From bb8beecd98de45f821a3360e0b061fc1f8da947c Mon Sep 17 00:00:00 2001 From: Wolfgang Muees Date: Fri, 22 May 2009 01:11:02 +0000 Subject: spi/bfin_spi: force sane master-mode state at boot We should make sure the SPI controller is in a sane state in case the boot loader left it in a crappy state. Such as DMA pending which causes interrupts to fire on us. When setting a sane initial state, do not default to slave mode. If we do, then the SPI peripheral may implicitly take over the SPISS pin which other things might be using. For example, the BF533-STAMP uses this pin as a GPIO to control switching between ethernet and flash. If the SPI peripheral controls the output state instead, the ethernet is no longer accessible. URL: http://blackfin.uclinux.org/gf/tracker/5630 Signed-off-by: Wolfgang Muees Signed-off-by: Michael Hennerich Signed-off-by: Mike Frysinger --- drivers/spi/spi_bfin5xx.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'drivers/spi') diff --git a/drivers/spi/spi_bfin5xx.c b/drivers/spi/spi_bfin5xx.c index 61c2ebf..b835254 100644 --- a/drivers/spi/spi_bfin5xx.c +++ b/drivers/spi/spi_bfin5xx.c @@ -1354,6 +1354,12 @@ static int __init bfin_spi_probe(struct platform_device *pdev) goto out_error_queue_alloc; } + /* Reset SPI registers. If these registers were used by the boot loader, + * the sky may fall on your head if you enable the dma controller. + */ + write_CTRL(drv_data, BIT_CTL_CPHA | BIT_CTL_MASTER); + write_FLAG(drv_data, 0xFF00); + /* Register with the SPI framework */ platform_set_drvdata(pdev, drv_data); status = spi_register_master(master); -- cgit v1.1