1 // SPDX-License-Identifier: GPL-2.0-or-later
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
41 /*----------------------------------------------------------------------*/
45  * per transferred bit can make performance a problem, this code
48  *   - The slow generic way:  set up platform_data to hold the GPIO
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"
123  * costs for a txrx bit, often by factors of around ten (by instruction
125  * even with default 8-bit words.
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()
251 	 * be left logic high if there is a pull-up. Transmitting  in spi_gpio_set_direction()
255 	if (spi->mode & SPI_3WIRE) {  in spi_gpio_set_direction()
256 		ret = gpiod_direction_input(spi_gpio->mosi);  in spi_gpio_set_direction()
264 	 * nsec delay function for bit-banged GPIO is simply  in spi_gpio_set_direction()
265 	 * {} because bit-banging just doesn't get fast enough  in spi_gpio_set_direction()
268 	if (spi->mode & SPI_3WIRE_HIZ) {  in spi_gpio_set_direction()
269 		gpiod_set_value_cansleep(spi_gpio->sck,  in spi_gpio_set_direction()
270 					 !(spi->mode & SPI_CPOL));  in spi_gpio_set_direction()
271 		gpiod_set_value_cansleep(spi_gpio->sck,  in spi_gpio_set_direction()
272 					 !!(spi->mode & SPI_CPOL));  in spi_gpio_set_direction()
290  * drivers expect to see all-ones data as the no slave "response".)
294 	spi_gpio->mosi = devm_gpiod_get_optional(dev, "mosi", GPIOD_OUT_LOW);  in spi_gpio_request()
295 	if (IS_ERR(spi_gpio->mosi))  in spi_gpio_request()
296 		return PTR_ERR(spi_gpio->mosi);  in spi_gpio_request()
298 	spi_gpio->miso = devm_gpiod_get_optional(dev, "miso", GPIOD_IN);  in spi_gpio_request()
299 	if (IS_ERR(spi_gpio->miso))  in spi_gpio_request()
300 		return PTR_ERR(spi_gpio->miso);  in spi_gpio_request()
302 	spi_gpio->sck = devm_gpiod_get(dev, "sck", GPIOD_OUT_LOW);  in spi_gpio_request()
303 	return PTR_ERR_OR_ZERO(spi_gpio->sck);  in spi_gpio_request()
308 	{ .compatible = "spi-gpio" },
316 	master->dev.of_node = pdev->dev.of_node;  in spi_gpio_probe_dt()
317 	master->use_gpio_descriptors = true;  in spi_gpio_probe_dt()
332 	struct device *dev = &pdev->dev;  in spi_gpio_probe_pdata()
338 	if (!pdata || !pdata->num_chipselect)  in spi_gpio_probe_pdata()
339 		return -ENODEV;  in spi_gpio_probe_pdata()
345 	master->num_chipselect = pdata->num_chipselect ?: 1;  in spi_gpio_probe_pdata()
347 	spi_gpio->cs_gpios = devm_kcalloc(dev, master->num_chipselect,  in spi_gpio_probe_pdata()
348 					  sizeof(*spi_gpio->cs_gpios),  in spi_gpio_probe_pdata()
350 	if (!spi_gpio->cs_gpios)  in spi_gpio_probe_pdata()
351 		return -ENOMEM;  in spi_gpio_probe_pdata()
353 	for (i = 0; i < master->num_chipselect; i++) {  in spi_gpio_probe_pdata()
354 		spi_gpio->cs_gpios[i] = devm_gpiod_get_index(dev, "cs", i,  in spi_gpio_probe_pdata()
356 		if (IS_ERR(spi_gpio->cs_gpios[i]))  in spi_gpio_probe_pdata()
357 			return PTR_ERR(spi_gpio->cs_gpios[i]);  in spi_gpio_probe_pdata()
368 	struct device			*dev = &pdev->dev;  in spi_gpio_probe()
373 		return -ENOMEM;  in spi_gpio_probe()
375 	if (pdev->dev.of_node)  in spi_gpio_probe()
389 	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32);  in spi_gpio_probe()
390 	master->mode_bits = SPI_3WIRE | SPI_3WIRE_HIZ | SPI_CPHA | SPI_CPOL |  in spi_gpio_probe()
392 	if (!spi_gpio->mosi) {  in spi_gpio_probe()
395 		 * No setting SPI_MASTER_NO_RX here - if there is only  in spi_gpio_probe()
399 		master->flags = SPI_MASTER_NO_TX;  in spi_gpio_probe()
402 	master->bus_num = pdev->id;  in spi_gpio_probe()
403 	master->setup = spi_gpio_setup;  in spi_gpio_probe()
404 	master->cleanup = spi_gpio_cleanup;  in spi_gpio_probe()
406 	bb = &spi_gpio->bitbang;  in spi_gpio_probe()
407 	bb->master = master;  in spi_gpio_probe()
413 	master->flags |= SPI_MASTER_GPIO_SS;  in spi_gpio_probe()
414 	bb->chipselect = spi_gpio_chipselect;  in spi_gpio_probe()
415 	bb->set_line_direction = spi_gpio_set_direction;  in spi_gpio_probe()
417 	if (master->flags & SPI_MASTER_NO_TX) {  in spi_gpio_probe()
418 		bb->txrx_word[SPI_MODE_0] = spi_gpio_spec_txrx_word_mode0;  in spi_gpio_probe()
419 		bb->txrx_word[SPI_MODE_1] = spi_gpio_spec_txrx_word_mode1;  in spi_gpio_probe()
420 		bb->txrx_word[SPI_MODE_2] = spi_gpio_spec_txrx_word_mode2;  in spi_gpio_probe()
421 		bb->txrx_word[SPI_MODE_3] = spi_gpio_spec_txrx_word_mode3;  in spi_gpio_probe()
423 		bb->txrx_word[SPI_MODE_0] = spi_gpio_txrx_word_mode0;  in spi_gpio_probe()
424 		bb->txrx_word[SPI_MODE_1] = spi_gpio_txrx_word_mode1;  in spi_gpio_probe()
425 		bb->txrx_word[SPI_MODE_2] = spi_gpio_txrx_word_mode2;  in spi_gpio_probe()
426 		bb->txrx_word[SPI_MODE_3] = spi_gpio_txrx_word_mode3;  in spi_gpio_probe()
428 	bb->setup_transfer = spi_bitbang_setup_transfer;  in spi_gpio_probe()
430 	status = spi_bitbang_init(&spi_gpio->bitbang);  in spi_gpio_probe()
434 	return devm_spi_register_master(&pdev->dev, master);  in spi_gpio_probe()