1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Arcx Anybus-S Controller driver 4 * 5 * Copyright (C) 2018 Arcx Inc 6 */ 7 8 #include <linux/kernel.h> 9 #include <linux/module.h> 10 #include <linux/init.h> 11 #include <linux/slab.h> 12 #include <linux/platform_device.h> 13 #include <linux/gpio/consumer.h> 14 #include <linux/io.h> 15 #include <linux/of.h> 16 #include <linux/delay.h> 17 #include <linux/idr.h> 18 #include <linux/mutex.h> 19 #include <linux/regulator/driver.h> 20 #include <linux/regulator/machine.h> 21 #include <linux/regmap.h> 22 23 /* move to <linux/anybuss-controller.h> when taking this out of staging */ 24 #include "anybuss-controller.h" 25 26 #define CPLD_STATUS1 0x80 27 #define CPLD_CONTROL 0x80 28 #define CPLD_CONTROL_CRST 0x40 29 #define CPLD_CONTROL_RST1 0x04 30 #define CPLD_CONTROL_RST2 0x80 31 #define CPLD_STATUS1_AB 0x02 32 #define CPLD_STATUS1_CAN_POWER 0x01 33 #define CPLD_DESIGN_LO 0x81 34 #define CPLD_DESIGN_HI 0x82 35 #define CPLD_CAP 0x83 36 #define CPLD_CAP_COMPAT 0x01 37 #define CPLD_CAP_SEP_RESETS 0x02 38 39 struct controller_priv { 40 struct device *class_dev; 41 bool common_reset; 42 struct gpio_desc *reset_gpiod; 43 void __iomem *cpld_base; 44 struct mutex ctrl_lock; /* protects CONTROL register */ 45 u8 control_reg; 46 char version[3]; 47 u16 design_no; 48 }; 49 50 static void do_reset(struct controller_priv *cd, u8 rst_bit, bool reset) 51 { 52 mutex_lock(&cd->ctrl_lock); 53 /* 54 * CPLD_CONTROL is write-only, so cache its value in 55 * cd->control_reg 56 */ 57 if (reset) 58 cd->control_reg &= ~rst_bit; 59 else 60 cd->control_reg |= rst_bit; 61 writeb(cd->control_reg, cd->cpld_base + CPLD_CONTROL); 62 /* 63 * h/w work-around: 64 * the hardware is 'too fast', so a reset followed by an immediate 65 * not-reset will _not_ change the anybus reset line in any way, 66 * losing the reset. to prevent this from happening, introduce 67 * a minimum reset duration. 68 * Verified minimum safe duration required using a scope 69 * on 14-June-2018: 100 us. 70 */ 71 if (reset) 72 usleep_range(100, 200); 73 mutex_unlock(&cd->ctrl_lock); 74 } 75 76 static int anybuss_reset(struct controller_priv *cd, 77 unsigned long id, bool reset) 78 { 79 if (id >= 2) 80 return -EINVAL; 81 if (cd->common_reset) 82 do_reset(cd, CPLD_CONTROL_CRST, reset); 83 else 84 do_reset(cd, id ? CPLD_CONTROL_RST2 : CPLD_CONTROL_RST1, reset); 85 return 0; 86 } 87 88 static void export_reset_0(struct device *dev, bool assert) 89 { 90 struct controller_priv *cd = dev_get_drvdata(dev); 91 92 anybuss_reset(cd, 0, assert); 93 } 94 95 static void export_reset_1(struct device *dev, bool assert) 96 { 97 struct controller_priv *cd = dev_get_drvdata(dev); 98 99 anybuss_reset(cd, 1, assert); 100 } 101 102 /* 103 * parallel bus limitation: 104 * 105 * the anybus is 8-bit wide. we can't assume that the hardware will translate 106 * word accesses on the parallel bus to multiple byte-accesses on the anybus. 107 * 108 * the imx WEIM bus does not provide this type of translation. 109 * 110 * to be safe, we will limit parallel bus accesses to a single byte 111 * at a time for now. 112 */ 113 114 static const struct regmap_config arcx_regmap_cfg = { 115 .reg_bits = 16, 116 .val_bits = 8, 117 .max_register = 0x7ff, 118 .use_single_read = true, 119 .use_single_write = true, 120 /* 121 * single-byte parallel bus accesses are atomic, so don't 122 * require any synchronization. 