I try to increase the volume on the headphone output manage by the SGTL5000.
This chip use two differents volume stage to output sound on the headphone.
The first CHIP_DAC_VOL 0x0010 and the second CHIP_ANA_HP_CTRL 0x0022.
These two registers has default value(at reset of the chip) which correspond to 0dB (0x3C3C to DAC_VOL and 0x1818 to HP_CTRL).
But when the drivers initialize this chip is write these value to -24dB (0x6C6C) to DAC_VOL and -20dB (0x4040) to HP_CTRL.
Is there a way to change these values from user space without using I2C_SLAVE_FORCE ?
I have written a software which changes these values but it use I2C_SLAVE_FORCE which is not very clean.