Forum Post: question about the adc_channels

I've read the post http://e2e.ti.com/support/arm/sitara_arm/f/791/t/250914.aspx?pi301021=1.

and I have my adc working now. But there is still a problem I can't understand.

following are my codes about adc:

static struct tsc_data am335x_touchscreen_data  = {
    .wires  = 0,
    .x_plate_resistance = 200,
    .steps_to_configure = 5,
};

static struct adc_data am335x_adc_data = {
    .adc_channels = 8,
};

static struct mfd_tscadc_board tscadc = {
    .tsc_init = &am335x_touchscreen_data,
    .adc_init = &am335x_adc_data,
};

static struct pinmux_config adc_pin_mux[] = {
 {"ain0.ain0",           OMAP_MUX_MODE0 | AM33XX_INPUT_EN},
    {"vrefp.vrefp", OMAP_MUX_MODE0 | AM33XX_INPUT_EN},
    {"vrefn.vrefn", OMAP_MUX_MODE0 | AM33XX_INPUT_EN},
 {NULL, 0},
};

when I use this code, the correspoding file in iio is: /sys/bus/iio/devices/iio\:device0/in_voltage0_raw

that's OK.

however, because I use only the "ain0" to get the battery voltage.  when I change the code to :

static struct adc_data am335x_adc_data = {
    .adc_channels = 1,
};

with anything else unchanged. there is only one file in iio, it's "in_voltage7_raw". and it can not work right !

Does anyone know how this happen ?