cpufreq: imx6q-cpufreq: assign cpu_dev correctly to cpu0 device

Commit cdc58d6 "cpufreq: imx6q-cpufreq:
remove device tree parsing for cpu nodes" assumed the pdev->dev is set to
cpu0 device in the platform code. But it actually points to the virtual
cpufreq-cpu0 platform device which is not present in the device tree.
Most of the information needed by cpufreq is stored in cpu0 DT node.
So cpu_dev must point to cpu0 device.

This patch fixes the wrong assignment to cpu_dev.

Reported-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

arch/arm/mach-imx/mach-imx6q.c

@@ -233,10 +233,15 @@ static void __init imx6q_opp_check_1p2ghz(struct device *cpu_dev)
 	of_node_put(np);
 }
 
-static void __init imx6q_opp_init(struct device *cpu_dev)
+static void __init imx6q_opp_init(void)
 {
 	struct device_node *np;
+	struct device *cpu_dev = get_cpu_device(0);
 
+	if (!cpu_dev) {
+		pr_warn("failed to get cpu0 device\n");
+		return;
+	}
 	np = of_node_get(cpu_dev->of_node);
 	if (!np) {
 		pr_warn("failed to find cpu0 node\n");
@@ -268,7 +273,7 @@ static void __init imx6q_init_late(void)
 		imx6q_cpuidle_init();
 
 	if (IS_ENABLED(CONFIG_ARM_IMX6Q_CPUFREQ)) {
-		imx6q_opp_init(&imx6q_cpufreq_pdev.dev);
+		imx6q_opp_init();
 		platform_device_register(&imx6q_cpufreq_pdev);
 	}
 }

drivers/cpufreq/imx6q-cpufreq.c

@@ -7,6 +7,7 @@
  */
 
 #include <linux/clk.h>
+#include <linux/cpu.h>
 #include <linux/cpufreq.h>
 #include <linux/delay.h>
 #include <linux/err.h>
@@ -202,7 +203,11 @@ static int imx6q_cpufreq_probe(struct platform_device *pdev)
 	unsigned long min_volt, max_volt;
 	int num, ret;
 
-	cpu_dev = &pdev->dev;
+	cpu_dev = get_cpu_device(0);
+	if (!cpu_dev) {
+		pr_err("failed to get cpu0 device\n");
+		return -ENODEV;
+	}
 
 	np = of_node_get(cpu_dev->of_node);
 	if (!np) {