3  * SPI master driver using generic bitbanged GPIO
15 #include <linux/spi/spi.h>
16 #include <linux/spi/spi_bitbang.h>
17 #include <linux/spi/spi_gpio.h>
21  * This bitbanging SPI master driver should help make systems usable
22  * when a native hardware SPI engine is not available, perhaps because
28  * spi->controller_state ... reserved for bitbang framework code
30  * spi->master->dev.driver_data ... points to spi_gpio->bitbang
63  *		#include "spi-gpio.c"
76 spi_to_spi_gpio(const struct spi_device *spi)  in spi_to_spi_gpio()  argument
81 	bang = spi_master_get_devdata(spi->master);  in spi_to_spi_gpio()
87 static inline void setsck(const struct spi_device *spi, int is_on)  in setsck()  argument
89 	struct spi_gpio *spi_gpio = spi_to_spi_gpio(spi);  in setsck()
94 static inline void setmosi(const struct spi_device *spi, int is_on)  in setmosi()  argument
96 	struct spi_gpio *spi_gpio = spi_to_spi_gpio(spi);  in setmosi()
101 static inline int getmiso(const struct spi_device *spi)  in getmiso()  argument
103 	struct spi_gpio *spi_gpio = spi_to_spi_gpio(spi);  in getmiso()
105 	if (spi->mode & SPI_3WIRE)  in getmiso()
119 #include "spi-bitbang-txrx.h"
135 static u32 spi_gpio_txrx_word_mode0(struct spi_device *spi,  in spi_gpio_txrx_word_mode0()  argument
138 	if (unlikely(spi->mode & SPI_LSB_FIRST))  in spi_gpio_txrx_word_mode0()
139 		return bitbang_txrx_le_cpha0(spi, nsecs, 0, flags, word, bits);  in spi_gpio_txrx_word_mode0()
141 		return bitbang_txrx_be_cpha0(spi, nsecs, 0, flags, word, bits);  in spi_gpio_txrx_word_mode0()
144 static u32 spi_gpio_txrx_word_mode1(struct spi_device *spi,  in spi_gpio_txrx_word_mode1()  argument
147 	if (unlikely(spi->mode & SPI_LSB_FIRST))  in spi_gpio_txrx_word_mode1()
148 		return bitbang_txrx_le_cpha1(spi, nsecs, 0, flags, word, bits);  in spi_gpio_txrx_word_mode1()
150 		return bitbang_txrx_be_cpha1(spi, nsecs, 0, flags, word, bits);  in spi_gpio_txrx_word_mode1()
153 static u32 spi_gpio_txrx_word_mode2(struct spi_device *spi,  in spi_gpio_txrx_word_mode2()  argument
156 	if (unlikely(spi->mode & SPI_LSB_FIRST))  in spi_gpio_txrx_word_mode2()
157 		return bitbang_txrx_le_cpha0(spi, nsecs, 1, flags, word, bits);  in spi_gpio_txrx_word_mode2()
159 		return bitbang_txrx_be_cpha0(spi, nsecs, 1, flags, word, bits);  in spi_gpio_txrx_word_mode2()
162 static u32 spi_gpio_txrx_word_mode3(struct spi_device *spi,  in spi_gpio_txrx_word_mode3()  argument
165 	if (unlikely(spi->mode & SPI_LSB_FIRST))  in spi_gpio_txrx_word_mode3()
166 		return bitbang_txrx_le_cpha1(spi, nsecs, 1, flags, word, bits);  in spi_gpio_txrx_word_mode3()
168 		return bitbang_txrx_be_cpha1(spi, nsecs, 1, flags, word, bits);  in spi_gpio_txrx_word_mode3()
181 static u32 spi_gpio_spec_txrx_word_mode0(struct spi_device *spi,  in spi_gpio_spec_txrx_word_mode0()  argument
184 	flags = spi->master->flags;  in spi_gpio_spec_txrx_word_mode0()
185 	if (unlikely(spi->mode & SPI_LSB_FIRST))  in spi_gpio_spec_txrx_word_mode0()
186 		return bitbang_txrx_le_cpha0(spi, nsecs, 0, flags, word, bits);  in spi_gpio_spec_txrx_word_mode0()
188 		return bitbang_txrx_be_cpha0(spi, nsecs, 0, flags, word, bits);  in spi_gpio_spec_txrx_word_mode0()
