On Thu, Oct 12, 2017 at 12:40:10PM +0200, Lukas Wunner wrote: > 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@xxxxxxxxx> > --- > Changes v1 -> v2: > > - Newly inserted patch. > > .../devicetree/bindings/common-properties.txt | 26 ++++++++++++++++++++++ > 1 file changed, 26 insertions(+) Acked-by: Rob Herring <robh@xxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
