David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 1 | /* |
Grant Likely | ca632f5 | 2011-06-06 01:16:30 -0600 | [diff] [blame] | 2 | * SPI master driver using generic bitbanged GPIO |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 3 | * |
| 4 | * Copyright (C) 2006,2008 David Brownell |
Linus Walleij | 9b00bc7 | 2018-02-12 13:45:30 +0100 | [diff] [blame] | 5 | * Copyright (C) 2017 Linus Walleij |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU General Public License as published by |
| 9 | * the Free Software Foundation; either version 2 of the License, or |
| 10 | * (at your option) any later version. |
| 11 | * |
| 12 | * This program is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | * GNU General Public License for more details. |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 16 | */ |
| 17 | #include <linux/kernel.h> |
Paul Gortmaker | d7614de | 2011-07-03 15:44:29 -0400 | [diff] [blame] | 18 | #include <linux/module.h> |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 19 | #include <linux/platform_device.h> |
Linus Walleij | 9b00bc7 | 2018-02-12 13:45:30 +0100 | [diff] [blame] | 20 | #include <linux/gpio/consumer.h> |
Sachin Kamat | ecc7777 | 2013-10-11 17:21:53 +0530 | [diff] [blame] | 21 | #include <linux/of.h> |
Daniel Mack | 38ab18c | 2012-09-05 11:04:36 +0200 | [diff] [blame] | 22 | #include <linux/of_device.h> |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 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; |
Linus Walleij | 9b00bc7 | 2018-02-12 13:45:30 +0100 | [diff] [blame] | 47 | struct gpio_desc *sck; |
| 48 | struct gpio_desc *miso; |
| 49 | struct gpio_desc *mosi; |
| 50 | struct gpio_desc **cs_gpios; |
| 51 | bool has_cs; |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 52 | }; |
| 53 | |
| 54 | /*----------------------------------------------------------------------*/ |
| 55 | |
| 56 | /* |
| 57 | * Because the overhead of going through four GPIO procedure calls |
| 58 | * per transferred bit can make performance a problem, this code |
| 59 | * is set up so that you can use it in either of two ways: |
| 60 | * |
| 61 | * - The slow generic way: set up platform_data to hold the GPIO |
| 62 | * numbers used for MISO/MOSI/SCK, and issue procedure calls for |
| 63 | * each of them. This driver can handle several such busses. |
| 64 | * |
| 65 | * - The quicker inlined way: only helps with platform GPIO code |
| 66 | * that inlines operations for constant GPIOs. This can give |
| 67 | * you tight (fast!) inner loops, but each such bus needs a |
| 68 | * new driver. You'll define a new C file, with Makefile and |
| 69 | * Kconfig support; the C code can be a total of six lines: |
| 70 | * |
| 71 | * #define DRIVER_NAME "myboard_spi2" |
| 72 | * #define SPI_MISO_GPIO 119 |
| 73 | * #define SPI_MOSI_GPIO 120 |
| 74 | * #define SPI_SCK_GPIO 121 |
| 75 | * #define SPI_N_CHIPSEL 4 |
Grant Likely | ca632f5 | 2011-06-06 01:16:30 -0600 | [diff] [blame] | 76 | * #include "spi-gpio.c" |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 77 | */ |
| 78 | |
| 79 | #ifndef DRIVER_NAME |
| 80 | #define DRIVER_NAME "spi_gpio" |