191 static u32 spi_gpio_spec_txrx_word_mode1(struct spi_device *spi,  in spi_gpio_spec_txrx_word_mode1()  argument
194 	flags = spi->master->flags;  in spi_gpio_spec_txrx_word_mode1()
195 	if (unlikely(spi->mode & SPI_LSB_FIRST))  in spi_gpio_spec_txrx_word_mode1()
196 		return bitbang_txrx_le_cpha1(spi, nsecs, 0, flags, word, bits);  in spi_gpio_spec_txrx_word_mode1()
198 		return bitbang_txrx_be_cpha1(spi, nsecs, 0, flags, word, bits);  in spi_gpio_spec_txrx_word_mode1()
201 static u32 spi_gpio_spec_txrx_word_mode2(struct spi_device *spi,  in spi_gpio_spec_txrx_word_mode2()  argument
204 	flags = spi->master->flags;  in spi_gpio_spec_txrx_word_mode2()
205 	if (unlikely(spi->mode & SPI_LSB_FIRST))  in spi_gpio_spec_txrx_word_mode2()
206 		return bitbang_txrx_le_cpha0(spi, nsecs, 1, flags, word, bits);  in spi_gpio_spec_txrx_word_mode2()
208 		return bitbang_txrx_be_cpha0(spi, nsecs, 1, flags, word, bits);  in spi_gpio_spec_txrx_word_mode2()
211 static u32 spi_gpio_spec_txrx_word_mode3(struct spi_device *spi,  in spi_gpio_spec_txrx_word_mode3()  argument
214 	flags = spi->master->flags;  in spi_gpio_spec_txrx_word_mode3()
215 	if (unlikely(spi->mode & SPI_LSB_FIRST))  in spi_gpio_spec_txrx_word_mode3()
216 		return bitbang_txrx_le_cpha1(spi, nsecs, 1, flags, word, bits);  in spi_gpio_spec_txrx_word_mode3()
218 		return bitbang_txrx_be_cpha1(spi, nsecs, 1, flags, word, bits);  in spi_gpio_spec_txrx_word_mode3()
223 static void spi_gpio_chipselect(struct spi_device *spi, int is_active)  in spi_gpio_chipselect()  argument
225 	struct spi_gpio *spi_gpio = spi_to_spi_gpio(spi);  in spi_gpio_chipselect()
229 		gpiod_set_value_cansleep(spi_gpio->sck, spi->mode & SPI_CPOL);  in spi_gpio_chipselect()
233 		struct gpio_desc *cs = spi_gpio->cs_gpios[spi->chip_select];  in spi_gpio_chipselect()
235 		/* SPI chip selects are normally active-low */  in spi_gpio_chipselect()
236 		gpiod_set_value_cansleep(cs, (spi->mode & SPI_CS_HIGH) ? is_active : !is_active);  in spi_gpio_chipselect()
240 static int spi_gpio_setup(struct spi_device *spi)  in spi_gpio_setup()  argument
244 	struct spi_gpio		*spi_gpio = spi_to_spi_gpio(spi);  in spi_gpio_setup()
251 		cs = spi_gpio->cs_gpios[spi->chip_select];  in spi_gpio_setup()
252 		if (!spi->controller_state && cs)  in spi_gpio_setup()
254 						  !(spi->mode & SPI_CS_HIGH));  in spi_gpio_setup()
258 		status = spi_bitbang_setup(spi);  in spi_gpio_setup()
263 static int spi_gpio_set_direction(struct spi_device *spi, bool output)  in spi_gpio_set_direction()  argument
265 	struct spi_gpio *spi_gpio = spi_to_spi_gpio(spi);  in spi_gpio_set_direction()
282 	if (spi->mode & SPI_3WIRE_HIZ) {  in spi_gpio_set_direction()
284 					 !(spi->mode & SPI_CPOL));  in spi_gpio_set_direction()
286 					 !!(spi->mode & SPI_CPOL));  in spi_gpio_set_direction()
291 static void spi_gpio_cleanup(struct spi_device *spi)  in spi_gpio_cleanup()  argument
293 	spi_bitbang_cleanup(spi);  in spi_gpio_cleanup()
298  * functions associated with a "native" SPI controller if a driver for that
322 	{ .compatible = "spi-gpio" },
462 MODULE_DESCRIPTION("SPI master driver using generic bitbanged GPIO ");