ARM: imx: use device_initcall for imx_soc_device_init

This is preparation to move imx_soc_device_init to drivers/soc/imx/

There is no reason to must put dt devices under /sys/devices/soc0,
they could also be under /sys/devices/platform, so we could
pass NULL as parent when calling of_platform_default_populate.

Following soc-imx8.c soc-imx-scu.c using device_initcall, need
to change return type to int type for imx_soc_device_init.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/mach-imx/common.h

@@ -49,7 +49,6 @@ void imx_aips_allow_unprivileged_access(const char *compat);
 int mxc_device_init(void);
 void imx_set_soc_revision(unsigned int rev);
 void imx_init_revision_from_anatop(void);
-struct device *imx_soc_device_init(void);
 void imx6_enable_rbc(bool enable);
 void imx_gpc_check_dt(void);
 void imx_gpc_set_arm_power_in_lpm(bool power_off);

arch/arm/mach-imx/cpu.c

@@ -83,7 +83,7 @@ void __init imx_aips_allow_unprivileged_access(
 	}
 }
 
-struct device * __init imx_soc_device_init(void)
+static int __init imx_soc_device_init(void)
 {
 	struct soc_device_attribute *soc_dev_attr;
 	const char *ocotp_compat = NULL;
@@ -97,7 +97,7 @@ struct device * __init imx_soc_device_init(void)
 
 	soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL);
 	if (!soc_dev_attr)
-		return NULL;
+		return -ENOMEM;
 
 	soc_dev_attr->family = "Freescale i.MX";
 
@@ -224,24 +224,31 @@ struct device * __init imx_soc_device_init(void)
 	soc_dev_attr->revision = kasprintf(GFP_KERNEL, "%d.%d",
 					   (imx_soc_revision >> 4) & 0xf,
 					   imx_soc_revision & 0xf);
-	if (!soc_dev_attr->revision)
+	if (!soc_dev_attr->revision) {
+		ret = -ENOMEM;
 		goto free_soc;
+	}
 
 	soc_dev_attr->serial_number = kasprintf(GFP_KERNEL, "%016llX", soc_uid);
-	if (!soc_dev_attr->serial_number)
+	if (!soc_dev_attr->serial_number) {
+		ret = -ENOMEM;
 		goto free_rev;
+	}
 
 	soc_dev = soc_device_register(soc_dev_attr);
-	if (IS_ERR(soc_dev))
+	if (IS_ERR(soc_dev)) {
+		ret = PTR_ERR(soc_dev);
 		goto free_serial_number;
+	}
 
-	return soc_device_to_device(soc_dev);
+	return 0;
 
 free_serial_number:
 	kfree(soc_dev_attr->serial_number);
 free_rev:
 	kfree(soc_dev_attr->revision);
 free_soc:
 	kfree(soc_dev_attr);
-	return NULL;
+	return ret;
 }
+device_initcall(imx_soc_device_init);

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

@@ -245,21 +245,15 @@ static void __init imx6q_axi_init(void)
 
 static void __init imx6q_init_machine(void)
 {
-	struct device *parent;
-
 	if (cpu_is_imx6q() && imx_get_soc_revision() == IMX_CHIP_REVISION_2_0)
 		imx_print_silicon_rev("i.MX6QP", IMX_CHIP_REVISION_1_0);
 	else
 		imx_print_silicon_rev(cpu_is_imx6dl() ? "i.MX6DL" : "i.MX6Q",
 				imx_get_soc_revision());
 
-	parent = imx_soc_device_init();
-	if (parent == NULL)
-		pr_warn("failed to initialize soc device\n");
-
 	imx6q_enet_phy_init();
 
-	of_platform_default_populate(NULL, NULL, parent);
+	of_platform_default_populate(NULL, NULL, NULL);
 
 	imx_anatop_init();
 	cpu_is_imx6q() ?  imx6q_pm_init() : imx6dl_pm_init();

arch/arm/mach-imx/mach-imx6sl.c

@@ -45,13 +45,7 @@ static void __init imx6sl_init_late(void)
 
 static void __init imx6sl_init_machine(void)
 {
-	struct device *parent;
-
-	parent = imx_soc_device_init();
-	if (parent == NULL)
-		pr_warn("failed to initialize soc device\n");
-
-	of_platform_default_populate(NULL, NULL, parent);
+	of_platform_default_populate(NULL, NULL, NULL);
 
 	if (cpu_is_imx6sl())
 		imx6sl_fec_init();

arch/arm/mach-imx/mach-imx6sx.c

@@ -63,13 +63,7 @@ static inline void imx6sx_enet_init(void)
 
 static void __init imx6sx_init_machine(void)
 {
-	struct device *parent;
-
-	parent = imx_soc_device_init();
-	if (parent == NULL)
-		pr_warn("failed to initialize soc device\n");
-
-	of_platform_default_populate(NULL, NULL, parent);
+	of_platform_default_populate(NULL, NULL, NULL);
 
 	imx6sx_enet_init();
 	imx_anatop_init();

arch/arm/mach-imx/mach-imx6ul.c

@@ -55,13 +55,7 @@ static inline void imx6ul_enet_init(void)
 
 static void __init imx6ul_init_machine(void)
 {
-	struct device *parent;
-
-	parent = imx_soc_device_init();
-	if (parent == NULL)
-		pr_warn("failed to initialize soc device\n");
-
-	of_platform_default_populate(NULL, NULL, parent);
+	of_platform_default_populate(NULL, NULL, NULL);
 	imx6ul_enet_init();
 	imx_anatop_init();
 	imx6ul_pm_init();

arch/arm/mach-imx/mach-imx7d.c

@@ -78,12 +78,6 @@ static inline void imx7d_enet_init(void)
 
 static void __init imx7d_init_machine(void)
 {
-	struct device *parent;
-
-	parent = imx_soc_device_init();
-	if (parent == NULL)
-		pr_warn("failed to initialize soc device\n");
-
 	imx_anatop_init();
 	imx7d_enet_init();
 }

arch/arm/mach-imx/mach-imx7ulp.c

@@ -57,7 +57,7 @@ static void __init imx7ulp_init_machine(void)
 
 	mxc_set_cpu_type(MXC_CPU_IMX7ULP);
 	imx7ulp_set_revision();
-	of_platform_default_populate(NULL, NULL, imx_soc_device_init());
+	of_platform_default_populate(NULL, NULL, NULL);
 }
 
 static const char *const imx7ulp_dt_compat[] __initconst = {

arch/arm/mach-imx/mach-vf610.c

@@ -49,15 +49,9 @@ static void __init vf610_detect_cpu(void)
 
 static void __init vf610_init_machine(void)
 {
-	struct device *parent;
-
 	vf610_detect_cpu();
 
-	parent = imx_soc_device_init();
-	if (parent == NULL)
-		pr_warn("failed to initialize soc device\n");
-
-	of_platform_default_populate(NULL, NULL, parent);
+	of_platform_default_populate(NULL, NULL, NULL);
 }
 
 static const char * const vf610_dt_compat[] __initconst = {