Linux/AM3352: SPI communication from userspace

yingjie gu

Intellectual 810 points

Part Number: AM3352

Tool/software: Linux

I found there are some posts and documents showing how to read and write through /dev/spidev.

Is there another way to read, write and config SPI , other than file descriptor?

over 7 years ago

0 Cvetolin Shulev-XID over 7 years ago

TI__Guru 65405 points

Hi Yingjie Gu,

The most popular way for SPI read/write in user space is through character device /dev/spidev but this way gives you only half-duplex access.
An other way for SPI read/write in user space is through ioctl SPI_IOC_MESSAGE(N) request that gives you full-duplex access.
You can find details at:
www.kernel.org/.../spidev
www.haifux.org/.../gpio_spi_i2c_userspace.pdf
brew-j2me.blogspot.bg/.../linux-accessing-spi-bus-from-user-space_06.html

BR
Tsvetolin Shulev

0 yingjie gu over 7 years ago in reply to Cvetolin Shulev-XID

Intellectual 810 points

Do I need to erase before writing to /dev/spidev, or the spi driver will do it automatically? If I need to explicitly erase spi sectors, how can I do it?
Thank you.

0 Cvetolin Shulev-XID over 7 years ago in reply to yingjie gu

TI__Guru 65405 points

You can directly write to /dev/spidev. You can find some clarifications and example at:
stackoverflow.com/.../can-i-select-on-a-dev-spidev-file-descriptor

BR
Tsvetolin Shulev

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Linux/AM3352: SPI communication from userspace