1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * GPIO interface for IT87xx Super I/O chips 4 * 5 * Author: Diego Elio Pettenò <flameeyes@flameeyes.eu> 6 * Copyright (c) 2017 Google, Inc. 7 * 8 * Based on it87_wdt.c by Oliver Schuster 9 * gpio-it8761e.c by Denis Turischev 10 * gpio-stmpe.c by Rabin Vincent 11 */ 12 13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 14 15 #include <linux/init.h> 16 #include <linux/kernel.h> 17 #include <linux/module.h> 18 #include <linux/io.h> 19 #include <linux/errno.h> 20 #include <linux/ioport.h> 21 #include <linux/slab.h> 22 #include <linux/gpio/driver.h> 23 24 /* Chip Id numbers */ 25 #define NO_DEV_ID 0xffff 26 #define IT8613_ID 0x8613 27 #define IT8620_ID 0x8620 28 #define IT8628_ID 0x8628 29 #define IT8718_ID 0x8718 30 #define IT8728_ID 0x8728 31 #define IT8732_ID 0x8732 32 #define IT8761_ID 0x8761 33 #define IT8772_ID 0x8772 34 #define IT8786_ID 0x8786 35 36 /* IO Ports */ 37 #define REG 0x2e 38 #define VAL 0x2f 39 40 /* Logical device Numbers LDN */ 41 #define GPIO 0x07 42 43 /* Configuration Registers and Functions */ 44 #define LDNREG 0x07 45 #define CHIPID 0x20 46 #define CHIPREV 0x22 47 48 /** 49 * struct it87_gpio - it87-specific GPIO chip 50 * @chip: the underlying gpio_chip structure 51 * @lock: a lock to avoid races between operations 52 * @io_base: base address for gpio ports 53 * @io_size: size of the port rage starting from io_base. 54 * @output_base: Super I/O register address for Output Enable register 55 * @simple_base: Super I/O 'Simple I/O' Enable register 56 * @simple_size: Super IO 'Simple I/O' Enable register size; this is 57 * required because IT87xx chips might only provide Simple I/O 58 * switches on a subset of lines, whereas the others keep the 59 * same status all time. 60 */ 61 struct it87_gpio { 62 struct gpio_chip chip; 63 spinlock_t lock; 64 u16 io_base; 65 u16 io_size; 66 u8 output_base; 67 u8 simple_base; 68 u8 simple_size; 69 }; 70 71 static struct it87_gpio it87_gpio_chip = { 72 .lock = __SPIN_LOCK_UNLOCKED(it87_gpio_chip.lock), 73 }; 74 75 /* Superio chip access functions; copied from wdt_it87 */ 76 77 static inline int superio_enter(void) 78 { 79 /* 80 * Try to reserve REG and REG + 1 for exclusive access. 81 */ 82 if (!request_muxed_region(REG, 2, KBUILD_MODNAME)) 83 return -EBUSY; 84 85 outb(0x87, REG); 86 outb(0x01, REG); 87 outb(0x55, REG); 88 outb(0x55, REG); 89 return 0; 90 } 91 92 static inline void superio_exit(void) 93 { 94 outb(0x02, REG); 95 outb(0x02, VAL); 96 release_region(REG, 2); 97 } 98 99 static inline void superio_select(int ldn) 100 { 101 outb(LDNREG, REG); 102 outb(ldn, VAL); 103 } 104 105 static inline int superio_inb(int reg) 106 { 107 outb(reg, REG); 108 return inb(VAL); 109 } 110 111 static inline void superio_outb(int val, int reg) 112 { 113 outb(reg, REG); 114 outb(val, VAL); 115 } 116 117 static inline int superio_inw(int reg) 118 { 119 int val; 120 121 outb(reg++, REG); 122 val = inb(VAL) << 8; 123 outb(reg, REG); 124 val |= inb(VAL); 125 return val; 126 } 127 128 static inline void superio_outw(int val, int reg) 129 { 130 outb(reg++, REG); 131 outb(val >> 8, VAL); 132 outb(reg, REG); 133 outb(val, VAL); 134 } 135 136 static inline void superio_set_mask(int mask, int reg) 137 { 138 u8 curr_val = superio_inb(reg); 139 u8 new_val = curr_val | mask; 140 141 if (curr_val != new_val) 142 superio_outb(new_val, reg); 143 } 144 145 static inline void superio_clear_mask(int mask, int reg) 146 { 147 