linguini1 opened a new pull request, #16428: URL: https://github.com/apache/nuttx/pull/16428
## Summary This implements an interrupt-based SPI driver for the BCM2711 SPI interfaces (excluding auxiliary SPI interfaces). Only tested on SPI0 since proprietary firmware does not initialize any other SPI interfaces, and doing so will require reverse engineering. ## Impact This PR impacts the BCM2711 chip support code and subset of the build system. Now users can enable SPI interfaces 0-6 for the BCM2711 and will be able to use SPI on at least SPI0. SPI1 & SPI2 currently throw compiler errors since they were left unimplemented. They are auxiliary interfaces and thus require a different implementation. SPI3-6 were not tested since it appears that the proprietary `start4.elf` firmware initialization does not enable these interfaces by default, nor when using the overlays provided by Raspberry Pi. I have not been able to find a solution to this issue so I am putting this driver in under the caveat that only SPI0 is tested, this is noted in the docs. ## Testing As mentioned, testing was performed using only SPI0 (marked GPIO pins for this interface are listed as MISO, MOSI, SCLK, CSE0 on this image https://external-content.duckduckgo.com/iu/?u=https%3A%2F%2Fuelectronics.com%2Fwp-content%2Fuploads%2F2019%2F09%2FAR1099-Raspberry-4-B-PINOUT-min.jpg&f=1&nofb=1&ipt=691d4ea7c6e08fc730fbf54219e6d4a9d409ac370f1011cf840a381c05f35b51) with only CSE0 being used. I used the MCP3008 ADC driver to test the SPI implementation since that is the only device I have on hand. It appears to work just fine, I was able to read the different channel voltages with the `adc` example. Here are the logs, you can see that channel 0, 2 and 6 stay constant. 0 & 2 have 3.3V power connected to them and therefore read quite high (out of 1024), while channel 6 is tied to ground. The other channels have changing values due to noise: ``` nsh> adc adc_main: g_adcstate.count: 1 adc_main: Hardware initialized. Opening the ADC device: /dev/adc0 Reading Read 35 Sample: 1: channel: 0 value: 999 2: channel: 1 value: 124 3: channel: 2 value: 1007 4: channel: 3 value: 119 5: channel: 4 value: 120 6: channel: 5 value: 124 7: channel: 6 value: 0 nsh> adc adc_main: g_adcstate.count: 1 adc_main: Hardware initialized. Opening the ADC device: /dev/adc0 Reading Read 35 Sample: 1: channel: 0 value: 999 2: channel: 1 value: 120 3: channel: 2 value: 1007 4: channel: 3 value: 112 5: channel: 4 value: 119 6: channel: 5 value: 120 7: channel: 6 value: 0 nsh> adc adc_main: g_adcstate.count: 1 adc_main: Hardware initialized. Opening the ADC device: /dev/adc0 Reading Read 35 Sample: 1: channel: 0 value: 1007 2: channel: 1 value: 119 3: channel: 2 value: 999 4: channel: 3 value: 126 5: channel: 4 value: 193 6: channel: 5 value: 119 7: channel: 6 value: 0 nsh> adc adc_main: g_adcstate.count: 1 adc_main: Hardware initialized. Opening the ADC device: /dev/adc0 Reading Read 35 Sample: 1: channel: 0 value: 1006 2: channel: 1 value: 120 3: channel: 2 value: 1007 4: channel: 3 value: 112 5: channel: 4 value: 119 6: channel: 5 value: 120 7: channel: 6 value: 0 nsh> adc adc_main: g_adcstate.count: 1 adc_main: Hardware initialized. Opening the ADC device: /dev/adc0 Reading Read 35 Sample: 1: channel: 0 value: 1006 2: channel: 1 value: 111 3: channel: 2 value: 1007 4: channel: 3 value: 112 5: channel: 4 value: 115 6: channel: 5 value: 120 7: channel: 6 value: 0 nsh> adc adc_main: g_adcstate.count: 1 adc_main: Hardware initialized. Opening the ADC device: /dev/adc0 Reading Read 35 Sample: 1: channel: 0 value: 1007 2: channel: 1 value: 112 3: channel: 2 value: 999 4: channel: 3 value: 123 5: channel: 4 value: 124 6: channel: 5 value: 112 7: channel: 6 value: 0 nsh> adc adc_main: g_adcstate.count: 1 adc_main: Hardware initialized. Opening the ADC device: /dev/adc0 Reading Read 35 Sample: 1: channel: 0 value: 999 2: channel: 1 value: 0 3: channel: 2 value: 1007 4: channel: 3 value: 0 5: channel: 4 value: 0 6: channel: 5 value: 0 7: channel: 6 value: 0 nsh> adc adc_main: g_adcstate.count: 1 adc_main: Hardware initialized. Opening the ADC device: /dev/adc0 Reading Read 35 Sample: 1: channel: 0 value: 999 2: channel: 1 value: 112 3: channel: 2 value: 1007 4: channel: 3 value: 123 5: channel: 4 value: 124 6: channel: 5 value: 112 7: channel: 6 value: 0 nsh> adc adc_main: g_adcstate.count: 1 adc_main: Hardware initialized. Opening the ADC device: /dev/adc0 Reading Read 35 Sample: 1: channel: 0 value: 999 2: channel: 1 value: 123 3: channel: 2 value: 1007 4: channel: 3 value: 119 5: channel: 4 value: 126 6: channel: 5 value: 123 7: channel: 6 value: 0 ``` I would appreciate if there is anyone with a Pi 4B and some SPI device on hand that would like to try testing as well to verify on another device, although it might not be necessary. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: commits-unsubscr...@nuttx.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
