clk: at91: generated: consider range when calculating best rate

[ Upstream commit d0031e6 ]

clk_generated_best_diff() helps in finding the parent and the divisor to
compute a rate closest to the required one. However, it doesn't take into
account the request's range for the new rate. Make sure the new rate
is within the required range.

Fixes: 8a8f4bf ("clk: at91: clk-generated: create function to find best_diff")
Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
Link: https://lore.kernel.org/r/20220413071318.244912-1-codrin.ciubotariu@microchip.com
Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/clk/at91/clk-generated.c

@@ -106,6 +106,10 @@ static void clk_generated_best_diff(struct clk_rate_request *req,
 		tmp_rate = parent_rate;
 	else
 		tmp_rate = parent_rate / div;
+
+	if (tmp_rate < req->min_rate || tmp_rate > req->max_rate)
+		return;
+
 	tmp_diff = abs(req->rate - tmp_rate);
 
 	if (*best_diff < 0 || *best_diff >= tmp_diff) {