| 1 | /* |
| 2 | * SPI master driver using generic bitbanged GPIO |
| 3 | * |
| 4 | * Copyright (C) 2006,2008 David Brownell |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License as published by |
| 8 | * the Free Software Foundation; either version 2 of the License, or |
| 9 | * (at your option) any later version. |
| 10 | * |
| 11 | * This program is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | * GNU General Public License for more details. |
| 15 | */ |
| 16 | #include <linux/kernel.h> |
| 17 | #include <linux/module.h> |
| 18 | #include <linux/platform_device.h> |
| 19 | #include <linux/gpio.h> |
| 20 | #include <linux/of.h> |
| 21 | #include <linux/of_device.h> |
| 22 | #include <linux/of_gpio.h> |
| 23 | |
| 24 | #include <linux/spi/spi.h> |
| 25 | #include <linux/spi/spi_bitbang.h> |
| 26 | #include <linux/spi/spi_gpio.h> |
| 27 | |
| 28 | |
| 29 | /* |
| 30 | * This bitbanging SPI master driver should help make systems usable |
| 31 | * when a native hardware SPI engine is not available, perhaps because |
| 32 | * its driver isn't yet working or because the I/O pins it requires |
| 33 | * are used for other purposes. |
| 34 | * |
| 35 | * platform_device->driver_data ... points to spi_gpio |
| 36 | * |
| 37 | * spi->controller_state ... reserved for bitbang framework code |
| 38 | * spi->controller_data ... holds chipselect GPIO |
| 39 | * |
| 40 | * spi->master->dev.driver_data ... points to spi_gpio->bitbang |
| 41 | */ |
| 42 | |
| 43 | struct spi_gpio { |
| 44 | struct spi_bitbang bitbang; |
| 45 | struct spi_gpio_platform_data pdata; |
| 46 | struct platform_device *pdev; |
| 47 | unsigned long cs_gpios[0]; |
| 48 | }; |
| 49 | |
| 50 | /*----------------------------------------------------------------------*/ |
| 51 | |
| 52 | /* |
| 53 | * Because the overhead of going through four GPIO procedure calls |
| 54 | * per transferred bit can make performance a problem, this code |
| 55 | * is set up so that you can use it in either of two ways: |
| 56 | * |
| 57 | * - The slow generic way: set up platform_data to hold the GPIO |
| 58 | * numbers used for MISO/MOSI/SCK, and issue procedure calls for |
| 59 | * each of them. This driver can handle several such busses. |
| 60 | * |
| 61 | * - The quicker inlined way: only helps with platform GPIO code |
| 62 | * that inlines operations for constant GPIOs. This can give |
| 63 | * you tight (fast!) inner loops, but each such bus needs a |
| 64 | * new driver. You'll define a new C file, with Makefile and |
| 65 | * Kconfig support; the C code can be a total of six lines: |
| 66 | * |
| 67 | * #define DRIVER_NAME "myboard_spi2" |
| 68 | * #define SPI_MISO_GPIO 119 |
| 69 | * #define SPI_MOSI_GPIO 120 |
| 70 | * #define SPI_SCK_GPIO 121 |
| 71 | * #define SPI_N_CHIPSEL 4 |
| 72 | * #include "spi-gpio.c" |
| 73 | */ |
| 74 | |
| 75 | #ifndef DRIVER_NAME |
| 76 | #define DRIVER_NAME "spi_gpio" |
| 77 | |
| 78 | #define GENERIC_BITBANG /* vs tight inlines */ |
| 79 | |
| 80 | /* all functions referencing these symbols must define pdata */ |
| 81 | #define SPI_MISO_GPIO ((pdata)->miso) |
| 82 | #define SPI_MOSI_GPIO ((pdata)->mosi) |
| 83 | #define SPI_SCK_GPIO ((pdata)->sck) |
| 84 | |
| 85 | #define SPI_N_CHIPSEL ((pdata)->num_chipselect) |
