Re: Accessing SPI
Merrill Harriman <[email protected]>
| Newsgroups | gmane.linux.uclinux.devel |
|---|---|
| Message-ID | <[email protected]> |
cc:NSA - LOL ... What platform? I have very recently been through a long process of getting the spidev working on an Emcraft STM-SOM with STM32F4. The documentation was lacking but once I got the right hint from emcraft support I was able to get it going. I am using SPI1 and SPI2 as built in kernel modules. I am then using ioctl ops on the /dev/spidev0.0 and /dev/spidev1.0. The supported ioctl accesses are defined in .../A2F/root/usr/include/linux/spi/spidev.h. Here is a brief overview of the process: make kmenuconfig => enable spis make bmenuconfig => enable mdev In .../linux/arch/arm/mach-stm32/... iomux.c - configure required port.pins for alternate functions spi.c - add board info structs for each spidev In .../linux/drivers/spi/... spi_stm32.c - configure spi_cr1 for correct format spidev.c - instrument as necessary with debug printk's to see progress I am sure there is some stuff I left out here. I have a demo spidev project from emcraft that uses spi2 and spi5 - if you would like that I can forward it to your private email ... I think some of the key ingredients are the configurations they used in initramfs, busybox, kernel config, and rc. These are in the demo project also ... Good luck ... Date: Tue, 28 Jan 2014 15:45:04 -0800 From: [email protected] To: [email protected] Subject: [uClinux-dev] Accessing SPI I have an Emcraft distro with a SPI device at /dev/spi. I wish to access the device for (for instance) controlling the chip select pin, read, write, etc. I have seen a document on controlling a SPI driver on ucLinux from user space (http://www.uclinux.org/pub/uClinux/ports/blackfin/docs/pdf-docs/SPI_device_driver.pdf) , but it references IOCTLs that are not in my source tree. I did find a file, linux/spi/spidev.h, that has a struct defined that seems to be used by user mode SPI code, but it is not clear how I am to use it, in particular, which IOCTLs are available, and how I can get access to the interface at low levels. How in general do ucLinux app developers access SPI devices? Eric -- cc:NSA _______________________________________________ uClinux-dev mailing list [email protected] http://mailman.uclinux.org/mailman/listinfo/uclinux-dev This message was resent by [email protected] To unsubscribe see: http://mailman.uclinux.org/mailman/options/uclinux-dev _______________________________________________ uClinux-dev mailing list [email protected] http://mailman.uclinux.org/mailman/listinfo/uclinux-dev This message was resent by [email protected] To unsubscribe see: http://mailman.uclinux.org/mailman/options/uclinux-dev