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
50 		unsigned nsecs, unsigned cpol, unsigned flags,  in bitbang_txrx_be_cpha0()  argument
53 	/* if (cpol == 0) this is SPI_MODE_0; else this is SPI_MODE_2 */  in bitbang_txrx_be_cpha0()
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()
62 				setmosi(spi, word & (1 << 31));  in bitbang_txrx_be_cpha0()
68 		setsck(spi, !cpol);  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
82 		unsigned nsecs, unsigned cpol, unsigned flags,  in bitbang_txrx_be_cpha1()  argument
85 	/* if (cpol == 0) this is SPI_MODE_1; else this is SPI_MODE_3 */  in bitbang_txrx_be_cpha1()
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()
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()
107 			word |= getmiso(spi);  in bitbang_txrx_be_cpha1()
113 bitbang_txrx_le_cpha0(struct spi_device *spi,  in bitbang_txrx_le_cpha0()  argument
114 		unsigned int nsecs, unsigned int cpol, unsigned int flags,  in bitbang_txrx_le_cpha0()  argument
117 	/* if (cpol == 0) this is SPI_MODE_0; else this is SPI_MODE_2 */  in bitbang_txrx_le_cpha0()
119 	u8 rxbit = bits - 1;  in bitbang_txrx_le_cpha0()
122 	for (; likely(bits); bits--) {  in bitbang_txrx_le_cpha0()
127 				setmosi(spi, word & 1);  in bitbang_txrx_le_cpha0()
133 		setsck(spi, !cpol);  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
147 		unsigned int nsecs, unsigned int cpol, unsigned int flags,  in bitbang_txrx_le_cpha1()  argument
150 	/* if (cpol == 0) this is SPI_MODE_1; else this is SPI_MODE_3 */  in bitbang_txrx_le_cpha1()
152 	u8 rxbit = bits - 1;  in bitbang_txrx_le_cpha1()
155 	for (; likely(bits); bits--) {  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()
173 			word |= getmiso(spi) << rxbit;  in bitbang_txrx_le_cpha1()