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+====== AD7291 IIO ADC Linux Driver ======
+===== Supported Devices =====
+  * [[adi>AD7291]]
+===== Evaluation Boards =====
+  * [[adi>EVAL-AD7291SDZ]]
+===== Description =====
+This is a Linux industrial I/O ([[software:linux:docs:iio:iio|IIO]]) subsystem driver, targeting multi channel serial 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 [[software:linux:docs:iio:iio|IIO]] for more information.
+====== Source Code ======
+===== Status =====
+^  Source  ^  Mainlined?  ^
+| [[staging.kernel.org>drivers/staging/iio/adc/ad7291.c|git]] |  [[git.linux.org>drivers/staging/iio/adc/ad7291.c|Yes]]  |
+===== Files =====
+^ Function ^ File ^
+| driver  | [[staging.kernel.org>drivers/staging/iio/adc/ad7291.c]] |
+====== Example platform device initialization ======
+===== Specifying reference voltage via the regulator framework =====
+<note tip>
+In case the AD7291 on-chip 2.5V reference is not used,
+this driver requires specifying the reference voltage, by using the Linux regulator framework.
+</note>
+Below example specifies a 3.3 Volt reference for the I2C device 0-002a on I2C-Bus 0. (**0-002a**)
+<code c>
+#if defined(CONFIG_REGULATOR_FIXED_VOLTAGE) || defined(CONFIG_REGULATOR_FIXED_VOLTAGE_MODULE)
+static struct regulator_consumer_supply ad7291_consumer_supplies[] = {
+	REGULATOR_SUPPLY("vcc", "0-002a"),
+};
+static struct regulator_init_data board_avdd_reg_init_data = {
+	.constraints	= {
+		.name	= "3V3",
+		.valid_ops_mask = REGULATOR_CHANGE_STATUS,
+	},
+	.consumer_supplies = ad7291_consumer_supplies,
+	.num_consumer_supplies = ARRAY_SIZE(ad7291_consumer_supplies),
+};
+static struct fixed_voltage_config board_vdd_pdata = {
+	.supply_name	= "board-3V3",
+	.microvolts	= 3300000,
+	.gpio		= -EINVAL,
+	.enabled_at_boot = 0,
+	.init_data	= &board_avdd_reg_init_data,
+};
+static struct platform_device brd_voltage_regulator = {
+	.name		= "reg-fixed-voltage",
+	.id		= -1,
+	.num_resources	= 0,
+	.dev		= {
+		.platform_data	= &board_vdd_pdata,
+	},
+};
+#endif
+</code>
+<code c>
+static struct platform_device *board_devices[] __initdata = {
+#if defined(CONFIG_REGULATOR_FIXED_VOLTAGE) || defined(CONFIG_REGULATOR_FIXED_VOLTAGE_MODULE)
+	&brd_voltage_regulator
+#endif
+};
+</code>
+<code c>
+static int __init board_init(void)
+{
+	[--snip--]
+	platform_add_devices(board_devices, ARRAY_SIZE(board_devices));
+	[--snip--]
+	return 0;
+}
+arch_initcall(board_init);
+</code>
+{{page>software/linux/docs/platform_and_bus_model#Declaring I2C devices&firstseconly&noeditbtn}}
+Depending on the converter IC used, you may need to set the I2C_BOARD_INFO name accordingly, matching your part name.