| 86 | |
| 87 | #endif |
| 88 | |
| 89 | /*----------------------------------------------------------------------*/ |
| 90 | |
| 91 | static inline struct spi_gpio *__pure |
| 92 | spi_to_spi_gpio(const struct spi_device *spi) |
| 93 | { |
| 94 | const struct spi_bitbang *bang; |
| 95 | struct spi_gpio *spi_gpio; |
| 96 | |
| 97 | bang = spi_master_get_devdata(spi->master); |
| 98 | spi_gpio = container_of(bang, struct spi_gpio, bitbang); |
| 99 | return spi_gpio; |
| 100 | } |
| 101 | |
| 102 | static inline struct spi_gpio_platform_data *__pure |
| 103 | spi_to_pdata(const struct spi_device *spi) |
| 104 | { |
| 105 | return &spi_to_spi_gpio(spi)->pdata; |
| 106 | } |
| 107 | |
| 108 | /* this is #defined to avoid unused-variable warnings when inlining */ |
| 109 | #define pdata spi_to_pdata(spi) |
| 110 | |
| 111 | static inline void setsck(const struct spi_device *spi, int is_on) |
| 112 | { |
| 113 | gpio_set_value_cansleep(SPI_SCK_GPIO, is_on); |
| 114 | } |
| 115 | |
| 116 | static inline void setmosi(const struct spi_device *spi, int is_on) |
| 117 | { |
| 118 | gpio_set_value_cansleep(SPI_MOSI_GPIO, is_on); |
| 119 | } |
| 120 | |
| 121 | static inline int getmiso(const struct spi_device *spi) |
| 122 | { |
| 123 | return !!gpio_get_value_cansleep(SPI_MISO_GPIO); |
| 124 | } |
| 125 | |
| 126 | #undef pdata |
| 127 | |
| 128 | /* |
| 129 | * NOTE: this clocks "as fast as we can". It "should" be a function of the |
| 130 | * requested device clock. Software overhead means we usually have trouble |
| 131 | * reaching even one Mbit/sec (except when we can inline bitops), so for now |
| 132 | * we'll just assume we never need additional per-bit slowdowns. |
| 133 | */ |
| 134 | #define spidelay(nsecs) do {} while (0) |
| 135 | |
| 136 | #include "spi-bitbang-txrx.h" |
| 137 | |
| 138 | /* |
| 139 | * These functions can leverage inline expansion of GPIO calls to shrink |
| 140 | * costs for a txrx bit, often by factors of around ten (by instruction |
| 141 | * count). That is particularly visible for larger word sizes, but helps |
| 142 | * even with default 8-bit words. |
| 143 | * |
| 144 | * REVISIT overheads calling these functions for each word also have |
| 145 | * significant performance costs. Having txrx_bufs() calls that inline |
| 146 | * the txrx_word() logic would help performance, e.g. on larger blocks |
| 147 | * used with flash storage or MMC/SD. There should also be ways to make |
| 148 | * GCC be less stupid about reloading registers inside the I/O loops, |
| 149 | * even without inlined GPIO calls; __attribute__((hot)) on GCC 4.3? |
| 150 | */ |
| 151 | |
| 152 | static u32 spi_gpio_txrx_word_mode0(struct spi_device *spi, |
| 153 | unsigned nsecs, u32 word, u8 bits) |
| 154 | { |
| 155 | return bitbang_txrx_be_cpha0(spi, nsecs, 0, 0, word, bits); |
| 156 | } |
| 157 | |
| 158 | static u32 spi_gpio_txrx_word_mode1(struct spi_device *spi, |
| 159 | unsigned nsecs, u32 word, u8 bits) |
| 160 | { |
| 161 | return bitbang_txrx_be_cpha1(spi, nsecs, 0, 0, word, bits); |
| 162 | } |
| 163 | |
| 164 | static u32 spi_gpio_txrx_word_mode2(struct spi_device *spi, |
| 165 | unsigned nsecs, u32 word, u8 bits) |
| 166 | { |
| 167 | return bitbang_txrx_be_cpha0(spi, nsecs, 1, 0, word, bits); |
