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resources:tools-software:linux-drivers:iio-dds:ad9834 [27 Apr 2016 17:14] – [Example platform device initialization] Fix typo Lars-Peter Clausenresources:tools-software:linux-drivers:iio-dds:ad9834 [15 Mar 2019 08:14] (current) – change platform to DT Alexandru Ardelean
Line 37: Line 37:
 | include | [[git.linux.org>drivers/staging/iio/frequency/ad9834.h]] | | include | [[git.linux.org>drivers/staging/iio/frequency/ad9834.h]] |
  
-====== Example platform device initialization ======+====== Example device-tree ======
  
-{{page>software/linux/docs/platform_and_bus_model#Platform Data&noheader&firstseconly&noeditbtn}}+In the example below, it's assumed that **spi0** is the SPI controller to which the AD983X is attached to. Typically, these are defined in the board device-tree where the AD983X is attached to.
  
-The reference voltage may vary between boards and models. The platform_data for the device's "struct device" holds this information.+<code c>
  
-<source trunk/drivers/staging/iio/dds/ad9834.h:ad9834_platform_data{} c linux-kernel>+ &spi0 { 
 + #address-cells = <1>; 
 + #size-cells = <0>; 
 + status = "okay";
  
-<code c> + ad9833@0{ 
-/** + #clock-cells = <0>; 
- * struct ad9834_platform_data - platform specific information + compatible = "adi,ad9833"; 
- * @mclk: master clock in Hz + reg = <0>; 
- * @freq0: power up freq0 tuning word in Hz + spi-max-frequency = <1000000>; 
- * @freq1: power up freq1 tuning word in Hz + spi-cpol; 
- * @phase0: power up phase0 value [0..4095] correlates with 0..2PI + clocks = <&osc>; 
- * @phase1: power up phase1 value [0..4095] correlates with 0..2PI + vcc-supply = <&vcc>; 
- * @en_div2: digital output/2 is passed to the SIGN BIT OUT pin + }; 
- * @en_signbit_msb_out: the MSB (or MSB/2) of the DAC data is connected to the + };
- * SIGN BIT OUT pin. en_div2 controls whether it is the MSB +
- * or MSB/2 that is output. if en_signbit_msb_out=false, +
- * the on-board comparator is connected to SIGN BIT OUT +
- */ +
- +
-struct ad9834_platform_data ad9834_pdata = { +
- .mclk = 75000000, +
- .freq0 = 1000000, +
- .freq1 = 5000000, +
- .phase0 = 512, +
- .phase1 = 1024, +
- .en_div2 = false, +
- .en_signbit_msb_out = false, +
-};+
 </code> </code>
  
-{{page>software/linux/docs/platform_and_bus_model#Declaring SPI slave devices&firstseconly&noeditbtn}}+This example also references a regulator (vcc-supply) and a clock (osc). These can be left out, in which case it's assumed they are somehow hard-wired on the board to a proper voltage supply and clock source.
  
-Depending on the DDS IC used, you may need to set the modalias accordingly, matching your part name. +The **compabtible** string can be any of the following: 
-It may also required to adjust max_speed_hz. Please consult the datasheet, for maximum spi clock supported by the device in question.+  * adi,ad9833 
 +  * adi,ad9834 
 +  * adi,ad9837 
 +  * adi,ad9838
  
-<code c> +Note that, the *adi,* prefix can be omitted and this still works. It is preferred to be added to avoid any potential collisions with other drivers from other vendors. 
-static struct spi_board_info board_spi_board_info[] __initdata = { + 
-#if defined(CONFIG_AD9834) \ +However, the voltage supply & clock can be defined via device-tree as well. 
- || defined(CONFIG_AD9834_MODULE) +See example below:
- { +
- .modalias = "ad9834", +
- .max_speed_hz = 1000000,     /* max spi clock (SCK) speed in HZ */ +
- .bus_num = 0, +
- .chip_select = 3, /* CS, change it for your board */ +
- .platform_data = &ad9834_pdata, /* No spi_driver specific config */ +
- .mode = SPI_MODE_2, +
- }, +
-#endif +
-}; +
-</code>+
  
 <code c> <code c>
-static int __init board_init(void) + / { 
-{ + vcc: fixedregulator@0 { 
- [--snip--]+ compatible = "regulator-fixed"; 
 + regulator-name = "fixed-supply"; 
 + regulator-min-microvolt = <2500000>; 
 + regulator-max-microvolt = <2500000>; 
 + regulator-boot-on; 
 + };
  
- spi_register_board_info(board_spi_board_info, ARRAY_SIZE(board_spi_board_info));+ osc: oscillator { 
 + #clock-cells = <0>; 
 + compatible = "fixed-clock"; 
 + clock-frequency = <25000000>; 
 + }; 
 + }; 
 +</code>
  
- [--snip--] +This assumes that the board has the chips & drivers to generate voltages like this & clock frequencies.
- +
- return 0; +
-} +
-arch_initcall(board_init); +
-</code>+
  
 ====== Adding Linux driver support ====== ====== Adding Linux driver support ======
resources/tools-software/linux-drivers/iio-dds/ad9834.txt · Last modified: 15 Mar 2019 08:14 by Alexandru Ardelean

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