1 files changed, 362 insertions, 0 deletions
diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c
new file mode 100644
index 000000000..21a7fcdd2
--- /dev/null
+++ b/drivers/mfd/syscon.c
@@ -0,0 +1,362 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * System Control Driver
+ *
+ * Copyright (C) 2012 Freescale Semiconductor, Inc.
+ * Copyright (C) 2012 Linaro Ltd.
+ *
+ * Author: Dong Aisheng <dong.aisheng@linaro.org>
+ */
+
+#include <linux/cleanup.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/hwspinlock.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+#include <linux/mfd/syscon.h>
+#include <linux/slab.h>
+
+static DEFINE_MUTEX(syscon_list_lock);
+static LIST_HEAD(syscon_list);
+
+struct syscon {
+	struct device_node *np;
+	struct regmap *regmap;
+	struct reset_control *reset;
+	struct list_head list;
+};
+
+static const struct regmap_config syscon_regmap_config = {
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_stride = 4,
+};
+
+static struct syscon *of_syscon_register(struct device_node *np, bool check_res)
+{
+	struct clk *clk;
+	struct regmap *regmap;
+	void __iomem *base;
+	u32 reg_io_width;
+	int ret;
+	struct regmap_config syscon_config = syscon_regmap_config;
+	struct resource res;
+	struct reset_control *reset;
+	resource_size_t res_size;
+
+	WARN_ON(!mutex_is_locked(&syscon_list_lock));
+
+	struct syscon *syscon __free(kfree) = kzalloc_obj(*syscon);
+	if (!syscon)
+		return ERR_PTR(-ENOMEM);
+
+	if (of_address_to_resource(np, 0, &res))
+		return ERR_PTR(-ENOMEM);
+
+	base = of_iomap(np, 0);
+	if (!base)
+		return ERR_PTR(-ENOMEM);
+
+	/* Parse the device's DT node for an endianness specification */
+	if (of_property_read_bool(np, "big-endian"))
+		syscon_config.val_format_endian = REGMAP_ENDIAN_BIG;
+	else if (of_property_read_bool(np, "little-endian"))
+		syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE;
+	else if (of_property_read_bool(np, "native-endian"))
+		syscon_config.val_format_endian = REGMAP_ENDIAN_NATIVE;
+
+	/*
+	 * search for reg-io-width property in DT. If it is not provided,
+	 * default to 4 bytes. regmap_init_mmio will return an error if values
+	 * are invalid so there is no need to check them here.
+	 */
+	ret = of_property_read_u32(np, "reg-io-width", &reg_io_width);
+	if (ret)
+		reg_io_width = 4;
+
+	ret = of_hwspin_lock_get_id(np, 0);
+	if (ret > 0 || (IS_ENABLED(CONFIG_HWSPINLOCK) && ret == 0)) {
+		syscon_config.use_hwlock = true;
+		syscon_config.hwlock_id = ret;
+		syscon_config.hwlock_mode = HWLOCK_IRQSTATE;
+	} else if (ret < 0) {
+		switch (ret) {
+		case -ENOENT:
+			/* Ignore missing hwlock, it's optional. */
+			break;
+		default:
+			pr_err("Failed to retrieve valid hwlock: %d\n", ret);
+			fallthrough;
+		case -EPROBE_DEFER:
+			goto err_regmap;
+		}
+	}
+
+	res_size = resource_size(&res);
+	if (res_size < reg_io_width) {
+		ret = -EFAULT;
+		goto err_regmap;
+	}
+
+	syscon_config.name = kasprintf(GFP_KERNEL, "%pOFn@%pa", np, &res.start);
+	if (!syscon_config.name) {
+		ret = -ENOMEM;
+		goto err_regmap;
+	}
+	syscon_config.reg_stride = reg_io_width;
+	syscon_config.val_bits = reg_io_width * 8;
+	syscon_config.max_register = res_size - reg_io_width;
+	if (!syscon_config.max_register)
+		syscon_config.max_register_is_0 = true;
+
+	regmap = regmap_init_mmio(NULL, base, &syscon_config);
+	kfree(syscon_config.name);
+	if (IS_ERR(regmap)) {
+		pr_err("regmap init failed\n");
+		ret = PTR_ERR(regmap);
+		goto err_regmap;
+	}
+
+	if (check_res) {
+		clk = of_clk_get(np, 0);
+		if (IS_ERR(clk)) {
+			ret = PTR_ERR(clk);
+			/* clock is optional */
+			if (ret != -ENOENT)
+				goto err_clk;
+		} else {
+			ret = regmap_mmio_attach_clk(regmap, clk);
+			if (ret)
+				goto err_attach_clk;
+		}
+
+		reset = of_reset_control_get_optional_exclusive(np, NULL);
+		if (IS_ERR(reset)) {
+			ret = PTR_ERR(reset);
+			goto err_attach_clk;
+		}
+
+		ret = reset_control_deassert(reset);
+		if (ret)
+			goto err_reset;
+	}
+
+	syscon->regmap = regmap;
+	syscon->np = np;
+
+	list_add_tail(&syscon->list, &syscon_list);
+
+	return_ptr(syscon);
+
+err_reset:
+	reset_control_put(reset);
+err_attach_clk:
+	if (!IS_ERR(clk))
+		clk_put(clk);
+err_clk:
+	regmap_exit(regmap);
+err_regmap:
+	iounmap(base);
+	return ERR_PTR(ret);
+}
+
+static struct regmap *device_node_get_regmap(struct device_node *np,
+					     bool create_regmap,
+					     bool check_res)
+{
+	struct syscon *entry, *syscon = NULL;
+
+	mutex_lock(&syscon_list_lock);
+
+	list_for_each_entry(entry, &syscon_list, list)
+		if (entry->np == np) {
+			syscon = entry;
+			break;
+		}
+
+	if (!syscon) {
+		if (create_regmap)
+			syscon = of_syscon_register(np, check_res);
+		else
+			syscon = ERR_PTR(-EPROBE_DEFER);
+	}
+	mutex_unlock(&syscon_list_lock);
+
+	if (IS_ERR(syscon))
+		return ERR_CAST(syscon);
+
+	return syscon->regmap;
+}
+
+/**
+ * of_syscon_register_regmap() - Register regmap for specified device node
+ * @np: Device tree node
+ * @regmap: Pointer to regmap object
+ *
+ * Register an externally created regmap object with syscon for the specified
+ * device tree node. This regmap will then be returned to client drivers using
+ * the syscon_regmap_lookup_by_phandle() API.
