watchdog: renesas_wdt: check rate also for upper limit

When checking the clock rate, ensure also that counting all 16 bits
takes at least one second to match the granularity of the framework.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

diff --git a/drivers/watchdog/renesas_wdt.c b/drivers/watchdog/renesas_wdt.c
index 22b0348826deb107323425e0f330e0c06b352d23..8437dd521532089583c9c71ad1070bfafc47b521 100644 (file)
--- a/drivers/watchdog/renesas_wdt.c
+++ b/drivers/watchdog/renesas_wdt.c
@@ -134,14 +134,14 @@ static int rwdt_probe(struct platform_device *pdev)
 
        for (i = ARRAY_SIZE(clk_divs) - 1; i >= 0; i--) {
                clks_per_sec = DIV_ROUND_UP(rate, clk_divs[i]);
-               if (clks_per_sec) {
+               if (clks_per_sec && clks_per_sec < 65536) {
                        priv->clks_per_sec = clks_per_sec;
                        priv->cks = i;
                        break;
                }
        }
 
-       if (!clks_per_sec) {
+       if (i < 0) {
                dev_err(&pdev->dev, "Can't find suitable clock divider\n");
                return -ERANGE;
        }