[PATCH v2.1] watchdog: make DesignWare watchdog allow users to set bigger timeout value

["Wang, Peng 1. (NSB - CN/Hangzhou)" <peng.1.wang@nokia-sbell.com>]

From aabaa4b709bd451e566c906e8d1dca48f92f9b12 Mon Sep 17 00:00:00 2001
From: Peng Wang <peng.1.wang@nokia-sbell.com>
Date: Wed, 20 Nov 2019 15:12:59 +0800
Subject: [PATCH v2.1] watchdog: make DesignWare watchdog allow users to set bigger
 timeout value

watchdog_dev.c provides means to allow users to set bigger timeout value
than HW can support, make DesignWare watchdog align with this.

Signed-off-by: Peng Wang <peng.1.wang@nokia-sbell.com>
---

v2 -> v2.1:
    - move Signed-off-by to be ahead of section separator

v1 -> v2:
    - use top_s to compare with wdd->max_hw_heartbeat_ms
    - update wdd->timeout in case it's greater than HW supports
    - fix comments error

v1: initial version

---
 drivers/watchdog/dw_wdt.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c
index fef7c61..12c116e 100644
--- a/drivers/watchdog/dw_wdt.c
+++ b/drivers/watchdog/dw_wdt.c
@@ -114,7 +114,15 @@ static int dw_wdt_set_timeout(struct watchdog_device *wdd, unsigned int top_s)
 	writel(top_val | top_val << WDOG_TIMEOUT_RANGE_TOPINIT_SHIFT,
 	       dw_wdt->regs + WDOG_TIMEOUT_RANGE_REG_OFFSET);
 
-	wdd->timeout = dw_wdt_top_in_seconds(dw_wdt, top_val);
+	/*
+	 * In case users set bigger timeout value than HW can support,
+	 * kernel(watchdog_dev.c) helps to feed watchdog before
+	 * wdd->max_hw_heartbeat_ms
+	 */
+	if (top_s * 1000 <= wdd->max_hw_heartbeat_ms)
+		wdd->timeout = dw_wdt_top_in_seconds(dw_wdt, top_val);
+	else
+		wdd->timeout = top_s;
 
 	return 0;
 }
-- 
1.8.3.1