123 */ 124 .disable_locking = true, 125 }; 126 127 static struct regmap *create_parallel_regmap(struct platform_device *pdev, 128 int idx) 129 { 130 struct resource *res; 131 void __iomem *base; 132 struct device *dev = &pdev->dev; 133 134 res = platform_get_resource(pdev, IORESOURCE_MEM, idx + 1); 135 base = devm_ioremap_resource(dev, res); 136 if (IS_ERR(base)) 137 return ERR_CAST(base); 138 return devm_regmap_init_mmio(dev, base, &arcx_regmap_cfg); 139 } 140 141 static struct anybuss_host * 142 create_anybus_host(struct platform_device *pdev, int idx) 143 { 144 struct anybuss_ops ops = {}; 145 146 switch (idx) { 147 case 0: 148 ops.reset = export_reset_0; 149 break; 150 case 1: 151 ops.reset = export_reset_1; 152 break; 153 default: 154 return ERR_PTR(-EINVAL); 155 } 156 ops.host_idx = idx; 157 ops.regmap = create_parallel_regmap(pdev, idx); 158 if (IS_ERR(ops.regmap)) 159 return ERR_CAST(ops.regmap); 160 ops.irq = platform_get_irq(pdev, idx); 161 if (ops.irq <= 0) 162 return ERR_PTR(-EINVAL); 163 return devm_anybuss_host_common_probe(&pdev->dev, &ops); 164 } 165 166 static ssize_t version_show(struct device *dev, 167 struct device_attribute *attr, char *buf) 168 { 169 struct controller_priv *cd = dev_get_drvdata(dev); 170 171 return sprintf(buf, "%s\n", cd->version); 172 } 173 static DEVICE_ATTR_RO(version); 174 175 static ssize_t design_number_show(struct device *dev, 176 struct device_attribute *attr, char *buf) 177 { 178 struct controller_priv *cd = dev_get_drvdata(dev); 179 180 return sprintf(buf, "%d\n", cd->design_no); 181 } 182 static DEVICE_ATTR_RO(design_number); 183 184 static struct attribute *controller_attributes[] = { 185 &dev_attr_version.attr, 186 &dev_attr_design_number.attr, 187 NULL, 188 }; 189 190 static struct attribute_group controller_attribute_group = { 191 .attrs = controller_attributes, 192 }; 193 194 static const struct attribute_group *controller_attribute_groups[] = { 195 &controller_attribute_group, 196 NULL, 197 }; 198 199 static void controller_device_release(struct device *dev) 200 { 201 kfree(dev); 202 } 203 204 static int can_power_is_enabled(struct regulator_dev *rdev) 205 { 206 struct controller_priv *cd = rdev_get_drvdata(rdev); 207 208 return !(readb(cd->cpld_base + CPLD_STATUS1) & CPLD_STATUS1_CAN_POWER); 209 } 210 211 static struct regulator_ops can_power_ops = { 212 .is_enabled = can_power_is_enabled, 213 }; 214 215 static const struct regulator_desc can_power_desc = { 216 .name = "regulator-can-power", 217 .id = -1, 218 .type = REGULATOR_VOLTAGE, 219 .owner = THIS_MODULE, 220 .ops = &can_power_ops, 221 }; 222 223 static struct class *controller_class; 224 static DEFINE_IDA(controller_index_ida); 225 226 static int controller_probe(struct platform_device *pdev) 227 { 228 struct controller_priv *cd; 229 struct device *dev = &pdev->dev; 230 struct regulator_config config = { }; 231 struct regulator_dev *regulator; 232 int err, id; 233 struct resource *res; 234 struct anybuss_host *host; 235 u8 status1, cap; 236 237 cd = devm_kzalloc(dev, sizeof(*cd), GFP_KERNEL); 238 if (!cd) 239 return -ENOMEM; 240 dev_set_drvdata(dev, cd); 241 mutex_init(&cd->ctrl_lock); 242 cd->reset_gpiod = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW); 243 if (IS_ERR(cd->reset_gpiod)) 244 return PTR_ERR(cd->reset_gpiod); 245 246 /* CPLD control memory, sits at index 0 */ 247 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 248 cd->cpld_base = devm_ioremap_resource(dev, res); 249 if (IS_ERR(cd->cpld_base)) { 250 dev_err(dev, 251 "failed to map cpld base address\n"); 252 err = PTR_ERR(cd->cpld_base); 253 goto out_reset; 254 } 255 256 /* identify cpld */ 257 status1 = readb(cd->cpld_base + CPLD_STATUS1); 258 cd->design_no = (readb(cd->cpld_base + CPLD_DESIGN_HI) << 8) | 259 readb(cd->cpld_base + CPLD_DESIGN_LO); 260 snprintf(cd->version, sizeof(cd->version), "%c%d", 261 'A' + ((status1 >> 5) & 0x7), 262 (status1 >> 2) & 0x7); 263 dev_info(dev, "design number %d, revision %s\n", 264 cd->design_no, 265 cd->version); 266 cap = readb(cd->cpld_base + CPLD_CAP); 267 if (!