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authorLucas Stach <dev@lynxeye.de>2014-05-14 22:45:28 +0200
committerSascha Hauer <s.hauer@pengutronix.de>2014-05-15 14:17:11 +0200
commit45b95b50cd0b6fc587c459be4c2defce41ba4ac5 (patch)
tree63d5282bc2d874da16000dac0872cbc7c4ef84d7 /drivers/reset
parentcaa31714b55a542dad81d59c271c87fdadff6e1a (diff)
downloadbarebox-45b95b50cd0b6fc587c459be4c2defce41ba4ac5.tar.gz
reset: add reset controller framework
Add stripped sown version of the reset controller framework from the Linux kernel. Signed-off-by: Lucas Stach <dev@lynxeye.de> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Diffstat (limited to 'drivers/reset')
-rw-r--r--drivers/reset/Kconfig13
-rw-r--r--drivers/reset/Makefile1
-rw-r--r--drivers/reset/core.c236
3 files changed, 250 insertions, 0 deletions
diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
new file mode 100644
index 0000000..c9d04f7
--- /dev/null
+++ b/drivers/reset/Kconfig
@@ -0,0 +1,13 @@
+config ARCH_HAS_RESET_CONTROLLER
+ bool
+
+menuconfig RESET_CONTROLLER
+ bool "Reset Controller Support"
+ default y if ARCH_HAS_RESET_CONTROLLER
+ help
+ Generic Reset Controller support.
+
+ This framework is designed to abstract reset handling of devices
+ via GPIOs or SoC-internal reset controller modules.
+
+ If unsure, say no.
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
new file mode 100644
index 0000000..1e2d83f
--- /dev/null
+++ b/drivers/reset/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_RESET_CONTROLLER) += core.o
diff --git a/drivers/reset/core.c b/drivers/reset/core.c
new file mode 100644
index 0000000..101913a
--- /dev/null
+++ b/drivers/reset/core.c
@@ -0,0 +1,236 @@
+/*
+ * Reset Controller framework
+ *
+ * Copyright 2013 Philipp Zabel, Pengutronix
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+#include <common.h>
+#include <malloc.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/reset.h>
+#include <linux/reset-controller.h>
+
+static LIST_HEAD(reset_controller_list);
+
+/**
+ * struct reset_control - a reset control
+ * @rcdev: a pointer to the reset controller device
+ * this reset control belongs to
+ * @id: ID of the reset controller in the reset
+ * controller device
+ */
+struct reset_control {
+ struct reset_controller_dev *rcdev;
+ struct device_d *dev;
+ unsigned int id;
+};
+
+/**
+ * of_reset_simple_xlate - translate reset_spec to the reset line number
+ * @rcdev: a pointer to the reset controller device
+ * @reset_spec: reset line specifier as found in the device tree
+ * @flags: a flags pointer to fill in (optional)
+ *
+ * This simple translation function should be used for reset controllers
+ * with 1:1 mapping, where reset lines can be indexed by number without gaps.
+ */
+static int of_reset_simple_xlate(struct reset_controller_dev *rcdev,
+ const struct of_phandle_args *reset_spec)
+{
+ if (WARN_ON(reset_spec->args_count != rcdev->of_reset_n_cells))
+ return -EINVAL;
+
+ if (reset_spec->args[0] >= rcdev->nr_resets)
+ return -EINVAL;
+
+ return reset_spec->args[0];
+}
+
+/**
+ * reset_controller_register - register a reset controller device
+ * @rcdev: a pointer to the initialized reset controller device
+ */
+int reset_controller_register(struct reset_controller_dev *rcdev)
+{
+ if (!rcdev->of_xlate) {
+ rcdev->of_reset_n_cells = 1;
+ rcdev->of_xlate = of_reset_simple_xlate;
+ }
+
+ list_add(&rcdev->list, &reset_controller_list);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(reset_controller_register);
+
+/**
+ * reset_controller_unregister - unregister a reset controller device
+ * @rcdev: a pointer to the reset controller device
+ */
+void reset_controller_unregister(struct reset_controller_dev *rcdev)
+{
+ list_del(&rcdev->list);
+}
+EXPORT_SYMBOL_GPL(reset_controller_unregister);
+
+/**
+ * reset_control_reset - reset the controlled device
+ * @rstc: reset controller
+ */
+int reset_control_reset(struct reset_control *rstc)
+{
+ if (rstc->rcdev->ops->reset)
+ return rstc->rcdev->ops->reset(rstc->rcdev, rstc->id);
+
+ return -ENOSYS;
+}
+EXPORT_SYMBOL_GPL(reset_control_reset);
+
+/**
+ * reset_control_assert - asserts the reset line
+ * @rstc: reset controller
+ */
+int reset_control_assert(struct reset_control *rstc)
+{
+ if (rstc->rcdev->ops->assert)
+ return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id);
+
+ return -ENOSYS;
+}
+EXPORT_SYMBOL_GPL(reset_control_assert);
+
+/**
+ * reset_control_deassert - deasserts the reset line
+ * @rstc: reset controller
+ */
+int reset_control_deassert(struct reset_control *rstc)
+{
+ if (rstc->rcdev->ops->deassert)
+ return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id);
+
+ return -ENOSYS;
+}
+EXPORT_SYMBOL_GPL(reset_control_deassert);
+
+/**
+ * of_reset_control_get - Lookup and obtain a reference to a reset controller.