| 81 | |
| 82 | #define GENERIC_BITBANG /* vs tight inlines */ |
| 83 | |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 84 | #endif |
| 85 | |
| 86 | /*----------------------------------------------------------------------*/ |
| 87 | |
Nizam Haider | 650705c | 2015-01-05 17:31:03 +0530 | [diff] [blame] | 88 | static inline struct spi_gpio *__pure |
Daniel Mack | 161c2dd | 2012-09-05 11:04:35 +0200 | [diff] [blame] | 89 | spi_to_spi_gpio(const struct spi_device *spi) |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 90 | { |
| 91 | const struct spi_bitbang *bang; |
Daniel Mack | 161c2dd | 2012-09-05 11:04:35 +0200 | [diff] [blame] | 92 | struct spi_gpio *spi_gpio; |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 93 | |
| 94 | bang = spi_master_get_devdata(spi->master); |
| 95 | spi_gpio = container_of(bang, struct spi_gpio, bitbang); |
Daniel Mack | 161c2dd | 2012-09-05 11:04:35 +0200 | [diff] [blame] | 96 | return spi_gpio; |
| 97 | } |
| 98 | |
Nizam Haider | 650705c | 2015-01-05 17:31:03 +0530 | [diff] [blame] | 99 | static inline struct spi_gpio_platform_data *__pure |
Daniel Mack | 161c2dd | 2012-09-05 11:04:35 +0200 | [diff] [blame] | 100 | spi_to_pdata(const struct spi_device *spi) |
| 101 | { |
| 102 | return &spi_to_spi_gpio(spi)->pdata; |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 103 | } |
| 104 | |
Linus Walleij | 9b00bc7 | 2018-02-12 13:45:30 +0100 | [diff] [blame] | 105 | /* These helpers are in turn called by the bitbang inlines */ |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 106 | static inline void setsck(const struct spi_device *spi, int is_on) |
| 107 | { |
Linus Walleij | 9b00bc7 | 2018-02-12 13:45:30 +0100 | [diff] [blame] | 108 | struct spi_gpio *spi_gpio = spi_to_spi_gpio(spi); |
| 109 | |
| 110 | gpiod_set_value_cansleep(spi_gpio->sck, is_on); |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 111 | } |
| 112 | |
| 113 | static inline void setmosi(const struct spi_device *spi, int is_on) |
| 114 | { |
Linus Walleij | 9b00bc7 | 2018-02-12 13:45:30 +0100 | [diff] [blame] | 115 | struct spi_gpio *spi_gpio = spi_to_spi_gpio(spi); |
| 116 | |
| 117 | gpiod_set_value_cansleep(spi_gpio->mosi, is_on); |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 118 | } |
| 119 | |
| 120 | static inline int getmiso(const struct spi_device *spi) |
| 121 | { |
Linus Walleij | 9b00bc7 | 2018-02-12 13:45:30 +0100 | [diff] [blame] | 122 | struct spi_gpio *spi_gpio = spi_to_spi_gpio(spi); |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 123 | |
Linus Walleij | 9b00bc7 | 2018-02-12 13:45:30 +0100 | [diff] [blame] | 124 | return !!gpiod_get_value_cansleep(spi_gpio->miso); |
| 125 | } |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 126 | |
| 127 | /* |
| 128 | * NOTE: this clocks "as fast as we can". It "should" be a function of the |
| 129 | * requested device clock. Software overhead means we usually have trouble |
| 130 | * reaching even one Mbit/sec (except when we can inline bitops), so for now |
| 131 | * we'll just assume we never need additional per-bit slowdowns. |
| 132 | */ |
| 133 | #define spidelay(nsecs) do {} while (0) |
