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| author | Lukas Wunner <lukas@wunner.de> | 2017-10-12 12:40:10 +0200 |
|---|---|---|
| committer | Linus Walleij <linus.walleij@linaro.org> | 2017-10-19 22:33:11 +0200 |
| commit | 1f63fab955dbcb8f6db56d67a4c63fc0746e4fe1 (patch) | |
| tree | 2335c929d016f9878e1199885e87ade31c6cb032 /lib/errseq.c | |
| parent | gpiolib: clear irq handler and data in one go (diff) | |
| download | linux-1f63fab955dbcb8f6db56d67a4c63fc0746e4fe1.tar.xz linux-1f63fab955dbcb8f6db56d67a4c63fc0746e4fe1.zip | |
dt-bindings: Document common property for daisy-chained devices
Many serially-attached GPIO and IIO devices are daisy-chainable.
Examples for GPIO devices are Maxim MAX3191x and TI SN65HVS88x:
https://datasheets.maximintegrated.com/en/ds/MAX31913.pdf
http://www.ti.com/lit/ds/symlink/sn65hvs880.pdf
Examples for IIO devices are TI DAC128S085 and TI DAC161S055:
http://www.ti.com/lit/ds/symlink/dac128s085.pdf
http://www.ti.com/lit/ds/symlink/dac161s055.pdf
We already have drivers for daisy-chainable devices in the tree but
their devicetree bindings are somewhat inconsistent and ill-named:
The gpio-74x164.c driver uses "registers-number" to convey the
number of devices in the daisy-chain. (Sans vendor prefix,
multiple vendors sell compatible versions of this chip.)
The gpio-pisosr.c driver takes a different approach and calculates
the number of devices in the daisy-chain by dividing the common
"ngpios" property (Documentation/devicetree/bindings/gpio/gpio.txt)
by 8 (which assumes that each chip has 8 inputs).
Let's standardize on a common "#daisy-chained-devices" property.
That name was chosen because it's the term most frequently used in
datasheets. (A less frequently used synonym is "cascaded devices".)
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'lib/errseq.c')
0 files changed, 0 insertions, 0 deletions