spin_lock(&syscon_list_slock); 158 159 list_for_each_entry(entry, &syscon_list, list) 160 if (entry->np == np) { 161 syscon = entry; 162 break; 163 } 164 165 spin_unlock(&syscon_list_slock); 166 167 if (!syscon) 168 syscon = of_syscon_register(np); 169 170 if (IS_ERR(syscon)) 171 return ERR_CAST(syscon); 172 173 return syscon->regmap; 174 } 175 EXPORT_SYMBOL_GPL(syscon_node_to_regmap); 176 177 struct regmap *syscon_regmap_lookup_by_compatible(const char *s) 178 { 179 struct device_node *syscon_np; 180 struct regmap *regmap; 181 182 syscon_np = of_find_compatible_node(NULL, NULL, s); 183 if (!syscon_np) 184 return ERR_PTR(-ENODEV); 185 186 regmap = syscon_node_to_regmap(syscon_np); 187 of_node_put(syscon_np); 188 189 return regmap; 190 } 191 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible); 192 193 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np, 194 const char *property) 195 { 196 struct device_node *syscon_np; 197 struct regmap *regmap; 198 199 if (property) 200 syscon_np = of_parse_phandle(np, property, 0); 201 else 202 syscon_np = np; 203 204 if (!syscon_np) 205 return ERR_PTR(-ENODEV); 206 207 regmap = syscon_node_to_regmap(syscon_np); 208 of_node_put(syscon_np); 209 210 return regmap; 211 } 212 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle); 213 214 static int syscon_probe(struct platform_device *pdev) 215 { 216 struct device *dev = &pdev->dev; 217 struct syscon_platform_data *pdata = dev_get_platdata(dev); 218 struct syscon *syscon; 219 struct regmap_config syscon_config = syscon_regmap_config; 220 struct resource *res; 221 void __iomem *base; 222 223 syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL); 224 if (!syscon) 225 return -ENOMEM; 226 227 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 228 if (!res) 229 return -ENOENT; 230 231 base = devm_ioremap(dev, res->start, resource_size(res)); 232 if (!base) 233 return -ENOMEM; 234 235 syscon_config.max_register = res->end - res->start - 3; 236 if (pdata) 237 syscon_config.name = pdata->label; 238 syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config); 239 if (IS_ERR(syscon->regmap)) { 240 dev_err(dev, "regmap init failed\n"); 241 return PTR_ERR(syscon->regmap); 242 } 243 244 platform_set_drvdata(pdev, syscon); 245 246 dev_dbg(dev, "regmap %pR registered\n", res); 247 248 return 0; 249 } 250 251 static const struct platform_device_id syscon_ids[] = { 252 { "syscon", }, 253 { } 254 }; 255 256 static struct platform_driver syscon_driver = { 257 .driver = { 258 .name = "syscon", 259 }, 260 .probe = syscon_probe, 261 .id_table = syscon_ids, 262 }; 263 264 static int __init syscon_init(void) 265 { 266 return platform_driver_register(&syscon_driver); 267 } 268 postcore_initcall(syscon_init); 269