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 22b0348..8437dd5 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;
        }