Spi device tree source code - Revision history

Ted: /* ^ Overview */ - redirect external link to local list of device bindings references.

2022-08-19T18:08:56Z

^ Overview: - redirect external link to local list of device bindings references.

Ted: /* ^ Overview */

2022-08-19T17:50:48Z

^ Overview

Ted: /* ^ Overview */ - updating with notes on dts coding progress, next steps driver API writing anticipations.

2022-08-19T17:19:51Z

^ Overview: - updating with notes on dts coding progress, next steps driver API writing anticipations.

Ted: /* ^ Reference */

2022-08-16T22:36:49Z

^ Reference

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^ Reference

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Ted: section name change, content amendments.

2022-08-16T12:51:07Z

section name change, content amendments.

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2022-08-16T12:03:10Z

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@@ Line 18: / Line 18: @@
 RPi Pico SDK offers a starting point to understand needed wrapper code between Zephyr and Pico DMA driver, in their [https://github.com/raspberrypi/pico-examples/blob/master/dma/hello_dma/hello_dma.c hello_dma sample app].
-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:
+Nordic Semi provides a list of some sixty hardware makers and bindings files to their hardware at their [[External-refs--device-tree-bindings#nordic-semi--device-bindings-index|Nordic device tree bindings index page]].
 Though Ted wouldn't normally include links in an overview section, another important starting point to understand device tree to describe SPI peripherals is at this github link to a SPI dts bindings file:

@@ Line 14: / Line 14: @@
 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.  As of 2022-08-19 Friday we have device tree source for SPI and DMA peripherals of the RP2040 compiling correctly in a small project, github hosted at [https://github.com/tedhavelka/rpi-pico-zephyr-exploration/tree/spi-dts-work].  The compilation involves `dtc` or similar reading the device node's "compatible" property value and finding a bindings file in YAML format.  The device tree compiler then checks that the given node contains all required properties which are called out in the given compatible's bindings file, and correct data types as well.  ( The build process was able to report a mal-formed device address, "dma0@5000000" should be "dma0@50000000". )  So this tells us that while Zephyr RTOS Project does not use device tree source to generate device tree blobs, there is yet great debugging and correctness assurance benefit to using device tree to describe a system's or product's hardware.
-So as of this 8-19 Friday it now appears that crafting the wrapping code between [https://docs.zephyrproject.org/3.1.0/kernel/drivers/index.html Zephyr device model API pointers] and a non-Zephyr third party driver code will be the harder part of the effort to bring up DMA and full SPI functionality on MCUs not yet supported by Zephyr RTOS.
+So as of this 8-19 Friday it now appears that crafting the wrapping code between [https://docs.zephyrproject.org/3.1.0/kernel/drivers/index.html Zephyr device model] API pointers and third party driver code will be the harder part of the effort to bring up DMA and full SPI functionality on MCUs not yet supported by Zephyr RTOS.
 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:

@@ Line 12: / Line 12: @@
 == [[#top|^]] Overview ==
-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:
+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.  As of 2022-08-19 Friday we have device tree source for SPI and DMA peripherals of the RP2040 compiling correctly in a small project, github hosted at [https://github.com/tedhavelka/rpi-pico-zephyr-exploration/tree/spi-dts-work].  The compilation involves `dtc` or similar reading the device node's "compatible" property value and finding a bindings file in YAML format.  The device tree compiler then checks that the given node contains all required properties which are called out in the given compatible's bindings file, and correct data types as well.  ( The build process was able to report a mal-formed device address, "dma0@5000000" should be "dma0@50000000". )  So this tells us that while Zephyr RTOS Project does not use device tree source to generate device tree blobs, there is yet great debugging and correctness assurance benefit to using device tree to describe a system's or product's hardware.
 *  https://developer.nordicsemi.com/nRF_Connect_SDK/doc/1.5.1/zephyr/reference/devicetree/bindings.html

@@ Line 571: / Line 571: @@
 SPI frame format defines in Zephyr 3.1.0:
 <ul>
-<span style="font-family: monospace; size=3.5em;">
+<span style="font-family: monospace; size=4em;">
 ./include/zephyr/dt-bindings/spi/spi.h:39:#define SPI_FRAME_FORMAT_MOTOROLA	(0U << 15)<br />
 ./include/zephyr/dt-bindings/spi/spi.h:40:#define SPI_FRAME_FORMAT_TI		(1U << 15)<br />

@@ Line 571: / Line 571: @@
 SPI frame format defines in Zephyr 3.1.0:
 <ul>
-<span style="font-family: monospace; size=3em;">
+<span style="font-family: monospace; size=3.5em;">
 ./include/zephyr/dt-bindings/spi/spi.h:39:#define SPI_FRAME_FORMAT_MOTOROLA	(0U << 15)<br />
 ./include/zephyr/dt-bindings/spi/spi.h:40:#define SPI_FRAME_FORMAT_TI		(1U << 15)<br />

← Older revision		Revision as of 22:30, 16 August 2022
Line 568:		Line 568:
	An NXP device tree reference document, not specifically SPI but detailed:		An NXP device tree reference document, not specifically SPI but detailed:
	* [[Device_tree_documentation#AN5125.pdf\|AN5125.pdf]] <!-- https://www.nxp.com/docs/en/application-note/AN5125.pdf -->		* [[Device_tree_documentation#AN5125.pdf\|AN5125.pdf]] <!-- https://www.nxp.com/docs/en/application-note/AN5125.pdf -->
		+
		+	SPI frame format defines in Zephyr 3.1.0:
		+	<ul>
		+	<code>
		+	./include/zephyr/dt-bindings/spi/spi.h:39:#define SPI_FRAME_FORMAT_MOTOROLA (0U << 15)
		+	./include/zephyr/dt-bindings/spi/spi.h:40:#define SPI_FRAME_FORMAT_TI (1U << 15)
		+	</code>
		+	</ul>

@@ Line 291: / Line 291: @@
 <!-- comentario -->
-== [[#top|^]] edit point dts excerpt 5 ==
+== [[#top|^]] RPi Pico dts in Zephyr 3.1.0 ==
-From the zephyr/boards/arm/rpi_pico/doc/index.rst file:
+From the zephyr/boards/arm/rpi_pico/doc/index.rst file there's no mention of SPI support, though SPI peripherals exist in the RP2040.  Zephyr has a [https://github.com/zephyrproject-rtos/zephyr/blob/main/boards/arm/rpi_pico/rpi_pico.dts RP2040 dts file] that covers some on chip peripherals.  RaspberryPi's restructured text document does not mention SPI support either:
 <pre>
-== [[#top|^]] edit point dts excerpt 5 ==
       Raspberry Pi Pico (Image courtesy of Raspberry Pi)

← Older revision		Revision as of 12:03, 16 August 2022
Line 567:		Line 567:

	An NXP device tree reference document, not specifically SPI but detailed:		An NXP device tree reference document, not specifically SPI but detailed:
−	* https://www.nxp.com/docs/en/application-note/AN5125.pdf	+	* [[Device_tree_documentation#AN5125.pdf\|AN5125.pdf]] <!-- https://www.nxp.com/docs/en/application-note/AN5125.pdf -->