| 134 | |
Grant Likely | ca632f5 | 2011-06-06 01:16:30 -0600 | [diff] [blame] | 135 | #include "spi-bitbang-txrx.h" |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 136 | |
| 137 | /* |
| 138 | * These functions can leverage inline expansion of GPIO calls to shrink |
| 139 | * costs for a txrx bit, often by factors of around ten (by instruction |
| 140 | * count). That is particularly visible for larger word sizes, but helps |
| 141 | * even with default 8-bit words. |
| 142 | * |
| 143 | * REVISIT overheads calling these functions for each word also have |
| 144 | * significant performance costs. Having txrx_bufs() calls that inline |
| 145 | * the txrx_word() logic would help performance, e.g. on larger blocks |
| 146 | * used with flash storage or MMC/SD. There should also be ways to make |
| 147 | * GCC be less stupid about reloading registers inside the I/O loops, |
| 148 | * even without inlined GPIO calls; __attribute__((hot)) on GCC 4.3? |
| 149 | */ |
| 150 | |
| 151 | static u32 spi_gpio_txrx_word_mode0(struct spi_device *spi, |
| 152 | unsigned nsecs, u32 word, u8 bits) |
| 153 | { |
Marek Szyprowski | 04bb2a0 | 2010-06-30 14:27:32 -0600 | [diff] [blame] | 154 | return bitbang_txrx_be_cpha0(spi, nsecs, 0, 0, word, bits); |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 155 | } |
| 156 | |
| 157 | static u32 spi_gpio_txrx_word_mode1(struct spi_device *spi, |
| 158 | unsigned nsecs, u32 word, u8 bits) |
| 159 | { |
Marek Szyprowski | 04bb2a0 | 2010-06-30 14:27:32 -0600 | [diff] [blame] | 160 | return bitbang_txrx_be_cpha1(spi, nsecs, 0, 0, word, bits); |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 161 | } |
| 162 | |
| 163 | static u32 spi_gpio_txrx_word_mode2(struct spi_device *spi, |
| 164 | unsigned nsecs, u32 word, u8 bits) |
| 165 | { |
Marek Szyprowski | 04bb2a0 | 2010-06-30 14:27:32 -0600 | [diff] [blame] | 166 | return bitbang_txrx_be_cpha0(spi, nsecs, 1, 0, word, bits); |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 167 | } |
| 168 | |
| 169 | static u32 spi_gpio_txrx_word_mode3(struct spi_device *spi, |
| 170 | unsigned nsecs, u32 word, u8 bits) |
| 171 | { |
Marek Szyprowski | 04bb2a0 | 2010-06-30 14:27:32 -0600 | [diff] [blame] | 172 | return bitbang_txrx_be_cpha1(spi, nsecs, 1, 0, word, bits); |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 173 | } |
| 174 | |
Marek Szyprowski | 3c8e1a8 | 2010-06-30 14:27:37 -0600 | [diff] [blame] | 175 | /* |
| 176 | * These functions do not call setmosi or getmiso if respective flag |
| 177 | * (SPI_MASTER_NO_RX or SPI_MASTER_NO_TX) is set, so they are safe to |
| 178 | * call when such pin is not present or defined in the controller. |
| 179 | * A separate set of callbacks is defined to get highest possible |
| 180 | * speed in the generic case (when both MISO and MOSI lines are |
| 181 | * available), as optimiser will remove the checks when argument is |
| 182 | * constant. |
| 183 | */ |
| 184 | |
| 185 | static u32 spi_gpio_spec_txrx_word_mode0(struct spi_device *spi, |
| 186 | unsigned nsecs, u32 word, u8 bits) |
| 187 | { |
| 188 | unsigned flags = spi->master->flags; |