+<code c>
+static struct i2c_board_info __initdata board_i2c_board_info[] = {
+#if defined(CONFIG_AD7291) || defined(CONFIG_AD7291_MODULE)
+	{
+		I2C_BOARD_INFO("ad7291", 0x2A),
+		.irq = IRQ_PG14,
+	},
+#endif
+};
+</code>
+<code c>
+static int __init board_init(void)
+{
+	[--snip--]
+	i2c_register_board_info(0, board_i2c_board_info,
+				ARRAY_SIZE(board_i2c_board_info));
+	[--snip--]
+	return 0;
+}
+arch_initcall(board_init);
+</code>
+====== Adding Linux driver support ======
+Configure kernel with "make menuconfig" (alternatively use "make xconfig" or
+"make qconfig")
+<note>
+The driver depends on **CONFIG_I2C**
+</note>
+<code>
+Linux Kernel Configuration
+	Device Drivers  --->
+		[*] Staging drivers  --->
+			<*>     Industrial I/O support --->
+			    --- Industrial I/O support
+			    -*-   Enable ring buffer support within IIO
+			    -*-     Industrial I/O lock free software ring
+			    -*-   Enable triggered sampling support
+			          *** Analog to digital converters ***
+			    [--snip--]
+			    <*>   Analog Devices AD7291 ADC driver
+			    [--snip--]
+</code>
+====== Hardware configuration ======
+{{:resources:tools-software:linux-drivers:iio-adc:ad7291_eval_lr.jpg?600|}}
+====== Driver testing ======
+{{page>software:linux:docs:iio:iio_snippets#iio device files&noheader&firstseconly&noeditbtn}}
+<box 100% green|shell prompt running on the target>
+<xterm>
+root:/> **cd /sys/bus/iio/devices/**
+root:/sys/bus/iio/devices> **ls**
+iio:device0
+root:/sys/bus/iio/devices> **cd iio:device0**
+root:/sys/devices/platform/i2c-bfin-twi.0/i2c-0/0-002a/iio:device0> **ls -l**
+-r--r--r--    1 root     root          4096 Jan  1 00:38 dev
+drwxr-xr-x    2 root     root             0 Jan  1 00:38 events
+-rw-r--r--    1 root     root          4096 Jan  1 00:38 in_temp0_mean_raw
+-r--r--r--    1 root     root          4096 Jan  1 00:38 in_temp0_raw
+-rw-r--r--    1 root     root          4096 Jan  1 00:38 in_temp0_scale
+-r--r--r--    1 root     root          4096 Jan  1 00:38 in_voltage0_raw
+-r--r--r--    1 root     root          4096 Jan  1 00:38 in_voltage1_raw
+-r--r--r--    1 root     root          4096 Jan  1 00:38 in_voltage2_raw
+-r--r--r--    1 root     root          4096 Jan  1 00:38 in_voltage3_raw
+-r--r--r--    1 root     root          4096 Jan  1 00:38 in_voltage4_raw
+-r--r--r--    1 root     root          4096 Jan  1 00:38 in_voltage5_raw
+-r--r--r--    1 root     root          4096 Jan  1 00:38 in_voltage6_raw
+-r--r--r--    1 root     root          4096 Jan  1 00:38 in_voltage7_raw
+-rw-r--r--    1 root     root          4096 Jan  1 00:38 in_voltage_scale
+-r--r--r--    1 root     root          4096 Jan  1 00:38 name
+drwxr-xr-x    2 root     root             0 Jan  1 00:38 power
+--w-------    1 root     root          4096 Jan  1 00:38 reset
+lrwxrwxrwx    1 root     root             0 Jan  1 00:38 subsystem -> ../../../../../../bus/iio
+-rw-r--r--    1 root     root          4096 Jan  1 00:38 uevent
+</xterm></box>
+=== Show device name ===
+<box 100% green|shell prompt running on the target>
+<xterm>
+root:/sys/devices/platform/i2c-bfin-twi.0/i2c-0/0-002a/iio:device0> **cat name**
+ad7291
+</xterm></box>
+=== Show scale ===
+**__Description:__**\\
+scale to be applied to in_voltageX_raw in order to obtain the measured voltage in millivolts.
+<box 100% green|shell prompt running on the target>
+<xterm>
+root:/sys/devices/platform/i2c-bfin-twi.0/i2c-0/0-002a/iio:device0> **cat in_voltage_scale**
+.610000
+</xterm></box>
+=== Show channel 0 measurement ===
+**__Description:__**\\
+Raw unscaled voltage measurement on channel 0
+^ ADC Input ^ Channel name ^
+| VIN0 | in_voltage0_raw |
+| VIN1 | in_voltage1_raw |
+| VIN2 | in_voltage2_raw |
+| VIN3 | in_voltage3_raw |
+| VIN4 | in_voltage4_raw |
+| VIN5 | in_voltage5_raw |
+| VIN6 | in_voltage6_raw |
+| VIN7 | in_voltage7_raw |
+<box 100% green|shell prompt running on the target>
+<xterm>
+root:/sys/devices/platform/i2c-bfin-twi.0/i2c-0/0-002a/iio:device0> **cat in_voltage0_raw**
+</xterm></box>
+**U** = //in_voltage0_raw * in_voltage_scale// = 1641 * 0.610000 = **1001,01 //mV//**
+=== Show internal temperature ===
+**__Description:__** /sys/bus/iio/devices/iio:deviceX/in_temp0_raw \\
+Shows raw unscaled temperature.
