If "speed" is zero then we use it as a divisor to find "prescale". It's better to move the check for zero to the very start of the function.
Fixes: 9eeec26a1339 ("drm/amd/display: Refine i2c frequency calculating sequence") Signed-off-by: Dan Carpenter dan.carpenter@oracle.com --- drivers/gpu/drm/amd/display/dc/dce/dce_i2c_hw.c | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_i2c_hw.c b/drivers/gpu/drm/amd/display/dc/dce/dce_i2c_hw.c index 066188ba7949..24adec407972 100644 --- a/drivers/gpu/drm/amd/display/dc/dce/dce_i2c_hw.c +++ b/drivers/gpu/drm/amd/display/dc/dce/dce_i2c_hw.c @@ -267,6 +267,9 @@ static void set_speed( uint32_t xtal_ref_div = 0; uint32_t prescale = 0;
+ if (speed == 0) + return; + REG_GET(MICROSECOND_TIME_BASE_DIV, XTAL_REF_DIV, &xtal_ref_div);
if (xtal_ref_div == 0) @@ -274,17 +277,15 @@ static void set_speed(
prescale = ((dce_i2c_hw->reference_frequency * 2) / xtal_ref_div) / speed;
- if (speed) { - if (dce_i2c_hw->masks->DC_I2C_DDC1_START_STOP_TIMING_CNTL) - REG_UPDATE_N(SPEED, 3, - FN(DC_I2C_DDC1_SPEED, DC_I2C_DDC1_PRESCALE), prescale, - FN(DC_I2C_DDC1_SPEED, DC_I2C_DDC1_THRESHOLD), 2, - FN(DC_I2C_DDC1_SPEED, DC_I2C_DDC1_START_STOP_TIMING_CNTL), speed > 50 ? 2:1); - else - REG_UPDATE_N(SPEED, 2, - FN(DC_I2C_DDC1_SPEED, DC_I2C_DDC1_PRESCALE), prescale, - FN(DC_I2C_DDC1_SPEED, DC_I2C_DDC1_THRESHOLD), 2); - } + if (dce_i2c_hw->masks->DC_I2C_DDC1_START_STOP_TIMING_CNTL) + REG_UPDATE_N(SPEED, 3, + FN(DC_I2C_DDC1_SPEED, DC_I2C_DDC1_PRESCALE), prescale, + FN(DC_I2C_DDC1_SPEED, DC_I2C_DDC1_THRESHOLD), 2, + FN(DC_I2C_DDC1_SPEED, DC_I2C_DDC1_START_STOP_TIMING_CNTL), speed > 50 ? 2:1); + else + REG_UPDATE_N(SPEED, 2, + FN(DC_I2C_DDC1_SPEED, DC_I2C_DDC1_PRESCALE), prescale, + FN(DC_I2C_DDC1_SPEED, DC_I2C_DDC1_THRESHOLD), 2); }
static bool setup_engine(