1 // SPDX-License-Identifier: GPL-2.0-or-later
3  * SPI host driver using generic bitbanged GPIO
8 #include <linux/gpio/consumer.h>
25  * platform_device->driver_data ... points to spi_gpio
27  * spi->controller_state ... reserved for bitbang framework code
29  * spi->controller->dev.driver_data ... points to spi_gpio->bitbang
34 	struct gpio_desc		*sck;  member
40 /*----------------------------------------------------------------------*/
44 /*----------------------------------------------------------------------*/
52 	bang = spi_controller_get_devdata(spi->controller);  in spi_to_spi_gpio()
62 	gpiod_set_value_cansleep(spi_gpio->sck, is_on);  in setsck()
69 	gpiod_set_value_cansleep(spi_gpio->mosi, is_on);  in setmosi()
76 	if (spi->mode & SPI_3WIRE)  in getmiso()
77 		return !!gpiod_get_value_cansleep(spi_gpio->mosi);  in getmiso()
79 		return !!gpiod_get_value_cansleep(spi_gpio->miso);  in getmiso()
86  * we'll just assume we never need additional per-bit slowdowns.
90 #include "spi-bitbang-txrx.h"
93  * These functions can leverage inline expansion of GPIO calls to shrink
96  * even with default 8-bit words.
103  * even without inlined GPIO calls; __attribute__((hot)) on GCC 4.3?
109 	if (unlikely(spi->mode & SPI_LSB_FIRST))  in spi_gpio_txrx_word_mode0()
118 	if (unlikely(spi->mode & SPI_LSB_FIRST))  in spi_gpio_txrx_word_mode1()
127 	if (unlikely(spi->mode & SPI_LSB_FIRST))  in spi_gpio_txrx_word_mode2()
136 	if (unlikely(spi->mode & SPI_LSB_FIRST))  in spi_gpio_txrx_word_mode3()
155 	flags = spi->controller->flags;  in spi_gpio_spec_txrx_word_mode0()
156 	if (unlikely(spi->mode & SPI_LSB_FIRST))  in spi_gpio_spec_txrx_word_mode0()
165 	flags = spi->controller->flags;  in spi_gpio_spec_txrx_word_mode1()
166 	if (unlikely(spi->mode & SPI_LSB_FIRST))  in spi_gpio_spec_txrx_word_mode1()
175 	flags = spi->controller->flags;  in spi_gpio_spec_txrx_word_mode2()
176 	if (unlikely(spi->mode & SPI_LSB_FIRST))  in spi_gpio_spec_txrx_word_mode2()
185 	flags = spi->controller->flags;  in spi_gpio_spec_txrx_word_mode3()
186 	if (unlikely(spi->mode & SPI_LSB_FIRST))  in spi_gpio_spec_txrx_word_mode3()
192 /*----------------------------------------------------------------------*/
200 		gpiod_set_value_cansleep(spi_gpio->sck, spi->mode & SPI_CPOL);  in spi_gpio_chipselect()
203 	if (spi_gpio->cs_gpios) {  in spi_gpio_chipselect()
204 		struct gpio_desc *cs = spi_gpio->cs_gpios[spi_get_chipselect(spi, 0)];  in spi_gpio_chipselect()
206 		/* SPI chip selects are normally active-low */  in spi_gpio_chipselect()
207 		gpiod_set_value_cansleep(cs, (spi->mode & SPI_CS_HIGH) ? is_active : !is_active);  in spi_gpio_chipselect()
215 	gpiod_set_value_cansleep(spi_gpio->mosi,  in spi_gpio_set_mosi_idle()
216 				 !!(spi->mode & SPI_MOSI_IDLE_HIGH));  in spi_gpio_set_mosi_idle()
229 	if (spi_gpio->cs_gpios) {  in spi_gpio_setup()
230 		cs = spi_gpio->cs_gpios[spi_get_chipselect(spi, 0)];  in spi_gpio_setup()
231 		if (!spi->controller_state && cs) {  in spi_gpio_setup()
232 			ret = gpiod_direction_output(cs, !(spi->mode & SPI_CS_HIGH));  in spi_gpio_setup()
247 		return gpiod_direction_output(spi_gpio->mosi, 1);  in spi_gpio_set_direction()
253 	 * be left logic high if there is a pull-up. Transmitting  in spi_gpio_set_direction()
257 	if (spi->mode & SPI_3WIRE) {  in spi_gpio_set_direction()
258 		ret = gpiod_direction_input(spi_gpio->mosi);  in spi_gpio_set_direction()
266 	 * nsec delay function for bit-banged GPIO is simply  in spi_gpio_set_direction()
267 	 * {} because bit-banging just doesn't get fast enough  in spi_gpio_set_direction()
270 	if (spi->mode & SPI_3WIRE_HIZ) {  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()
273 		gpiod_set_value_cansleep(spi_gpio->sck,  in spi_gpio_set_direction()
274 					 !!(spi->mode & SPI_CPOL));  in spi_gpio_set_direction()
292  * drivers expect to see all-ones data as the no target "response".)
