[v5,07/39] soc: Add SoC driver for Cirrus ep93xx

diff --git a/drivers/soc/Kconfig b/drivers/soc/Kconfig
index 10a9ff84ff41..47692deb68e4 100644
--- a/drivers/soc/Kconfig
+++ b/drivers/soc/Kconfig
@@ -7,6 +7,7 @@  source "drivers/soc/aspeed/Kconfig"
 source "drivers/soc/atmel/Kconfig"
 source "drivers/soc/bcm/Kconfig"
 source "drivers/soc/canaan/Kconfig"
+source "drivers/soc/cirrus/Kconfig"
 source "drivers/soc/fsl/Kconfig"
 source "drivers/soc/fujitsu/Kconfig"
 source "drivers/soc/hisilicon/Kconfig"
diff --git a/drivers/soc/Makefile b/drivers/soc/Makefile
index 0706a27d13be..6bfd520c325a 100644
--- a/drivers/soc/Makefile
+++ b/drivers/soc/Makefile
@@ -8,6 +8,7 @@  obj-y				+= aspeed/
 obj-$(CONFIG_ARCH_AT91)		+= atmel/
 obj-y				+= bcm/
 obj-$(CONFIG_SOC_CANAAN)	+= canaan/
+obj-$(CONFIG_EP93XX_SOC)        += cirrus/
 obj-$(CONFIG_ARCH_DOVE)		+= dove/
 obj-$(CONFIG_MACH_DOVE)		+= dove/
 obj-y				+= fsl/
diff --git a/drivers/soc/cirrus/Kconfig b/drivers/soc/cirrus/Kconfig
new file mode 100644
index 000000000000..fea3c3c82be0
--- /dev/null
+++ b/drivers/soc/cirrus/Kconfig
@@ -0,0 +1,13 @@ 
+# SPDX-License-Identifier: GPL-2.0
+
+if ARCH_EP93XX
+
+config EP93XX_SOC
+	bool "Cirrus EP93xx chips SoC"
+	select SOC_BUS
+	select AUXILIARY_BUS
+	default y if !EP93XX_SOC_COMMON
+	help
+	  Support SoC for Cirrus EP93xx chips.
+
+endif
diff --git a/drivers/soc/cirrus/Makefile b/drivers/soc/cirrus/Makefile
new file mode 100644
index 000000000000..ed6752844c6f
--- /dev/null
+++ b/drivers/soc/cirrus/Makefile
@@ -0,0 +1,2 @@ 
+# SPDX-License-Identifier: GPL-2.0
+obj-y	+= soc-ep93xx.o
diff --git a/drivers/soc/cirrus/soc-ep93xx.c b/drivers/soc/cirrus/soc-ep93xx.c
new file mode 100644
index 000000000000..47211ac1e64f
--- /dev/null
+++ b/drivers/soc/cirrus/soc-ep93xx.c
@@ -0,0 +1,247 @@ 
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * SoC driver for Cirrus EP93xx chips.
+ * Copyright (C) 2022 Nikita Shubin <nikita.shubin@maquefel.me>
+ *
+ * Based on a rewrite of arch/arm/mach-ep93xx/core.c
+ * Copyright (C) 2006 Lennert Buytenhek <buytenh@wantstofly.org>
+ * Copyright (C) 2007 Herbert Valerio Riedel <hvr@gnu.org>
+ *
+ * Thanks go to Michael Burian and Ray Lehtiniemi for their key
+ * role in the ep93xx Linux community
+ */
+
+#include <linux/bits.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of.h>
+#include <linux/of_fdt.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/sys_soc.h>
+#include <linux/soc/cirrus/ep93xx.h>
+
+
+#define EP93XX_SYSCON_DEVCFG		0x80
+
+#define EP93XX_SWLOCK_MAGICK		0xaa
+#define EP93XX_SYSCON_SWLOCK		0xc0
+#define EP93XX_SYSCON_SYSCFG		0x9c
+#define EP93XX_SYSCON_SYSCFG_REV_MASK	GENMASK(31, 28)
+#define EP93XX_SYSCON_SYSCFG_REV_SHIFT	28
+
+struct ep93xx_map_info {
+	spinlock_t lock;
+	void __iomem *base;
+	struct regmap *map;
+};
+
+/*
+ * EP93xx System Controller software locked register write
+ *
+ * Logic safeguards are included to condition the control signals for
+ * power connection to the matrix to prevent part damage. In addition, a
+ * software lock register is included that must be written with 0xAA
+ * before each register write to change the values of the four switch
+ * matrix control registers.