u8 curr_val = superio_inb(reg); 148 u8 new_val = curr_val & ~mask; 149 150 if (curr_val != new_val) 151 superio_outb(new_val, reg); 152 } 153 154 static int it87_gpio_request(struct gpio_chip *chip, unsigned gpio_num) 155 { 156 u8 mask, group; 157 int rc = 0; 158 struct it87_gpio *it87_gpio = gpiochip_get_data(chip); 159 160 mask = 1 << (gpio_num % 8); 161 group = (gpio_num / 8); 162 163 spin_lock(&it87_gpio->lock); 164 165 rc = superio_enter(); 166 if (rc) 167 goto exit; 168 169 /* not all the IT87xx chips support Simple I/O and not all of 170 * them allow all the lines to be set/unset to Simple I/O. 171 */ 172 if (group < it87_gpio->simple_size) 173 superio_set_mask(mask, group + it87_gpio->simple_base); 174 175 /* clear output enable, setting the pin to input, as all the 176 * newly-exported GPIO interfaces are set to input. 177 */ 178 superio_clear_mask(mask, group + it87_gpio->output_base); 179 180 superio_exit(); 181 182 exit: 183 spin_unlock(&it87_gpio->lock); 184 return rc; 185 } 186 187 static int it87_gpio_get(struct gpio_chip *chip, unsigned gpio_num) 188 { 189 u16 reg; 190 u8 mask; 191 struct it87_gpio *it87_gpio = gpiochip_get_data(chip); 192 193 mask = 1 << (gpio_num % 8); 194 reg = (gpio_num / 8) + it87_gpio->io_base; 195 196 return !!(inb(reg) & mask); 197 } 198 199 static int it87_gpio_direction_in(struct gpio_chip *chip, unsigned gpio_num) 200 { 201 u8 mask, group; 202 int rc = 0; 203 struct it87_gpio *it87_gpio = gpiochip_get_data(chip); 204 205 mask = 1 << (gpio_num % 8); 206 group = (gpio_num / 8); 207 208 spin_lock(&it87_gpio->lock); 209 210 rc = superio_enter(); 211 if (rc) 212 goto exit; 213 214 /* clear the output enable bit */ 215 superio_clear_mask(mask, group + it87_gpio->output_base); 216 217 superio_exit(); 218 219 exit: 220 spin_unlock(&it87_gpio->lock); 221 return rc; 222 } 223 224 static void it87_gpio_set(struct gpio_chip *chip, 225 unsigned gpio_num, int val) 226 { 227 u8 mask, curr_vals; 228 u16 reg; 229 struct it87_gpio *it87_gpio = gpiochip_get_data(chip); 230 231 mask = 1 << (gpio_num % 8); 232 reg = (gpio_num / 8) + it87_gpio->io_base; 233 234 curr_vals = inb(reg); 235 if (val) 236 outb(curr_vals | mask, reg); 237 else 238 outb(curr_vals & ~mask, reg); 239 } 240 241 static int it87_gpio_direction_out(struct gpio_chip *chip, 242 unsigned gpio_num, int val) 243 { 244 u8 mask, group; 245 int rc = 0; 246 struct it87_gpio *it87_gpio = gpiochip_get_data(chip); 247 248 mask = 1 << (gpio_num % 8); 249 group = (gpio_num / 8); 250 251 spin_lock(&it87_gpio->lock); 252 253 rc = superio_enter(); 254 if (rc) 255 goto exit; 256 257 /* set the output enable bit */ 258 superio_set_mask(mask, group + it87_gpio->output_base); 259 260 it87_gpio_set(chip, gpio_num, val); 261 262 superio_exit(); 263 264 exit: 265 spin_unlock(&it87_gpio->lock); 266 return rc; 267 } 268 269 static const struct gpio_chip it87_template_chip = { 270 .label = KBUILD_MODNAME, 271 .owner = THIS_MODULE, 272 .request = it87_gpio_request, 273 .get = it87_gpio_get, 274 .direction_input = it87_gpio_direction_in, 275 .set = it87_gpio_set, 276 .direction_output = it87_gpio_direction_out, 277 .base = -1 278 }; 279 280 static int __init it87_gpio_init(void) 281 { 282 int rc = 0, i; 283 u16 chip_type; 284 u8 chip_rev, gpio_ba_reg; 285 char *labels, **labels_table; 286 287 struct it87_gpio *it87_gpio = &it87_gpio_chip; 288 289 rc = superio_enter(); 290 if (rc) 291 return rc; 292 293 chip_type = superio_inw(CHIPID); 294 