| 189 | return bitbang_txrx_be_cpha0(spi, nsecs, 0, flags, word, bits); |
| 190 | } |
| 191 | |
| 192 | static u32 spi_gpio_spec_txrx_word_mode1(struct spi_device *spi, |
| 193 | unsigned nsecs, u32 word, u8 bits) |
| 194 | { |
| 195 | unsigned flags = spi->master->flags; |
| 196 | return bitbang_txrx_be_cpha1(spi, nsecs, 0, flags, word, bits); |
| 197 | } |
| 198 | |
| 199 | static u32 spi_gpio_spec_txrx_word_mode2(struct spi_device *spi, |
| 200 | unsigned nsecs, u32 word, u8 bits) |
| 201 | { |
| 202 | unsigned flags = spi->master->flags; |
| 203 | return bitbang_txrx_be_cpha0(spi, nsecs, 1, flags, word, bits); |
| 204 | } |
| 205 | |
| 206 | static u32 spi_gpio_spec_txrx_word_mode3(struct spi_device *spi, |
| 207 | unsigned nsecs, u32 word, u8 bits) |
| 208 | { |
| 209 | unsigned flags = spi->master->flags; |
| 210 | return bitbang_txrx_be_cpha1(spi, nsecs, 1, flags, word, bits); |
| 211 | } |
| 212 | |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 213 | /*----------------------------------------------------------------------*/ |
| 214 | |
| 215 | static void spi_gpio_chipselect(struct spi_device *spi, int is_active) |
| 216 | { |
Daniel Mack | 161c2dd | 2012-09-05 11:04:35 +0200 | [diff] [blame] | 217 | struct spi_gpio *spi_gpio = spi_to_spi_gpio(spi); |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 218 | |
Linus Walleij | 9b00bc7 | 2018-02-12 13:45:30 +0100 | [diff] [blame] | 219 | /* set initial clock line level */ |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 220 | if (is_active) |
Linus Walleij | 9b00bc7 | 2018-02-12 13:45:30 +0100 | [diff] [blame] | 221 | gpiod_set_value_cansleep(spi_gpio->sck, spi->mode & SPI_CPOL); |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 222 | |
Linus Walleij | 9b00bc7 | 2018-02-12 13:45:30 +0100 | [diff] [blame] | 223 | /* Drive chip select line, if we have one */ |
| 224 | if (spi_gpio->has_cs) { |
| 225 | struct gpio_desc *cs = spi_gpio->cs_gpios[spi->chip_select]; |
| 226 | |
| 227 | /* SPI chip selects are normally active-low */ |
| 228 | gpiod_set_value_cansleep(cs, (spi->mode & SPI_CS_HIGH) ? is_active : !is_active); |
Michael Buesch | bfb9bcd | 2009-04-02 16:57:07 -0700 | [diff] [blame] | 229 | } |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 230 | } |
| 231 | |
| 232 | static int spi_gpio_setup(struct spi_device *spi) |
| 233 | { |
Linus Walleij | 9b00bc7 | 2018-02-12 13:45:30 +0100 | [diff] [blame] | 234 | struct gpio_desc *cs; |
Daniel Mack | 161c2dd | 2012-09-05 11:04:35 +0200 | [diff] [blame] | 235 | int status = 0; |
| 236 | struct spi_gpio *spi_gpio = spi_to_spi_gpio(spi); |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 237 | |
Linus Walleij | 9b00bc7 | 2018-02-12 13:45:30 +0100 | [diff] [blame] | 238 | /* |
| 239 | * The CS GPIOs have already been |
| 240 | * initialized from the descriptor lookup. |
| 241 | */ |
| 242 | cs = spi_gpio->cs_gpios[spi->chip_select]; |
| 243 | if (!spi->controller_state && cs) |
| 244 | status = gpiod_direction_output(cs, |
| 245 | !(spi->mode & SPI_CS_HIGH)); |
Daniel Mack | 38ab18c | 2012-09-05 11:04:36 +0200 | [diff] [blame] | 246 | |
Linus Walleij | 9b00bc7 | 2018-02-12 13:45:30 +0100 | [diff] [blame] | 247 | if (!status) |
