• AD5360
• AD5361
• AD5362
• AD5363
• AD5370
• AD5371
• AD5372
• AD5373

• EVAL-AD5360EBZ
• EVAL-AD5361EBZ
• EVAL-AD5362EBZ
• EVAL-AD5363EBZ
• EVAL-AD5370EBZ
• EVAL-AD5371EBZ
• EVAL-AD5372EBZ
• EVAL-AD5373EBZ

This is a Linux industrial I/O (IIO) subsystem driver, targeting multi-channel serial interface DACs. 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.

	fragment@0 {
		target-path = "/";
		__overlay__ {
			vref0: fixedregulator@0 {
				compatible = "regulator-fixed";
				regulator-name = "fixed-supply";
				regulator-min-microvolt = <3000000>;
				regulator-max-microvolt = <3000000>;
				regulator-boot-on;
			};
			vref1: fixedregulator@1 {
				compatible = "regulator-fixed";
				regulator-name = "fixed-supply";
				regulator-min-microvolt = <3000000>;
				regulator-max-microvolt = <3000000>;
				regulator-boot-on;
			};
		};
	};
 
	fragment@1 {
		target = <&spi0>;
		__overlay__ {
			#address-cells = <1>;
			#size-cells = <0>;
			status = "okay";
 
			ad5370@0{
				compatible = "adi,ad5370";
				reg = <0>;
				spi-max-frequency = <1000000>;
				spi-cpha;
				vref0-supply = <&vref0>;
				vref1-supply = <&vref1>;
			};
		};
	};
};

Below example specifies a 2.5 Volt reference for the SPI device 3 on SPI-Bus 0. (spi0.3) In this example all 4 reference voltage are supplied by the same regulator.

Except for the AD5371 devices expect two supplies named “vref0” and “vref1”. The AD5371 expects a third supply named “vref2”.

#if defined(CONFIG_REGULATOR_FIXED_VOLTAGE) || defined(CONFIG_REGULATOR_FIXED_VOLTAGE_MODULE)
static struct regulator_consumer_supply ad5360_consumer_supplies[] = {
	REGULATOR_SUPPLY("vref0", "spi0.3"),
	REGULATOR_SUPPLY("vref1", "spi0.3"),
	REGULATOR_SUPPLY("vref2", "spi0.3"),
};
 
static struct regulator_init_data stamp_avdd_reg_init_data = {
	.constraints	= {
		.name	= "2V5",
		.valid_ops_mask = REGULATOR_CHANGE_STATUS,
	},
	.consumer_supplies = ad5360_consumer_supplies,
	.num_consumer_supplies = ARRAY_SIZE(ad5360_consumer_supplies),
};
 
static struct fixed_voltage_config stamp_vdd_pdata = {
	.supply_name	= "board-2V5",
	.microvolts	= 2500000,
	.gpio		= -EINVAL,
	.enabled_at_boot = 0,
	.init_data	= &stamp_avdd_reg_init_data,
};
static struct platform_device brd_voltage_regulator = {
	.name		= "reg-fixed-voltage",
	.id		= -1,
	.num_resources	= 0,
	.dev		= {
		.platform_data	= &stamp_vdd_pdata,
	},
};
#endif

static struct platform_device *board_devices[] __initdata = {
#if defined(CONFIG_REGULATOR_FIXED_VOLTAGE) || defined(CONFIG_REGULATOR_FIXED_VOLTAGE_MODULE)
	&brd_voltage_regulator
#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 accordingly, 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_AD5360_SPI) || /
 	defined(CONFIG_AD5360_SPI_MODULE)
	{
		/* the modalias must be the same as spi device driver name */
		.modalias = "ad5360", /* Name of spi_driver for this device */
		.max_speed_hz = 1000000,     /* max spi clock (SCK) speed in HZ */
		.bus_num = 0, /* Framework bus number */
		.chip_select = 3, /* Framework chip select */
		.mode = SPI_MODE_1,
	},
#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
            ...
            Digital to analog converters  ---> 
                ...
                <*>  Analog Devices Analog Devices AD5360/61/62/63/70/71/73 DAC driver
                ...
            ...
        ...

Description:
/sys/bus/iio/devices/iio:deviceX/out_voltageY_scale

scale to be applied to out_voltage0_raw in order to obtain the measured voltage in millivolts.

root:/sys/devices/platform/bfin-spi.0/spi0.3/iio:device0> cat out_voltage0_scale
0.038140

Description:
/sys/bus/iio/devices/iio:deviceX/out_voltageY_raw

Raw (unscaled, no bias etc.) output voltage for channel Y.

root:/sys/devices/platform/bfin-spi.0/spi0.3/iio:device0> echo 10000 > out_voltage0_raw

U = out_voltage0_raw * out_voltage0_scale = 10000 * 0,038140 mV = 381,14 mV

Description:
/sys/bus/iio/devices/iio:deviceX/out_voltageY_calibscale

Each channel has an adjustable gain which can be used to calibrate the channel's scale and compensate for full-scale errors. The default value is 65535.

If scale calibration is used the following formula can be used calculate the output voltage: U = ( ( out_voltageY_raw * ( out_voltageY_calibscale + 1 ) ) / 2^16 - out_voltageY_calibbias ) * out_voltageY_scale

Description:
/sys/bus/iio/devices/iio:deviceX/out_voltageY_calibbias

Each channel has an adjustable offset which can be used to calibrate the channel's offset and compensate for zero-scale errors. The default value is 0.

If offset calibration is used the following formula can be used calculate the output voltage: U = ( ( out_voltageY_raw * ( out_voltageY_calibscale + 1 ) ) / 2^16 - out_voltageY_calibbias ) * out_voltageY_scale

/sys/bus/iio/devices/iio:deviceX/out_voltage_powerdown

Description:
Writing 1 causes the device to enter power down mode. Clearing returns to normal operation.

root:/sys/devices/platform/bfin-spi.0/spi0.3/iio:device0> echo 1 > out_voltage_powerdown
root:/sys/devices/platform/bfin-spi.0/spi0.3/iio:device0> cat out_voltage_powerdown
1
root:/sys/devices/platform/bfin-spi.0/spi0.3/iio:device0> echo 0 > out_voltage_powerdown
root:/sys/devices/platform/bfin-spi.0/spi0.3/iio:device0> cat out_voltage_powerdown
0