On 4/01/2017 22:21, Peter Rosin wrote:
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.
I think this also needs a comment in the code, including a description
of the limitations. If the interrupt is shared between two devices on
the same bus, you would have the exact same problem and this workaround
would be no good...
Overall, this series fixes the issues I had with the patch from half
a year ago or so. Thanks!
With nitpicks fixed,
Acked-by: Peter Rosin <peda@xxxxxxxxxx>
G'day Pater,
Thanks for the review. v2 on it's way.
--
Regards
Phil Reid
--
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
