Messages in this thread | | | Subject | Re: [PATCH] reset: Add generic GPIO reset driver. | From | Philipp Zabel <> | Date | Mon, 10 Feb 2014 14:16:31 +0100 |
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Hi Martin,
Am Montag, den 10.02.2014, 13:54 +0100 schrieb Martin Fuzzey: > This driver allows GPIO lines to be used as reset signals. > It has two main use cases: > > 1) Allow drivers to reset their hardware via a GPIO line in a standard fashion > as supplied by the reset framework. > This allows adhoc driver code requesting GPIOs etc to be replaced with a > single call to device_reset().
have you seen the patch at https://lkml.org/lkml/2014/1/8/190: "reset: Add GPIO support to reset controller framework" ?
Adding a GPIO reset controller device node to the device tree is the wrong approach for devices enumerated in the device tree. Those should just declare their reset-gpios directly.
> 2) Allow hardware on discoverable busses to be rest via a GPIO line > without driver modifications. > > Examples of the second use case include: > * SDIO wifi modules > * USB hub chips with a reset line
Now this is interesting. But if you export it to userspace anyway, why not use the existing gpio sysfs API?
I think a proper solution should handle this in the kernel. For SDIO wifi modules you usually have a powerdown line that can be implemented as an rfkill switch.
regards Philipp
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