+ */
+static void ep93xx_regmap_write(struct regmap *map, spinlock_t *lock,
+				 unsigned int reg, unsigned int val)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(lock, flags);
+
+	regmap_write(map, EP93XX_SYSCON_SWLOCK, EP93XX_SWLOCK_MAGICK);
+	regmap_write(map, reg, val);
+
+	spin_unlock_irqrestore(lock, flags);
+}
+
+static void ep93xx_regmap_update_bits(struct regmap *map, spinlock_t *lock,
+				      unsigned int reg, unsigned int mask,
+				      unsigned int val)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(lock, flags);
+
+	regmap_write(map, EP93XX_SYSCON_SWLOCK, EP93XX_SWLOCK_MAGICK);
+	/* force write is required to clear swlock if is no changes are made */
+	regmap_update_bits_base(map, reg, mask, val, NULL, false, true);
+
+	spin_unlock_irqrestore(lock, flags);
+}
+
+static void ep93xx_unregister_adev(void *_adev)
+{
+	struct auxiliary_device *adev = _adev;
+
+	auxiliary_device_delete(adev);
+	auxiliary_device_uninit(adev);
+}
+
+static void ep93xx_adev_release(struct device *dev)
+{
+	struct auxiliary_device *adev = to_auxiliary_dev(dev);
+
+	kfree(adev);
+}
+
+static struct auxiliary_device *ep93xx_adev_alloc(struct device *parent, const char *name,
+						  struct ep93xx_map_info *info)
+{
+	struct ep93xx_regmap_adev *rdev;
+	struct auxiliary_device *adev;
+	int ret;
+
+	rdev = kzalloc(sizeof(*rdev), GFP_KERNEL);
+	if (!rdev)
+		return ERR_PTR(-ENOMEM);
+
+	rdev->map = info->map;
+	rdev->base = info->base;
+	rdev->lock = &info->lock;
+	rdev->write = ep93xx_regmap_write;
+	rdev->update_bits = ep93xx_regmap_update_bits;
+
+	adev = &rdev->adev;
+	adev->name = name;
+	adev->dev.parent = parent;
+	adev->dev.release = ep93xx_adev_release;
+
+	ret = auxiliary_device_init(adev);
+	if (ret) {
+		kfree(adev);
+		return ERR_PTR(ret);
+	}
+
+	return adev;
+}
+
+static int ep93xx_controller_register(struct device *parent, const char *name,
+				      struct ep93xx_map_info *info)
+{
+	struct auxiliary_device *adev;
+	int ret;
+
+	adev = ep93xx_adev_alloc(parent, name, info);
+	if (IS_ERR(adev))
+		return PTR_ERR(adev);
+
+	ret = auxiliary_device_add(adev);
+	if (ret) {
+		auxiliary_device_uninit(adev);
+		return ret;
+	}
+
+	return devm_add_action_or_reset(parent, ep93xx_unregister_adev, adev);
+}
+
+static unsigned int __init ep93xx_soc_revision(struct regmap *map)
+{
+	unsigned int val;
+
+	regmap_read(map, EP93XX_SYSCON_SYSCFG, &val);
+	val &= EP93XX_SYSCON_SYSCFG_REV_MASK;
+	val >>= EP93XX_SYSCON_SYSCFG_REV_SHIFT;
+	return val;
+}
+
+static const char __init *ep93xx_get_soc_rev(struct regmap *map)
+{
+	switch (ep93xx_soc_revision(map)) {
