Lines Matching +full:gpio +full:- +full:sck
1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * SPI master driver using generic bitbanged GPIO
11 #include <linux/gpio/consumer.h>
26 * platform_device->driver_data ... points to spi_gpio
28 * spi->controller_state ... reserved for bitbang framework code
30 * spi->master->dev.driver_data ... points to spi_gpio->bitbang
35 struct gpio_desc *sck; member
41 /*----------------------------------------------------------------------*/
44 * Because the overhead of going through four GPIO procedure calls
48 * - The slow generic way: set up platform_data to hold the GPIO
49 * numbers used for MISO/MOSI/SCK, and issue procedure calls for
52 * - The quicker inlined way: only helps with platform GPIO code
63 * #include "spi-gpio.c"
73 /*----------------------------------------------------------------------*/
81 bang = spi_master_get_devdata(spi->master); in spi_to_spi_gpio()
91 gpiod_set_value_cansleep(spi_gpio->sck, is_on); in setsck()
98 gpiod_set_value_cansleep(spi_gpio->mosi, is_on); in setmosi()
105 if (spi->mode & SPI_3WIRE) in getmiso()
106 return !!gpiod_get_value_cansleep(spi_gpio->mosi); in getmiso()
108 return !!gpiod_get_value_cansleep(spi_gpio->miso); in getmiso()
115 * we'll just assume we never need additional per-bit slowdowns.
119 #include "spi-bitbang-txrx.h"
122 * These functions can leverage inline expansion of GPIO calls to shrink
125 * even with default 8-bit words.
132 * even without inlined GPIO calls; __attribute__((hot)) on GCC 4.3?
172 flags = spi->master->flags; in spi_gpio_spec_txrx_word_mode0()
179 flags = spi->master->flags; in spi_gpio_spec_txrx_word_mode1()
186 flags = spi->master->flags; in spi_gpio_spec_txrx_word_mode2()
193 flags = spi->master->flags; in spi_gpio_spec_txrx_word_mode3()
197 /*----------------------------------------------------------------------*/
205 gpiod_set_value_cansleep(spi_gpio->sck, spi->mode & SPI_CPOL); in spi_gpio_chipselect()
208 if (spi_gpio->cs_gpios) { in spi_gpio_chipselect()
209 struct gpio_desc *cs = spi_gpio->cs_gpios[spi->chip_select]; in spi_gpio_chipselect()
211 /* SPI chip selects are normally active-low */ in spi_gpio_chipselect()
212 gpiod_set_value_cansleep(cs, (spi->mode & SPI_CS_HIGH) ? is_active : !is_active); in spi_gpio_chipselect()
226 if (spi_gpio->cs_gpios) { in spi_gpio_setup()
227 cs = spi_gpio->cs_gpios[spi->chip_select]; in spi_gpio_setup()
228 if (!spi->controller_state && cs) in spi_gpio_setup()
230 !(spi->mode & SPI_CS_HIGH)); in spi_gpio_setup()
245 return gpiod_direction_output(spi_gpio->mosi, 1); in spi_gpio_set_direction()
247 ret = gpiod_direction_input(spi_gpio->mosi); in spi_gpio_set_direction()
254 * nsec delay function for bit-banged GPIO is simply in spi_gpio_set_direction()
255 * {} because bit-banging just doesn't get fast enough in spi_gpio_set_direction()
258 if (spi->mode & SPI_3WIRE_HIZ) { in spi_gpio_set_direction()
259 gpiod_set_value_cansleep(spi_gpio->sck, in spi_gpio_set_direction()
260 !(spi->mode & SPI_CPOL)); in spi_gpio_set_direction()
261 gpiod_set_value_cansleep(spi_gpio->sck, in spi_gpio_set_direction()
262 !!(spi->mode & SPI_CPOL)); in spi_gpio_set_direction()
280 * drivers expect to see all-ones data as the no slave "response".)