| 168 | } |
| 169 | |
| 170 | static u32 spi_gpio_txrx_word_mode3(struct spi_device *spi, |
| 171 | unsigned nsecs, u32 word, u8 bits) |
| 172 | { |
| 173 | return bitbang_txrx_be_cpha1(spi, nsecs, 1, 0, word, bits); |
| 174 | } |
| 175 | |
| 176 | /* |
| 177 | * These functions do not call setmosi or getmiso if respective flag |
| 178 | * (SPI_MASTER_NO_RX or SPI_MASTER_NO_TX) is set, so they are safe to |
| 179 | * call when such pin is not present or defined in the controller. |
| 180 | * A separate set of callbacks is defined to get highest possible |
| 181 | * speed in the generic case (when both MISO and MOSI lines are |
| 182 | * available), as optimiser will remove the checks when argument is |
| 183 | * constant. |
| 184 | */ |
| 185 | |
| 186 | static u32 spi_gpio_spec_txrx_word_mode0(struct spi_device *spi, |
| 187 | unsigned nsecs, u32 word, u8 bits) |
| 188 | { |
| 189 | unsigned flags = spi->master->flags; |
| 190 | return bitbang_txrx_be_cpha0(spi, nsecs, 0, flags, word, bits); |
| 191 | } |
| 192 | |
| 193 | static u32 spi_gpio_spec_txrx_word_mode1(struct spi_device *spi, |
| 194 | unsigned nsecs, u32 word, u8 bits) |
| 195 | { |
| 196 | unsigned flags = spi->master->flags; |
| 197 | return bitbang_txrx_be_cpha1(spi, nsecs, 0, flags, word, bits); |
| 198 | } |
| 199 | |
| 200 | static u32 spi_gpio_spec_txrx_word_mode2(struct spi_device *spi, |
| 201 | unsigned nsecs, u32 word, u8 bits) |
| 202 | { |
| 203 | unsigned flags = spi->master->flags; |
| 204 | return bitbang_txrx_be_cpha0(spi, nsecs, 1, flags, word, bits); |
| 205 | } |
| 206 | |
| 207 | static u32 spi_gpio_spec_txrx_word_mode3(struct spi_device *spi, |
| 208 | unsigned nsecs, u32 word, u8 bits) |
| 209 | { |
| 210 | unsigned flags = spi->master->flags; |
| 211 | return bitbang_txrx_be_cpha1(spi, nsecs, 1, flags, word, bits); |
| 212 | } |
| 213 | |
| 214 | /*----------------------------------------------------------------------*/ |
| 215 | |
| 216 | static void spi_gpio_chipselect(struct spi_device *spi, int is_active) |
| 217 | { |
| 218 | struct spi_gpio *spi_gpio = spi_to_spi_gpio(spi); |
| 219 | unsigned long cs = spi_gpio->cs_gpios[spi->chip_select]; |
| 220 | |
| 221 | /* set initial clock polarity */ |
| 222 | if (is_active) |
| 223 | setsck(spi, spi->mode & SPI_CPOL); |
| 224 | |
| 225 | if (cs != SPI_GPIO_NO_CHIPSELECT) { |
| 226 | /* SPI is normally active-low */ |
| 227 | gpio_set_value_cansleep(cs, (spi->mode & SPI_CS_HIGH) ? is_active : !is_active); |
| 228 | } |
| 229 | } |
| 230 | |
| 231 | static int spi_gpio_setup(struct spi_device *spi) |
| 232 | { |
| 233 | unsigned long cs; |
| 234 | int status = 0; |
| 235 | struct spi_gpio *spi_gpio = spi_to_spi_gpio(spi); |
| 236 | struct device_node *np = spi->master->dev.of_node; |
| 237 | |
| 238 | if (np) { |
| 239 | /* |
| 240 | * In DT environments, the CS GPIOs have already been |
| 241 | * initialized from the "cs-gpios" property of the node. |
| 242 | */ |
| 243 | cs = spi_gpio->cs_gpios[spi->chip_select]; |
| 244 | } else { |
| 245 | /* |
| 246 | * ... otherwise, take it from spi->controller_data |
| 247 | */ |
| 248 | cs = (uintptr_t) spi->controller_data; |
| 249 | } |
| 250 | |
| 251 | if (!spi->controller_state) { |
