Difference between revisions of "Spi device tree source code"

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m (Nordic Semi information page on device bindings files and vendors.)
m (Add note and mention need to investigate file in `zephyr/soc/arm/rpi_pico/rp2`.)
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*  https://developer.nordicsemi.com/nRF_Connect_SDK/doc/1.5.1/zephyr/reference/devicetree/bindings.html
 
*  https://developer.nordicsemi.com/nRF_Connect_SDK/doc/1.5.1/zephyr/reference/devicetree/bindings.html
  
 +
NEED TO INVESTIGATE files in following Zephyr SDK directories:
 +
 +
`zephyr/soc/arm/rpi_pico` and `zephyr/soc/arm/rpi_pico/rp2`
  
  

Revision as of 05:59, 12 August 2022

2022-08-11 Thursday

Notes on SPI device tree source, with goal to add SPI device to modified RPi Pico DTS files, which build firmware to run on Sparkfun DEV-18288 board. An interesting link at Nordic Semi documentation pages, link to page which mentions Synopsis as designer of designware-spi device bindings and related bindings is:

NEED TO INVESTIGATE files in following Zephyr SDK directories:

`zephyr/soc/arm/rpi_pico` and `zephyr/soc/arm/rpi_pico/rp2`


SPI dts examples

In Zephyr RTOS' supported board dts files we find SPI peripherals defined for several boards. Here are excerpts

Excerpt 1 - zephyr/boards/arm/sparkfun_thing_plus_nrf9160/sparkfun_thing_plus_nrf9160_common.dts


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&spi3 {
        compatible = "nordic,nrf-spim";
        status = "okay";
        cs-gpios = <&gpio0 7 GPIO_ACTIVE_LOW>;
        pinctrl-0 = <&spi3_default>;
        pinctrl-1 = <&spi3_sleep>;
        pinctrl-names = "default", "sleep";
        w25q32jv: w25q32jv@0 {
                compatible = "jedec,spi-nor";
                label = "W25Q32JV";
                reg = <0>;
                spi-max-frequency = <40000000>;
                wp-gpios = <&gpio0 8 GPIO_ACTIVE_LOW>;
                hold-gpios = <&gpio0 10 GPIO_ACTIVE_LOW>;
                size = <0x2000000>;
                has-dpd;
                t-enter-dpd = <3000>;
                t-exit-dpd = <30000>;
                jedec-id = [ ef 40 16 ];
        };
};

a
 81         spi3_default: spi3_default {
 82                 group1 {
 83                         psels = <NRF_PSEL(SPIM_SCK, 0, 11)>,
 84                                 <NRF_PSEL(SPIM_MOSI, 0, 9)>,
 85                                 <NRF_PSEL(SPIM_MISO, 0, 28)>;
 86                 };
 87         };
 88 
 89         spi3_sleep: spi3_sleep {
 90                 group1 {
 91                         psels = <NRF_PSEL(SPIM_SCK, 0, 11)>,
 92                                 <NRF_PSEL(SPIM_MOSI, 0, 9)>,
 93                                 <NRF_PSEL(SPIM_MISO, 0, 28)>;
 94                         low-power-enable;
 95                 };
 96         };


^ edit point dts excerpt 2

Excerpt 2 - zephyr/boards/arm/96b_carbon_nrf51/96b_carbon_nrf51.dts and 96b_carbon_nrf51-pinctrl.dtsi

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&spi1 {
        compatible = "nordic,nrf-spis";
        status = "okay";
        def-char = <0x00>;

        pinctrl-0 = <&spi1_default>;
        pinctrl-names = "default";
        bt-hci@0 {
                compatible = "zephyr,bt-hci-spi-slave";
                reg = <0>;
                irq-gpios = <&gpio0 28 (GPIO_ACTIVE_HIGH | GPIO_PULL_DOWN)>;
        };
};
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        spi1_default: spi1_default {
                group1 {
                        psels = <NRF_PSEL(SPIS_SCK, 0, 7)>,
                                <NRF_PSEL(SPIS_MOSI, 0, 0)>,
                                <NRF_PSEL(SPIS_MISO, 0, 30)>,
                                <NRF_PSEL(SPIS_CSN, 0, 25)>;
                };
        };

