1 /* 2 * GPIO Testing Device Driver 3 * 4 * Copyright (C) 2014 Kamlakant Patel <kamlakant.patel@broadcom.com> 5 * Copyright (C) 2015-2016 Bamvor Jian Zhang <bamv2005@gmail.com> 6 * Copyright (C) 2017 Bartosz Golaszewski <brgl@bgdev.pl> 7 * 8 * This program is free software; you can redistribute it and/or modify it 9 * under the terms of the GNU General Public License as published by the 10 * Free Software Foundation; either version 2 of the License, or (at your 11 * option) any later version. 12 * 13 */ 14 15 #include <linux/init.h> 16 #include <linux/module.h> 17 #include <linux/gpio/driver.h> 18 #include <linux/gpio/consumer.h> 19 #include <linux/platform_device.h> 20 #include <linux/slab.h> 21 #include <linux/interrupt.h> 22 #include <linux/irq.h> 23 #include <linux/irq_sim.h> 24 #include <linux/debugfs.h> 25 #include <linux/uaccess.h> 26 27 #include "gpiolib.h" 28 29 #define GPIO_MOCKUP_NAME "gpio-mockup" 30 #define GPIO_MOCKUP_MAX_GC 10 31 /* 32 * We're storing two values per chip: the GPIO base and the number 33 * of GPIO lines. 34 */ 35 #define GPIO_MOCKUP_MAX_RANGES (GPIO_MOCKUP_MAX_GC * 2) 36 37 #define gpio_mockup_err(...) pr_err(GPIO_MOCKUP_NAME ": " __VA_ARGS__) 38 39 enum { 40 GPIO_MOCKUP_DIR_OUT = 0, 41 GPIO_MOCKUP_DIR_IN = 1, 42 }; 43 44 /* 45 * struct gpio_pin_status - structure describing a GPIO status 46 * @dir: Configures direction of gpio as "in" or "out", 0=in, 1=out 47 * @value: Configures status of the gpio as 0(low) or 1(high) 48 */ 49 struct gpio_mockup_line_status { 50 int dir; 51 int value; 52 }; 53 54 struct gpio_mockup_chip { 55 struct gpio_chip gc; 56 struct gpio_mockup_line_status *lines; 57 struct irq_sim irqsim; 58 struct dentry *dbg_dir; 59 }; 60 61 struct gpio_mockup_dbgfs_private { 62 struct gpio_mockup_chip *chip; 63 struct gpio_desc *desc; 64 int offset; 65 }; 66 67 struct gpio_mockup_platform_data { 68 int base; 69 int ngpio; 70 int index; 71 bool named_lines; 72 }; 73 74 static int gpio_mockup_ranges[GPIO_MOCKUP_MAX_RANGES]; 75 static int gpio_mockup_num_ranges; 76 module_param_array(gpio_mockup_ranges, int, &gpio_mockup_num_ranges, 0400); 77 78 static bool gpio_mockup_named_lines; 79 module_param_named(gpio_mockup_named_lines, 80 gpio_mockup_named_lines, bool, 0400); 81 82 static struct dentry *gpio_mockup_dbg_dir; 83 84 static int gpio_mockup_range_base(unsigned int index) 85 { 86 return gpio_mockup_ranges[index * 2]; 87 } 88 89 static int gpio_mockup_range_ngpio(unsigned int index) 90 { 91 return gpio_mockup_ranges[index * 2 + 1]; 92 } 93 94 static int gpio_mockup_get(struct gpio_chip *gc, unsigned int offset) 95 { 96 struct gpio_mockup_chip *chip = gpiochip_get_data(gc); 97 98 return chip->lines[offset].value; 99 } 100 101 static void gpio_mockup_set(struct gpio_chip *gc, 102 unsigned int offset, int value) 103 { 104 struct gpio_mockup_chip *chip = gpiochip_get_data(gc); 105 106 chip->lines[offset].value = !!value; 107 } 108 109 static void gpio_mockup_set_multiple(struct gpio_chip *gc, 110 unsigned long *mask, unsigned long *bits) 111 { 112 unsigned int bit; 113 114 for_each_set_bit(bit, mask, gc->ngpio) 115 gpio_mockup_set(gc, bit, test_bit(bit, bits)); 116 117 } 118 119 static int gpio_mockup_dirout(struct gpio_chip *gc, 120 unsigned int offset, int value) 121 { 122 struct gpio_mockup_chip *chip = gpiochip_get_data(gc); 123 124 gpio_mockup_set(gc, offset, value); 125 chip->lines[offset].dir = GPIO_MOCKUP_DIR_OUT; 126 127 return 0; 128 } 129 130 static int gpio_mockup_dirin(struct gpio_chip *gc, unsigned int offset) 131 { 132 struct gpio_mockup_chip *chip = gpiochip_get_data(gc); 133 134 chip->lines[offset].dir = GPIO_MOCKUP_DIR_IN; 135 136 