From: Guenter Roeck Date: Thu, 20 Mar 2014 15:12:28 +0000 (-0700) Subject: mfd: kempld-core: Fix potential hang-up during boot X-Git-Tag: upstream/snapshot3+hdmi~3134 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=00834e4d81ffd1e58206d24ed096f8210958096f;p=platform%2Fadaptation%2Frenesas_rcar%2Frenesas_kernel.git mfd: kempld-core: Fix potential hang-up during boot commit 204747c970c0d568721c76ab8a57dde0e5dcf0d5 upstream. On PXT and COMe-cPC2 boards it is observed that the hardware mutex is acquired but not being released during initialization. This can result in a hang-up during boot if the driver is built into the kernel. Releasing the mutex twice if it was acquired fixes the problem. Subsequent request/release cycles work as expected, so the fix is only needed during initialization. Reviewed-by: Michael Brunner Tested-by: Michael Brunner Signed-off-by: Guenter Roeck Signed-off-by: Lee Jones Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/mfd/kempld-core.c b/drivers/mfd/kempld-core.c index d3e2327..38917a8 100644 --- a/drivers/mfd/kempld-core.c +++ b/drivers/mfd/kempld-core.c @@ -322,9 +322,12 @@ static int kempld_detect_device(struct kempld_device_data *pld) return -ENODEV; } - /* Release hardware mutex if aquired */ - if (!(index_reg & KEMPLD_MUTEX_KEY)) + /* Release hardware mutex if acquired */ + if (!(index_reg & KEMPLD_MUTEX_KEY)) { iowrite8(KEMPLD_MUTEX_KEY, pld->io_index); + /* PXT and COMe-cPC2 boards may require a second release */ + iowrite8(KEMPLD_MUTEX_KEY, pld->io_index); + } mutex_unlock(&pld->lock);