^ edit point dts excerpt 3

Excerpt 3 - zephyr/boards/arm/stm32l562e_dk/stm32l562e_dk_common.dts and stm32l562e_dk_common.dtsi


Looks like pin control names value 'default'
may be defined in Kconfig.default for this board . . .
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&spi1 {
        pinctrl-0 = <&spi1_sck_pg2 &spi1_miso_pg3 &spi1_mosi_pg4>;
        pinctrl-names = "default";
        cs-gpios = <&gpiog 5 (GPIO_ACTIVE_HIGH | GPIO_PULL_UP)>;
        status = "okay";

        spbtle-rf@0 {
                compatible = "zephyr,bt-hci-spi";
                reg = <0>;
                irq-gpios = <&gpiog 6 (GPIO_ACTIVE_HIGH | GPIO_PULL_DOWN)>;
                reset-gpios = <&gpiog 8 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
                spi-max-frequency = <2000000>;
                label = "SPBTLE-RF";
        };
};

^ edit point dts excerpt 4

Excerpt 4 -





^ edit point dts excerpt 5

Excerpt 5 -







^ edit point dts excerpt 5

From the zephyr/boards/arm/rpi_pico/doc/index.rst file:

== [[#top|^]] edit point dts excerpt 5 ==
 37      Raspberry Pi Pico (Image courtesy of Raspberry Pi)
 38 
 39 Supported Features
 40 ==================
 41 
 42 The rpi_pico board configuration supports the following
 43 hardware features:
 44 
 45 .. list-table::
 46    :header-rows: 1
 47 
 48    * - Peripheral
 49      - Kconfig option
 50      - Devicetree compatible
 51    * - NVIC
 52      - N/A
 53      - :dtcompatible:`arm,v6m-nvic`
 54    * - UART
 55      - :kconfig:option:`CONFIG_SERIAL`
 56      - :dtcompatible:`rpi,pico-uart`
 57    * - GPIO
 58      - :kconfig:option:`CONFIG_GPIO`
 59      - :dtcompatible:`rpi,pico-gpio`
 60    * - I2C
 61      - :kconfig:option:`CONFIG_I2C`
 62      - :dtcompatible:`snps,designware-i2c`
 63    * - USB Device
 64      - :kconfig:option:`CONFIG_USB_DEVICE_STACK`
 65      - :dtcompatible:`raspberrypi,pico-usbd`
 66    * - HWINFO
 67      - :kconfig:option:`CONFIG_HWINFO`
 68      - N/A
 69 
 70 Programming and Debugging
 71 *************************
 72 
 73 Flashing

There is a clue here on line 62 "- :dtcompatible:`snps,designware-i2c`". This is for I2C, but a search via startpage.com for "snps,designware-spi" gives a first or near first result of:

This still leaves the open question, where are RPi Pico's I2C and SPI driver implementations in Zephyr RTOS release 3.1.0?


^ YAML device bindings files

To support a typical development kit or custom board with multiple peripherals we need a device bindings file comparable to this ... bindings file:

  1. ~/projects-sandbox/workspace-for-rpi/zephyr/boards/arm/nrf9160dk_nrf9160/nrf9160dk_nrf9160.yaml
identifier: nrf9160dk_nrf9160
name: nRF9160-DK-NRF9160
type: mcu 
arch: arm 
toolchain:
  - gnuarmemb
  - xtools
  - zephyr
ram: 88
flash: 256 
supported:
  - arduino_gpio
  - arduino_i2c
  - gpio
  - i2c
  - pwm
  - spi
  - watchdog
  - counter

Or possibly this bindings file by Jared Wolff of Circuit Dojo: