The i2c timing values specified in the driver are the minimun values defined in the I2C specifications. The I2C specification does not specify any default or maximum values.
Some I2C devices are out of spec, and might not work properly with minimum values. This patch adds a 10% margin on all the timings. Signed-off-by: Maxime Coquelin <[email protected]> --- drivers/i2c/busses/i2c-st.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) diff --git a/drivers/i2c/busses/i2c-st.c b/drivers/i2c/busses/i2c-st.c index 8720161..09142f1 100644 --- a/drivers/i2c/busses/i2c-st.c +++ b/drivers/i2c/busses/i2c-st.c @@ -210,21 +210,21 @@ static inline void st_i2c_clr_bits(void __iomem *reg, u32 mask) static struct st_i2c_timings i2c_timings[] = { [I2C_MODE_STANDARD] = { .rate = 100000, - .rep_start_hold = 4000, - .rep_start_setup = 4700, - .start_hold = 4000, - .data_setup_time = 250, - .stop_setup_time = 4000, - .bus_free_time = 4700, + .rep_start_hold = 4400, + .rep_start_setup = 5170, + .start_hold = 4400, + .data_setup_time = 275, + .stop_setup_time = 4400, + .bus_free_time = 5170, }, [I2C_MODE_FAST] = { .rate = 400000, - .rep_start_hold = 600, - .rep_start_setup = 600, - .start_hold = 600, - .data_setup_time = 100, - .stop_setup_time = 600, - .bus_free_time = 1300, + .rep_start_hold = 660, + .rep_start_setup = 660, + .start_hold = 660, + .data_setup_time = 110, + .stop_setup_time = 660, + .bus_free_time = 1430, }, }; -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
