ARM: tegra: expose chip ID and revision

Expose Tegra chip ID and revision in /sys/devices/soc for user mode
usage

Signed-off-by: Danny Huang <dahuang@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>

arch/arm/Kconfig

@@ -675,6 +675,7 @@ config ARCH_TEGRA
 	select HAVE_CLK
 	select HAVE_SMP
 	select MIGHT_HAVE_CACHE_L2X0
+	select SOC_BUS
 	select SPARSE_IRQ
 	select USE_OF
 	help

arch/arm/mach-tegra/tegra.c

@@ -33,6 +33,8 @@
 #include <linux/io.h>
 #include <linux/i2c.h>
 #include <linux/i2c-tegra.h>
+#include <linux/slab.h>
+#include <linux/sys_soc.h>
 #include <linux/usb/tegra_usb_phy.h>
 
 #include <asm/mach-types.h>
@@ -42,6 +44,7 @@
 
 #include "board.h"
 #include "common.h"
+#include "fuse.h"
 #include "iomap.h"
 
 static struct tegra_ehci_platform_data tegra_ehci1_pdata = {
@@ -80,12 +83,36 @@ static struct of_dev_auxdata tegra20_auxdata_lookup[] __initdata = {
 
 static void __init tegra_dt_init(void)
 {
+	struct soc_device_attribute *soc_dev_attr;
+	struct soc_device *soc_dev;
+	struct device *parent = NULL;
+
+	soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL);
+	if (!soc_dev_attr)
+		goto out;
+
+	soc_dev_attr->family = kasprintf(GFP_KERNEL, "Tegra");
+	soc_dev_attr->revision = kasprintf(GFP_KERNEL, "%d", tegra_revision);
+	soc_dev_attr->soc_id = kasprintf(GFP_KERNEL, "%d", tegra_chip_id);
+
+	soc_dev = soc_device_register(soc_dev_attr);
+	if (IS_ERR(soc_dev)) {
+		kfree(soc_dev_attr->family);
+		kfree(soc_dev_attr->revision);
+		kfree(soc_dev_attr->soc_id);
+		kfree(soc_dev_attr);
+		goto out;
+	}
+
+	parent = soc_device_to_device(soc_dev);
+
 	/*
 	 * Finished with the static registrations now; fill in the missing
 	 * devices
 	 */
+out:
 	of_platform_populate(NULL, of_default_bus_match_table,
-				tegra20_auxdata_lookup, NULL);
+				tegra20_auxdata_lookup, parent);
 }
 
 static void __init trimslice_init(void)