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resources:tools-software:linux-drivers:iio-dds:ad9834 [27 Apr 2016 17:14] Lars-Peter Clausen [Example platform device initialization] Fix typo |
resources:tools-software:linux-drivers:iio-dds:ad9834 [15 Mar 2019 08:14] Alexandru Ardelean change platform to DT |
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| | 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