return 0; 137 } 138 139 static int gpio_mockup_get_direction(struct gpio_chip *gc, unsigned int offset) 140 { 141 struct gpio_mockup_chip *chip = gpiochip_get_data(gc); 142 143 return chip->lines[offset].dir; 144 } 145 146 static int gpio_mockup_to_irq(struct gpio_chip *gc, unsigned int offset) 147 { 148 struct gpio_mockup_chip *chip = gpiochip_get_data(gc); 149 150 return irq_sim_irqnum(&chip->irqsim, offset); 151 } 152 153 static ssize_t gpio_mockup_event_write(struct file *file, 154 const char __user *usr_buf, 155 size_t size, loff_t *ppos) 156 { 157 struct gpio_mockup_dbgfs_private *priv; 158 struct gpio_mockup_chip *chip; 159 struct seq_file *sfile; 160 struct gpio_desc *desc; 161 int rv, val; 162 163 rv = kstrtoint_from_user(usr_buf, size, 0, &val); 164 if (rv) 165 return rv; 166 if (val != 0 && val != 1) 167 return -EINVAL; 168 169 sfile = file->private_data; 170 priv = sfile->private; 171 desc = priv->desc; 172 chip = priv->chip; 173 174 gpiod_set_value_cansleep(desc, val); 175 irq_sim_fire(&chip->irqsim, priv->offset); 176 177 return size; 178 } 179 180 static int gpio_mockup_event_open(struct inode *inode, struct file *file) 181 { 182 return single_open(file, NULL, inode->i_private); 183 } 184 185 static const struct file_operations gpio_mockup_event_ops = { 186 .owner = THIS_MODULE, 187 .open = gpio_mockup_event_open, 188 .write = gpio_mockup_event_write, 189 .llseek = no_llseek, 190 }; 191 192 static void gpio_mockup_debugfs_setup(struct device *dev, 193 struct gpio_mockup_chip *chip) 194 { 195 struct gpio_mockup_dbgfs_private *priv; 196 struct dentry *evfile, *link; 197 struct gpio_chip *gc; 198 const char *devname; 199 char *name; 200 int i; 201 202 gc = &chip->gc; 203 devname = dev_name(&gc->gpiodev->dev); 204 205 chip->dbg_dir = debugfs_create_dir(devname, gpio_mockup_dbg_dir); 206 if (IS_ERR_OR_NULL(chip->dbg_dir)) 207 goto err; 208 209 link = debugfs_create_symlink(gc->label, gpio_mockup_dbg_dir, devname); 210 if (IS_ERR_OR_NULL(link)) 211 goto err; 212 213 for (i = 0; i < gc->ngpio; i++) { 214 name = devm_kasprintf(dev, GFP_KERNEL, "%d", i); 215 if (!name) 216 goto err; 217 218 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); 219 if (!priv) 220 goto err; 221 222 priv->chip = chip; 223 priv->offset = i; 224 priv->desc = &gc->gpiodev->descs[i]; 225 226 evfile = debugfs_create_file(name, 0200, chip->dbg_dir, priv, 227 &gpio_mockup_event_ops); 228 if (IS_ERR_OR_NULL(evfile)) 229 goto err; 230 } 231 232 return; 233 234 err: 235 dev_err(dev, "error creating debugfs event files\n"); 236 } 237 238 static int gpio_mockup_name_lines(struct device *dev, 239 struct gpio_mockup_chip *chip) 240 { 241 struct gpio_chip *gc = &chip->gc; 242 char **names; 243 int i; 244 245 names = devm_kcalloc(dev, gc->ngpio, sizeof(char *), GFP_KERNEL); 246 if (!names) 247 return -ENOMEM; 248 249 for (i = 0; i < gc->ngpio; i++) { 250 names[i] = devm_kasprintf(dev, GFP_KERNEL, 251 "%s-%d", gc->label, i); 252 if (!names[i]) 253 return -ENOMEM; 254 } 255 256 gc->names = (const char *const *)names; 257 258 return 0; 259 } 260 261 static int gpio_mockup_probe(struct platform_device *pdev) 262 { 263 struct gpio_mockup_platform_data *pdata; 264 struct gpio_mockup_chip *chip; 265 struct gpio_chip *gc; 266 int rv, base, ngpio; 267 struct device *dev; 268 char *name; 269 270 dev = &pdev->dev; 271 pdata = dev_get_platdata(dev); 272 base = pdata->base; 273 ngpio = pdata->ngpio; 274 275 chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL); 276 if (!chip) 277 return -ENOMEM; 278 279 name = devm_kasprintf(dev, GFP_KERNEL, "%s-%c", 280 pdev->name, pdata->index); 281 if (!name) 282 return -ENOMEM; 283 