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 void __iomem *base; 131 struct device *dev = &pdev->dev; 132 133 base = devm_platform_ioremap_resource(pdev, idx + 1); 134 if (IS_ERR(base)) 135 return ERR_CAST(base); 136 return devm_regmap_init_mmio(dev, base, &arcx_regmap_cfg); 137 } 138 139 static struct anybuss_host * 140 create_anybus_host(struct platform_device *pdev, int idx) 141 { 142 struct anybuss_ops ops = {}; 143 144 switch (idx) { 145 case 0: 146 ops.reset = export_reset_0; 147 break; 148 case 1: 149 ops.reset = export_reset_1; 150 break; 151 default: 152 return ERR_PTR(-EINVAL); 153 } 154 ops.host_idx = idx; 155 ops.regmap = create_parallel_regmap(pdev, idx); 156 if (IS_ERR(ops.regmap)) 157 return ERR_CAST(ops.regmap); 158 ops.irq = platform_get_irq(pdev, idx); 159 if (ops.irq < 0) 160 return ERR_PTR(ops.irq); 161 return devm_anybuss_host_common_probe(&pdev->dev, &ops); 162 } 163 164 static ssize_t version_show(struct device *dev, 165 struct device_attribute *attr, char *buf) 166 { 167 struct controller_priv *cd = dev_get_drvdata(dev); 168 169 return sprintf(buf, "%s\n", cd->version); 170 } 171 static DEVICE_ATTR_RO(version); 172 173 static ssize_t design_number_show(struct device *dev, 174 struct device_attribute *attr, char *buf) 175 { 176 struct controller_priv *cd = dev_get_drvdata(dev); 177 178 return sprintf(buf, "%d\n", cd->design_no); 179 } 180 static DEVICE_ATTR_RO(design_number); 181 182 static struct attribute *controller_attributes[] = { 183 &dev_attr_version.attr, 184 &dev_attr_design_number.attr, 185 NULL, 186 }; 187 188 static const struct attribute_group controller_attribute_group = { 189 .attrs = controller_attributes, 190 }; 191 192 static const struct attribute_group *controller_attribute_groups[] = { 193 &controller_attribute_group, 194 NULL, 195 }; 196 197 static void controller_device_release(struct device *dev) 198 { 199 kfree(dev); 200 } 201 202 static int can_power_is_enabled(struct regulator_dev *rdev) 203 { 204 struct controller_priv *cd = rdev_get_drvdata(rdev); 205 206 return !(readb(cd->cpld_base + CPLD_STATUS1) & CPLD_STATUS1_CAN_POWER); 207 } 208 209 static const struct regulator_ops can_power_ops = { 210 .is_enabled = can_power_is_enabled, 211 }; 212 213 static const struct regulator_desc can_power_desc = { 214 .name = "regulator-can-power", 215 .id = -1, 216 .type = REGULATOR_VOLTAGE, 217 .owner = THIS_MODULE, 218 .ops = &can_power_ops, 219 }; 220 221 static struct class *controller_class; 222 static DEFINE_IDA(controller_index_ida); 223 224 static int controller_probe(struct platform_device *pdev) 225 { 226 struct controller_priv *cd; 227 struct device *dev = &pdev->dev; 228 struct regulator_config config = { }; 229 struct regulator_dev *regulator; 230 int err, id; 231 struct anybuss_host *host; 232 u8 status1, cap; 233 234 cd = devm_kzalloc(dev, sizeof(*cd), GFP_KERNEL); 235 if (!cd) 236 return -ENOMEM; 237 dev_set_drvdata(dev, cd); 238 mutex_init(&cd->ctrl_lock); 239 cd->reset_gpiod = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW); 240 if (IS_ERR(cd->reset_gpiod)) 241 return PTR_ERR(cd->reset_gpiod); 242 243 /* CPLD control memory, sits at index 0 */ 244 cd->cpld_base = devm_platform_ioremap_resource(pdev, 0); 245 if (IS_ERR(cd->cpld_base)) { 246 dev_err(dev, 247 "failed to map cpld base address\n"); 248 err = PTR_ERR(cd->cpld_base); 249 goto out_reset; 250 } 251 252 /* identify cpld */ 253 status1 = readb(cd->cpld_base + CPLD_STATUS1); 254 cd->design_no = (readb(cd->cpld_base + CPLD_DESIGN_HI) << 8) | 255 readb(cd->cpld_base + CPLD_DESIGN_LO); 256 snprintf(cd->version, sizeof(cd->version), "%c%d", 257 'A' + ((status1 >> 5) & 0x7), 258 (status1 >> 2) & 0x7); 259 dev_info(dev, "design number %d, revision %s\n", 260 cd->design_no, 261 cd->version); 262 cap = readb(cd->cpld_base + CPLD_CAP); 263 if (!