chip_rev = superio_inb(CHIPREV) & 0x0f; 295 superio_exit(); 296 297 it87_gpio->chip = it87_template_chip; 298 299 switch (chip_type) { 300 case IT8613_ID: 301 gpio_ba_reg = 0x62; 302 it87_gpio->io_size = 8; /* it8613 only needs 6, use 8 for alignment */ 303 it87_gpio->output_base = 0xc8; 304 it87_gpio->simple_base = 0xc0; 305 it87_gpio->simple_size = 6; 306 it87_gpio->chip.ngpio = 64; /* has 48, use 64 for convenient calc */ 307 break; 308 case IT8620_ID: 309 case IT8628_ID: 310 gpio_ba_reg = 0x62; 311 it87_gpio->io_size = 11; 312 it87_gpio->output_base = 0xc8; 313 it87_gpio->simple_size = 0; 314 it87_gpio->chip.ngpio = 64; 315 break; 316 case IT8718_ID: 317 case IT8728_ID: 318 case IT8732_ID: 319 case IT8772_ID: 320 case IT8786_ID: 321 gpio_ba_reg = 0x62; 322 it87_gpio->io_size = 8; 323 it87_gpio->output_base = 0xc8; 324 it87_gpio->simple_base = 0xc0; 325 it87_gpio->simple_size = 5; 326 it87_gpio->chip.ngpio = 64; 327 break; 328 case IT8761_ID: 329 gpio_ba_reg = 0x60; 330 it87_gpio->io_size = 4; 331 it87_gpio->output_base = 0xf0; 332 it87_gpio->simple_size = 0; 333 it87_gpio->chip.ngpio = 16; 334 break; 335 case NO_DEV_ID: 336 pr_err("no device\n"); 337 return -ENODEV; 338 default: 339 pr_err("Unknown Chip found, Chip %04x Revision %x\n", 340 chip_type, chip_rev); 341 return -ENODEV; 342 } 343 344 rc = superio_enter(); 345 if (rc) 346 return rc; 347 348 superio_select(GPIO); 349 350 /* fetch GPIO base address */ 351 it87_gpio->io_base = superio_inw(gpio_ba_reg); 352 353 superio_exit(); 354 355 pr_info("Found Chip IT%04x rev %x. %u GPIO lines starting at %04xh\n", 356 chip_type, chip_rev, it87_gpio->chip.ngpio, 357 it87_gpio->io_base); 358 359 if (!request_region(it87_gpio->io_base, it87_gpio->io_size, 360 KBUILD_MODNAME)) 361 return -EBUSY; 362 363 /* Set up aliases for the GPIO connection. 364 * 365 * ITE documentation for recent chips such as the IT8728F 366 * refers to the GPIO lines as GPxy, with a coordinates system 367 * where x is the GPIO group (starting from 1) and y is the 368 * bit within the group. 369 * 370 * By creating these aliases, we make it easier to understand 371 * to which GPIO pin we're referring to. 372 */ 373 labels = kcalloc(it87_gpio->chip.ngpio, sizeof("it87_gpXY"), 374 GFP_KERNEL); 375 labels_table = kcalloc(it87_gpio->chip.ngpio, sizeof(const char *), 376 GFP_KERNEL); 377 378 if (!labels || !labels_table) { 379 rc = -ENOMEM; 380 goto labels_free; 381 } 382 383 for (i = 0; i < it87_gpio->chip.ngpio; i++) { 384 char *label = &labels[i * sizeof("it87_gpXY")]; 385 386 sprintf(label, "it87_gp%u%u", 1+(i/8), i%8); 387 labels_table[i] = label; 388 } 389 390 it87_gpio->chip.names = (const char *const*)labels_table; 391 392 rc = gpiochip_add_data(&it87_gpio->chip, it87_gpio); 393 if (rc) 394 goto labels_free; 395 396 return 0; 397 398 labels_free: 399 kfree(labels_table); 400 kfree(labels); 401 release_region(it87_gpio->io_base, it87_gpio->io_size); 402 return rc; 403 } 404 405 static void __exit it87_gpio_exit(void) 406 { 407 struct it87_gpio *it87_gpio = &it87_gpio_chip; 408 409 gpiochip_remove(&it87_gpio->chip); 410 release_region(it87_gpio->io_base, it87_gpio->io_size); 411 kfree(it87_gpio->chip.names[0]); 412 kfree(it87_gpio->chip.names); 413 } 414 415 module_init(it87_gpio_init); 416 module_exit(it87_gpio_exit); 417 418 MODULE_AUTHOR("Diego Elio Pettenò <flameeyes@flameeyes.eu>"); 419 MODULE_DESCRIPTION("GPIO interface for IT87xx Super I/O chips"); 420 MODULE_LICENSE("GPL"); 421