| 252 | if (cs != SPI_GPIO_NO_CHIPSELECT) { |
| 253 | status = gpio_request(cs, dev_name(&spi->dev)); |
| 254 | if (status) |
| 255 | return status; |
| 256 | status = gpio_direction_output(cs, |
| 257 | !(spi->mode & SPI_CS_HIGH)); |
| 258 | } |
| 259 | } |
| 260 | if (!status) { |
| 261 | /* in case it was initialized from static board data */ |
| 262 | spi_gpio->cs_gpios[spi->chip_select] = cs; |
| 263 | status = spi_bitbang_setup(spi); |
| 264 | } |
| 265 | |
| 266 | if (status) { |
| 267 | if (!spi->controller_state && cs != SPI_GPIO_NO_CHIPSELECT) |
| 268 | gpio_free(cs); |
| 269 | } |
| 270 | return status; |
| 271 | } |
| 272 | |
| 273 | static void spi_gpio_cleanup(struct spi_device *spi) |
| 274 | { |
| 275 | struct spi_gpio *spi_gpio = spi_to_spi_gpio(spi); |
| 276 | unsigned long cs = spi_gpio->cs_gpios[spi->chip_select]; |
| 277 | |
| 278 | if (cs != SPI_GPIO_NO_CHIPSELECT) |
| 279 | gpio_free(cs); |
| 280 | spi_bitbang_cleanup(spi); |
| 281 | } |
| 282 | |
| 283 | static int spi_gpio_alloc(unsigned pin, const char *label, bool is_in) |
| 284 | { |
| 285 | int value; |
| 286 | |
| 287 | value = gpio_request(pin, label); |
| 288 | if (value == 0) { |
| 289 | if (is_in) |
| 290 | value = gpio_direction_input(pin); |
| 291 | else |
| 292 | value = gpio_direction_output(pin, 0); |
| 293 | } |
| 294 | return value; |
| 295 | } |
| 296 | |
| 297 | static int spi_gpio_request(struct spi_gpio_platform_data *pdata, |
| 298 | const char *label, u16 *res_flags) |
| 299 | { |
| 300 | int value; |
| 301 | |
| 302 | /* NOTE: SPI_*_GPIO symbols may reference "pdata" */ |
| 303 | |
| 304 | if (SPI_MOSI_GPIO != SPI_GPIO_NO_MOSI) { |
| 305 | value = spi_gpio_alloc(SPI_MOSI_GPIO, label, false); |
| 306 | if (value) |
| 307 | goto done; |
| 308 | } else { |
| 309 | /* HW configuration without MOSI pin */ |
| 310 | *res_flags |= SPI_MASTER_NO_TX; |
| 311 | } |
| 312 | |
| 313 | if (SPI_MISO_GPIO != SPI_GPIO_NO_MISO) { |
| 314 | value = spi_gpio_alloc(SPI_MISO_GPIO, label, true); |
| 315 | if (value) |
| 316 | goto free_mosi; |
| 317 | } else { |
| 318 | /* HW configuration without MISO pin */ |
| 319 | *res_flags |= SPI_MASTER_NO_RX; |
| 320 | } |
| 321 | |
| 322 | value = spi_gpio_alloc(SPI_SCK_GPIO, label, false); |
| 323 | if (value) |
| 324 | goto free_miso; |
| 325 | |
| 326 | goto done; |
| 327 | |
| 328 | free_miso: |
| 329 | if (SPI_MISO_GPIO != SPI_GPIO_NO_MISO) |
| 330 | gpio_free(SPI_MISO_GPIO); |
| 331 | free_mosi: |
| 332 | if (SPI_MOSI_GPIO != SPI_GPIO_NO_MOSI) |
| 333 | gpio_free(SPI_MOSI_GPIO); |
| 334 | done: |
| 335 | return value; |
| 336 | } |
| 337 | |
| 338 | #ifdef CONFIG_OF |
| 339 | static const struct of_device_id spi_gpio_dt_ids[] = { |
| 340 | { .compatible = "spi-gpio" }, |
| 341 | {} |
| 342 | }; |
| 343 | MODULE_DEVICE_TABLE(of, spi_gpio_dt_ids); |
| 344 | |
| 345 | static int spi_gpio_probe_dt(struct platform_device *pdev) |
| 346 | { |
| 347 | int ret; |
| 348 | u32 tmp; |
| 349 | struct spi_gpio_platform_data *pdata; |
| 350 | struct device_node *np = pdev->dev.of_node; |
| 351 | const struct of_device_id *of_id = |
| 352 | of_match_device(spi_gpio_dt_ids, &pdev->dev); |
| 353 | |
| 354 | if (!of_id) |
| 355 | return 0; |
| 356 | |
| 357 | pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); |