(cap & CPLD_CAP_COMPAT)) { 268 dev_err(dev, "unsupported controller [cap=0x%02X]", cap); 269 err = -ENODEV; 270 goto out_reset; 271 } 272 273 if (status1 & CPLD_STATUS1_AB) { 274 dev_info(dev, "has anybus-S slot(s)"); 275 cd->common_reset = !(cap & CPLD_CAP_SEP_RESETS); 276 dev_info(dev, "supports %s", cd->common_reset ? 277 "a common reset" : "separate resets"); 278 for (id = 0; id < 2; id++) { 279 host = create_anybus_host(pdev, id); 280 if (!IS_ERR(host)) 281 continue; 282 err = PTR_ERR(host); 283 /* -ENODEV is fine, it just means no card detected */ 284 if (err != -ENODEV) 285 goto out_reset; 286 } 287 } 288 289 id = ida_simple_get(&controller_index_ida, 0, 0, GFP_KERNEL); 290 if (id < 0) { 291 err = id; 292 goto out_reset; 293 } 294 /* export can power readout as a regulator */ 295 config.dev = dev; 296 config.driver_data = cd; 297 regulator = devm_regulator_register(dev, &can_power_desc, &config); 298 if (IS_ERR(regulator)) { 299 err = PTR_ERR(regulator); 300 goto out_reset; 301 } 302 /* make controller info visible to userspace */ 303 cd->class_dev = kzalloc(sizeof(*cd->class_dev), GFP_KERNEL); 304 if (!cd->class_dev) { 305 err = -ENOMEM; 306 goto out_ida; 307 } 308 cd->class_dev->class = controller_class; 309 cd->class_dev->groups = controller_attribute_groups; 310 cd->class_dev->parent = dev; 311 cd->class_dev->id = id; 312 cd->class_dev->release = controller_device_release; 313 dev_set_name(cd->class_dev, "%d", cd->class_dev->id); 314 dev_set_drvdata(cd->class_dev, cd); 315 err = device_register(cd->class_dev); 316 if (err) 317 goto out_dev; 318 return 0; 319 out_dev: 320 put_device(cd->class_dev); 321 out_ida: 322 ida_simple_remove(&controller_index_ida, id); 323 out_reset: 324 gpiod_set_value_cansleep(cd->reset_gpiod, 1); 325 return err; 326 } 327 328 static int controller_remove(struct platform_device *pdev) 329 { 330 struct controller_priv *cd = platform_get_drvdata(pdev); 331 int id = cd->class_dev->id; 332 333 device_unregister(cd->class_dev); 334 ida_simple_remove(&controller_index_ida, id); 335 gpiod_set_value_cansleep(cd->reset_gpiod, 1); 336 return 0; 337 } 338 339 static const struct of_device_id controller_of_match[] = { 340 { .compatible = "arcx,anybus-controller" }, 341 { } 342 }; 343 344 MODULE_DEVICE_TABLE(of, controller_of_match); 345 346 static struct platform_driver controller_driver = { 347 .probe = controller_probe, 348 .remove = controller_remove, 349 .driver = { 350 .name = "arcx-anybus-controller", 351 .of_match_table = of_match_ptr(controller_of_match), 352 }, 353 }; 354 355 static int __init controller_init(void) 356 { 357 int err; 358 359 controller_class = class_create(THIS_MODULE, "arcx_anybus_controller"); 360 if (IS_ERR(controller_class)) 361 return PTR_ERR(controller_class); 362 err = platform_driver_register(&controller_driver); 363 if (err) 364 class_destroy(controller_class); 365 366 return err; 367 } 368 369 static void __exit controller_exit(void) 370 { 371 platform_driver_unregister(&controller_driver); 372 class_destroy(controller_class); 373 ida_destroy(&controller_index_ida); 374 } 375 376 module_init(controller_init); 377 module_exit(controller_exit); 378 379 MODULE_DESCRIPTION("Arcx Anybus-S Controller driver"); 380 MODULE_AUTHOR("Sven Van Asbroeck <TheSven73@gmail.com>"); 381 MODULE_LICENSE("GPL v2"); 382