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
49 bitbang_txrx_be_cpha0(struct spi_device *spi,  in bitbang_txrx_be_cpha0()  argument
55 	u32 oldbit = (!(word & (1<<(bits-1)))) << 31;  in bitbang_txrx_be_cpha0()
57 	for (word <<= (32 - bits); likely(bits); bits--) {  in bitbang_txrx_be_cpha0()
59 		/* setup MSB (to slave) on trailing edge */  in bitbang_txrx_be_cpha0()
62 				setmosi(spi, word & (1 << 31));  in bitbang_txrx_be_cpha0()
68 		setsck(spi, !cpol);  in bitbang_txrx_be_cpha0()
71 		/* sample MSB (from slave) on leading edge */  in bitbang_txrx_be_cpha0()
74 			word |= getmiso(spi);  in bitbang_txrx_be_cpha0()
75 		setsck(spi, cpol);  in bitbang_txrx_be_cpha0()
81 bitbang_txrx_be_cpha1(struct spi_device *spi,  in bitbang_txrx_be_cpha1()  argument
87 	u32 oldbit = (!(word & (1<<(bits-1)))) << 31;  in bitbang_txrx_be_cpha1()
89 	for (word <<= (32 - bits); likely(bits); bits--) {  in bitbang_txrx_be_cpha1()
91 		/* setup MSB (to slave) on leading edge */  in bitbang_txrx_be_cpha1()
92 		setsck(spi, !cpol);  in bitbang_txrx_be_cpha1()
95 				setmosi(spi, word & (1 << 31));  in bitbang_txrx_be_cpha1()
101 		setsck(spi, cpol);  in bitbang_txrx_be_cpha1()
104 		/* sample MSB (from slave) on trailing edge */  in bitbang_txrx_be_cpha1()
107 			word |= getmiso(spi);  in bitbang_txrx_be_cpha1()
113 bitbang_txrx_le_cpha0(struct spi_device *spi,  in bitbang_txrx_le_cpha0()  argument
119 	u8 rxbit = bits - 1;  in bitbang_txrx_le_cpha0()
122 	for (; likely(bits); bits--) {  in bitbang_txrx_le_cpha0()
124 		/* setup LSB (to slave) on trailing edge */  in bitbang_txrx_le_cpha0()
127 				setmosi(spi, word & 1);  in bitbang_txrx_le_cpha0()
133 		setsck(spi, !cpol);  in bitbang_txrx_le_cpha0()
136 		/* sample LSB (from slave) on leading edge */  in bitbang_txrx_le_cpha0()
139 			word |= getmiso(spi) << rxbit;  in bitbang_txrx_le_cpha0()
140 		setsck(spi, cpol);  in bitbang_txrx_le_cpha0()
146 bitbang_txrx_le_cpha1(struct spi_device *spi,  in bitbang_txrx_le_cpha1()  argument
152 	u8 rxbit = bits - 1;  in bitbang_txrx_le_cpha1()
155 	for (; likely(bits); bits--) {  in bitbang_txrx_le_cpha1()
157 		/* setup LSB (to slave) on leading edge */  in bitbang_txrx_le_cpha1()
158 		setsck(spi, !cpol);  in bitbang_txrx_le_cpha1()
161 				setmosi(spi, word & 1);  in bitbang_txrx_le_cpha1()
167 		setsck(spi, cpol);  in bitbang_txrx_le_cpha1()
170 		/* sample LSB (from slave) on trailing edge */  in bitbang_txrx_le_cpha1()
173 			word |= getmiso(spi) << rxbit;  in bitbang_txrx_le_cpha1()