From: Thomas Koeller <thomas.koel...@baslerweb.com> Computation of the clock prescaler value returned bogus results if the requested SPI clock was impossible to set. It now sets either the maximum or minimum clock frequency, as appropriate.
Signed-off-by: Thomas Koeller <thomas.koel...@baslerweb.com> --- drivers/spi/davinci_spi.c | 12 +++++++++--- 1 files changed, 9 insertions(+), 3 deletions(-) diff --git a/drivers/spi/davinci_spi.c b/drivers/spi/davinci_spi.c index 956f617..02e1a76 100644 --- a/drivers/spi/davinci_spi.c +++ b/drivers/spi/davinci_spi.c @@ -153,7 +153,7 @@ static int davinci_spi_setup_transfer(struct spi_device *spi, struct davinci_spi *davinci_spi; struct davinci_spi_platform_data *pdata; u8 bits_per_word = 0; - u32 hz = 0, prescale; + u32 hz = 0, prescale = 0, clkspeed; davinci_spi = spi_master_get_devdata(spi->master); pdata = davinci_spi->pdata; @@ -190,10 +190,16 @@ static int davinci_spi_setup_transfer(struct spi_device *spi, set_fmt_bits(davinci_spi->base, bits_per_word & 0x1f, spi->chip_select); - prescale = ((clk_get_rate(davinci_spi->clk) / hz) - 1) & 0xff; + clkspeed = clk_get_rate(davinci_spi->clk); + if (hz > clkspeed / 2) + prescale = 1 << 8; + if (hz < clkspeed / 256) + prescale = 255 << 8; + if (!prescale) + prescale = ((clkspeed / hz - 1) << 8) & 0x0000ff00; clear_fmt_bits(davinci_spi->base, 0x0000ff00, spi->chip_select); - set_fmt_bits(davinci_spi->base, prescale << 8, spi->chip_select); + set_fmt_bits(davinci_spi->base, prescale, spi->chip_select); return 0; } -- 1.7.0.3 _______________________________________________ Davinci-linux-open-source mailing list Davinci-linux-open-source@linux.davincidsp.com http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source