diff options
| author | Marek Szyprowski <m.szyprowski@samsung.com> | 2010-07-01 00:27:32 +0400 |
|---|---|---|
| committer | Grant Likely <grant.likely@secretlab.ca> | 2010-07-04 08:45:44 +0400 |
| commit | 04bb2a031cf95b34b7432dd47b318a932a895b4c (patch) | |
| tree | d5c831a56c01b4a357450abae47f1afe8d61de34 /drivers/spi/spi_bitbang_txrx.h | |
| parent | 5c2818cdfad1973ede3dcd2a8709620a192f8385 (diff) | |
| download | linux-04bb2a031cf95b34b7432dd47b318a932a895b4c.tar.xz | |
spi/bitbang: add support for SPI_MASTER_NO_{TX, RX} modes
This patch adds a new flags argument to bitbang_txrx_be_cpha0 and
bitbang_txrx_be_cpha1 transfer functions. This enables support for
SPI_MASTER_NO_{TX,RX} transfer modes. The change should have no impact
on speed of the existing drivers. bitbank_txrx_* functions are usually
inlined into the drivers. When the argument is equal to constant zero,
the optimizer would be able to eliminate the dead code (flags checks)
easily. Tested on ARM and GCC 4.4.x and in all cases the checks were
eliminated in the inlined function.
Reviewed-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Diffstat (limited to 'drivers/spi/spi_bitbang_txrx.h')
| -rw-r--r-- | drivers/spi/spi_bitbang_txrx.h | 16 |
1 files changed, 10 insertions, 6 deletions
diff --git a/drivers/spi/spi_bitbang_txrx.h b/drivers/spi/spi_bitbang_txrx.h index fc033bbf9180..c16bf853c3eb 100644 --- a/drivers/spi/spi_bitbang_txrx.h +++ b/drivers/spi/spi_bitbang_txrx.h @@ -44,7 +44,7 @@ static inline u32 bitbang_txrx_be_cpha0(struct spi_device *spi, - unsigned nsecs, unsigned cpol, + unsigned nsecs, unsigned cpol, unsigned flags, u32 word, u8 bits) { /* if (cpol == 0) this is SPI_MODE_0; else this is SPI_MODE_2 */ @@ -53,7 +53,8 @@ bitbang_txrx_be_cpha0(struct spi_device *spi, for (word <<= (32 - bits); likely(bits); bits--) { /* setup MSB (to slave) on trailing edge */ - setmosi(spi, word & (1 << 31)); + if ((flags & SPI_MASTER_NO_TX) == 0) + setmosi(spi, word & (1 << 31)); spidelay(nsecs); /* T(setup) */ setsck(spi, !cpol); @@ -61,7 +62,8 @@ bitbang_txrx_be_cpha0(struct spi_device *spi, /* sample MSB (from slave) on leading edge */ word <<= 1; - word |= getmiso(spi); + if ((flags & SPI_MASTER_NO_RX) == 0) + word |= getmiso(spi); setsck(spi, cpol); } return word; @@ -69,7 +71,7 @@ bitbang_txrx_be_cpha0(struct spi_device *spi, static inline u32 bitbang_txrx_be_cpha1(struct spi_device *spi, - unsigned nsecs, unsigned cpol, + unsigned nsecs, unsigned cpol, unsigned flags, u32 word, u8 bits) { /* if (cpol == 0) this is SPI_MODE_1; else this is SPI_MODE_3 */ @@ -79,7 +81,8 @@ bitbang_txrx_be_cpha1(struct spi_device *spi, /* setup MSB (to slave) on leading edge */ setsck(spi, !cpol); - setmosi(spi, word & (1 << 31)); + if ((flags & SPI_MASTER_NO_TX) == 0) + setmosi(spi, word & (1 << 31)); spidelay(nsecs); /* T(setup) */ setsck(spi, cpol); @@ -87,7 +90,8 @@ bitbang_txrx_be_cpha1(struct spi_device *spi, /* sample MSB (from slave) on trailing edge */ word <<= 1; - word |= getmiso(spi); + if ((flags & SPI_MASTER_NO_RX) == 0) + word |= getmiso(spi); } return word; } |