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--- resources:tools-software:linux-drivers:iio-dac:ad5593r [22 Feb 2016 17:52] – [Device tree example] Michael Hennerich
+++ resources:tools-software:linux-drivers:iio-dac:ad5593r [05 Dec 2017 14:11] – Michael Hennerich
@@ Line 18: / Line 18: @@
 The AD5593R have eight I/Ox pins (I/O0 to I/O7) that can be independently configured as digital-to-analog converter (DAC) outputs, analog-to-digital converter (ADC) inputs, digital outputs, or digital inputs.
 When an I/Ox pin is configured as an analog output, it is driven by a 12-bit DAC. The output range of the DAC is 0 V to VREF or 0 V to 2 × VREF.
 When an I/Ox pin is configured as an analog input, it is connected to a 12-bit ADC via an analog multiplexer. The input range of the ADC is 0 V to VREF or 0 V to 2 × VREF. The ADC has a total throughput rate of 400 kSPS.
 The I/Ox pins can also be configured as digital, general-purpose input or output (GPIO) pins. The state of the GPIO pins can be set or read back by accessing the GPIO write data register or the GPIO read configuration register, respectively, via an I2C write or read operation.
 The AD5593R have an integrated 2.5 V, 25 ppm/°C reference, which is turned off by default, and an integrated temperature indicator, which gives an indication of the die temperature. The temperature value is read back as part of an ADC read sequence.
+====== Source Code ======
+===== Status =====
+^ Source ^ Mainlined? ^
+| [[git.linux.org>drivers/iio/dac/ad5592r-base.c|git]] | [[git.linux.org>drivers/iio/dac/ad5592r-base.c|Yes]] |
+===== Files =====
+^ Function ^ File ^
+| driver  | [[linux.github>xcomm_zynq?drivers/iio/dac/ad5592r-base.c | drivers/iio/dac/ad5592r-base.c]] |
+| include  | [[linux.github>xcomm_zynq?drivers/iio/dac/ad5592r-base.h | drivers/iio/dac/ad5592r-base.h]] |
+| driver  | [[linux.github>xcomm_zynq?drivers/iio/dac/ad5593r.c | drivers/iio/dac/ad5593r.c]] |
+| include  | [[linux.github>xcomm_zynq?include/dt-bindings/iio/adi,ad5592r.h | include/dt-bindings/iio/adi,ad5592r.h]] |
+| Documentation  | [[linux.github>xcomm_zynq?Documentation/devicetree/bindings/iio/dac/ad5592r.txt | Documentation/devicetree/bindings/iio/dac/ad5592r.txt]] |
 ====== Hardware configuration ======
@@ Line 66: / Line 78: @@
     * "adi,ad5593r"
   * **reg**: I2C address of the chip (generally 0x10).
-  * **channel-modes**: An array of eight 8-bit values (one per channel) describing the mode of each channel. Macros specifying the valid values can be found in <dt-bindings/iio/adi,ad5592r.h>. The following values are currently supported:
+  * **#address-cells**: Should be 1.
-		* CH_MODE_ADC			(the pin is ADC input)
+  * **#size-cells**: Should be 0.
-		* CH_MODE_DAC			(the pin is DAC output)
+  * **channel nodes**:
-		* CH_MODE_DAC_AND_ADC		(the pin is DAC output but can be monitored by an ADC)
+    * Each child node represents one channel and has the following
-		* CH_MODE_UNUSED_PULL_DOWN  	(the pin is pulled down)
+    * **Required properties**:
-		* CH_MODE_UNUSED_OUT_LOW 	(the pin is output low)
+     * **reg**: Pin on which this channel is connected to.
-		* CH_MODE_UNUSED_OUT_HIGH	(the pin is output high)
+     * **adi,mode**: Mode or function of this channel. Macros specifying the valid values can be found in <dt-bindings/iio/adi,ad5592r.h>. The following values are currently supported:
-		* CH_MODE_UNUSED_OUT_TRISTATE	(the pin is tristated output)
+       * CH_MODE_UNUSED (the pin is unused)
-		* CH_MODE_GPIO			(the pin is registered with GPIOLIB)
+       * CH_MODE_ADC (the pin is ADC input)
-		* CH_MODE_GPIO_OPEN_DRAIN	(the pin is configured open drain and registered with GPIOLIB)
+       * CH_MODE_DAC (the pin is DAC output)
+       * CH_MODE_DAC_AND_ADC (the pin is DAC output but can be monitored by an ADC, since there is no disadvantage this this should be considered as the preferred DAC mode)
+       * CH_MODE_GPIO (the pin is registered with GPIOLIB)
+  * **Optional properties**:
+   * **adi,off-state**: State of this channel when unused or the device is removed. Macros specifying the valid values can be found in <dt-bindings/iio/adi,ad5592r.h>.