Josef Ahmad | 6b8cc33 | 2013-04-09 18:25:34 +0100 | [diff] [blame] | 248 | status = spi_bitbang_setup(spi); |
Daniel Mack | 161c2dd | 2012-09-05 11:04:35 +0200 | [diff] [blame] | 249 | |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 250 | return status; |
| 251 | } |
| 252 | |
| 253 | static void spi_gpio_cleanup(struct spi_device *spi) |
| 254 | { |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 255 | spi_bitbang_cleanup(spi); |
| 256 | } |
| 257 | |
Linus Walleij | 9b00bc7 | 2018-02-12 13:45:30 +0100 | [diff] [blame] | 258 | /* |
| 259 | * It can be convenient to use this driver with pins that have alternate |
| 260 | * functions associated with a "native" SPI controller if a driver for that |
| 261 | * controller is not available, or is missing important functionality. |
| 262 | * |
| 263 | * On platforms which can do so, configure MISO with a weak pullup unless |
| 264 | * there's an external pullup on that signal. That saves power by avoiding |
| 265 | * floating signals. (A weak pulldown would save power too, but many |
| 266 | * drivers expect to see all-ones data as the no slave "response".) |
| 267 | */ |
| 268 | static int spi_gpio_request(struct device *dev, |
| 269 | struct spi_gpio *spi_gpio, |
| 270 | unsigned int num_chipselects, |
| 271 | u16 *mflags) |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 272 | { |
Linus Walleij | 9b00bc7 | 2018-02-12 13:45:30 +0100 | [diff] [blame] | 273 | int i; |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 274 | |
Linus Walleij | 9b00bc7 | 2018-02-12 13:45:30 +0100 | [diff] [blame] | 275 | spi_gpio->mosi = devm_gpiod_get_optional(dev, "mosi", GPIOD_OUT_LOW); |
| 276 | if (IS_ERR(spi_gpio->mosi)) |
| 277 | return PTR_ERR(spi_gpio->mosi); |
| 278 | if (!spi_gpio->mosi) |
Marek Szyprowski | 3c8e1a8 | 2010-06-30 14:27:37 -0600 | [diff] [blame] | 279 | /* HW configuration without MOSI pin */ |
Linus Walleij | 9b00bc7 | 2018-02-12 13:45:30 +0100 | [diff] [blame] | 280 | *mflags |= SPI_MASTER_NO_TX; |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 281 | |
Linus Walleij | 9b00bc7 | 2018-02-12 13:45:30 +0100 | [diff] [blame] | 282 | spi_gpio->miso = devm_gpiod_get_optional(dev, "miso", GPIOD_IN); |
| 283 | if (IS_ERR(spi_gpio->miso)) |
| 284 | return PTR_ERR(spi_gpio->miso); |
| 285 | if (!spi_gpio->miso) |
Marek Szyprowski | 3c8e1a8 | 2010-06-30 14:27:37 -0600 | [diff] [blame] | 286 | /* HW configuration without MISO pin */ |
Linus Walleij | 9b00bc7 | 2018-02-12 13:45:30 +0100 | [diff] [blame] | 287 | *mflags |= SPI_MASTER_NO_RX; |
| 288 | |
| 289 | spi_gpio->sck = devm_gpiod_get(dev, "sck", GPIOD_OUT_LOW); |
| 290 | if (IS_ERR(spi_gpio->mosi)) |
| 291 | return PTR_ERR(spi_gpio->mosi); |
| 292 | |
| 293 | for (i = 0; i < num_chipselects; i++) { |
| 294 | spi_gpio->cs_gpios[i] = devm_gpiod_get_index(dev, "cs", |
| 295 | i, GPIOD_OUT_HIGH); |
| 296 | if (IS_ERR(spi_gpio->cs_gpios[i])) |
| 297 | return PTR_ERR(spi_gpio->cs_gpios[i]); |
Marek Szyprowski | 3c8e1a8 | 2010-06-30 14:27:37 -0600 | [diff] [blame] | 298 | } |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 299 | |
