Prevents that cdiv can be an uneven number as per datasheet cdiv is always rounded down to an even number.
Datasheet at page 34 on http://www.raspberrypi.org/wp-content/uploads/2012/02/BCM2835-ARM-Peripherals.pdf Signed-off-by: Silvan Wicki <[email protected]> --- drivers/i2c/busses/i2c-bcm2708.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/busses/i2c-bcm2708.c b/drivers/i2c/busses/i2c-bcm2708.c index 81e9374..dd7094a 100644 --- a/drivers/i2c/busses/i2c-bcm2708.c +++ b/drivers/i2c/busses/i2c-bcm2708.c @@ -67,6 +67,9 @@ #define BSC_S_DONE 0x00000002 #define BSC_S_TA 0x00000001 +#define BSC_CDIV_MAX 0xFFFE +#define BSC_CDIV_BITMASK 0xFFFE + #define I2C_TIMEOUT_MS 150 #define I2C_WAIT_LOOP_COUNT 40 @@ -441,9 +444,15 @@ static int bcm2708_i2c_probe(struct platform_device *pdev) bus_hz = clk_get_rate(bi->clk); cdiv = bus_hz / baudrate; - if (cdiv > 0xffff) { - cdiv = 0xffff; + /* as per datasheet cdiv is always rounded down to an even number */ + if (cdiv > BSC_CDIV_MAX) { + cdiv = BSC_CDIV_MAX; baudrate = bus_hz / cdiv; + } else { + if ((cdiv & BSC_CDIV_BITMASK) != cdiv) { + cdiv &= BSC_CDIV_BITMASK; + baudrate = bus_hz / cdiv; + } } bi->cdiv = cdiv; -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
