[Ce-android-mainline] timed gpio and timed output drivers

Colin Cross ccross at android.com
Mon Feb 27 21:51:07 UTC 2012


On Mon, Feb 27, 2012 at 7:26 AM, Shuah Khan <shuahkhan at gmail.com> wrote:
> I saw a timed_gpio patch come through on lkml. Looks like this driver
> is being used and patched.  Could somebody from Andorid team comment
> on the need for a special driver instead of using leds.

It has been used in the past for vibrator control.  The main feature
it provides vs. leds is one shot timed enables, which prevents a
userspace crash from leaving the vibrator on, which would kill the
battery very quickly.  Plus, putting the vibrator in /sys/class/leds
is counterintuitive.

It hasn't been used as much recently as more vibrators end up
connected to PWM pins, on the SoC or PMIC, with custom apis.


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