+    * CH_OFFSTATE_PULLDOWN (the pin is pulled down)
+    * CH_OFFSTATE_OUT_LOW  (the pin is output low)
+    * CH_OFFSTATE_OUT_HIGH (the pin is output high)
+    * CH_OFFSTATE_OUT_TRISTATE (the pin is tristated output)
 ==== Optional properties ====
   * **vref-supply**: Phandle to the external reference voltage supply. This should only be set if there is an external reference voltage connected to the VREF pin. If the property is not set the internal 2.5V reference is used.
-  * **reset-gpios**: GPIO spec for the RESET pin. If specified, it will be asserted during driver probe.
+  * **reset-gpios** : GPIO spec for the RESET pin. If specified, it will be asserted during driver probe.
+  * **gpio-controller**: Marks the device node as a GPIO controller.
+  * **#gpio-cells**: Should be 2. The first cell is the GPIO number and the second cell specifies GPIO flags, as defined in <dt-bindings/gpio/gpio.h>.
 ==== Device tree example ====
 The following example instanciates the ad5593r driver for a AD5593R device connected on a I2C bus. It sets the I/O0 port as a DAC, the I/O1 port as ADC. I/O2 and I/O3 are configured for primary function DAC the additional ADC can measure the voltage being provided by the DAC. This feature can monitor the output voltage to detect short circuits or overload conditions. I/O4 is connected to the ground with a pull-down resistor. The other I/Os are registered with the Linux GPIO subsystem.
@@ Line 97: / Line 121: @@
 	status = "okay";
 	clock-frequency = <400000>;
 	ad5593r@10 {
+		#size-cells = <0>;
+		#address-cells = <1>;
+		#gpio-cells = <2>;
 		compatible = "adi,ad5593r";
 		reg = <0x10>;
+		gpio-controller;
-		channel-modes = /bits/ 8 <
+		channel@0 {
-			CH_MODE_DAC
+			reg = <0>;
-			CH_MODE_ADC
+			adi,mode = <CH_MODE_DAC>;
-			CH_MODE_DAC_AND_ADC
+			adi,off-state = <CH_OFFSTATE_PULLDOWN>;
-			CH_MODE_DAC_AND_ADC
+		};
-			CH_MODE_UNUSED_PULL_DOWN
+		channel@1 {
-			CH_MODE_GPIO
+			reg = <1>;
-			CH_MODE_GPIO
+			adi,mode = <CH_MODE_ADC>;
-			CH_MODE_GPIO
+			adi,off-state = <CH_OFFSTATE_PULLDOWN>;
-		>;
+		};
+		channel@2 {
+			reg = <2>;
+			adi,mode = <CH_MODE_DAC_AND_ADC>;
+			adi,off-state = <CH_OFFSTATE_PULLDOWN>;
+		};
+		channel@6 {
+			reg = <6>;
+			adi,mode = <CH_MODE_GPIO>;
+			adi,off-state = <CH_OFFSTATE_PULLDOWN>;
+		};
 		vref-supply = <&vref>; /* optional */
 		reset-gpios = <&gpio0 86 0>;  /* optional */
 	};
 };
 </code>
-==== Driver testing ====
+====== Driver testing ======
 If the driver correctly detected the device, the "iio_info" program should inform us about the available channels:
@@ Line 164: / Line 204: @@
                                 attr 2: scale value: 452.147700000
+</code>
+====== IIO sysfs interface ======
+<code>
+root@linaro-ubuntu-desktop:/sys/bus/iio/devices/iio:device2# ls -al
+total 0
+drwxr-xr-x 3 root root    0 Jan  1  1970 .
+drwxr-xr-x 5 root root    0 Jan  1  1970 ..
