phy: zynqmp: Allow variation in refclk rate

Due to limited available frequency ratios, the reference clock rate may
not be exactly the same as the required rate. Allow a small (100 ppm)
deviation.

Signed-off-by: Sean Anderson <sean.anderson@seco.com>
Link: https://lore.kernel.org/r/20230711194542.898230-1-sean.anderson@seco.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

Author: sean-anderson-seco

drivers/phy/xilinx/phy-zynqmp.c

@@ -904,7 +904,10 @@ static int xpsgtr_get_ref_clocks(struct xpsgtr_dev *gtr_dev)
 		rate = clk_get_rate(clk);
 
 		for (i = 0 ; i < ARRAY_SIZE(ssc_lookup); i++) {
-			if (rate == ssc_lookup[i].refclk_rate) {
+			/* Allow an error of 100 ppm */
+			unsigned long error = ssc_lookup[i].refclk_rate / 10000;
+
+			if (abs(rate - ssc_lookup[i].refclk_rate) < error) {
 				gtr_dev->refclk_sscs[refclk] = &ssc_lookup[i];
 				break;
 			}