msp_read_dsp
state->rev1 = msp_read_dsp(client, 0x1e);
state->rev2 = msp_read_dsp(client, 0x1f);
int msp_read_dsp(struct i2c_client *client, int addr);
val = msp_read_dsp(client, 0x18);
val = msp_read_dsp(client, 0x1b);
val = msp_read_dsp(client, 0x1b);