From 210b49231af6a3ede5de3c90850dbf1134a855c2 Mon Sep 17 00:00:00 2001 From: Martin Sperl Date: Thu, 19 Mar 2015 09:01:52 +0000 Subject: [PATCH] spi: bcm2835: clock divider can be a multiple of 2 The official documentation is wrong in this respect. Has been tested empirically for dividers 2-1024 Signed-off-by: Martin Sperl Signed-off-by: Mark Brown --- drivers/spi/spi-bcm2835.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c index 960dcce607c2c..8de1925fe5548 100644 --- a/drivers/spi/spi-bcm2835.c +++ b/drivers/spi/spi-bcm2835.c @@ -153,8 +153,9 @@ static int bcm2835_spi_start_transfer(struct spi_device *spi, if (spi_hz >= clk_hz / 2) { cdiv = 2; /* clk_hz/2 is the fastest we can go */ } else if (spi_hz) { - /* CDIV must be a power of two */ - cdiv = roundup_pow_of_two(DIV_ROUND_UP(clk_hz, spi_hz)); + /* CDIV must be a multiple of two */ + cdiv = DIV_ROUND_UP(clk_hz, spi_hz); + cdiv += (cdiv % 2); if (cdiv >= 65536) cdiv = 0; /* 0 is the slowest we can go */