| 358 | if (!pdata) |
| 359 | return -ENOMEM; |
| 360 | |
| 361 | ret = of_get_named_gpio(np, "gpio-sck", 0); |
| 362 | if (ret < 0) { |
| 363 | dev_err(&pdev->dev, "gpio-sck property not found\n"); |
| 364 | goto error_free; |
| 365 | } |
| 366 | pdata->sck = ret; |
| 367 | |
| 368 | ret = of_get_named_gpio(np, "gpio-miso", 0); |
| 369 | if (ret < 0) { |
| 370 | dev_info(&pdev->dev, "gpio-miso property not found, switching to no-rx mode\n"); |
| 371 | pdata->miso = SPI_GPIO_NO_MISO; |
| 372 | } else |
| 373 | pdata->miso = ret; |
| 374 | |
| 375 | ret = of_get_named_gpio(np, "gpio-mosi", 0); |
| 376 | if (ret < 0) { |
| 377 | dev_info(&pdev->dev, "gpio-mosi property not found, switching to no-tx mode\n"); |
| 378 | pdata->mosi = SPI_GPIO_NO_MOSI; |
| 379 | } else |
| 380 | pdata->mosi = ret; |
| 381 | |
| 382 | ret = of_property_read_u32(np, "num-chipselects", &tmp); |
| 383 | if (ret < 0) { |
| 384 | dev_err(&pdev->dev, "num-chipselects property not found\n"); |
| 385 | goto error_free; |
| 386 | } |
| 387 | |
| 388 | pdata->num_chipselect = tmp; |
| 389 | pdev->dev.platform_data = pdata; |
| 390 | |
| 391 | return 1; |
| 392 | |
| 393 | error_free: |
| 394 | devm_kfree(&pdev->dev, pdata); |
| 395 | return ret; |
| 396 | } |
| 397 | #else |
| 398 | static inline int spi_gpio_probe_dt(struct platform_device *pdev) |
| 399 | { |
| 400 | return 0; |
| 401 | } |
| 402 | #endif |
| 403 | |
| 404 | static int spi_gpio_probe(struct platform_device *pdev) |
| 405 | { |
| 406 | int status; |
| 407 | struct spi_master *master; |
| 408 | struct spi_gpio *spi_gpio; |
| 409 | struct spi_gpio_platform_data *pdata; |
| 410 | u16 master_flags = 0; |
| 411 | bool use_of = 0; |
| 412 | int num_devices; |
| 413 | |
| 414 | status = spi_gpio_probe_dt(pdev); |
| 415 | if (status < 0) |
| 416 | return status; |
| 417 | if (status > 0) |
| 418 | use_of = 1; |
| 419 | |
| 420 | pdata = dev_get_platdata(&pdev->dev); |
| 421 | #ifdef GENERIC_BITBANG |
| 422 | if (!pdata || (!use_of && !pdata->num_chipselect)) |
| 423 | return -ENODEV; |
| 424 | #endif |
| 425 | |
| 426 | if (use_of && !SPI_N_CHIPSEL) |
| 427 | num_devices = 1; |
| 428 | else |
| 429 | num_devices = SPI_N_CHIPSEL; |
| 430 | |
| 431 | status = spi_gpio_request(pdata, dev_name(&pdev->dev), &master_flags); |
| 432 | if (status < 0) |
| 433 | return status; |
| 434 | |
| 435 | master = spi_alloc_master(&pdev->dev, sizeof(*spi_gpio) + |
| 436 | (sizeof(unsigned long) * num_devices)); |
| 437 | if (!master) { |
| 438 | status = -ENOMEM; |
| 439 | goto gpio_free; |
| 440 | } |
| 441 | spi_gpio = spi_master_get_devdata(master); |
| 442 | platform_set_drvdata(pdev, spi_gpio); |
| 443 | |
| 444 | spi_gpio->pdev = pdev; |
| 445 | if (pdata) |
| 446 | spi_gpio->pdata = *pdata; |
| 447 | |
| 448 | master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32); |
| 449 | master->flags = master_flags; |
| 450 | master->bus_num = pdev->id; |
| 451 | master->num_chipselect = num_devices; |
| 452 | master->setup = spi_gpio_setup; |
| 453 | master->cleanup = spi_gpio_cleanup; |
| 454 | #ifdef CONFIG_OF |
| 455 | master->dev.of_node = pdev->dev.of_node; |
| 456 | |
| 457 | if (use_of) { |
| 458 | int i; |
| 459 | struct device_node *np = pdev->dev.of_node; |
