AD7616 LINUX DRIVERS with ADS8686S -timeout issue in getting data for adc channel

Question

I am using AM625 processor and ADS8686S chip connected to SPI ( AD7616 linux drivers as they both have same register set) . I use the device in Software mode and the device tree configuration is as below, &main_spi0 { ti,spi-num-cs = <2>; status = "okay"; spidev@0 { compatible = "rohm,dh2228fv"; reg = <0>; spi-max-frequency = <23000000>; }; adc@1 { compatible = "adi,ad7616"; reg = <1>; spi-max-frequency = <1000000>; spi-cpol; label = "ad7616"; avcc-supply = <®_5v_dummy>; // Reference the 5V dummy regulator //avcc-supply = <®_3v3>; // Reference the 5V dummy regulator interrupt-parent = <&mcu_gpio0>; interrupts = <7 IRQ_TYPE_LEVEL_HIGH>; // (A6) DI_1V8_BUSY_AFE_1 SODIMM 61 reset-gpios = <&main_gpio0 3 GPIO_ACTIVE_LOW>; //(E25) OSPI0_D0 GPIO0_3 RESET SODIMM 56 adi,conversion-start-gpios = <&main_gpio0 4 GPIO_ACTIVE_HIGH>; // OSPI0_D1 (G24) OSPI0_D1 GPIO0_4 SODIMM 58 adi,sw-mode; }; I see below signals on my MOSI,MISO CLOCK, RESET AND CONVST AND Busy pin. But each time I try to read the values of analog channel it returns timeout error.

v310 · Accepted Answer

It works for me, I am able to read data from ADS8686S using Linux drivers the, I am writing this to make it helpful for others. (The SPIDEV is another device not required for our chip. I have 2 devices).

&main_spi0 {

ti,spi-num-cs = <2>;
status = "okay";

spidev@0 {
compatible = "rohm,dh2228fv";
reg = <0>;
spi-max-frequency = <23000000>;
};

adc@1 {
compatible = "adi,ad7616";
reg = <1>;
spi-max-frequency = <1000000>;
spi-cpol;
label = "ad7616";
avcc-supply = <&reg_5v_dummy>; // Reference the 5V dummy regulator
//avcc-supply = <&reg_3v3>; // Reference the 5V dummy regulator
interrupt-parent = <&mcu_gpio0>;
interrupts = <7 IRQ_TYPE_LEVEL_HIGH>; // (A6) DI_1V8_BUSY_AFE_1 SODIMM 61
reset-gpios = <&main_gpio0 3 GPIO_ACTIVE_LOW>; //(E25) OSPI0_D0 GPIO0_3 RESET SODIMM 56
adi,conversion-start-gpios = <&main_gpio0 4 GPIO_ACTIVE_HIGH>; // OSPI0_D1 (G24) OSPI0_D1 GPIO0_4 SODIMM 58

adi,sw-mode;

};

Make sure all the pins are defined at pinmux and added in respective group of pin.

Check all pins of your IC AS BELOW ,

To make it work in Software mode above pins are important ,

Make sure HW_RNGSEL all pins are ground and Serial,SER/PAR = HIGH , other pins must be verified as above table.

Once your board is booted and you must have device added in your /sys/bus/iio/devices/iio:deviceX

After that cat each channel as below.

root:/sys/bus/iio/devices/iio:device0> cat in_voltage0_raw
5789

multiply this with value you get while doing,

root:/sys/bus/iio/devices/iio:device0> cat in_voltage0_scale

You will get mV.


Must check the current counsumption is 0.5A while board is active. You can also debug the registers directly as below,

hange directory to /sys/kernel/debug/iio/ iio:deviceX and check if the direct_reg_access file exists.

This specifies any shell prompt running on the target

root@analog:~# cd /sys/kernel/debug/iio/iio\:device1
root@analog:/sys/kernel/debug/iio/iio:device1# ls direct_reg_access 
direct_reg_access

Reading

This specifies any shell prompt running on the target

root@analog:/sys/kernel/debug/iio/iio:device1# echo 0x7 > direct_reg_access                                                                                                                                 
root@analog:/sys/kernel/debug/iio/iio:device1# cat direct_reg_access 
0x40

Writing

Write ADDRESS VALUE

This specifies any shell prompt running on the target

root@analog:/sys/kernel/debug/iio/iio:device1# echo 0x7 0x50  > direct_reg_access                                                                                                                            
root@analog:/sys/kernel/debug/iio/iio:device1# cat direct_reg_access 
0x50

 Thanks

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AD7616 LINUX DRIVERS with ADS8686S -timeout issue in getting data for adc channel