BQ27542-G1: HDQ Communication between BQ27542 and msm8953(Qualcomm processor)

When I connect BQ27542 with msm8953 with HDQ communication, I find that BQ27542 do not response. I follow the directions in datasheet and get the waveform in oscilloscope. HDQ is pulled down for 500us and then pulled up for 60us.

The code in msm8953 as following shown.
 gpio_set_value(onewire_gpio,0);
 w1_delay(500);
 gpio_set_value(onewire_gpio,1);
 w1_delay(60); 
 gpio_direction_input(onewire_gpio);