[PATCH v9 04/12] soc: samsung: add exynos chipid driver support

[Pankaj Dubey <pankaj.dubey@samsung.com>]

Exynos SoCs have Chipid, for identification of product IDs and SoC
revisions. This patch intends to provide initialization code for all
these functionalities, at the same time it provides some sysfs entries
for accessing these information to user-space.

This driver uses existing binding for exynos-chipid.

CC: Grant Likely <grant.likely@linaro.org>
CC: Rob Herring <robh+dt@kernel.org>
CC: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Pankaj Dubey <pankaj.dubey@samsung.com>
[m.szyprowski: for suggestion and code snippet of product_id_to_soc_id]
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 drivers/soc/samsung/Kconfig         |   5 ++
 drivers/soc/samsung/Makefile        |   1 +
 drivers/soc/samsung/exynos-chipid.c | 109 ++++++++++++++++++++++++++++++++++++
 3 files changed, 115 insertions(+)
 create mode 100644 drivers/soc/samsung/exynos-chipid.c

diff --git a/drivers/soc/samsung/Kconfig b/drivers/soc/samsung/Kconfig
index 8b25bd5..a90a4ad 100644
--- a/drivers/soc/samsung/Kconfig
+++ b/drivers/soc/samsung/Kconfig
@@ -6,6 +6,11 @@ menuconfig SOC_SAMSUNG
 
 if SOC_SAMSUNG
 
+config EXYNOS_CHIPID
+	bool "Exynos Chipid controller driver" if COMPILE_TEST
+	depends on ARCH_EXYNOS || COMPILE_TEST
+	select SOC_BUS
+
 config EXYNOS_PMU
 	bool "Exynos PMU controller driver" if COMPILE_TEST
 	depends on ARCH_EXYNOS || ((ARM || ARM64) && COMPILE_TEST)
diff --git a/drivers/soc/samsung/Makefile b/drivers/soc/samsung/Makefile
index 4d7694a..be3b6bb 100644
--- a/drivers/soc/samsung/Makefile
+++ b/drivers/soc/samsung/Makefile
@@ -1,3 +1,4 @@
+obj-$(CONFIG_EXYNOS_CHIPID)	+= exynos-chipid.o
 obj-$(CONFIG_EXYNOS_PMU)	+= exynos-pmu.o
 
 obj-$(CONFIG_EXYNOS_PMU_ARM_DRIVERS)	+= exynos3250-pmu.o exynos4-pmu.o \
diff --git a/drivers/soc/samsung/exynos-chipid.c b/drivers/soc/samsung/exynos-chipid.c
new file mode 100644
index 0000000..1e9fb6b
--- /dev/null
+++ b/drivers/soc/samsung/exynos-chipid.c
@@ -0,0 +1,109 @@
+/*
+ * Copyright (c) 2017 Samsung Electronics Co., Ltd.
+ *	      http://www.samsung.com/
+ *
+ * EXYNOS - CHIP ID support
+ * Author: Pankaj Dubey <pankaj.dubey@samsung.com>
+ *
+ * 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/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/sys_soc.h>
+
+#define EXYNOS_SUBREV_MASK	(0xF << 4)
+#define EXYNOS_MAINREV_MASK	(0xF << 0)
+#define EXYNOS_REV_MASK		(EXYNOS_SUBREV_MASK | EXYNOS_MAINREV_MASK)
+
+static const struct exynos_soc_id {
+	const char *name;
+	unsigned int id;
+	unsigned int mask;
+} soc_ids[] = {
+	{ "EXYNOS3250", 0xE3472000, 0xFFFFF000 },
+	{ "EXYNOS4210", 0x43210000, 0xFFFFF000 },
+	{ "EXYNOS4212", 0x43220000, 0xFFFFF000 },
+	{ "EXYNOS4412", 0xE4412000, 0xFFFFF000 },
+	{ "EXYNOS5250", 0x43520000, 0xFFFFF000 },
+	{ "EXYNOS5260", 0xE5260000, 0xFFFFF000 },
+	{ "EXYNOS5410", 0xE5410000, 0xFFFFF000 },
+	{ "EXYNOS5420", 0xE5420000, 0xFFFFF000 },
+	{ "EXYNOS5440", 0xE5440000, 0xFFFFF000 },
+	{ "EXYNOS5800", 0xE5422000, 0xFFFFF000 },
+	{ "EXYNOS7420", 0xE7420000, 0xFFFFF000 },
+	{ "EXYNOS5433", 0xE5433000, 0xFFFFF000 },
+};
+
+static const char * __init product_id_to_soc_id(unsigned int product_id)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(soc_ids); i++)
+		if ((product_id & soc_ids[i].mask) == soc_ids[i].id)
+			return soc_ids[i].name;
+	return "UNKNOWN";
+}
+
+int __init exynos_chipid_early_init(void)
+{
+	struct soc_device_attribute *soc_dev_attr;
+	void __iomem *exynos_chipid_base;
+	struct soc_device *soc_dev;
+	struct device_node *root;
+	struct device_node *np;
+	struct device *dev;
+	u32 product_id;
+	u32 revision;
+
+	/* look up for chipid node */
+	np = of_find_compatible_node(NULL, NULL, "samsung,exynos4210-chipid");
+	if (!np)
+		return -ENODEV;
+
+	exynos_chipid_base = of_iomap(np, 0);
+	of_node_put(np);
+
+	if (!exynos_chipid_base) {
+		pr_err("%s: failed to map chipid\n", np->name);
+		return -ENOMEM;
+	}
+
+	product_id = readl_relaxed(exynos_chipid_base);
+	revision = product_id & EXYNOS_REV_MASK;
+	iounmap(exynos_chipid_base);
+
+	soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL);
+	if (!soc_dev_attr)
+		return -ENODEV;
+
+	soc_dev_attr->family = "Samsung Exynos";
+
+	root = of_find_node_by_path("/");
+	of_property_read_string(root, "model", &soc_dev_attr->machine);
+	of_node_put(root);
+
+	soc_dev_attr->revision = kasprintf(GFP_KERNEL, "%x", revision);
+	soc_dev_attr->soc_id = product_id_to_soc_id(product_id);
+
+	soc_dev = soc_device_register(soc_dev_attr);
+	if (IS_ERR(soc_dev)) {
+		kfree(soc_dev_attr->revision);
+		kfree_const(soc_dev_attr->soc_id);
+		kfree(soc_dev_attr);
+		return PTR_ERR(soc_dev);
+	}
+	dev = soc_device_to_device(soc_dev);
+
+	dev_info(dev, "Exynos: CPU[%s] PRO_ID[0x%x] REV[0x%x] Detected\n",
+			soc_dev_attr->soc_id, product_id, revision);
+
+	return 0;
+}
+early_initcall(exynos_chipid_early_init);
-- 
2.7.4