From ccf77cc4af5b048e20cfd9327fcc286cb69c34cc Mon Sep 17 00:00:00 2001 From: David Brownell Date: Mon, 3 Apr 2006 15:46:22 -0700 Subject: [PATCH] SPI: devices can require LSB-first encodings Add spi_device hook for LSB-first word encoding, and update all the (in-tree) controller drivers to reject such devices. Eventually, some controller drivers will be updated to support lsb-first encodings on the wire; no current drivers need this. Signed-off-by: David Brownell Signed-off-by: Greg Kroah-Hartman --- drivers/spi/spi_bitbang.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'drivers') diff --git a/drivers/spi/spi_bitbang.c b/drivers/spi/spi_bitbang.c index 6c3da64d609a69..0f7f5c64391cbb 100644 --- a/drivers/spi/spi_bitbang.c +++ b/drivers/spi/spi_bitbang.c @@ -187,13 +187,22 @@ int spi_bitbang_setup(struct spi_device *spi) if (!spi->max_speed_hz) return -EINVAL; + bitbang = spi_master_get_devdata(spi->master); + + /* REVISIT: some systems will want to support devices using lsb-first + * bit encodings on the wire. In pure software that would be trivial, + * just bitbang_txrx_le_cphaX() routines shifting the other way, and + * some hardware controllers also have this support. + */ + if ((spi->mode & SPI_LSB_FIRST) != 0) + return -EINVAL; + if (!cs) { cs = kzalloc(sizeof *cs, SLAB_KERNEL); if (!cs) return -ENOMEM; spi->controller_state = cs; } - bitbang = spi_master_get_devdata(spi->master); if (!spi->bits_per_word) spi->bits_per_word = 8; -- cgit 1.2.3-korg