(cap & CPLD_CAP_COMPAT)) { 264 dev_err(dev, "unsupported controller [cap=0x%02X]", cap); 265 err = -ENODEV; 266 goto out_reset; 267 } 268 269 if (status1 & CPLD_STATUS1_AB) { 270 dev_info(dev, "has anybus-S slot(s)"); 271 cd->common_reset = !(cap & CPLD_CAP_SEP_RESETS); 272 dev_info(dev, "supports %s", cd->common_reset ? 273 "a common reset" : "separate resets"); 274 for (id = 0; id < 2; id++) { 275 host = create_anybus_host(pdev, id); 276 if (!IS_ERR(host)) 277 continue; 278 err = PTR_ERR(host); 279 /* -ENODEV is fine, it just means no card detected */ 280 if (err != -ENODEV) 281 goto out_reset; 282 } 283 } 284 285 id = ida_simple_get(&controller_index_ida, 0, 0, GFP_KERNEL); 286 if (id < 0) { 287 err = id; 288 goto out_reset; 289 } 290 /* export can power readout as a regulator */ 291 config.dev = dev; 292 config.driver_data = cd; 293 regulator = devm_regulator_register(dev, &can_power_desc, &config); 294 if (IS_ERR(regulator)) { 295 err = PTR_ERR(regulator); 296 goto out_ida; 297 } 298 /* make controller info visible to userspace */ 299 cd->class_dev = kzalloc(sizeof(*cd->class_dev), GFP_KERNEL); 300 if (!cd->class_dev) { 301 err = -ENOMEM; 302 goto out_ida; 303 } 304 cd->class_dev->class = controller_class; 305 cd->class_dev->groups = controller_attribute_groups; 306 cd->class_dev->parent = dev; 307 cd->class_dev->id = id; 308 cd->class_dev->release = controller_device_release; 309 dev_set_name(cd->class_dev, "%d", cd->class_dev->id); 310 dev_set_drvdata(cd->class_dev, cd); 311 err = device_register(cd->class_dev); 312 if (err) 313 goto out_dev; 314 return 0; 315 out_dev: 316 put_device(cd->class_dev); 317 out_ida: 318 ida_simple_remove(&controller_index_ida, id); 319 out_reset: 320 gpiod_set_value_cansleep(cd->reset_gpiod, 1); 321 return err; 322 } 323 324 static void controller_remove(struct platform_device *pdev) 325 { 326 struct controller_priv *cd = platform_get_drvdata(pdev); 327 int id = cd->class_dev->id; 328 329 device_unregister(cd->class_dev); 330 ida_simple_remove(&controller_index_ida, id); 331 gpiod_set_value_cansleep(cd->reset_gpiod, 1); 332 } 333 334 static const struct of_device_id controller_of_match[] = { 335 { .compatible = "arcx,anybus-controller" }, 336 { } 337 }; 338 339 MODULE_DEVICE_TABLE(of, controller_of_match); 340 341 static struct platform_driver controller_driver = { 342 .probe = controller_probe, 343 .remove_new = controller_remove, 344 .driver = { 345 .name = "arcx-anybus-controller", 346 .of_match_table = controller_of_match, 347 }, 348 }; 349 350 static int __init controller_init(void) 351 { 352 int err; 353 354 controller_class = class_create("arcx_anybus_controller"); 355 if (IS_ERR(controller_class)) 356 return PTR_ERR(controller_class); 357 err = platform_driver_register(&controller_driver); 358 if (err) 359 class_destroy(controller_class); 360 361 return err; 362 } 363 364 static void __exit controller_exit(void) 365 { 366 platform_driver_unregister(&controller_driver); 367 class_destroy(controller_class); 368 ida_destroy(&controller_index_ida); 369 } 370 371 module_init(controller_init); 372 module_exit(controller_exit); 373 374 MODULE_DESCRIPTION("Arcx Anybus-S Controller driver"); 375 MODULE_AUTHOR("Sven Van Asbroeck <TheSven73@gmail.com>"); 376 MODULE_LICENSE("GPL v2"); 377