summaryrefslogtreecommitdiffstats
path: root/include/linux/spi/spi_bitbang.h
diff options
context:
space:
mode:
Diffstat (limited to 'include/linux/spi/spi_bitbang.h')
-rw-r--r--include/linux/spi/spi_bitbang.h101
1 files changed, 0 insertions, 101 deletions
diff --git a/include/linux/spi/spi_bitbang.h b/include/linux/spi/spi_bitbang.h
index 3274c507b8a..f987a2bee16 100644
--- a/include/linux/spi/spi_bitbang.h
+++ b/include/linux/spi/spi_bitbang.h
@@ -1,24 +1,6 @@
#ifndef __SPI_BITBANG_H
#define __SPI_BITBANG_H
-/*
- * Mix this utility code with some glue code to get one of several types of
- * simple SPI master driver. Two do polled word-at-a-time I/O:
- *
- * - GPIO/parport bitbangers. Provide chipselect() and txrx_word[](),
- * expanding the per-word routines from the inline templates below.
- *
- * - Drivers for controllers resembling bare shift registers. Provide
- * chipselect() and txrx_word[](), with custom setup()/cleanup() methods
- * that use your controller's clock and chipselect registers.
- *
- * Some hardware works well with requests at spi_transfer scope:
- *
- * - Drivers leveraging smarter hardware, with fifos or DMA; or for half
- * duplex (MicroWire) controllers. Provide chipselect() and txrx_bufs(),
- * and custom setup()/cleanup() methods.
- */
-
#include <linux/workqueue.h>
struct spi_bitbang {
@@ -68,86 +50,3 @@ extern int spi_bitbang_start(struct spi_bitbang *spi);
extern int spi_bitbang_stop(struct spi_bitbang *spi);
#endif /* __SPI_BITBANG_H */
-
-/*-------------------------------------------------------------------------*/
-
-#ifdef EXPAND_BITBANG_TXRX
-
-/*
- * The code that knows what GPIO pins do what should have declared four
- * functions, ideally as inlines, before #defining EXPAND_BITBANG_TXRX
- * and including this header:
- *
- * void setsck(struct spi_device *, int is_on);
- * void setmosi(struct spi_device *, int is_on);
- * int getmiso(struct spi_device *);
- * void spidelay(unsigned);
- *
- * setsck()'s is_on parameter is a zero/nonzero boolean.
- *
- * setmosi()'s is_on parameter is a zero/nonzero boolean.
- *
- * getmiso() is required to return 0 or 1 only. Any other value is invalid
- * and will result in improper operation.
- *
- * A non-inlined routine would call bitbang_txrx_*() routines. The
- * main loop could easily compile down to a handful of instructions,
- * especially if the delay is a NOP (to run at peak speed).
- *
- * Since this is software, the timings may not be exactly what your board's
- * chips need ... there may be several reasons you'd need to tweak timings
- * in these routines, not just make to make it faster or slower to match a
- * particular CPU clock rate.
- */
-
-static inline u32
-bitbang_txrx_be_cpha0(struct spi_device *spi,
- unsigned nsecs, unsigned cpol,
- u32 word, u8 bits)
-{
- /* if (cpol == 0) this is SPI_MODE_0; else this is SPI_MODE_2 */
-
- /* clock starts at inactive polarity */
- for (word <<= (32 - bits); likely(bits); bits--) {
-
- /* setup MSB (to slave) on trailing edge */
- setmosi(spi, word & (1 << 31));
- spidelay(nsecs); /* T(setup) */
-
- setsck(spi, !cpol);
- spidelay(nsecs);
-
- /* sample MSB (from slave) on leading edge */
- word <<= 1;
- word |= getmiso(spi);
- setsck(spi, cpol);
- }
- return word;
-}
-
-static inline u32
-bitbang_txrx_be_cpha1(struct spi_device *spi,
- unsigned nsecs, unsigned cpol,
- u32 word, u8 bits)
-{
- /* if (cpol == 0) this is SPI_MODE_1; else this is SPI_MODE_3 */
-
- /* clock starts at inactive polarity */
- for (word <<= (32 - bits); likely(bits); bits--) {
-
- /* setup MSB (to slave) on leading edge */
- setsck(spi, !cpol);
- setmosi(spi, word & (1 << 31));
- spidelay(nsecs); /* T(setup) */
-
- setsck(spi, cpol);
- spidelay(nsecs);
-
- /* sample MSB (from slave) on trailing edge */
- word <<= 1;
- word |= getmiso(spi);
- }
- return word;
-}
-
-#endif /* EXPAND_BITBANG_TXRX */