[review] drivers: stm32_iwdg: provide timeout range

Prevent division by zero.

Signed-off-by: Etienne Carriere <[email protected]>

core/drivers/stm32_iwdg.c

@@ -188,11 +188,14 @@ static TEE_Result iwdg_wdt_init(struct wdt_chip *chip,
 				unsigned long *max_timeout)
 {
 	struct stm32_iwdg_device *iwdg = wdt_chip_to_iwdg(chip);
+	unsigned long rate = clk_get_rate(iwdg->clk_lsi);
+
+	if (!rate)
+		return TEE_ERROR_GENERIC;
 
 	/* Be safe and expect any counter to be above 2 */
-	*min_timeout = 3 * IWDG_PRESCALER_256 / clk_get_rate(iwdg->clk_lsi);
-	*max_timeout = (IWDG_CNT_MASK + 1) * IWDG_PRESCALER_256 /
-		       clk_get_rate(iwdg->clk_lsi);
+	*min_timeout = 3 * IWDG_PRESCALER_256 / rate;
+	*max_timeout = (IWDG_CNT_MASK + 1) * IWDG_PRESCALER_256 / rate;
 
 	return TEE_SUCCESS;
 }