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Dobrica Pavlinušić 77bcc2e63b ina219 device tree overlay (#1 )

shunt-resistor is 10 times bigger than default values, and this
corresponds to cheap ebay modules with ina219, but if your current
readings are off, you will have to modify it

2017-10-26 13:35:00 +03:00

examples

ina219 device tree overlay (#1 )

2017-10-26 13:35:00 +03:00

sun4i-a10

Fix A10/A20 UART3 overlay and add a second ppinmux option to it

2017-10-24 14:58:17 +03:00

sun7i-a20

Add A20 I2S overlays

2017-10-25 13:09:35 +03:00

sun8i-h3

Activate USBPHY in USB host overlays

2017-10-24 15:05:10 +03:00

sun50i-a64

Add A64 overlays

2017-05-17 20:26:42 +03:00

sun50i-h5

Activate USBPHY in USB host overlays

2017-10-24 15:05:10 +03:00

LICENSE

Initial commit

2017-03-10 17:13:46 +03:00

README.md

Update the README

2017-06-07 15:32:38 +03:00

Device Tree overlays for sunxi devices

💬 Forum thread for issues and suggestions

Technical info

Requirements

mainline u-boot 2017.03 or newer with CONFIG_OF_LIBFDT_OVERLAY enabled
latest version of appropriate boot script
existing armbianEnv.txt with correct overlay_prefix value
Device Tree compiler with overlays support for compiling the overlays

Notes:

Older u-boot versions require this patch to fix endiannes of values obtained with fdt get value command

Implementation details

Boot script reads /boot/armbianEnv.txt which may contain following environment variables:

overlay_prefix
overlays
user_overlays
overlay specific parameters

Overlay files referenced by overlays and user_overlays variables are loaded and applied using fdt apply command. After applying all overlays a SoC specific fixup script is executed to process overlay specific parameters.

Limitations

U-boot fdt command does not support "tuples" values which limits implementing things like GPIO SPI chip selects with variable GPIO pins that require this type of values:

cs-gpios = <0>, <&pio 0 1 0>, <&pio 7 7 0>; /* Native, PA1, PH7 */

U-boot does not support overlay parameters, so changing values is implemented via executing a "fixup" script after all overlays were applied. This script uses environment variables loaded from /boot/armbianEnv.txt to change the live tree using fdt command.
Since SoCs have multiple controllers of the same type (I2C, SPI) that can be exposed in different combinations on different boards, slave devices (I2C, I2S, SPI, ...) are provided not as ready to use overlays but as examples that require minimal editing to match the used configuration.