Linus Walleij | 9b00bc7 | 2018-02-12 13:45:30 +0100 | [diff] [blame] | 300 | return 0; |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 301 | } |
| 302 | |
Daniel Mack | 38ab18c | 2012-09-05 11:04:36 +0200 | [diff] [blame] | 303 | #ifdef CONFIG_OF |
Jingoo Han | d9e1528 | 2014-05-07 16:48:59 +0900 | [diff] [blame] | 304 | static const struct of_device_id spi_gpio_dt_ids[] = { |
Daniel Mack | 38ab18c | 2012-09-05 11:04:36 +0200 | [diff] [blame] | 305 | { .compatible = "spi-gpio" }, |
| 306 | {} |
| 307 | }; |
| 308 | MODULE_DEVICE_TABLE(of, spi_gpio_dt_ids); |
| 309 | |
| 310 | static int spi_gpio_probe_dt(struct platform_device *pdev) |
| 311 | { |
| 312 | int ret; |
| 313 | u32 tmp; |
| 314 | struct spi_gpio_platform_data *pdata; |
| 315 | struct device_node *np = pdev->dev.of_node; |
| 316 | const struct of_device_id *of_id = |
| 317 | of_match_device(spi_gpio_dt_ids, &pdev->dev); |
| 318 | |
| 319 | if (!of_id) |
| 320 | return 0; |
| 321 | |
| 322 | pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); |
| 323 | if (!pdata) |
| 324 | return -ENOMEM; |
| 325 | |
Daniel Mack | 38ab18c | 2012-09-05 11:04:36 +0200 | [diff] [blame] | 326 | |
| 327 | ret = of_property_read_u32(np, "num-chipselects", &tmp); |
| 328 | if (ret < 0) { |
| 329 | dev_err(&pdev->dev, "num-chipselects property not found\n"); |
| 330 | goto error_free; |
| 331 | } |
| 332 | |
| 333 | pdata->num_chipselect = tmp; |
| 334 | pdev->dev.platform_data = pdata; |
| 335 | |
| 336 | return 1; |
| 337 | |
| 338 | error_free: |
| 339 | devm_kfree(&pdev->dev, pdata); |
| 340 | return ret; |
| 341 | } |
| 342 | #else |
Mark Brown | ac2cb30 | 2012-09-07 08:23:06 +0800 | [diff] [blame] | 343 | static inline int spi_gpio_probe_dt(struct platform_device *pdev) |
Daniel Mack | 38ab18c | 2012-09-05 11:04:36 +0200 | [diff] [blame] | 344 | { |
| 345 | return 0; |
| 346 | } |
| 347 | #endif |
| 348 | |
Grant Likely | fd4a319 | 2012-12-07 16:57:14 +0000 | [diff] [blame] | 349 | static int spi_gpio_probe(struct platform_device *pdev) |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 350 | { |
| 351 | int status; |
| 352 | struct spi_master *master; |
| 353 | struct spi_gpio *spi_gpio; |
| 354 | struct spi_gpio_platform_data *pdata; |
Marek Szyprowski | 3c8e1a8 | 2010-06-30 14:27:37 -0600 | [diff] [blame] | 355 | u16 master_flags = 0; |
Daniel Mack | 38ab18c | 2012-09-05 11:04:36 +0200 | [diff] [blame] | 356 | bool use_of = 0; |
| 357 | |
| 358 | status = spi_gpio_probe_dt(pdev); |
| 359 | if (status < 0) |
| 360 | return status; |
| 361 | if (status > 0) |
| 362 | use_of = 1; |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 363 | |
Jingoo Han | 8074cf0 | 2013-07-30 16:58:59 +0900 | [diff] [blame] | 364 | pdata = dev_get_platdata(&pdev->dev); |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 365 | #ifdef GENERIC_BITBANG |
Torsten Fleischer | d1d8180 | 2014-11-03 17:17:55 +0100 | [diff] [blame] | 366 | if (!pdata || (!use_of && !pdata->num_chipselect)) |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 367 | return -ENODEV; |
| 368 | #endif |
| 369 | |