| 460 | |
| 461 | /* |
| 462 | * In DT environments, take the CS GPIO from the "cs-gpios" |
| 463 | * property of the node. |
| 464 | */ |
| 465 | |
| 466 | if (!SPI_N_CHIPSEL) |
| 467 | spi_gpio->cs_gpios[0] = SPI_GPIO_NO_CHIPSELECT; |
| 468 | else |
| 469 | for (i = 0; i < SPI_N_CHIPSEL; i++) { |
| 470 | status = of_get_named_gpio(np, "cs-gpios", i); |
| 471 | if (status < 0) { |
| 472 | dev_err(&pdev->dev, |
| 473 | "invalid cs-gpios property\n"); |
| 474 | goto gpio_free; |
| 475 | } |
| 476 | spi_gpio->cs_gpios[i] = status; |
| 477 | } |
| 478 | } |
| 479 | #endif |
| 480 | |
| 481 | spi_gpio->bitbang.master = master; |
| 482 | spi_gpio->bitbang.chipselect = spi_gpio_chipselect; |
| 483 | |
| 484 | if ((master_flags & (SPI_MASTER_NO_TX | SPI_MASTER_NO_RX)) == 0) { |
| 485 | spi_gpio->bitbang.txrx_word[SPI_MODE_0] = spi_gpio_txrx_word_mode0; |
| 486 | spi_gpio->bitbang.txrx_word[SPI_MODE_1] = spi_gpio_txrx_word_mode1; |
| 487 | spi_gpio->bitbang.txrx_word[SPI_MODE_2] = spi_gpio_txrx_word_mode2; |
| 488 | spi_gpio->bitbang.txrx_word[SPI_MODE_3] = spi_gpio_txrx_word_mode3; |
| 489 | } else { |
| 490 | spi_gpio->bitbang.txrx_word[SPI_MODE_0] = spi_gpio_spec_txrx_word_mode0; |
| 491 | spi_gpio->bitbang.txrx_word[SPI_MODE_1] = spi_gpio_spec_txrx_word_mode1; |
| 492 | spi_gpio->bitbang.txrx_word[SPI_MODE_2] = spi_gpio_spec_txrx_word_mode2; |
| 493 | spi_gpio->bitbang.txrx_word[SPI_MODE_3] = spi_gpio_spec_txrx_word_mode3; |
| 494 | } |
| 495 | spi_gpio->bitbang.setup_transfer = spi_bitbang_setup_transfer; |
| 496 | spi_gpio->bitbang.flags = SPI_CS_HIGH; |
| 497 | |
| 498 | status = spi_bitbang_start(&spi_gpio->bitbang); |
| 499 | if (status < 0) { |
| 500 | gpio_free: |
| 501 | if (SPI_MISO_GPIO != SPI_GPIO_NO_MISO) |
| 502 | gpio_free(SPI_MISO_GPIO); |
| 503 | if (SPI_MOSI_GPIO != SPI_GPIO_NO_MOSI) |
| 504 | gpio_free(SPI_MOSI_GPIO); |
| 505 | gpio_free(SPI_SCK_GPIO); |
| 506 | spi_master_put(master); |
| 507 | } |
| 508 | |
| 509 | return status; |
| 510 | } |
| 511 | |
| 512 | static int spi_gpio_remove(struct platform_device *pdev) |
| 513 | { |
| 514 | struct spi_gpio *spi_gpio; |
| 515 | struct spi_gpio_platform_data *pdata; |
| 516 | |
| 517 | spi_gpio = platform_get_drvdata(pdev); |
| 518 | pdata = dev_get_platdata(&pdev->dev); |
| 519 | |
| 520 | /* stop() unregisters child devices too */ |
| 521 | spi_bitbang_stop(&spi_gpio->bitbang); |
| 522 | |
| 523 | if (SPI_MISO_GPIO != SPI_GPIO_NO_MISO) |
| 524 | gpio_free(SPI_MISO_GPIO); |
| 525 | if (SPI_MOSI_GPIO != SPI_GPIO_NO_MOSI) |
| 526 | gpio_free(SPI_MOSI_GPIO); |
| 527 | gpio_free(SPI_SCK_GPIO); |
| 528 | spi_master_put(spi_gpio->bitbang.master); |
| 529 | |
| 530 | return 0; |
| 531 | } |
| 532 | |
| 533 | MODULE_ALIAS("platform:" DRIVER_NAME); |
| 534 | |
| 535 | static struct platform_driver spi_gpio_driver = { |
| 536 | .driver = { |
| 537 | .name = DRIVER_NAME, |
| 538 | .of_match_table = of_match_ptr(spi_gpio_dt_ids), |
| 539 | }, |
| 540 | .probe = spi_gpio_probe, |
| 541 | .remove = spi_gpio_remove, |
| 542 | }; |
| 543 | module_platform_driver(spi_gpio_driver); |
| 544 | |
| 545 | MODULE_DESCRIPTION("SPI master driver using generic bitbanged GPIO "); |
| 546 | MODULE_AUTHOR("David Brownell"); |
| 547 | MODULE_LICENSE("GPL"); |