+ * @node: device to be reset by the controller
+ * @id: reset line name
+ *
+ * Returns a struct reset_control or IS_ERR() condition containing errno.
+ *
+ * Use of id names is optional.
+ */
+struct reset_control *of_reset_control_get(struct device_node *node,
+ const char *id)
+{
+ struct reset_control *rstc = ERR_PTR(-ENODEV);
+ struct reset_controller_dev *r, *rcdev;
+ struct of_phandle_args args;
+ int index = 0;
+ int rstc_id;
+ int ret;
+
+ if (id)
+ index = of_property_match_string(node,
+ "reset-names", id);
+ ret = of_parse_phandle_with_args(node, "resets", "#reset-cells",
+ index, &args);
+ if (ret)
+ return ERR_PTR(ret);
+
+ rcdev = NULL;
+ list_for_each_entry(r, &reset_controller_list, list) {
+ if (args.np == r->of_node) {
+ rcdev = r;
+ break;
+ }
+ }
+
+ if (!rcdev) {
+ return ERR_PTR(-ENODEV);
+ }
+
+ rstc_id = rcdev->of_xlate(rcdev, &args);
+ if (rstc_id < 0)
+ return ERR_PTR(rstc_id);
+
+ rstc = kzalloc(sizeof(*rstc), GFP_KERNEL);
+ if (!rstc)
+ return ERR_PTR(-ENOMEM);
+
+ rstc->rcdev = rcdev;
+ rstc->id = rstc_id;
+
+ return rstc;
+}
+EXPORT_SYMBOL_GPL(of_reset_control_get);
+
+/**
+ * reset_control_get - Lookup and obtain a reference to a reset controller.
+ * @dev: device to be reset by the controller
+ * @id: reset line name
+ *
+ * Returns a struct reset_control or IS_ERR() condition containing errno.
+ *
+ * Use of id names is optional.
+ */
+struct reset_control *reset_control_get(struct device_d *dev, const char *id)
+{
+ struct reset_control *rstc;
+
+ if (!dev)
+ return ERR_PTR(-EINVAL);
+
+ rstc = of_reset_control_get(dev->device_node, id);
+ if (!IS_ERR(rstc))
+ rstc->dev = dev;
+
+ return rstc;
+}
+EXPORT_SYMBOL_GPL(reset_control_get);
+
+/**
+ * reset_control_put - free the reset controller
+ * @rstc: reset controller
+ */
+
+void reset_control_put(struct reset_control *rstc)
+{
+ if (IS_ERR(rstc))
+ return;
+
+ kfree(rstc);
+}
+EXPORT_SYMBOL_GPL(reset_control_put);
+
+/**
+ * device_reset - find reset controller associated with the device
+ * and perform reset
+ * @dev: device to be reset by the controller
+ *
+ * Convenience wrapper for reset_control_get() and reset_control_reset().
+ * This is useful for the common case of devices with single, dedicated reset
+ * lines.
+ */
+int device_reset(struct device_d *dev)
+{
+ struct reset_control *rstc;
+ int ret;
+
+ rstc = reset_control_get(dev, NULL);
+ if (IS_ERR(rstc))
+ return PTR_ERR(rstc);
+
+ ret = reset_control_reset(rstc);
+
+ reset_control_put(rstc);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(device_reset);