+	case EP93XX_CHIP_REV_D0:
+		return "D0";
+	case EP93XX_CHIP_REV_D1:
+		return "D1";
+	case EP93XX_CHIP_REV_E0:
+		return "E0";
+	case EP93XX_CHIP_REV_E1:
+		return "E1";
+	case EP93XX_CHIP_REV_E2:
+		return "E2";
+	default:
+		return "unknown";
+	}
+}
+const char *pinctrl_names[] = {
+	"pinctrl-ep9301",	/* EP93XX_9301_SOC */
+	"pinctrl-ep9307",	/* EP93XX_9307_SOC */
+	"pinctrl-ep9312"	/* EP93XX_9312_SOC */
+};
+
+static int __init ep93xx_syscon_probe(struct platform_device *pdev)
+{
+	enum ep93xx_soc_model model = (int)of_device_get_match_data(&pdev->dev);
+	struct ep93xx_map_info *map_info;
+	struct soc_device_attribute *attrs;
+	struct soc_device *soc_dev;
+	struct device *dev = &pdev->dev;
+	struct regmap *map;
+	void __iomem *base;
+	int ret;
+
+	map = device_node_to_regmap(dev->of_node);
+	if (IS_ERR(map))
+		return PTR_ERR(map);
+
+	base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	attrs = devm_kzalloc(dev, sizeof(*attrs), GFP_KERNEL);
+	if (!attrs)
+		return -ENOMEM;
+
+	attrs->machine = of_flat_dt_get_machine_name();
+	attrs->family = "Cirrus Logic EP93xx";
+	attrs->revision = ep93xx_get_soc_rev(map);
+
+	soc_dev = soc_device_register(attrs);
+	if (IS_ERR(soc_dev))
+		return PTR_ERR(soc_dev);
+
+	map_info = devm_kzalloc(dev, sizeof(*map_info), GFP_KERNEL);
+	if (!map_info)
+		return -ENOMEM;
+
+	spin_lock_init(&map_info->lock);
+	map_info->map = map;
+	map_info->base = base;
+
+	ret = ep93xx_controller_register(dev, pinctrl_names[model], map_info);
+	if (ret)
+		dev_err(dev, "registering pinctrl controller failed\n");
+
+	ret = ep93xx_controller_register(dev, "clk-ep93xx", map_info);
+	if (ret)
+		dev_err(dev, "registering clock controller failed\n");
+
+	ret = ep93xx_controller_register(dev, "reset-ep93xx", map_info);
+	if (ret)
+		dev_err(dev, "registering reset controller failed\n");
+
+	dev_info(dev, "EP93xx SoC revision %s\n", attrs->revision);
+
+	return 0;
+}
+
+static const struct of_device_id ep9301_syscon_of_device_ids[] = {
+	{ .compatible	= "cirrus,ep9301-syscon", .data = (void *)EP93XX_9301_SOC },
+	{ .compatible	= "cirrus,ep9302-syscon", .data = (void *)EP93XX_9301_SOC },
+	{ .compatible	= "cirrus,ep9307-syscon", .data = (void *)EP93XX_9307_SOC },
+	{ .compatible	= "cirrus,ep9312-syscon", .data = (void *)EP93XX_9312_SOC },
+	{ .compatible	= "cirrus,ep9315-syscon", .data = (void *)EP93XX_9312_SOC },
+	{ /* sentinel */ }
+};
+
+static struct platform_driver ep9301_syscon_driver = {
+	.driver = {
+		.name = "ep9301-syscon",
+		.of_match_table = ep9301_syscon_of_device_ids,
+	},
+};
+builtin_platform_driver_probe(ep9301_syscon_driver, ep93xx_syscon_probe);