296 	spi_gpio->mosi = devm_gpiod_get_optional(dev, "mosi", GPIOD_OUT_LOW);  in spi_gpio_request()
297 	if (IS_ERR(spi_gpio->mosi))  in spi_gpio_request()
298 		return PTR_ERR(spi_gpio->mosi);  in spi_gpio_request()
300 	spi_gpio->miso = devm_gpiod_get_optional(dev, "miso", GPIOD_IN);  in spi_gpio_request()
301 	if (IS_ERR(spi_gpio->miso))  in spi_gpio_request()
302 		return PTR_ERR(spi_gpio->miso);  in spi_gpio_request()
304 	spi_gpio->sck = devm_gpiod_get(dev, "sck", GPIOD_OUT_LOW);  in spi_gpio_request()
305 	return PTR_ERR_OR_ZERO(spi_gpio->sck);  in spi_gpio_request()
311 	struct device *dev = &pdev->dev;  in spi_gpio_probe_pdata()
317 		return -ENODEV;  in spi_gpio_probe_pdata()
319 	/* It's just one always-selected device, fine to continue */  in spi_gpio_probe_pdata()
320 	if (!pdata->num_chipselect)  in spi_gpio_probe_pdata()
323 	host->num_chipselect = pdata->num_chipselect;  in spi_gpio_probe_pdata()
324 	spi_gpio->cs_gpios = devm_kcalloc(dev, host->num_chipselect,  in spi_gpio_probe_pdata()
325 					  sizeof(*spi_gpio->cs_gpios),  in spi_gpio_probe_pdata()
327 	if (!spi_gpio->cs_gpios)  in spi_gpio_probe_pdata()
328 		return -ENOMEM;  in spi_gpio_probe_pdata()
330 	for (i = 0; i < host->num_chipselect; i++) {  in spi_gpio_probe_pdata()
331 		spi_gpio->cs_gpios[i] = devm_gpiod_get_index(dev, "cs", i,  in spi_gpio_probe_pdata()
333 		if (IS_ERR(spi_gpio->cs_gpios[i]))  in spi_gpio_probe_pdata()
334 			return PTR_ERR(spi_gpio->cs_gpios[i]);  in spi_gpio_probe_pdata()
345 	struct device			*dev = &pdev->dev;  in spi_gpio_probe()
351 		return -ENOMEM;  in spi_gpio_probe()
354 		device_set_node(&host->dev, fwnode);  in spi_gpio_probe()
355 		host->use_gpio_descriptors = true;  in spi_gpio_probe()
368 	host->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32);  in spi_gpio_probe()
369 	host->mode_bits = SPI_3WIRE | SPI_3WIRE_HIZ | SPI_CPHA | SPI_CPOL |  in spi_gpio_probe()
372 	if (!spi_gpio->mosi) {  in spi_gpio_probe()
375 		 * No setting SPI_CONTROLLER_NO_RX here - if there is only  in spi_gpio_probe()
379 		host->flags = SPI_CONTROLLER_NO_TX;  in spi_gpio_probe()
382 	host->bus_num = pdev->id;  in spi_gpio_probe()
383 	host->setup = spi_gpio_setup;  in spi_gpio_probe()
384 	host->cleanup = spi_gpio_cleanup;  in spi_gpio_probe()
386 	bb = &spi_gpio->bitbang;  in spi_gpio_probe()
387 	bb->ctlr = host;  in spi_gpio_probe()
389 	 * There is some additional business, apart from driving the CS GPIO  in spi_gpio_probe()
393 	host->flags |= SPI_CONTROLLER_GPIO_SS;  in spi_gpio_probe()
394 	bb->chipselect = spi_gpio_chipselect;  in spi_gpio_probe()
395 	bb->set_line_direction = spi_gpio_set_direction;  in spi_gpio_probe()
396 	bb->set_mosi_idle = spi_gpio_set_mosi_idle;  in spi_gpio_probe()
398 	if (host->flags & SPI_CONTROLLER_NO_TX) {  in spi_gpio_probe()
399 		bb->txrx_word[SPI_MODE_0] = spi_gpio_spec_txrx_word_mode0;  in spi_gpio_probe()
400 		bb->txrx_word[SPI_MODE_1] = spi_gpio_spec_txrx_word_mode1;  in spi_gpio_probe()
401 		bb->txrx_word[SPI_MODE_2] = spi_gpio_spec_txrx_word_mode2;  in spi_gpio_probe()
402 		bb->txrx_word[SPI_MODE_3] = spi_gpio_spec_txrx_word_mode3;  in spi_gpio_probe()
404 		bb->txrx_word[SPI_MODE_0] = spi_gpio_txrx_word_mode0;  in spi_gpio_probe()
405 		bb->txrx_word[SPI_MODE_1] = spi_gpio_txrx_word_mode1;  in spi_gpio_probe()
406 		bb->txrx_word[SPI_MODE_2] = spi_gpio_txrx_word_mode2;  in spi_gpio_probe()
407 		bb->txrx_word[SPI_MODE_3] = spi_gpio_txrx_word_mode3;  in spi_gpio_probe()
409 	bb->setup_transfer = spi_bitbang_setup_transfer;  in spi_gpio_probe()
411 	status = spi_bitbang_init(&spi_gpio->bitbang);  in spi_gpio_probe()
415 	return devm_spi_register_controller(&pdev->dev, host);  in spi_gpio_probe()
419 	{ .compatible = "spi-gpio" },
433 MODULE_DESCRIPTION("SPI host driver using generic bitbanged GPIO ");