284 gc = &chip->gc; 285 gc->base = base; 286 gc->ngpio = ngpio; 287 gc->label = name; 288 gc->owner = THIS_MODULE; 289 gc->parent = dev; 290 gc->get = gpio_mockup_get; 291 gc->set = gpio_mockup_set; 292 gc->set_multiple = gpio_mockup_set_multiple; 293 gc->direction_output = gpio_mockup_dirout; 294 gc->direction_input = gpio_mockup_dirin; 295 gc->get_direction = gpio_mockup_get_direction; 296 gc->to_irq = gpio_mockup_to_irq; 297 298 chip->lines = devm_kcalloc(dev, gc->ngpio, 299 sizeof(*chip->lines), GFP_KERNEL); 300 if (!chip->lines) 301 return -ENOMEM; 302 303 if (pdata->named_lines) { 304 rv = gpio_mockup_name_lines(dev, chip); 305 if (rv) 306 return rv; 307 } 308 309 rv = devm_irq_sim_init(dev, &chip->irqsim, gc->ngpio); 310 if (rv < 0) 311 return rv; 312 313 rv = devm_gpiochip_add_data(dev, &chip->gc, chip); 314 if (rv) 315 return rv; 316 317 if (!IS_ERR_OR_NULL(gpio_mockup_dbg_dir)) 318 gpio_mockup_debugfs_setup(dev, chip); 319 320 return 0; 321 } 322 323 static struct platform_driver gpio_mockup_driver = { 324 .driver = { 325 .name = GPIO_MOCKUP_NAME, 326 }, 327 .probe = gpio_mockup_probe, 328 }; 329 330 static struct platform_device *gpio_mockup_pdevs[GPIO_MOCKUP_MAX_GC]; 331 332 static void gpio_mockup_unregister_pdevs(void) 333 { 334 struct platform_device *pdev; 335 int i; 336 337 for (i = 0; i < GPIO_MOCKUP_MAX_GC; i++) { 338 pdev = gpio_mockup_pdevs[i]; 339 340 if (pdev) 341 platform_device_unregister(pdev); 342 } 343 } 344 345 static int __init gpio_mockup_init(void) 346 { 347 int i, num_chips, err = 0, index = 'A'; 348 struct gpio_mockup_platform_data pdata; 349 struct platform_device *pdev; 350 351 if ((gpio_mockup_num_ranges < 2) || 352 (gpio_mockup_num_ranges % 2) || 353 (gpio_mockup_num_ranges > GPIO_MOCKUP_MAX_RANGES)) 354 return -EINVAL; 355 356 /* Each chip is described by two values. */ 357 num_chips = gpio_mockup_num_ranges / 2; 358 359 /* 360 * The second value in the <base GPIO - number of GPIOS> pair must 361 * always be greater than 0. 362 */ 363 for (i = 0; i < num_chips; i++) { 364 if (gpio_mockup_range_ngpio(i) < 0) 365 return -EINVAL; 366 } 367 368 gpio_mockup_dbg_dir = debugfs_create_dir("gpio-mockup-event", NULL); 369 if (IS_ERR_OR_NULL(gpio_mockup_dbg_dir)) 370 gpio_mockup_err("error creating debugfs directory\n"); 371 372 err = platform_driver_register(&gpio_mockup_driver); 373 if (err) { 374 gpio_mockup_err("error registering platform driver\n"); 375 return err; 376 } 377 378 for (i = 0; i < num_chips; i++) { 379 pdata.index = index++; 380 pdata.base = gpio_mockup_range_base(i); 381 pdata.ngpio = pdata.base < 0 382 ? gpio_mockup_range_ngpio(i) 383 : gpio_mockup_range_ngpio(i) - pdata.base; 384 pdata.named_lines = gpio_mockup_named_lines; 385 386 pdev = platform_device_register_resndata(NULL, 387 GPIO_MOCKUP_NAME, 388 i, NULL, 0, &pdata, 389 sizeof(pdata)); 390 if (IS_ERR(pdev)) { 391 gpio_mockup_err("error registering device"); 392 platform_driver_unregister(&gpio_mockup_driver); 393 gpio_mockup_unregister_pdevs(); 394 return PTR_ERR(pdev); 395 } 396 397 gpio_mockup_pdevs[i] = pdev; 398 } 399 400 return 0; 401 } 402 403 static void __exit gpio_mockup_exit(void) 404 { 405 debugfs_remove_recursive(gpio_mockup_dbg_dir); 406 platform_driver_unregister(&gpio_mockup_driver); 407 gpio_mockup_unregister_pdevs(); 408 } 409 410 module_init(gpio_mockup_init); 411 module_exit(gpio_mockup_exit); 412 413 MODULE_AUTHOR("Kamlakant Patel <kamlakant.patel@broadcom.com>"); 414 MODULE_AUTHOR("Bamvor Jian Zhang <bamv2005@gmail.com>"); 415 MODULE_AUTHOR("Bartosz Golaszewski <brgl@bgdev.pl>"); 416 MODULE_DESCRIPTION("GPIO Testing driver"); 417 MODULE_LICENSE("GPL v2"); 418