• AD7605-4
• AD7606
• AD7606-6
• AD7606-4
• AD7606B
• AD7616

• CN0148

• EVAL-AD7605-4
• EVAL-AD7606EDZ
• EVAL-AD7606-4EDZ
• EVAL-AD7606-6EDZ
• EVAL-AD7606BFMCZ
• EVAL-AD7616

This is a Linux industrial I/O (IIO) subsystem driver, targeting multi channel, dual interface serial/parallel interface ADCs. The industrial I/O subsystem provides a unified framework for drivers for many different types of converters and sensors using a number of different physical interfaces (i2c, spi, etc). See IIO for more information.

For the memory mapped parallel interface option, the user must specify the physical base address where the AD7606 is mapped into. A system IRQ number for the AD7606 BUSY indicator signal must be specified.

#if defined(CONFIG_AD7606) || defined(CONFIG_AD7606_MODULE)
static struct resource ad7606_resources[] = {
	[0] = {
		.start	= 0x20100000,        	/* SDP: AMS1 / CS_B */
		.end	= 0x20100000,
		.flags	= IORESOURCE_MEM,
	},
	[1] = {	/* general IRQ */
		.start	= IRQ_PH6,   	/* SDP: GPIO6 */
		.end	= IRQ_PH6,
		.flags	= IORESOURCE_IRQ | IORESOURCE_IRQ_HIGHLEVEL,
	},
};
 
static struct platform_device ad7606_device = {
	.name		= "ad7606-8",
	.dev = {
		.platform_data = &ad7606_pdata,
	},
	.num_resources	= ARRAY_SIZE(ad7606_resources),
	.resource	= ad7606_resources,
};
#endif

static struct platform_device *board_devices[] __initdata = {
#if defined(CONFIG_AD7606) || /
 	defined(CONFIG_AD7606_MODULE)
	&ad7606_device,
#endif
};

static int __init board_init(void)
{
	[--snip--]
 
	platform_add_devices(board_devices, ARRAY_SIZE(board_devices));
 
	[--snip--]
 
	return 0;
}
arch_initcall(board_init);

Depending on the converter IC used, you may need to set the modalias accordin gly, matching your part name. It may also required to adjust max_speed_hz. Please consult the datasheet, for maximum spi clock supported by the device in question.

static struct spi_board_info board_spi_board_info[] __initdata = {
#if defined(CONFIG_AD7606) || /
 	defined(CONFIG_AD7606_MODULE)
	{
		/* the modalias must be the same as spi device driver name */
		.modalias = "ad7606-8", /* Name of spi_driver for this device */
		.max_speed_hz = 10000000,     /* max spi clock (SCK) speed in HZ */
		.bus_num = 0, /* Framework bus number */
		.chip_select = 3, /* Framework chip select */
		.controller_data = &ad7606_chip_info, /* Blackfin only */
		.irq = IRQ_PH6,
		.mode = SPI_MODE_3,
	},
#endif
};

static int __init board_init(void)
{
	[--snip--]
 
	spi_register_board_info(board_spi_board_info, ARRAY_SIZE(board_spi_board_info));
 
	[--snip--]
 
	return 0;
}
arch_initcall(board_init);

Configure kernel with “make menuconfig” (alternatively use “make xconfig” or “make qconfig”)

Linux Kernel Configuration
	Device Drivers  --->
		<*>     Industrial I/O support --->
			--- Industrial I/O support
			          *** Analog to digital converters ***
			    [--snip--]

				<*>     Analog Devices AD7606 ADC driver with parallel interface support
				<*>     Analog Devices AD7606 ADC driver with spi interface support

			    [--snip--]

Analog Devices AD7606 Simultaneous Sampling ADC

Required properties for the AD7606:

- compatible: Must be one of

• “adi,ad7605-4”
• “adi,ad7606-8”
• “adi,ad7606-6”
• “adi,ad7606-4”
• “adi,ad7606b”
• “adi,ad7616”

- reg: SPI chip select number for the device - spi-max-frequency: Max SPI frequency to use.

      see: Documentation/devicetree/bindings/spi/spi-bus.txt

- spi-cpha: See Documentation/devicetree/bindings/spi/spi-bus.txt - avcc-supply: phandle to the Avcc power supply - interrupts: IRQ line for the ADC

      see: Documentation/devicetree/bindings/interrupt-controller/interrupts.txt

- adi,conversion-start-gpios: must be the device tree identifier of the CONVST pin. This logic input is used to initiate conversions on the analog input channels. As the line is active high, it should be marked GPIO_ACTIVE_HIGH.

Optional properties:

- reset-gpios: must be the device tree identifier of the RESET pin. If specified, it will be asserted during driver probe. As the line is active high, it should be marked GPIO_ACTIVE_HIGH.

- standby-gpios: must be the device tree identifier of the STBY pin. This pin is used to place the AD7606 into one of two power-down modes, Standby mode or Shutdown mode. As the line is active low, it should be marked GPIO_ACTIVE_LOW.

- adi,first-data-gpios: must be the device tree identifier of the FRSTDATA pin. The FRSTDATA output indicates when the first channel, V1, is being read back on either the parallel, byte or serial interface. As the line is active high, it should be marked GPIO_ACTIVE_HIGH.

- adi,range-gpios: must be the device tree identifier of the RANGE pin. The polarity on this pin determines the input range of the analog input channels. If this pin is tied to a logic high, the analog input range is ±10V for all channels. If this pin is tied to a logic low, the analog input range is ±5V for all channels. As the line is active high, it should be marked GPIO_ACTIVE_HIGH.

- adi,oversampling-ratio-gpios: must be the device tree identifier of the over-sampling mode pins. As the line is active high, it should be marked GPIO_ACTIVE_HIGH.

- adi,sw-mode: Boolean, software mode of operation, so far available only for ad7606b. Software mode is enabled when all three oversampling mode pins are connected to high level. The AD7606B is configured by the corresponding registers. If the adi,oversampling-ratio-gpios property is defined, then the driver will set the oversampling gpios to high. Otherwise, it is assumed that the pins are hardwired to VDD.

Example:

adc@0 {
	compatible = "adi,ad7606-8";
	reg = <0>;
	spi-max-frequency = <1000000>;
	spi-cpol;
	avcc-supply = <&adc_vref>;
	interrupts = <25 IRQ_TYPE_EDGE_FALLING>;
	interrupt-parent = <&gpio>;
	adi,conversion-start-gpios = <&gpio 17 GPIO_ACTIVE_HIGH>;
	reset-gpios = <&gpio 27 GPIO_ACTIVE_HIGH>;
	adi,first-data-gpios = <&gpio 22 GPIO_ACTIVE_HIGH>;
	adi,oversampling-ratio-gpios = <&gpio 18 GPIO_ACTIVE_HIGH
					&gpio 23 GPIO_ACTIVE_HIGH
					&gpio 26 GPIO_ACTIVE_HIGH>;
	standby-gpios = <&gpio 24 GPIO_ACTIVE_LOW>;
	adi,sw-mode;
};

Description:
scale to be applied to in0_raw in order to obtain the measured voltage in millivolts.

root:/sys/bus/iio/devices/iio:device0> cat in_voltage_scale
0.152

Description:
Raw unscaled voltage measurement on channel 2

root:/sys/bus/iio/devices/iio:device0> cat in_voltage2_raw
5789

U = in2_raw * in_scale = 5789 * 0.152 = 879,928 mV