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| resources:tools-software:linux-drivers:iio-adc:ad7998 [16 Nov 2012 13:29] – [Reference Circuit Notes] fix heading Lars-Peter Clausen | resources:tools-software:linux-drivers:iio-adc:ad7998 [06 Mar 2015 10:27] – update Michael Hennerich | ||
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| Line 15: | Line 15: | ||
| ===== Reference Circuits ===== | ===== Reference Circuits ===== | ||
| - | * [[adi> | ||
| * [[adi> | * [[adi> | ||
| - | * [[adi>CN0045]] | + | * [[adi>CN0288]] |
| + | * [[adi> | ||
| ===== Evaluation Boards ===== | ===== Evaluation Boards ===== | ||
| Line 40: | Line 40: | ||
| ^ Source | ^ Source | ||
| - | | [[git.linux.org> | + | | [[git.linux.org> |
| ===== Files ===== | ===== Files ===== | ||
| ^ Function ^ File ^ | ^ Function ^ File ^ | ||
| - | | driver | + | | driver |
| - | | driver | + | |
| - | | include | [[git.linux.org> | + | |
| ====== Example platform device initialization ====== | ====== Example platform device initialization ====== | ||
| Line 52: | Line 51: | ||
| {{page> | {{page> | ||
| - | The reference voltage may vary between boards and models. The platform_data for the device' | ||
| - | <source trunk/drivers/ | + | ===== Specifying reference voltage via the regulator framework ===== |
| + | |||
| + | <WRAP tip> | ||
| + | In case the AD799x on-chip reference is not used, | ||
| + | this driver requires specifying the reference voltage, by using the Linux regulator framework. | ||
| + | </WRAP> | ||
| + | |||
| + | Below example specifies a 2.5 Volt reference for the I2C device 0-0024 on I2C-Bus 0. (**0-0024**) | ||
| <code c> | <code c> | ||
| - | static struct | + | #if defined(CONFIG_REGULATOR_FIXED_VOLTAGE) || defined(CONFIG_REGULATOR_FIXED_VOLTAGE_MODULE) |
| - | .vref_mv = 2500, | + | static struct |
| + | REGULATOR_SUPPLY(" | ||
| }; | }; | ||
| + | |||
| + | static struct regulator_init_data board_avdd_reg_init_data = { | ||
| + | .constraints = { | ||
| + | .name = " | ||
| + | .valid_ops_mask = REGULATOR_CHANGE_STATUS, | ||
| + | }, | ||
| + | .consumer_supplies = ad7998_consumer_supplies, | ||
| + | .num_consumer_supplies = ARRAY_SIZE(ad7998_consumer_supplies), | ||
| + | }; | ||
| + | |||
| + | static struct fixed_voltage_config board_vref_pdata = { | ||
| + | .supply_name = " | ||
| + | .microvolts = 2500000, | ||
| + | .gpio = -EINVAL, | ||
| + | .enabled_at_boot = 0, | ||
| + | .init_data = & | ||
| + | }; | ||
| + | static struct platform_device brd_voltage_regulator = { | ||
| + | .name = " | ||
| + | .id = -1, | ||
| + | .num_resources = 0, | ||
| + | .dev = { | ||
| + | .platform_data = & | ||
| + | }, | ||
| + | }; | ||
| + | #endif | ||
| </ | </ | ||
| - | <note tip> | + | <code c> |
| - | In case platform_data is not present or set to NULL, the driver will use the AD7998 internal reference. | + | static struct platform_device *board_devices[] __initdata = { |
| - | </note> | + | #if defined(CONFIG_REGULATOR_FIXED_VOLTAGE) || defined(CONFIG_REGULATOR_FIXED_VOLTAGE_MODULE) |
| + | & | ||
| + | #endif | ||
| + | }; | ||
| + | </ | ||
| + | |||
| + | <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> | {{page> | ||
| Line 96: | Line 146: | ||
| </ | </ | ||
| - | ====== Adding Linux drive | + | ===== Devicetree ===== |
| - | r support ====== | + | |
| + | Required devicetree properties: | ||
| + | * compatible: Needs to be " | ||
| + | * reg: The slave address used for the device | ||
| + | * vcc-supply: Phandle to the supply regulator | ||
| + | |||
| + | < | ||
| + | | ||
| + | | ||
| + | | ||
| + | | ||
| + | | ||
| + | }; | ||
| + | |||
| + | | ||
| + | | ||
| + | | ||
| + | | ||
| + | | ||
| + | }; | ||
| + | |||
| + | i2c: i2c@e0007000 { | ||
| + | # | ||
| + | # | ||
| + | | ||
| + | ... | ||
| + | |||
| + | | ||
| + | | ||
| + | reg = < | ||
| + | | ||
| + | | ||
| + | }; | ||
| + | }; | ||
| + | </ | ||
| + | |||
| + | ====== Adding Linux driver | ||
| Configure kernel with "make menuconfig" | Configure kernel with "make menuconfig" | ||
| "make qconfig" | "make qconfig" | ||
| - | <note> | + | <WRAP round help> |
| The AD7998 Driver depends on **CONFIG_I2C** | The AD7998 Driver depends on **CONFIG_I2C** | ||
| - | </note> | + | </WRAP> |
| < | < | ||
| Line 133: | Line 219: | ||
| {{page> | {{page> | ||
| - | < | + | <WRAP box bggreen>< |
| < | < | ||
| root:/> **cd / | root:/> **cd / | ||
| Line 158: | Line 244: | ||
| drwxr-xr-x | drwxr-xr-x | ||
| -rw-r--r-- | -rw-r--r-- | ||
| - | </ | + | </ |
| === Show device name === | === Show device name === | ||
| - | < | + | <WRAP box bggreen>< |
| < | < | ||
| root:/ | root:/ | ||
| ad7998 | ad7998 | ||
| - | </ | + | </ |
| === Show scale === | === Show scale === | ||
| Line 173: | Line 259: | ||
| scale to be applied to in_voltage0_raw in order to obtain the measured voltage in millivolts. | scale to be applied to in_voltage0_raw in order to obtain the measured voltage in millivolts. | ||
| - | < | + | <WRAP box bggreen>< |
| < | < | ||
| root:/ | root:/ | ||
| 1.000 | 1.000 | ||
| - | </ | + | </ |
| === Show channel 0 measurement === | === Show channel 0 measurement === | ||
| Line 184: | Line 270: | ||
| Raw unscaled voltage measurement on channel 0 | Raw unscaled voltage measurement on channel 0 | ||
| - | < | + | <WRAP box bggreen>< |
| < | < | ||
| root:/ | root:/ | ||
| 1491 | 1491 | ||
| - | </ | + | </ |
| **U** = // | **U** = // | ||
| Line 202: | Line 288: | ||
| ===== Buffer management ===== | ===== Buffer management ===== | ||
| - | < | + | <WRAP box bggreen>< |
| < | < | ||
| root:/ | root:/ | ||
| **enable** | **enable** | ||
| root:/ | root:/ | ||
| - | </ | + | </ |
| {{page> | {{page> | ||
| - | < | + | <WRAP box bggreen>< |
| < | < | ||
| root:/ | root:/ | ||
| Line 220: | Line 306: | ||
| in_voltage2_en | in_voltage2_en | ||
| root:/ | root:/ | ||
| - | </ | + | </ |
resources/tools-software/linux-drivers/iio-adc/ad7998.txt · Last modified: 05 Jan 2021 16:01 by Ioana Chelaru