Depending on SKU i.MX6UL/i.MX6ULL support frequencies up to 900MHz.
Use PLL1 sys clock for all operating points higher than 528MHz.

Note: For higher operating points VDD_SOC_IN needs to be 125mV
higher than the ARM set-point (see datasheet). Specifically, the
i.MX6UL/ULL EVK boards have an external DC regulator which needs
adjustment. The regulator adjustment is not covered with this
change.

Signed-off-by: Stefan Agner <stefan@agner.ch>
---
 drivers/cpufreq/imx6q-cpufreq.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/cpufreq/imx6q-cpufreq.c b/drivers/cpufreq/imx6q-cpufreq.c
index 628fe899cb48..840f6386c780 100644
--- a/drivers/cpufreq/imx6q-cpufreq.c
+++ b/drivers/cpufreq/imx6q-cpufreq.c

@@ -114,12 +114,14 @@ static int imx6q_set_target(struct cpufreq_policy *policy, unsigned int index)
 		 */
 		clk_set_rate(arm_clk, (old_freq >> 1) * 1000);
 		clk_set_parent(pll1_sw_clk, pll1_sys_clk);
-		if (freq_hz > clk_get_rate(pll2_pfd2_396m_clk))
-			clk_set_parent(secondary_sel_clk, pll2_bus_clk);
-		else
-			clk_set_parent(secondary_sel_clk, pll2_pfd2_396m_clk);
-		clk_set_parent(step_clk, secondary_sel_clk);
-		clk_set_parent(pll1_sw_clk, step_clk);
+		if (freq_hz <= clk_get_rate(pll2_bus_clk)) {
+			if (freq_hz > clk_get_rate(pll2_pfd2_396m_clk))
+				clk_set_parent(secondary_sel_clk, pll2_bus_clk);
+			else
+				clk_set_parent(secondary_sel_clk, pll2_pfd2_396m_clk);
+			clk_set_parent(step_clk, secondary_sel_clk);
+			clk_set_parent(pll1_sw_clk, step_clk);
+		}
 	} else {
 		clk_set_parent(step_clk, pll2_pfd2_396m_clk);
 		clk_set_parent(pll1_sw_clk, step_clk);