+^ Channel name ^ Description ^
+| in_temp0_raw | Current temperature |
+| in_temp0_mean_raw | Averaged temperature |
+<box 100% green|shell prompt running on the target>
+<xterm>
+root:/sys/devices/platform/i2c-bfin-twi.0/i2c-0/0-002a/iio:device0> **cat in_temp0_raw**
+root:/sys/devices/platform/i2c-bfin-twi.0/i2c-0/0-002a/iio:device0> **cat in_temp0_scale**
+</xterm></box>
+**T** = in_temp0_raw * in_temp0_scale = 107 * 250 = 26750 = **26.75 //°C//**
+====== Hardware Events ======
+{{page>software:linux:docs:iio:iio_snippets#Event Management&firstseconly&noeditbtn}}
+{{page>software:linux:docs:iio:iio_snippets#Typical event attributes&firstseconly&noeditbtn}}
+===== Supported Events =====
+^ Event Attributes ^
+^ Channel Temp ^
+| in_temp0_thresh_both_hyst_raw |
+| in_temp0_thresh_falling_en |
+| in_temp0_thresh_falling_value |
+| in_temp0_thresh_rising_en |
+| in_temp0_thresh_rising_value |
+^ Channel VIN0 ^
+| in_voltage0_thresh_both_hyst_raw |
+| in_voltage0_thresh_falling_en |
+| in_voltage0_thresh_falling_value |
+| in_voltage0_thresh_rising_en |
+| in_voltage0_thresh_rising_value |
+^ Channel VIN1 ^
+| in_voltage1_thresh_both_hyst_raw |
+| in_voltage1_thresh_falling_en |
+| in_voltage1_thresh_falling_value |
+| in_voltage1_thresh_rising_en |
+| in_voltage1_thresh_rising_value |
+^ Channel VIN2 ^
+| in_voltage2_thresh_both_hyst_raw |
+| in_voltage2_thresh_falling_en |
+| in_voltage2_thresh_falling_value |
+| in_voltage2_thresh_rising_en |
+| in_voltage2_thresh_rising_value |
+^ Channel VIN3 ^
+| in_voltage3_thresh_both_hyst_raw |
+| in_voltage3_thresh_falling_en |
+| in_voltage3_thresh_falling_value |
+| in_voltage3_thresh_rising_en |
+| in_voltage3_thresh_rising_value |
+^ Channel VIN4 ^
+| in_voltage4_thresh_both_hyst_raw |
+| in_voltage4_thresh_falling_en |
+| in_voltage4_thresh_falling_value |
+| in_voltage4_thresh_rising_en |
+| in_voltage4_thresh_rising_value |
+^ Channel VIN5 ^
+| in_voltage5_thresh_both_hyst_raw |
+| in_voltage5_thresh_falling_en |
+| in_voltage5_thresh_falling_value |
+| in_voltage5_thresh_rising_en |
+| in_voltage5_thresh_rising_value |
+^ Channel VIN6 ^
+| in_voltage6_thresh_both_hyst_raw |
+| in_voltage6_thresh_falling_en |
+| in_voltage6_thresh_falling_value |
+| in_voltage6_thresh_rising_en |
+| in_voltage6_thresh_rising_value |
+^ Channel VIN7 ^
+| in_voltage7_thresh_both_hyst_raw |
+| in_voltage7_thresh_falling_en |
+| in_voltage7_thresh_falling_value |
+| in_voltage7_thresh_rising_en |
+| in_voltage7_thresh_rising_value |
+====== More Information ======
+{{page>software:linux:docs:iio:iio_snippets#iio pointers&noheader&firstseconly&noeditbtn}}

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