On 2017-01-04 10:29, Phil Reid wrote: > Unfortunately some hardware device will assert their irq line immediately > on power on and provide no mechanism to mask the irq. As the i2c muxes > provide no method to mask irq line this provides a work around by keeping > the parent irq masked until enough device drivers have loaded to service > all pending interrupts. > > For example the the ltc1760 assert its SMBALERT irq immediately on power > on. With two ltc1760 attached to bus 0 & 1 on a pca954x mux when the first > device is registered irq are enabled and fire continuously as the second > device driver has not yet loaded. Setting this parameter to 0x3 while > delay the irq being enabled until both devices are ready. > > Signed-off-by: Phil Reid <preid@xxxxxxxxxxxxxxxxx> > --- > Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.txt | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.txt b/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.txt > index 9f7c275..d3e63dc 100644 > --- a/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.txt > +++ b/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.txt > @@ -19,6 +19,8 @@ Optional Properties: > - i2c-mux-idle-disconnect: Boolean; if defined, forces mux to disconnect all > children in idle state. This is necessary for example, if there are several > multiplexers on the bus and the devices behind them use same I2C addresses. > + - i2c-mux-irq-mask-en: BitMask; Defines a mask for which irq lines need to be > + unmasked before the parent irq line in enabled. The prefix should be "nxp," instead of "i2c-mux-", and I don't think you should abbreviate enable. So, nxp,irq-mask-enable. With that fixed, Acked-by: Peter Rosin <peda@xxxxxxxxxx> Cheers, peda > - interrupt-parent: Phandle for the interrupt controller that services > interrupts for this device. > - interrupts: Interrupt mapping for IRQ. > @@ -36,6 +38,7 @@ Example: > #size-cells = <0>; > reg = <0x74>; > > + i2c-mux-irq-mask-en = <0x3>; > interrupt-parent = <&ipic>; > interrupts = <17 IRQ_TYPE_LEVEL_LOW>; > interrupt-controller; > -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