284 spi_gpio->mosi = devm_gpiod_get_optional(dev, "mosi", GPIOD_OUT_LOW); in spi_gpio_request()
285 if (IS_ERR(spi_gpio->mosi)) in spi_gpio_request()
286 return PTR_ERR(spi_gpio->mosi); in spi_gpio_request()
288 spi_gpio->miso = devm_gpiod_get_optional(dev, "miso", GPIOD_IN); in spi_gpio_request()
289 if (IS_ERR(spi_gpio->miso)) in spi_gpio_request()
290 return PTR_ERR(spi_gpio->miso); in spi_gpio_request()
292 spi_gpio->sck = devm_gpiod_get(dev, "sck", GPIOD_OUT_LOW); in spi_gpio_request()
293 return PTR_ERR_OR_ZERO(spi_gpio->sck); in spi_gpio_request()
298 { .compatible = "spi-gpio" },
306 master->dev.of_node = pdev->dev.of_node; in spi_gpio_probe_dt()
307 master->use_gpio_descriptors = true; in spi_gpio_probe_dt()
322 struct device *dev = &pdev->dev; in spi_gpio_probe_pdata()
328 if (!pdata || !pdata->num_chipselect) in spi_gpio_probe_pdata()
329 return -ENODEV; in spi_gpio_probe_pdata()
335 master->num_chipselect = pdata->num_chipselect ?: 1; in spi_gpio_probe_pdata()
337 spi_gpio->cs_gpios = devm_kcalloc(dev, master->num_chipselect, in spi_gpio_probe_pdata()
338 sizeof(*spi_gpio->cs_gpios), in spi_gpio_probe_pdata()
340 if (!spi_gpio->cs_gpios) in spi_gpio_probe_pdata()
341 return -ENOMEM; in spi_gpio_probe_pdata()
343 for (i = 0; i < master->num_chipselect; i++) { in spi_gpio_probe_pdata()
344 spi_gpio->cs_gpios[i] = devm_gpiod_get_index(dev, "cs", i, in spi_gpio_probe_pdata()
346 if (IS_ERR(spi_gpio->cs_gpios[i])) in spi_gpio_probe_pdata()
347 return PTR_ERR(spi_gpio->cs_gpios[i]); in spi_gpio_probe_pdata()
363 struct device *dev = &pdev->dev; in spi_gpio_probe()
368 return -ENOMEM; in spi_gpio_probe()
370 status = devm_add_action_or_reset(&pdev->dev, spi_gpio_put, master); in spi_gpio_probe()
376 if (pdev->dev.of_node) in spi_gpio_probe()
390 master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32); in spi_gpio_probe()
391 master->mode_bits = SPI_3WIRE | SPI_3WIRE_HIZ | SPI_CPHA | SPI_CPOL | in spi_gpio_probe()
393 if (!spi_gpio->mosi) { in spi_gpio_probe()
396 * No setting SPI_MASTER_NO_RX here - if there is only in spi_gpio_probe()
400 master->flags = SPI_MASTER_NO_TX; in spi_gpio_probe()
403 master->bus_num = pdev->id; in spi_gpio_probe()
404 master->setup = spi_gpio_setup; in spi_gpio_probe()
405 master->cleanup = spi_gpio_cleanup; in spi_gpio_probe()
407 bb = &spi_gpio->bitbang; in spi_gpio_probe()
408 bb->master = master; in spi_gpio_probe()
410 * There is some additional business, apart from driving the CS GPIO in spi_gpio_probe()
414 master->flags |= SPI_MASTER_GPIO_SS; in spi_gpio_probe()
415 bb->chipselect = spi_gpio_chipselect; in spi_gpio_probe()
416 bb->set_line_direction = spi_gpio_set_direction; in spi_gpio_probe()
418 if (master->flags & SPI_MASTER_NO_TX) { in spi_gpio_probe()
419 bb->txrx_word[SPI_MODE_0] = spi_gpio_spec_txrx_word_mode0; in spi_gpio_probe()
420 bb->txrx_word[SPI_MODE_1] = spi_gpio_spec_txrx_word_mode1; in spi_gpio_probe()
421 bb->txrx_word[SPI_MODE_2] = spi_gpio_spec_txrx_word_mode2; in spi_gpio_probe()
422 bb->txrx_word[SPI_MODE_3] = spi_gpio_spec_txrx_word_mode3; in spi_gpio_probe()
424 bb->txrx_word[SPI_MODE_0] = spi_gpio_txrx_word_mode0; in spi_gpio_probe()
425 bb->txrx_word[SPI_MODE_1] = spi_gpio_txrx_word_mode1; in spi_gpio_probe()
426 bb->txrx_word[SPI_MODE_2] = spi_gpio_txrx_word_mode2; in spi_gpio_probe()
427 bb->txrx_word[SPI_MODE_3] = spi_gpio_txrx_word_mode3; in spi_gpio_probe()
429 bb->setup_transfer = spi_bitbang_setup_transfer; in spi_gpio_probe()
431 status = spi_bitbang_init(&spi_gpio->bitbang); in spi_gpio_probe()
435 return devm_spi_register_master(&pdev->dev, spi_master_get(master)); in spi_gpio_probe()
449 MODULE_DESCRIPTION("SPI master driver using generic bitbanged GPIO ");