soc: add driver for the ARM RealView

This adds a SoC driver to be used by the ARM RealView
reference boards. We create the "versatile" directory to hold
the different ARM reference designs as per the pattern of the
clk directory layout. The driver utilze the syscon to get to
the register needed. After this we can use sysfs to get at
some SoC properties on RealView DT variants like this:

> cd /sysbus/soc/devices/soc0
> ls
board         family        machine       power         subsystem
build         fpga          manufacturer  soc_id        uevent
> cat family
Versatile
> cat fpga
Multi-layer AXI
> cat board
HBI-0147
> cat build
03
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Conflicts:
	drivers/soc/Kconfig
	drivers/soc/Makefile

drivers/soc/Kconfig

@@ -2,5 +2,6 @@ menu "SOC (System On Chip) specific Drivers"
 
 source "drivers/soc/qcom/Kconfig"
 source "drivers/soc/ti/Kconfig"
+source "drivers/soc/versatile/Kconfig"
 
 endmenu

drivers/soc/Makefile

@@ -5,3 +5,4 @@
 obj-$(CONFIG_ARCH_QCOM)		+= qcom/
 obj-$(CONFIG_ARCH_TEGRA)	+= tegra/
 obj-$(CONFIG_SOC_TI)		+= ti/
+obj-$(CONFIG_PLAT_VERSATILE)	+= versatile/

drivers/soc/versatile/Kconfig

+#
+# ARM Versatile SoC drivers
+#
+config SOC_REALVIEW
+	bool "SoC bus device for the ARM RealView platforms"
+	depends on ARCH_REALVIEW
+	select SOC_BUS
+	help
+	  Include support for the SoC bus on the ARM RealView platforms
+	  providing some sysfs information about the ASIC variant.

drivers/soc/versatile/Makefile

+obj-$(CONFIG_SOC_REALVIEW)	+= soc-realview.o

drivers/soc/versatile/soc-realview.c

+/*
+ * Copyright (C) 2014 Linaro Ltd.
+ *
+ * Author: Linus Walleij <linus.walleij@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2, as
+ * published by the Free Software Foundation.
+ *
+ */
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/sys_soc.h>
+#include <linux/platform_device.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regmap.h>
+#include <linux/of.h>
+
+/* System ID in syscon */
+#define REALVIEW_SYS_ID_OFFSET 0x00
+
+static const struct of_device_id realview_soc_of_match[] = {
+	{ .compatible = "arm,realview-eb-soc",	},
+	{ .compatible = "arm,realview-pb1176-soc", },
+	{ .compatible = "arm,realview-pb11mp-soc", },
+	{ .compatible = "arm,realview-pba8-soc", },
+	{ .compatible = "arm,realview-pbx-soc", },
+};
+
+static u32 realview_coreid;
+
+static const char *realview_board_str(u32 id)
+{
+	switch ((id >> 16) & 0xfff) {
+	case 0x0147:
+		return "HBI-0147";
+	default:
+		return "Unknown";
+	}
+}
+
+static const char *realview_arch_str(u32 id)
+{
+	switch ((id >> 8) & 0xf) {
+	case 0x05:
+		return "Multi-layer AXI";
+	default:
+		return "Unknown";
+	}
+}
+
+static ssize_t realview_get_manf(struct device *dev,
+			      struct device_attribute *attr,
+			      char *buf)
+{
+	return sprintf(buf, "%02x\n", realview_coreid >> 24);
+}
+
+static struct device_attribute realview_manf_attr =
+	__ATTR(manufacturer,  S_IRUGO, realview_get_manf,  NULL);
+
+static ssize_t realview_get_board(struct device *dev,
+			      struct device_attribute *attr,
+			      char *buf)
+{
+	return sprintf(buf, "%s\n", realview_board_str(realview_coreid));
+}
+
+static struct device_attribute realview_board_attr =
+	__ATTR(board,  S_IRUGO, realview_get_board,  NULL);
+
+static ssize_t realview_get_arch(struct device *dev,
+			      struct device_attribute *attr,
+			      char *buf)
+{
+	return sprintf(buf, "%s\n", realview_arch_str(realview_coreid));
+}
+
+static struct device_attribute realview_arch_attr =
+	__ATTR(fpga,  S_IRUGO, realview_get_arch,  NULL);
+
+static ssize_t realview_get_build(struct device *dev,
+			       struct device_attribute *attr,
+			       char *buf)
+{
+	return sprintf(buf, "%02x\n", (realview_coreid & 0xFF));
+}
+
+static struct device_attribute realview_build_attr =
+	__ATTR(build,  S_IRUGO, realview_get_build,  NULL);
+
+static int realview_soc_probe(struct platform_device *pdev)
+{
+	static struct regmap *syscon_regmap;
+	struct soc_device *soc_dev;
+	struct soc_device_attribute *soc_dev_attr;
+	struct device_node *np = pdev->dev.of_node;
+	int ret;
+
+	syscon_regmap = syscon_regmap_lookup_by_phandle(np, "regmap");
+	if (IS_ERR(syscon_regmap))
+		return PTR_ERR(syscon_regmap);
+
+	soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL);
+	if (!soc_dev_attr)
+		return -ENOMEM;
+
+	ret = of_property_read_string(np, "compatible",
+				      &soc_dev_attr->soc_id);
+	if (ret)
+		return -EINVAL;
+
+	soc_dev_attr->machine = "RealView";
+	soc_dev_attr->family = "Versatile";
+	soc_dev = soc_device_register(soc_dev_attr);
+	if (IS_ERR(soc_dev)) {
+		kfree(soc_dev_attr);
+		return -ENODEV;
+	}
+	ret = regmap_read(syscon_regmap, REALVIEW_SYS_ID_OFFSET,
+			  &realview_coreid);
+	if (ret)
+		return -ENODEV;
+
+	device_create_file(soc_device_to_device(soc_dev), &realview_manf_attr);
+	device_create_file(soc_device_to_device(soc_dev), &realview_board_attr);
+	device_create_file(soc_device_to_device(soc_dev), &realview_arch_attr);
+	device_create_file(soc_device_to_device(soc_dev), &realview_build_attr);
+
+	dev_info(&pdev->dev, "RealView Syscon Core ID: 0x%08x\n",
+		 realview_coreid);
+	/* FIXME: add attributes for SoC to sysfs */
+	return 0;
+}
+
+static struct platform_driver realview_soc_driver = {
+	.probe = realview_soc_probe,
+	.driver = {
+		.name = "realview-soc",
+		.of_match_table = realview_soc_of_match,
+	},
+};
+module_platform_driver(realview_soc_driver);