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resources:tools-software:linux-drivers:iio-adc:ad7998 [06 Mar 2015 09:39] – [Files] Michael Hennerichresources:tools-software:linux-drivers:iio-adc:ad7998 [05 Jan 2021 16:01] (current) – Removed old references Ioana Chelaru
Line 15: Line 15:
 ===== Reference Circuits ===== ===== Reference Circuits =====
  
-  * [[adi>CN0044]] 
   * [[adi>CN0288]]   * [[adi>CN0288]]
   * [[adi>CN0301]]   * [[adi>CN0301]]
Line 39: Line 38:
 ===== Status ===== ===== Status =====
  
-^  Source  ^  Mainlined?  ^ +^ Source ^ Mainlined? ^ 
-| [[git.linux.org>drivers/iio/adc/ad799x.c|git]] |  [[git.linux.org>drivers/iio/adc/ad799x.c|Yes]]  |+| [[git.linux.org>drivers/iio/adc/ad799x.c|git]] | [[git.linux.org>drivers/iio/adc/ad799x.c|Yes]] |
 ===== Files ===== ===== Files =====
  
Line 51: Line 50:
 {{page>software/linux/docs/platform_and_bus_model#Platform Data&noheader&firstseconly&noeditbtn}} {{page>software/linux/docs/platform_and_bus_model#Platform Data&noheader&firstseconly&noeditbtn}}
  
-The reference voltage may vary between boards and models. The platform_data for the device's "struct device" holds this information. 
  
-<source trunk/drivers/staging/iio/adc/ad799x.h:ad799x_platform_data{} c linux-kernel>+===== 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 ad799x_platform_data ad7998_pdata = { +#if defined(CONFIG_REGULATOR_FIXED_VOLTAGE) || defined(CONFIG_REGULATOR_FIXED_VOLTAGE_MODULE) 
- .vref_mv = 2500,+static struct regulator_consumer_supply ad7998_consumer_supplies[] = { 
 + REGULATOR_SUPPLY("vref", "0-0024"),
 }; };
 +
 +static struct regulator_init_data board_avdd_reg_init_data = {
 + .constraints = {
 + .name = "2V5",
 + .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 = "board-2V5",
 + .microvolts = 2500000,
 + .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_vref_pdata,
 + },
 +};
 +#endif
 </code> </code>
  
-<WRAP 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 = { 
-</WRAP>+#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}} {{page>software/linux/docs/platform_and_bus_model#Declaring I2C devices&firstseconly&noeditbtn}}
Line 93: Line 143:
 } }
 arch_initcall(board_init); arch_initcall(board_init);
 +</code>
 +
 +===== Devicetree =====
 +
 +Required devicetree properties:
 +  * compatible: Needs to be "adi," followed by the name of the device. E.g. "adi,ad7798"
 +  * reg: The slave address used for the device
 +  * vcc-supply: Phandle to the supply regulator
 +
 +<code>
 +       adc_supply: fixedregulator {
 +               compatible = "regulator-fixed";
 +               regulator-name = "fixed-supply";
 +               regulator-min-microvolt = <3300000>;
 +               regulator-max-microvolt = <3300000>;
 +       };
 +
 +       adc_vref: fixedregulator {
 +               compatible = "regulator-fixed";
 +               regulator-name = "fixed-supply";
 +               regulator-min-microvolt = <2500000>;
 +               regulator-max-microvolt = <2500000>;
 +       };
 +       
 +       i2c: i2c@e0007000 {
 +               #address-cells = <1>;
 +               #size-cells = <0>;
 +               compatible = "xlnx,xps-iic-2.00.a";
 +               ...
 +
 +               ad7798@24 {
 +                       compatible = "adi,ad7798";
 +                       reg = <0x24>;
 +                       vcc-supply = <&adc_supply>;
 +                       vref-supply = <&adc_vref>;
 +               };
 +        };
 </code> </code>
  
resources/tools-software/linux-drivers/iio-adc/ad7998.txt · Last modified: 05 Jan 2021 16:01 by Ioana Chelaru

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