mfd: kempld-core: Fix potential hang-up during boot
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. Cc: <stable@vger.kernel.org> Reviewed-by: Michael Brunner <michael.brunner@kontron.com> Tested-by: Michael Brunner <michael.brunner@kontron.com> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Lee Jones <lee.jones@linaro.org>
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1 changed files with 5 additions and 2 deletions
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@ -322,9 +322,12 @@ static int kempld_detect_device(struct kempld_device_data *pld)
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return -ENODEV;
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}
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/* Release hardware mutex if aquired */
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if (!(index_reg & KEMPLD_MUTEX_KEY))
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/* Release hardware mutex if acquired */
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if (!(index_reg & KEMPLD_MUTEX_KEY)) {
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iowrite8(KEMPLD_MUTEX_KEY, pld->io_index);
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/* PXT and COMe-cPC2 boards may require a second release */
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iowrite8(KEMPLD_MUTEX_KEY, pld->io_index);
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}
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mutex_unlock(&pld->lock);
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