3  * SPI host 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>
20  * This bitbanging SPI host driver should help make systems usable
21  * when a native hardware SPI engine is not available, perhaps because
27  * spi->controller_state ... reserved for bitbang framework code
29  * spi->controller->dev.driver_data ... points to spi_gpio->bitbang
47 spi_to_spi_gpio(const struct spi_device *spi)  in spi_to_spi_gpio()  argument
52 	bang = spi_controller_get_devdata(spi->controller);  in spi_to_spi_gpio()
58 static inline void setsck(const struct spi_device *spi, int is_on)  in setsck()  argument
60 	struct spi_gpio *spi_gpio = spi_to_spi_gpio(spi);  in setsck()
65 static inline void setmosi(const struct spi_device *spi, int is_on)  in setmosi()  argument
67 	struct spi_gpio *spi_gpio = spi_to_spi_gpio(spi);  in setmosi()
72 static inline int getmiso(const struct spi_device *spi)  in getmiso()  argument
74 	struct spi_gpio *spi_gpio = spi_to_spi_gpio(spi);  in getmiso()
76 	if (spi->mode & SPI_3WIRE)  in getmiso()
90 #include "spi-bitbang-txrx.h"
106 static u32 spi_gpio_txrx_word_mode0(struct spi_device *spi,  in spi_gpio_txrx_word_mode0()  argument
109 	if (unlikely(spi->mode & SPI_LSB_FIRST))  in spi_gpio_txrx_word_mode0()
110 		return bitbang_txrx_le_cpha0(spi, nsecs, 0, flags, word, bits);  in spi_gpio_txrx_word_mode0()
112 		return bitbang_txrx_be_cpha0(spi, nsecs, 0, flags, word, bits);  in spi_gpio_txrx_word_mode0()
115 static u32 spi_gpio_txrx_word_mode1(struct spi_device *spi,  in spi_gpio_txrx_word_mode1()  argument
118 	if (unlikely(spi->mode & SPI_LSB_FIRST))  in spi_gpio_txrx_word_mode1()
119 		return bitbang_txrx_le_cpha1(spi, nsecs, 0, flags, word, bits);  in spi_gpio_txrx_word_mode1()
121 		return bitbang_txrx_be_cpha1(spi, nsecs, 0, flags, word, bits);  in spi_gpio_txrx_word_mode1()
124 static u32 spi_gpio_txrx_word_mode2(struct spi_device *spi,  in spi_gpio_txrx_word_mode2()  argument
127 	if (unlikely(spi->mode & SPI_LSB_FIRST))  in spi_gpio_txrx_word_mode2()
128 		return bitbang_txrx_le_cpha0(spi, nsecs, 1, flags, word, bits);  in spi_gpio_txrx_word_mode2()
130 		return bitbang_txrx_be_cpha0(spi, nsecs, 1, flags, word, bits);  in spi_gpio_txrx_word_mode2()
133 static u32 spi_gpio_txrx_word_mode3(struct spi_device *spi,  in spi_gpio_txrx_word_mode3()  argument
136 	if (unlikely(spi->mode & SPI_LSB_FIRST))  in spi_gpio_txrx_word_mode3()
137 		return bitbang_txrx_le_cpha1(spi, nsecs, 1, flags, word, bits);  in spi_gpio_txrx_word_mode3()
139 		return bitbang_txrx_be_cpha1(spi, nsecs, 1, flags, word, bits);  in spi_gpio_txrx_word_mode3()
152 static u32 spi_gpio_spec_txrx_word_mode0(struct spi_device *spi,  in spi_gpio_spec_txrx_word_mode0()  argument
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()
157 		return bitbang_txrx_le_cpha0(spi, nsecs, 0, flags, word, bits);  in spi_gpio_spec_txrx_word_mode0()
159 		return bitbang_txrx_be_cpha0(spi, nsecs, 0, flags, word, bits);  in spi_gpio_spec_txrx_word_mode0()
162 static u32 spi_gpio_spec_txrx_word_mode1(struct spi_device *spi,  in spi_gpio_spec_txrx_word_mode1()  argument
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()
167 		return bitbang_txrx_le_cpha1(spi, nsecs, 0, flags, word, bits);  in spi_gpio_spec_txrx_word_mode1()
169 		return bitbang_txrx_be_cpha1(spi, nsecs, 0, flags, word, bits);  in spi_gpio_spec_txrx_word_mode1()
172 static u32 spi_gpio_spec_txrx_word_mode2(struct spi_device *spi,  in spi_gpio_spec_txrx_word_mode2()  argument
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()
177 		return bitbang_txrx_le_cpha0(spi, nsecs, 1, flags, word, bits);  in spi_gpio_spec_txrx_word_mode2()
179 		return bitbang_txrx_be_cpha0(spi, nsecs, 1, flags, word, bits);  in spi_gpio_spec_txrx_word_mode2()
182 static u32 spi_gpio_spec_txrx_word_mode3(struct spi_device *spi,  in spi_gpio_spec_txrx_word_mode3()  argument
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()
187 		return bitbang_txrx_le_cpha1(spi, nsecs, 1, flags, word, bits);  in spi_gpio_spec_txrx_word_mode3()
189 		return bitbang_txrx_be_cpha1(spi, nsecs, 1, flags, word, bits);  in spi_gpio_spec_txrx_word_mode3()
194 static void spi_gpio_chipselect(struct spi_device *spi, int is_active)  in spi_gpio_chipselect()  argument
196 	struct spi_gpio *spi_gpio = spi_to_spi_gpio(spi);  in spi_gpio_chipselect()
200 		gpiod_set_value_cansleep(spi_gpio->sck, spi->mode & SPI_CPOL);  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()
211 static void spi_gpio_set_mosi_idle(struct spi_device *spi)  in spi_gpio_set_mosi_idle()  argument
213 	struct spi_gpio *spi_gpio = spi_to_spi_gpio(spi);  in spi_gpio_set_mosi_idle()
216 				 !!(spi->mode & SPI_MOSI_IDLE_HIGH));  in spi_gpio_set_mosi_idle()
219 static int spi_gpio_setup(struct spi_device *spi)  in spi_gpio_setup()  argument
222 	struct spi_gpio		*spi_gpio = spi_to_spi_gpio(spi);  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()
238 	return spi_bitbang_setup(spi);  in spi_gpio_setup()
241 static int spi_gpio_set_direction(struct spi_device *spi, bool output)  in spi_gpio_set_direction()  argument
243 	struct spi_gpio *spi_gpio = spi_to_spi_gpio(spi);  in spi_gpio_set_direction()
255 	 * SPI devices in to a bad state.  in spi_gpio_set_direction()
257 	if (spi->mode & SPI_3WIRE) {  in spi_gpio_set_direction()
270 	if (spi->mode & SPI_3WIRE_HIZ) {  in spi_gpio_set_direction()
272 					 !(spi->mode & SPI_CPOL));  in spi_gpio_set_direction()
274 					 !!(spi->mode & SPI_CPOL));  in spi_gpio_set_direction()
279 static void spi_gpio_cleanup(struct spi_device *spi)  in spi_gpio_cleanup()  argument
281 	spi_bitbang_cleanup(spi);  in spi_gpio_cleanup()
286  * functions associated with a "native" SPI controller if a driver for that
419 	{ .compatible = "spi-gpio" },
433 MODULE_DESCRIPTION("SPI host driver using generic bitbanged GPIO ");