Xilinx Zynq-7000 User Manual page 35

PS-GPIO Driver
The GPIO SYSFS interface is used for GPIO configuration. The GPIO SYSFS interface allows
the user to control I/O pins using files under the /sys directory.
When the system boots, all GPIO pins are owned by the kernel. The pins do not show up in
the SYSFS system until they are exported. To export them, write the pin number (say 54) to
the file /sys/class/gpio/export.
This results in the pseudo files for pin 54 showing up under /sys/class/gpio/gpio54
as:
/sys/class/gpio/gpio54/direction
/sys/class/gpio/gpio54/value
The user can set the direction by writing in or out to the direction file. For the out
direction, writing 0 or 1 on the corresponding value file resets or sets the pin, respectively.
Similarly, the user can read the value file for the in direction.
XVDMA Driver
XVDMA is a character driver used for configuring and controlling video DMA transactions
for both TPG and Sobel hardware. XVDMA internally calls the Xilinx AXI VDMA driver to
complete the task and interrupt handling.
The device node that uses the XVDMA driver is /dev/xvdma. The following IOCTLs are
defined for the XVDMA driver and contain the corresponding IOCTL arguments to be used:
• XVDMA_GET_NUM_DEVICES
This call obtains the number of VDMA probed and available for use.
°
Argument: Address of unsigned int [unsigned int *].
°
- This gets filled up with the number of VDMA when the call returns.
• XVDMA_GET_DEV_INFO
This call gives device information like channel number, for the given VDMA ID.
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Argument: Address of structure xvdma_dev [struct xvdma_dev *].
°
- Before calling, the device_id field of this structure should be filled with VDMA
ID. On return the rest of the structure is filled by the driver.
• XVDMA_DEVICE_CONTROL
This call sets the VDMA channel configuration.
°
Argument: Address of structure xvdma_chan_cfg [struct xvdma_chan_cfg *].
°
- Before calling, this structure should be filled with required channel
configurations.
Zynq-7000 AP SoC ZC702 Base TRD
UG925 (v6.0) February 21, 2014
www.xilinx.com
Software Architecture
35
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