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| author | Martin Sperl <kernel@martin.sperl.org> | 2015-03-19 10:01:52 +0100 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2015-03-23 19:52:26 +0100 |
| commit | 210b49231af6a3ede5de3c90850dbf1134a855c2 (patch) | |
| tree | 958ee2e4829e813fcb02cb1d5a9b5e44dca5180a | |
| parent | spi: bcm2835: fill/drain SPI-fifo as much as possible during interrupt (diff) | |
| download | linux-210b49231af6a3ede5de3c90850dbf1134a855c2.tar.xz linux-210b49231af6a3ede5de3c90850dbf1134a855c2.zip | |
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 <kernel@martin.sperl.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
| -rw-r--r-- | drivers/spi/spi-bcm2835.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c index 960dcce607c2..8de1925fe554 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 */ |