--- /dev/null
+/*
+ * 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.
+ *
+ * Copyright (C) 2010 John Crispin <blogic@phrozen.org>
+ * Copyright (C) 2013-2015 Lantiq Beteiligungs-GmbH & Co.KG
+ * Copyright (C) 2016 Martin Blumenstingl <martin.blumenstingl@googlemail.com>
+ * Copyright (C) 2017 Hauke Mehrtens <hauke@hauke-m.de>
+ */
+
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/reset-controller.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+
+#define LANTIQ_RCU_RESET_TIMEOUT 10000
+
+struct lantiq_rcu_reset_priv {
+ struct reset_controller_dev rcdev;
+ struct device *dev;
+ struct regmap *regmap;
+ u32 reset_offset;
+ u32 status_offset;
+};
+
+static struct lantiq_rcu_reset_priv *to_lantiq_rcu_reset_priv(
+ struct reset_controller_dev *rcdev)
+{
+ return container_of(rcdev, struct lantiq_rcu_reset_priv, rcdev);
+}
+
+static int lantiq_rcu_reset_status(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ struct lantiq_rcu_reset_priv *priv = to_lantiq_rcu_reset_priv(rcdev);
+ unsigned int status = (id >> 8) & 0x1f;
+ u32 val;
+ int ret;
+
+ ret = regmap_read(priv->regmap, priv->status_offset, &val);
+ if (ret)
+ return ret;
+
+ return !!(val & BIT(status));
+}
+
+static int lantiq_rcu_reset_status_timeout(struct reset_controller_dev *rcdev,
+ unsigned long id, bool assert)
+{
+ int ret;
+ int retry = LANTIQ_RCU_RESET_TIMEOUT;
+
+ do {
+ ret = lantiq_rcu_reset_status(rcdev, id);
+ if (ret < 0)
+ return ret;
+ if (ret == assert)
+ return 0;
+ usleep_range(20, 40);
+ } while (--retry);
+
+ return -ETIMEDOUT;
+}
+
+static int lantiq_rcu_reset_update(struct reset_controller_dev *rcdev,
+ unsigned long id, bool assert)
+{
+ struct lantiq_rcu_reset_priv *priv = to_lantiq_rcu_reset_priv(rcdev);
+ unsigned int set = id & 0x1f;
+ u32 val = assert ? BIT(set) : 0;
+ int ret;
+
+ ret = regmap_update_bits(priv->regmap, priv->reset_offset, BIT(set),
+ val);
+ if (ret) {
+ dev_err(priv->dev, "Failed to set reset bit %u\n", set);
+ return ret;
+ }
+
+
+ ret = lantiq_rcu_reset_status_timeout(rcdev, id, assert);
+ if (ret)
+ dev_err(priv->dev, "Failed to %s bit %u\n",
+ assert ? "assert" : "deassert", set);
+
+ return ret;
+}
+
+static int lantiq_rcu_reset_assert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ return lantiq_rcu_reset_update(rcdev, id, true);
+}
+
+static int lantiq_rcu_reset_deassert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ return lantiq_rcu_reset_update(rcdev, id, false);
+}
+
+static int lantiq_rcu_reset_reset(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ int ret;
+
+ ret = lantiq_rcu_reset_assert(rcdev, id);
+ if (ret)
+ return ret;
+
+ return lantiq_rcu_reset_deassert(rcdev, id);
+}
+
+static const struct reset_control_ops lantiq_rcu_reset_ops = {
+ .assert = lantiq_rcu_reset_assert,
+ .deassert = lantiq_rcu_reset_deassert,
+ .status = lantiq_rcu_reset_status,
+ .reset = lantiq_rcu_reset_reset,
+};
+
+static int lantiq_rcu_reset_of_parse(struct platform_device *pdev,
+ struct lantiq_rcu_reset_priv *priv)
+{
+ struct device *dev = &pdev->dev;
+ const __be32 *offset;
+
+ priv->regmap = syscon_node_to_regmap(dev->of_node->parent);
+ if (IS_ERR(priv->regmap)) {
+ dev_err(&pdev->dev, "Failed to lookup RCU regmap\n");
+ return PTR_ERR(priv->regmap);
+ }
+
+ offset = of_get_address(dev->of_node, 0, NULL, NULL);
+ if (!offset) {
+ dev_err(&pdev->dev, "Failed to get RCU reset offset\n");
+ return -ENOENT;
+ }
+ priv->reset_offset = __be32_to_cpu(*offset);
+
+ offset = of_get_address(dev->of_node, 1, NULL, NULL);
+ if (!offset) {
+ dev_err(&pdev->dev, "Failed to get RCU status offset\n");
+ return -ENOENT;
+ }
+ priv->status_offset = __be32_to_cpu(*offset);
+
+ return 0;
+}
+
+static int lantiq_rcu_reset_xlate(struct reset_controller_dev *rcdev,
+ const struct of_phandle_args *reset_spec)
+{
+ unsigned int status, set;
+
+ set = reset_spec->args[0];
+ status = reset_spec->args[1];
+
+ if (set >= rcdev->nr_resets || status >= rcdev->nr_resets)
+ return -EINVAL;
+
+ return (status << 8) | set;
+}
+
+static int lantiq_rcu_reset_probe(struct platform_device *pdev)
+{
+ struct lantiq_rcu_reset_priv *priv;
+ int err;
+
+ priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->dev = &pdev->dev;
+ platform_set_drvdata(pdev, priv);
+
+ err = lantiq_rcu_reset_of_parse(pdev, priv);
+ if (err)
+ return err;
+
+ priv->rcdev.ops = &lantiq_rcu_reset_ops;
+ priv->rcdev.owner = THIS_MODULE;
+ priv->rcdev.of_node = pdev->dev.of_node;
+ priv->rcdev.nr_resets = 32;
+ priv->rcdev.of_xlate = lantiq_rcu_reset_xlate;
+ priv->rcdev.of_reset_n_cells = 2;
+
+ return reset_controller_register(&priv->rcdev);
+}
+
+static const struct of_device_id lantiq_rcu_reset_dt_ids[] = {
+ { .compatible = "lantiq,danube-reset", },
+ { .compatible = "lantiq,xrx200-reset", },
+ { },
+};
+MODULE_DEVICE_TABLE(of, lantiq_rcu_reset_dt_ids);
+
+static struct platform_driver lantiq_rcu_reset_driver = {
+ .probe = lantiq_rcu_reset_probe,
+ .driver = {
+ .name = "lantiq-reset",
+ .of_match_table = lantiq_rcu_reset_dt_ids,
+ },
+};
+module_platform_driver(lantiq_rcu_reset_driver);
+
+MODULE_AUTHOR("Martin Blumenstingl <martin.blumenstingl@googlemail.com>");
+MODULE_DESCRIPTION("Lantiq XWAY RCU Reset Controller Driver");
+MODULE_LICENSE("GPL");
projects / platform / kernel / linux-exynos.git / commitdiff