Some Renesas SoCs do not have a reset register and the only way to do a SW controlled reset is to use the watchdog timer. So while this series started out by only adding a reset feature, now it's a full watchdog timer driver that includes a reset handler. The longest WDT overflow you can get with a RZ/A1 (R7S72100) with its 8-bit wide counter is 125ms. Not very long. However, by setting max_hw_heartbeat_ms, the watchdog core will now handle pinging the WDT automatically and allow the user to set times as big as they want. Therefore, the default timeout for this driver is 30 seconds. Of course if system interrupts are disabled too long and wdt can't be pinged by the watchdog core, then the system will reset before the user specified timeout. But hey, it's better nothing. This driver was tested on an RZ/A1 RSK board using watchdog-simple.c from samples/watchdog/. v5: * rza_wdt.c changes only * removed extra lines from file header comments * changed (1<<#) to BIT(#) * changed #define WTSCR_CKS(i) i to (i) * changed format to #define SOMETHING<tab>value (and align values) * now check if clock rate < 16384 * added space before and after '/' for "(1000 * U8_MAX) / rate" * changed dev_info to dev_dbg for printing max_hw_heartbeat_ms * added watchdog_init_timeout() for user to set timeout in DT * switched to using devm_watchdog_register_device() * added error message if register fails * simplified rza_wdt_probe() return * removed function rza_wdt_remove() v4: * r7s72100.dtsi: changed from timer@ to watchdog@ v3: * changed from a reset driver to a watchdog timer driver * use udelay(20) instead of msleep for reset handler * added Reviewed-by for r7s72100.dtsi and renesas-wdt.txt * added Acked-by for renesas-wdt.txt v2: * added to renesas-wdt.txt instead of creating a new file * changed "renesas,r7s72100-reset" to "renesas,r7s72100-wdt" * changed "renesas,wdt-reset" to "renesas,rza-wdt" * added "renesas,rza-wdt" as a fallback * added interupt property (even though it is not used) * added clocks property * changed hard coded register values to defines * added msleep to while(1) loop * removed unnecessary #include files * added Reviewed-by: Geert Uytterhoeven for renesas-reset.c Chris Brandt (3): watchdog: add rza_wdt driver watchdog: renesas-wdt: add support for rza ARM: dts: r7s72100: Add watchdog timer .../devicetree/bindings/watchdog/renesas-wdt.txt | 4 +- arch/arm/boot/dts/r7s72100.dtsi | 7 + drivers/watchdog/Kconfig | 8 + drivers/watchdog/Makefile | 1 + drivers/watchdog/rza_wdt.c | 199 +++++++++++++++++++++ 5 files changed, 218 insertions(+), 1 deletion(-) create mode 100644 drivers/watchdog/rza_wdt.c -- 2.10.1