Linus Walleij | 9b00bc7 | 2018-02-12 13:45:30 +0100 | [diff] [blame] | 370 | master = spi_alloc_master(&pdev->dev, sizeof(*spi_gpio)); |
| 371 | if (!master) |
| 372 | return -ENOMEM; |
Torsten Fleischer | d1d8180 | 2014-11-03 17:17:55 +0100 | [diff] [blame] | 373 | |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 374 | spi_gpio = spi_master_get_devdata(master); |
Linus Walleij | 9b00bc7 | 2018-02-12 13:45:30 +0100 | [diff] [blame] | 375 | |
Kees Cook | a86854d | 2018-06-12 14:07:58 -0700 | [diff] [blame] | 376 | spi_gpio->cs_gpios = devm_kcalloc(&pdev->dev, |
| 377 | pdata->num_chipselect, |
| 378 | sizeof(*spi_gpio->cs_gpios), |
Linus Walleij | 9b00bc7 | 2018-02-12 13:45:30 +0100 | [diff] [blame] | 379 | GFP_KERNEL); |
| 380 | if (!spi_gpio->cs_gpios) |
| 381 | return -ENOMEM; |
| 382 | |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 383 | platform_set_drvdata(pdev, spi_gpio); |
| 384 | |
Linus Walleij | 9b00bc7 | 2018-02-12 13:45:30 +0100 | [diff] [blame] | 385 | /* Determine if we have chip selects connected */ |
| 386 | spi_gpio->has_cs = !!pdata->num_chipselect; |
| 387 | |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 388 | spi_gpio->pdev = pdev; |
| 389 | if (pdata) |
| 390 | spi_gpio->pdata = *pdata; |
| 391 | |
Linus Walleij | 9b00bc7 | 2018-02-12 13:45:30 +0100 | [diff] [blame] | 392 | status = spi_gpio_request(&pdev->dev, spi_gpio, |
| 393 | pdata->num_chipselect, &master_flags); |
| 394 | if (status) |
| 395 | return status; |
| 396 | |
Stephen Warren | 24778be | 2013-05-21 20:36:35 -0600 | [diff] [blame] | 397 | master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32); |
Marek Szyprowski | 3c8e1a8 | 2010-06-30 14:27:37 -0600 | [diff] [blame] | 398 | master->flags = master_flags; |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 399 | master->bus_num = pdev->id; |
Linus Walleij | 9b00bc7 | 2018-02-12 13:45:30 +0100 | [diff] [blame] | 400 | /* The master needs to think there is a chipselect even if not connected */ |
| 401 | master->num_chipselect = spi_gpio->has_cs ? pdata->num_chipselect : 1; |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 402 | master->setup = spi_gpio_setup; |
| 403 | master->cleanup = spi_gpio_cleanup; |
Daniel Mack | 38ab18c | 2012-09-05 11:04:36 +0200 | [diff] [blame] | 404 | #ifdef CONFIG_OF |
| 405 | master->dev.of_node = pdev->dev.of_node; |
Daniel Mack | 38ab18c | 2012-09-05 11:04:36 +0200 | [diff] [blame] | 406 | #endif |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 407 | |
Axel Lin | 94c69f7 | 2013-09-10 15:43:41 +0800 | [diff] [blame] | 408 | spi_gpio->bitbang.master = master; |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 409 | spi_gpio->bitbang.chipselect = spi_gpio_chipselect; |
Marek Szyprowski | 3c8e1a8 | 2010-06-30 14:27:37 -0600 | [diff] [blame] | 410 | |
Roel Kluin | 23699f9 | 2010-10-02 14:03:32 +0200 | [diff] [blame] | 411 | if ((master_flags & (SPI_MASTER_NO_TX | SPI_MASTER_NO_RX)) == 0) { |
Marek Szyprowski | 3c8e1a8 | 2010-06-30 14:27:37 -0600 | [diff] [blame] | 412 | spi_gpio->bitbang.txrx_word[SPI_MODE_0] = spi_gpio_txrx_word_mode0; |
| 413 | spi_gpio->bitbang.txrx_word[SPI_MODE_1] = spi_gpio_txrx_word_mode1; |
