2  * SPI master driver using generic bitbanged GPIO
26 #include <linux/spi/spi.h>
27 #include <linux/spi/spi_bitbang.h>
28 #include <linux/spi/spi_gpio.h>
32  * This bitbanging SPI master driver should help make systems usable
33  * when a native hardware SPI engine is not available, perhaps because
39  * spi->controller_state ... reserved for bitbang framework code
40  * spi->controller_data ... holds chipselect GPIO
42  * spi->master->dev.driver_data ... points to spi_gpio->bitbang
73  *		#include "spi-gpio.c"
93 spi_to_pdata(const struct spi_device *spi)  in spi_to_pdata()  argument
98 	bang = spi_master_get_devdata(spi->master);  in spi_to_pdata()
104 #define pdata		spi_to_pdata(spi)
106 static inline void setsck(const struct spi_device *spi, int is_on)  in setsck()  argument
111 static inline void setmosi(const struct spi_device *spi, int is_on)  in setmosi()  argument
116 static inline int getmiso(const struct spi_device *spi)  in getmiso()  argument
131 #include "spi-bitbang-txrx.h"
147 static u32 spi_gpio_txrx_word_mode0(struct spi_device *spi,  in spi_gpio_txrx_word_mode0()  argument
150 	return bitbang_txrx_be_cpha0(spi, nsecs, 0, 0, word, bits);  in spi_gpio_txrx_word_mode0()
153 static u32 spi_gpio_txrx_word_mode1(struct spi_device *spi,  in spi_gpio_txrx_word_mode1()  argument
156 	return bitbang_txrx_be_cpha1(spi, nsecs, 0, 0, word, bits);  in spi_gpio_txrx_word_mode1()
159 static u32 spi_gpio_txrx_word_mode2(struct spi_device *spi,  in spi_gpio_txrx_word_mode2()  argument
162 	return bitbang_txrx_be_cpha0(spi, nsecs, 1, 0, word, bits);  in spi_gpio_txrx_word_mode2()
165 static u32 spi_gpio_txrx_word_mode3(struct spi_device *spi,  in spi_gpio_txrx_word_mode3()  argument
168 	return bitbang_txrx_be_cpha1(spi, nsecs, 1, 0, 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 	unsigned flags = spi->master->flags;  in spi_gpio_spec_txrx_word_mode0()
185 	return bitbang_txrx_be_cpha0(spi, nsecs, 0, flags, word, bits);  in spi_gpio_spec_txrx_word_mode0()
188 static u32 spi_gpio_spec_txrx_word_mode1(struct spi_device *spi,  in spi_gpio_spec_txrx_word_mode1()  argument
191 	unsigned flags = spi->master->flags;  in spi_gpio_spec_txrx_word_mode1()
192 	return bitbang_txrx_be_cpha1(spi, nsecs, 0, flags, word, bits);  in spi_gpio_spec_txrx_word_mode1()
195 static u32 spi_gpio_spec_txrx_word_mode2(struct spi_device *spi,  in spi_gpio_spec_txrx_word_mode2()  argument
198 	unsigned flags = spi->master->flags;  in spi_gpio_spec_txrx_word_mode2()
199 	return bitbang_txrx_be_cpha0(spi, nsecs, 1, flags, word, bits);  in spi_gpio_spec_txrx_word_mode2()
202 static u32 spi_gpio_spec_txrx_word_mode3(struct spi_device *spi,  in spi_gpio_spec_txrx_word_mode3()  argument
205 	unsigned flags = spi->master->flags;  in spi_gpio_spec_txrx_word_mode3()
206 	return bitbang_txrx_be_cpha1(spi, nsecs, 1, flags, word, bits);  in spi_gpio_spec_txrx_word_mode3()
211 static void spi_gpio_chipselect(struct spi_device *spi, int is_active)  in spi_gpio_chipselect()  argument
213 	unsigned long cs = (unsigned long) spi->controller_data;  in spi_gpio_chipselect()
217 		setsck(spi, spi->mode & SPI_CPOL);  in spi_gpio_chipselect()
220 		/* SPI is normally active-low */  in spi_gpio_chipselect()
221 		gpio_set_value(cs, (spi->mode & SPI_CS_HIGH) ? is_active : !is_active);  in spi_gpio_chipselect()
225 static int spi_gpio_setup(struct spi_device *spi)  in spi_gpio_setup()  argument
227 	unsigned long	cs = (unsigned long) spi->controller_data;  in spi_gpio_setup()
230 	if (spi->bits_per_word > 32)  in spi_gpio_setup()
233 	if (!spi->controller_state) {  in spi_gpio_setup()
235 			status = gpio_request(cs, dev_name(&spi->dev));  in spi_gpio_setup()
238 			status = gpio_direction_output(cs, spi->mode & SPI_CS_HIGH);  in spi_gpio_setup()
242 		status = spi_bitbang_setup(spi);  in spi_gpio_setup()
244 		if (!spi->controller_state && cs != SPI_GPIO_NO_CHIPSELECT)  in spi_gpio_setup()
250 static void spi_gpio_cleanup(struct spi_device *spi)  in spi_gpio_cleanup()  argument
252 	unsigned long	cs = (unsigned long) spi->controller_data;  in spi_gpio_cleanup()
256 	spi_bitbang_cleanup(spi);  in spi_gpio_cleanup()
417 MODULE_DESCRIPTION("SPI master driver using generic bitbanged GPIO ");