mips: ralink: rt3883: introduce 'soc_device' initialization

RT3883 SoC have its own 'ralink_soc_info' structure with some
information about the soc itself. In order to be able to retrieve this
information from driver code and avoid architecture dependencies for
retrieving these details introduce this 'soc_device'. Set 'data' pointer
points to the struct 'ralink_soc_info' to be able to export also current
soc information using this mechanism. We need to select 'SOC_BUS' in
Kconfig configuration for these SoCs.
Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

arch/mips/ralink/Kconfig

@@ -37,6 +37,7 @@ choice
 	config SOC_RT3883
 		bool "RT3883"
 		select HAVE_PCI
+		select SOC_BUS
 
 	config SOC_MT7620
 		bool "MT7620/8"

arch/mips/ralink/rt3883.c

@@ -10,6 +10,8 @@
 
 #include <linux/kernel.h>
 #include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/sys_soc.h>
 
 #include <asm/mipsregs.h>
 #include <asm/mach-ralink/ralink_regs.h>
@@ -17,6 +19,8 @@
 
 #include "common.h"
 
+static struct ralink_soc_info *soc_info_ptr;
+
 void __init ralink_clk_init(void)
 {
 	unsigned long cpu_rate, sys_rate;
@@ -112,6 +116,30 @@ static unsigned int __init rt3883_get_soc_rev(void)
 	return (rt3883_get_soc_id() & RT3883_REVID_ECO_ID_MASK);
 }
 
+static int __init rt3883_soc_dev_init(void)
+{
+	struct soc_device *soc_dev;
+	struct soc_device_attribute *soc_dev_attr;
+
+	soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL);
+	if (!soc_dev_attr)
+		return -ENOMEM;
+
+	soc_dev_attr->family = "Ralink";
+	soc_dev_attr->soc_id = rt3883_get_soc_name();
+
+	soc_dev_attr->data = soc_info_ptr;
+
+	soc_dev = soc_device_register(soc_dev_attr);
+	if (IS_ERR(soc_dev)) {
+		kfree(soc_dev_attr);
+		return PTR_ERR(soc_dev);
+	}
+
+	return 0;
+}
+device_initcall(rt3883_soc_dev_init);
+
 void __init prom_soc_init(struct ralink_soc_info *soc_info)
 {
 	if (rt3883_soc_valid())
@@ -131,4 +159,5 @@ void __init prom_soc_init(struct ralink_soc_info *soc_info)
 	soc_info->mem_size_max = RT3883_MEM_SIZE_MAX;
 
 	ralink_soc = RT3883_SOC;
+	soc_info_ptr = soc_info;
 }