| 414 | spi_gpio->bitbang.txrx_word[SPI_MODE_2] = spi_gpio_txrx_word_mode2; |
| 415 | spi_gpio->bitbang.txrx_word[SPI_MODE_3] = spi_gpio_txrx_word_mode3; |
| 416 | } else { |
| 417 | spi_gpio->bitbang.txrx_word[SPI_MODE_0] = spi_gpio_spec_txrx_word_mode0; |
| 418 | spi_gpio->bitbang.txrx_word[SPI_MODE_1] = spi_gpio_spec_txrx_word_mode1; |
| 419 | spi_gpio->bitbang.txrx_word[SPI_MODE_2] = spi_gpio_spec_txrx_word_mode2; |
| 420 | spi_gpio->bitbang.txrx_word[SPI_MODE_3] = spi_gpio_spec_txrx_word_mode3; |
| 421 | } |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 422 | spi_gpio->bitbang.setup_transfer = spi_bitbang_setup_transfer; |
| 423 | spi_gpio->bitbang.flags = SPI_CS_HIGH; |
| 424 | |
| 425 | status = spi_bitbang_start(&spi_gpio->bitbang); |
Linus Walleij | 9b00bc7 | 2018-02-12 13:45:30 +0100 | [diff] [blame] | 426 | if (status) |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 427 | spi_master_put(master); |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 428 | |
| 429 | return status; |
| 430 | } |
| 431 | |
Grant Likely | fd4a319 | 2012-12-07 16:57:14 +0000 | [diff] [blame] | 432 | static int spi_gpio_remove(struct platform_device *pdev) |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 433 | { |
| 434 | struct spi_gpio *spi_gpio; |
| 435 | struct spi_gpio_platform_data *pdata; |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 436 | |
| 437 | spi_gpio = platform_get_drvdata(pdev); |
Jingoo Han | 8074cf0 | 2013-07-30 16:58:59 +0900 | [diff] [blame] | 438 | pdata = dev_get_platdata(&pdev->dev); |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 439 | |
| 440 | /* stop() unregisters child devices too */ |
Axel Lin | d9721ae | 2014-03-29 18:50:12 +0800 | [diff] [blame] | 441 | spi_bitbang_stop(&spi_gpio->bitbang); |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 442 | |
Axel Lin | 94c69f7 | 2013-09-10 15:43:41 +0800 | [diff] [blame] | 443 | spi_master_put(spi_gpio->bitbang.master); |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 444 | |
Axel Lin | d9721ae | 2014-03-29 18:50:12 +0800 | [diff] [blame] | 445 | return 0; |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 446 | } |
| 447 | |
| 448 | MODULE_ALIAS("platform:" DRIVER_NAME); |
| 449 | |
| 450 | static struct platform_driver spi_gpio_driver = { |
Daniel Mack | 38ab18c | 2012-09-05 11:04:36 +0200 | [diff] [blame] | 451 | .driver = { |
| 452 | .name = DRIVER_NAME, |
Daniel Mack | 38ab18c | 2012-09-05 11:04:36 +0200 | [diff] [blame] | 453 | .of_match_table = of_match_ptr(spi_gpio_dt_ids), |
| 454 | }, |
Grant Likely | 940ab88 | 2011-10-05 11:29:49 -0600 | [diff] [blame] | 455 | .probe = spi_gpio_probe, |
Grant Likely | fd4a319 | 2012-12-07 16:57:14 +0000 | [diff] [blame] | 456 | .remove = spi_gpio_remove, |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 457 | }; |
Grant Likely | 940ab88 | 2011-10-05 11:29:49 -0600 | [diff] [blame] | 458 | module_platform_driver(spi_gpio_driver); |
David Brownell | d29389d | 2009-01-06 14:41:41 -0800 | [diff] [blame] | 459 | |
| 460 | MODULE_DESCRIPTION("SPI master driver using generic bitbanged GPIO "); |
| 461 | MODULE_AUTHOR("David Brownell"); |
| 462 | MODULE_LICENSE("GPL"); |