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.pdfhttp://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.pdfhttp://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>
The Devicetree Specification has superseded the ePAPR as the
base specification for bindings. Update files in Documentation
to reference the new document.
First reference to ePAPR in Documentation/devicetree/bindings/arm/cci.txt
is generic, remove it.
Some files are not updated because there is no hypervisor chapter
in the Devicetree Specification:
Documentation/devicetree/bindings/powerpc/fsl/msi-pic.txt
Documenation/virtual/kvm/api.txt
Documenation/virtual/kvm/ppc-pv.txt
Signed-off-by: Frank Rowand <frank.rowand@sony.com>
Signed-off-by: Rob Herring <robh@kernel.org>
These apply to newly converted drivers, like serial8250/libahci/...
The examples were adapted from the regmap bindings document.
Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Rob Herring <robh@kernel.org>