+-rw-rw-rw- 1 root root 4096 Jan  1  1970 dev
+-rw-rw-rw- 1 root root 4096 Jan  1  1970 in_temp_offset
+-rw-rw-rw- 1 root root 4096 Jan  1  1970 in_temp_raw
+-rw-rw-rw- 1 root root 4096 Jan  1  1970 in_temp_scale
+-rw-rw-rw- 1 root root 4096 Jan  1  1970 in_voltage1_raw
+-rw-rw-rw- 1 root root 4096 Jan  1  1970 in_voltage2_raw
+-rw-rw-rw- 1 root root 4096 Jan  1  1970 in_voltage3_raw
+-rw-rw-rw- 1 root root 4096 Jan  1  1970 in_voltage_scale
+-rw-rw-rw- 1 root root 4096 Jan  1  1970 in_voltage_scale_available
+-rw-rw-rw- 1 root root 4096 Jan  1  1970 name
+lrwxrwxrwx 1 root root    0 Jan  1  1970 of_node -> ../../../../../../../firmware/devicetree/base/amba/i2c@e0004000/ad5593r@10
+-rw-rw-rw- 1 root root 4096 Jan  1  1970 out_voltage0_raw
+-rw-rw-rw- 1 root root 4096 Jan  1  1970 out_voltage2_raw
+-rw-rw-rw- 1 root root 4096 Jan  1  1970 out_voltage3_raw
+-rw-rw-rw- 1 root root 4096 Jan  1  1970 out_voltage_scale
+-rw-rw-rw- 1 root root 4096 Jan  1  1970 out_voltage_scale_available
+drwxrwxrwx 2 root root    0 Jan  1  1970 power
+lrwxrwxrwx 1 root root    0 Jan  1  1970 subsystem -> ../../../../../../../bus/iio
+-rw-rw-rw- 1 root root 4096 Jan  1  1970 uevent
+root@linaro-ubuntu-desktop:/sys/bus/iio/devices/iio:device2#
+</code>
+<code>
+root@linaro-ubuntu-desktop:/sys/bus/iio/devices/iio:device2# grep "" *
+dev:252:2
+in_temp_offset:-753
+in_temp_raw:810
+in_temp_scale:376.789750000
+in_voltage1_raw:0
+in_voltage2_raw:0
+in_voltage3_raw:0
+in_voltage_scale:0.610351562
+in_voltage_scale_available:0.610351562 1.220703124
+name:ad5592r
+out_voltage0_raw:0
+out_voltage2_raw:0
+out_voltage3_raw:0
+out_voltage_scale:0.610351562
+out_voltage_scale_available:0.610351562 1.220703124
+uevent:MINOR=2
+uevent:DEVNAME=iio:device2
+uevent:DEVTYPE=iio_device
+uevent:OF_NAME=ad5593r
+uevent:OF_FULLNAME=/amba/i2c@e0004000/ad5593r@10
+uevent:OF_COMPATIBLE_0=adi,ad5593r
+uevent:OF_COMPATIBLE_N=1
+</code>
+===== Show device name =====
+<WRAP box bggreen><wrap info>This specifies any shell prompt running on the target</wrap>
+<xterm>
+root@linaro-ubuntu-desktop:/sys/bus/iio/devices/iio:device2# **cat name**
+ad5593r
+</xterm></WRAP>
+===== Scales =====
+The output range of the DAC is 0 V to VREF or 0 V to 2 × VREF.
+**out_voltage_scale** is used to select the high or low range.
+Without external reference the driver selects the internal 2500mV VREF reference.
+So the scale computes as 2500mV/2^12 = 0.610351562 or 5000mV/2^12 = 1.220703124.
+The input range of the ADC is 0 V to VREF or 0 V to 2 × VREF.
+**in_voltage_scale** is used to select the high or low range.
+Without external reference the driver selects the internal 2500mV VREF reference.
+So the scale computes as 2500mV/2^12 = 0.610351562 or 5000mV/2^12 = 1.220703124.
+==== Show current scale ====
+**Description:**\\
+scale to be applied to out_voltageY_raw/in_voltageY_raw in order to obtain the measured voltage in millivolts.
+<WRAP box bggreen><wrap info>This specifies any shell prompt running on the target</wrap>
+<xterm>
+root@linaro-ubuntu-desktop:/sys/bus/iio/devices/iio:device2# **cat out_voltage_scale**
+.610351562
+</xterm></WRAP>
+==== Show available scales ====
+**Description:**\\
+scale to be applied to out_voltageY_raw/in_voltageY_raw in order to obtain the measured voltage in millivolts.
+<WRAP box bggreen><wrap info>This specifies any shell prompt running on the target</wrap>
+<xterm>
+root@linaro-ubuntu-desktop:/sys/bus/iio/devices/iio:device2# **cat in_voltage_scale_available**
+.610351562 1.220703124
+</xterm></WRAP>
+==== Change scales ====
+**Description:**\\
+scale to be applied to out_voltageY_raw/in_voltageY_raw in order to obtain the measured voltage in millivolts.
+<WRAP box bggreen><wrap info>This specifies any shell prompt running on the target</wrap>
+<xterm>
+root@linaro-ubuntu-desktop:/sys/bus/iio/devices/iio:device2# **echo 1.220703124 > in_voltage_scale**
+root@linaro-ubuntu-desktop:/sys/bus/iio/devices/iio:device2# **cat in_voltage_scale**
+.220703124
+</xterm></WRAP>
+===== Get channel Y input voltage =====
+Description:
+Raw unscaled voltage measurement on channel Y
+This specifies any shell prompt running on the target
+<WRAP box bggreen><wrap info>This specifies any shell prompt running on the target</wrap>
+<xterm>
+root@linaro-ubuntu-desktop:/sys/bus/iio/devices/iio:device2# cat in_voltage3_raw
+</xterm></WRAP>
+U = in_voltage3_raw * in_voltage_scale = 1491 * 0.610351562 = 910 mV
+===== Set channel Y output voltage =====
+**Description:**\\
+Raw (unscaled, no bias etc.) output voltage for channel Y.
