soc: amlogic: Add Meson6/Meson8/Meson8b/Meson8m2 SoC Information driver

Amlogic SoCs have an information register which contains the SoC type
and revision information.
This patchs adds support for decoding those registers and exposing the
resulting information via the SoC bus infrastructure.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>

drivers/soc/amlogic/meson-mx-socinfo.c

@@ -0,0 +1,175 @@
+/*
+ * Copyright (c) 2017 Martin Blumenstingl <martin.blumenstingl@googlemail.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#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>
+#include <linux/bitfield.h>
+#include <linux/regmap.h>
+#include <linux/mfd/syscon.h>
+
+#define MESON_SOCINFO_MAJOR_VER_MESON6		0x16
+#define MESON_SOCINFO_MAJOR_VER_MESON8		0x19
+#define MESON_SOCINFO_MAJOR_VER_MESON8B		0x1b
+
+#define MESON_MX_ASSIST_HW_REV			0x14c
+
+#define MESON_MX_ANALOG_TOP_METAL_REVISION	0x0
+
+#define MESON_MX_BOOTROM_MISC_VER		0x4
+
+static const char *meson_mx_socinfo_revision(unsigned int major_ver,
+					     unsigned int misc_ver,
+					     unsigned int metal_rev)
+{
+	unsigned int minor_ver;
+
+	switch (major_ver) {
+	case MESON_SOCINFO_MAJOR_VER_MESON6:
+		minor_ver = 0xa;
+		break;
+
+	case MESON_SOCINFO_MAJOR_VER_MESON8:
+		if (metal_rev == 0x11111112)
+			major_ver = 0x1d;
+
+		if (metal_rev == 0x11111111 || metal_rev == 0x11111112)
+			minor_ver = 0xa;
+		else if (metal_rev == 0x11111113)
+			minor_ver = 0xb;
+		else if (metal_rev == 0x11111133)
+			minor_ver = 0xc;
+		else
+			minor_ver = 0xd;
+
+		break;
+
+	case MESON_SOCINFO_MAJOR_VER_MESON8B:
+		if (metal_rev == 0x11111111)
+			minor_ver = 0xa;
+		else
+			minor_ver = 0xb;
+
+		break;
+
+	default:
+		minor_ver = 0x0;
+		break;
+	}
+
+	return kasprintf(GFP_KERNEL, "Rev%X (%x - 0:%X)", minor_ver, major_ver,
+			 misc_ver);
+}
+
+static const char *meson_mx_socinfo_soc_id(unsigned int major_ver,
+					   unsigned int metal_rev)
+{
+	const char *soc_id;
+
+	switch (major_ver) {
+	case MESON_SOCINFO_MAJOR_VER_MESON6:
+		soc_id = "Meson6 (AML8726-MX)";
+		break;
+
+	case MESON_SOCINFO_MAJOR_VER_MESON8:
+		if (metal_rev == 0x11111112)
+			soc_id = "Meson8m2 (S812)";
+		else
+			soc_id = "Meson8 (S802)";
+
+		break;
+
+	case MESON_SOCINFO_MAJOR_VER_MESON8B:
+		soc_id = "Meson8b (S805)";
+		break;
+
+	default:
+		soc_id = "Unknown";
+		break;
+	}
+
+	return kstrdup_const(soc_id, GFP_KERNEL);
+}
+
+static const struct of_device_id meson_mx_socinfo_analog_top_ids[] = {
+	{ .compatible = "amlogic,meson8-analog-top", },
+	{ .compatible = "amlogic,meson8b-analog-top", },
+	{ /* sentinel */ }
+};
+
+int __init meson_mx_socinfo_init(void)
+{
+	struct soc_device_attribute *soc_dev_attr;
+	struct soc_device *soc_dev;
+	struct device_node *np;
+	struct regmap *assist_regmap, *bootrom_regmap, *analog_top_regmap;
+	unsigned int major_ver, misc_ver, metal_rev = 0;
+	int ret;
+
+	assist_regmap =
+		syscon_regmap_lookup_by_compatible("amlogic,meson-mx-assist");
+	if (IS_ERR(assist_regmap))
+		return PTR_ERR(assist_regmap);
+
+	bootrom_regmap =
+		syscon_regmap_lookup_by_compatible("amlogic,meson-mx-bootrom");
+	if (IS_ERR(bootrom_regmap))
+		return PTR_ERR(bootrom_regmap);
+
+	np = of_find_matching_node(NULL, meson_mx_socinfo_analog_top_ids);
+	if (np) {
+		analog_top_regmap = syscon_node_to_regmap(np);
+		if (IS_ERR(analog_top_regmap))
+			return PTR_ERR(analog_top_regmap);
+
+		ret = regmap_read(analog_top_regmap,
+				  MESON_MX_ANALOG_TOP_METAL_REVISION,
+				  &metal_rev);
+		if (ret)
+			return ret;
+	}
+
+	ret = regmap_read(assist_regmap, MESON_MX_ASSIST_HW_REV, &major_ver);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_read(bootrom_regmap, MESON_MX_BOOTROM_MISC_VER,
+			  &misc_ver);
+	if (ret < 0)
+		return ret;
+
+	soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL);
+	if (!soc_dev_attr)
+		return -ENODEV;
+
+	soc_dev_attr->family = "Amlogic Meson";
+
+	np = of_find_node_by_path("/");
+	of_property_read_string(np, "model", &soc_dev_attr->machine);
+	of_node_put(np);
+
+	soc_dev_attr->revision = meson_mx_socinfo_revision(major_ver, misc_ver,
+							   metal_rev);
+	soc_dev_attr->soc_id = meson_mx_socinfo_soc_id(major_ver, metal_rev);
+
+	soc_dev = soc_device_register(soc_dev_attr);
+	if (IS_ERR(soc_dev)) {
+		kfree_const(soc_dev_attr->revision);
+		kfree_const(soc_dev_attr->soc_id);
+		kfree(soc_dev_attr);
+		return PTR_ERR(soc_dev);
+	}
+
+	dev_info(soc_device_to_device(soc_dev), "Amlogic %s %s detected\n",
+		 soc_dev_attr->soc_id, soc_dev_attr->revision);
+
+	return 0;
+}
+device_initcall(meson_mx_socinfo_init);