On 04/01/2016 11:16 AM, Tim Harvey wrote:
The IMX6 watchdog supports assertion of a signal (WDOG_B) which can be pinmux'd to an external pin. This is typically used for boards that have PMIC's in control of the IMX6 power rails. In fact, failure to use such an external reset on boards with external PMIC's can result in various hangs due to the IMX6 not being fully reset [1] as well as the board failing to reset because its PMIC has not been reset to provide adequate voltage for the CPU when coming out of reset at 800Mhz. This uses a new device-tree property 'fsl,ext-reset-output' to indicate the board has such a reset and to cause the watchdog to be configured to assert WDOG_B instead of an internal reset both on a watchdog timeout and in system_restart. [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2015-March/333689.html Cc: Fabio Estevam <festevam@xxxxxxxxx> Cc: Lucas Stach <l.stach@xxxxxxxxxxxxxx> Cc: Stefan Roese <sr@xxxxxxx> Cc: Iain Paton <ipaton0@xxxxxxxxx> Cc: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> Cc: Akshay Bhat <akshay.bhat@xxxxxxxxxxx> Cc: Guenter Roeck <linux@xxxxxxxxxxxx> Signed-off-by: Tim Harvey <tharvey@xxxxxxxxxxxxx> Reviewed-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx> Acked-by: Shawn Guo <shawn.guo@xxxxxxxxxx> --- v5: - rename property to 'fsl,ext-reset-output' v4: - change Property to Properties in documentation v3: - mandate use of 'either' internal or external reset but not both simultaneously v2: - rename property to 'ext-reset-output' based on ML feedback - simplify setting SRS bit if external-reset - update comments and commit msg Signed-off-by: Tim Harvey <tharvey@xxxxxxxxxxxxx> ---
Tested-by: Akshay Bhat <akshay.bhat@xxxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-watchdog" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
