mips: ralink: rt305x: introduce 'soc_device' initialization

RT305x SoCs have their 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

@@ -32,6 +32,7 @@ choice
 
 	config SOC_RT305X
 		bool "RT305x"
+		select SOC_BUS
 
 	config SOC_RT3883
 		bool "RT3883"

arch/mips/ralink/rt305x.c

@@ -11,6 +11,8 @@
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/bug.h>
+#include <linux/slab.h>
+#include <linux/sys_soc.h>
 
 #include <asm/io.h>
 #include <asm/mipsregs.h>
@@ -19,6 +21,8 @@
 
 #include "common.h"
 
+static struct ralink_soc_info *soc_info_ptr;
+
 static unsigned long rt5350_get_mem_size(void)
 {
 	unsigned long ret;
@@ -233,6 +237,46 @@ static unsigned int __init rt305x_get_soc_rev(void)
 	return (rt305x_get_soc_id() & CHIP_ID_REV_MASK);
 }
 
+static const char __init *rt305x_get_soc_id_name(void)
+{
+	if (soc_is_rt3050())
+		return "rt3050";
+	else if (soc_is_rt3052())
+		return "rt3052";
+	else if (soc_is_rt3350())
+		return "rt3350";
+	else if (soc_is_rt3352())
+		return "rt3352";
+	else if (soc_is_rt5350())
+		return "rt5350";
+	else
+		return "invalid";
+}
+
+static int __init rt305x_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 = rt305x_get_soc_id_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(rt305x_soc_dev_init);
+
 void __init prom_soc_init(struct ralink_soc_info *soc_info)
 {
 	const char *name = rt305x_get_soc_name(soc_info);
@@ -253,4 +297,6 @@ void __init prom_soc_init(struct ralink_soc_info *soc_info)
 		soc_info->mem_size_min = RT3352_MEM_SIZE_MIN;
 		soc_info->mem_size_max = RT3352_MEM_SIZE_MAX;
 	}
+
+	soc_info_ptr = soc_info;
 }