+<WRAP box bggreen><wrap info>This specifies any shell prompt running on the target</wrap>
+<xterm>
+root@linaro-ubuntu-desktop:/sys/bus/iio/devices/iio:device2# echo 1638 > out_voltage0_raw
+</xterm></WRAP>
+**U** = //out_voltage0_raw * out_voltage_scale// = 1638 * 0.610351562 = **999.76 //mV//**
+===== Example obtaining the temperature in °C =====
+T =  ( in_temp_raw + in_temp_offset ) * in_temp_scale
+T = ( 810 - 753 ) * 376.78975 =  21477 mdeg C = 21.5 °C
+For more information see also here: [[git.linux.org>Documentation/ABI/testing/sysfs-bus-iio | IIO Kernel Documentation]]
+===== GPIO Testing  =====
+The GPIO sysfs interface allows users to manipulate any GPIO from userspace. Userspace utilizes a sysfs control interface to dynamically request and release individual GPIOs. Once a GPIO has been requested, writing to the newly created path allows you to control the direction and the data while reading from it returns the GPIO data (which usually corresponds to a 0 or 1 which represents the signal level).
+For more information see also here: [[git.linux.org>Documentation/gpio/sysfs.txt | GPIO Kernel Documentation]]
+<code>
+root@linaro-ubuntu-desktop:~# cd /sys/class/gpio/
+root@linaro-ubuntu-desktop:/sys/class/gpio# ls
+export  gpiochip890  gpiochip898  gpiochip906  unexport
+root@linaro-ubuntu-desktop:/sys/class/gpio# cd gpiochip890
+root@linaro-ubuntu-desktop:/sys/class/gpio/gpiochip890# ls -al
+total 0
+drwxr-xr-x 3 root root    0 Jan  1  1970 .
+drwxr-xr-x 3 root root    0 Jan  1  1970 ..
+-r--r--r-- 1 root root 4096 Feb 23 08:06 base
+lrwxrwxrwx 1 root root    0 Feb 23 08:06 device -> ../../../0-0010
+-r--r--r-- 1 root root 4096 Feb 23 08:06 label
+-r--r--r-- 1 root root 4096 Feb 23 08:06 ngpio
+drwxr-xr-x 2 root root    0 Feb 23 08:06 power
+lrwxrwxrwx 1 root root    0 Jan  1  1970 subsystem -> ../../../../../../../../class/gpio
+-rw-r--r-- 1 root root 4096 Jan  1  1970 uevent
+root@linaro-ubuntu-desktop:/sys/class/gpio/gpiochip890# grep "" *
+base:890
+label:0-0010
+ngpio:8
+root@linaro-ubuntu-desktop:/sys/class/gpio/gpiochip890# cd ..
+root@linaro-ubuntu-desktop:/sys/class/gpio# echo 897 > export
+root@linaro-ubuntu-desktop:/sys/class/gpio# cd gpio897/
+root@linaro-ubuntu-desktop:/sys/class/gpio/gpio897# ls -al
+total 0
+drwxr-xr-x 3 root root    0 Feb 23 08:06 .
+drwxr-xr-x 4 root root    0 Feb 23 08:06 ..
+-rw-r--r-- 1 root root 4096 Feb 23 08:06 active_low
+lrwxrwxrwx 1 root root    0 Feb 23 08:06 device -> ../../../0-0010
+-rw-r--r-- 1 root root 4096 Feb 23 08:06 direction
+drwxr-xr-x 2 root root    0 Feb 23 08:06 power
+lrwxrwxrwx 1 root root    0 Feb 23 08:06 subsystem -> ../../../../../../../../class/gpio
+-rw-r--r-- 1 root root 4096 Feb 23 08:06 uevent
+-rw-r--r-- 1 root root 4096 Feb 23 08:06 value
+root@linaro-ubuntu-desktop:/sys/class/gpio/gpio897# cat direction
+in
+root@linaro-ubuntu-desktop:/sys/class/gpio/gpio897# cat value
+root@linaro-ubuntu-desktop:/sys/class/gpio/gpio897# echo low > direction
+root@linaro-ubuntu-desktop:/sys/class/gpio/gpio897# cat direction
+out
+root@linaro-ubuntu-desktop:/sys/class/gpio/gpio897# cat value
+root@linaro-ubuntu-desktop:/sys/class/gpio/gpio897# echo high > direction
+root@linaro-ubuntu-desktop:/sys/class/gpio/gpio897# cat value
 </code>

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