+ *
+ * Return: 0 on success, negative error code on failure.
+ */
+int of_syscon_register_regmap(struct device_node *np, struct regmap *regmap)
+{
+	struct syscon *entry, *syscon = NULL;
+	int ret;
+
+	if (!np || !regmap)
+		return -EINVAL;
+
+	syscon = kzalloc_obj(*syscon);
+	if (!syscon)
+		return -ENOMEM;
+
+	/* check if syscon entry already exists */
+	mutex_lock(&syscon_list_lock);
+
+	list_for_each_entry(entry, &syscon_list, list)
+		if (entry->np == np) {
+			ret = -EEXIST;
+			goto err_unlock;
+		}
+
+	syscon->regmap = regmap;
+	syscon->np = np;
+
+	/* register the regmap in syscon list */
+	list_add_tail(&syscon->list, &syscon_list);
+	mutex_unlock(&syscon_list_lock);
+
+	return 0;
+
+err_unlock:
+	mutex_unlock(&syscon_list_lock);
+	kfree(syscon);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(of_syscon_register_regmap);
+
+/**
+ * device_node_to_regmap() - Get or create a regmap for specified device node
+ * @np: Device tree node
+ *
+ * Get a regmap for the specified device node. If there's not an existing
+ * regmap, then one is instantiated. This function should not be used if the
+ * device node has a custom regmap driver or has resources (clocks, resets) to
+ * be managed. Use syscon_node_to_regmap() instead for those cases.
+ *
+ * Return: regmap ptr on success, negative error code on failure.
+ */
+struct regmap *device_node_to_regmap(struct device_node *np)
+{
+	return device_node_get_regmap(np, true, false);
+}
+EXPORT_SYMBOL_GPL(device_node_to_regmap);
+
+/**
+ * syscon_node_to_regmap() - Get or create a regmap for specified syscon device node
+ * @np: Device tree node
+ *
+ * Get a regmap for the specified device node. If there's not an existing
+ * regmap, then one is instantiated if the node is a generic "syscon". This
+ * function is safe to use for a syscon registered with
+ * of_syscon_register_regmap().
+ *
+ * Return: regmap ptr on success, negative error code on failure.
+ */
+struct regmap *syscon_node_to_regmap(struct device_node *np)
+{
+	return device_node_get_regmap(np, of_device_is_compatible(np, "syscon"), true);
+}
+EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
+
+struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
+{
+	struct device_node *syscon_np;
+	struct regmap *regmap;
+
+	syscon_np = of_find_compatible_node(NULL, NULL, s);
+	if (!syscon_np)
+		return ERR_PTR(-ENODEV);
+
+	regmap = syscon_node_to_regmap(syscon_np);
+	of_node_put(syscon_np);
+
+	return regmap;
+}
+EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
+
+struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
+					const char *property)
+{
+	struct device_node *syscon_np;
+	struct regmap *regmap;
+
+	if (property)
+		syscon_np = of_parse_phandle(np, property, 0);
+	else
+		syscon_np = np;
+
+	if (!syscon_np)
+		return ERR_PTR(-ENODEV);
+
+	regmap = syscon_node_to_regmap(syscon_np);
+
+	if (property)
+		of_node_put(syscon_np);
+
+	return regmap;
+}
+EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
+
+struct regmap *syscon_regmap_lookup_by_phandle_args(struct device_node *np,
+					const char *property,
+					int arg_count,
+					unsigned int *out_args)
+{
+	struct device_node *syscon_np;
+	struct of_phandle_args args;
+	struct regmap *regmap;
+	unsigned int index;
+	int rc;
+
+	rc = of_parse_phandle_with_fixed_args(np, property, arg_count,
+			0, &args);
+	if (rc)
+		return ERR_PTR(rc);
+
+	syscon_np = args.np;
+	if (!syscon_np)
+		return ERR_PTR(-ENODEV);
+
+	regmap = syscon_node_to_regmap(syscon_np);
+	for (index = 0; index < arg_count; index++)
+		out_args[index] = args.args[index];
+	of_node_put(syscon_np);
+
+	return regmap;
+}
+EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_args);
+
+/*
+ * It behaves the same as syscon_regmap_lookup_by_phandle() except where
+ * there is no regmap phandle. In this case, instead of returning -ENODEV,
+ * the function returns NULL.
+ */
+struct regmap *syscon_regmap_lookup_by_phandle_optional(struct device_node *np,
+					const char *property)
+{
+	struct regmap *regmap;
+
+	regmap = syscon_regmap_lookup_by_phandle(np, property);
+	if (IS_ERR(regmap) && PTR_ERR(regmap) == -ENODEV)
+		return NULL;
+
+	return regmap;
+}
+EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_optional);