1 /* SPDX-License-Identifier: GPL-2.0 */
4  * simple SPI master driver.  Two do polled word-at-a-time I/O:
6  *   -	GPIO/parport bitbangers.  Provide chipselect() and txrx_word[](),
7  *	expanding the per-word routines from the inline templates below.
9  *   -	Drivers for controllers resembling bare shift registers.  Provide
15  *   -	Drivers leveraging smarter hardware, with fifos or DMA; or for half
36  * A non-inlined routine would call bitbang_txrx_*() routines.  The
47 bitbang_txrx_be_cpha0(struct spi_device *spi,  in bitbang_txrx_be_cpha0()  argument
53 	u32 oldbit = (!(word & (1<<(bits-1)))) << 31;  in bitbang_txrx_be_cpha0()
55 	for (word <<= (32 - bits); likely(bits); bits--) {  in bitbang_txrx_be_cpha0()
57 		/* setup MSB (to slave) on trailing edge */  in bitbang_txrx_be_cpha0()
60 				setmosi(spi, word & (1 << 31));  in bitbang_txrx_be_cpha0()
66 		setsck(spi, !cpol);  in bitbang_txrx_be_cpha0()
69 		/* sample MSB (from slave) on leading edge */  in bitbang_txrx_be_cpha0()
72 			word |= getmiso(spi);  in bitbang_txrx_be_cpha0()
73 		setsck(spi, cpol);  in bitbang_txrx_be_cpha0()
79 bitbang_txrx_be_cpha1(struct spi_device *spi,  in bitbang_txrx_be_cpha1()  argument
85 	u32 oldbit = (!(word & (1<<(bits-1)))) << 31;  in bitbang_txrx_be_cpha1()
87 	for (word <<= (32 - bits); likely(bits); bits--) {  in bitbang_txrx_be_cpha1()
89 		/* setup MSB (to slave) on leading edge */  in bitbang_txrx_be_cpha1()
90 		setsck(spi, !cpol);  in bitbang_txrx_be_cpha1()
93 				setmosi(spi, word & (1 << 31));  in bitbang_txrx_be_cpha1()
99 		setsck(spi, cpol);  in bitbang_txrx_be_cpha1()
102 		/* sample MSB (from slave) on trailing edge */  in bitbang_txrx_be_cpha1()
105 			word |= getmiso(spi);  in bitbang_txrx_be_cpha1()