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authorLinus Torvalds <torvalds@linux-foundation.org>2013-05-04 12:31:18 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-05-04 12:31:18 -0700
commit6fa52ed33bea997374a88dbacbba5bf8c7ac4fef (patch)
treea0904b78d66c9b99d6acf944cf58bcaa0cffc511 /drivers/reset
parent1db772216f48978d5146b858586f6178433aad38 (diff)
parentbc8fd900c4d460b4e4bf785bb48bfced0ac9941b (diff)
Merge tag 'drivers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc
Pull ARM SoC driver changes from Olof Johansson: "This is a rather large set of patches for device drivers that for one reason or another the subsystem maintainer preferred to get merged through the arm-soc tree. There are both new drivers as well as existing drivers that are getting converted from platform-specific code into standalone drivers using the appropriate subsystem specific interfaces. In particular, we can now have pinctrl, clk, clksource and irqchip drivers in one file per driver, without the need to call into platform specific interface, or to get called from platform specific code, as long as all information about the hardware is provided through a device tree. Most of the drivers we touch this time are for clocksource. Since now most of them are part of drivers/clocksource, I expect that we won't have to touch these again from arm-soc and can let the clocksource maintainers take care of these in the future. Another larger part of this series is specific to the exynos platform, which is seeing some significant effort in upstreaming and modernization of its device drivers this time around, which unfortunately is also the cause for the churn and a lot of the merge conflicts. There is one new subsystem that gets merged as part of this series: the reset controller interface, which is a very simple interface for taking devices on the SoC out of reset or back into reset. Patches to use this interface on i.MX follow later in this merge window, and we are going to have other platforms (at least tegra and sirf) get converted in 3.11. This will let us get rid of platform specific callbacks in a number of platform independent device drivers." * tag 'drivers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (256 commits) irqchip: s3c24xx: add missing __init annotations ARM: dts: Disable the RTC by default on exynos5 clk: exynos5250: Fix parent clock for sclk_mmc{0,1,2,3} ARM: exynos: restore mach/regs-clock.h for exynos5 clocksource: exynos_mct: fix build error on non-DT pinctrl: vt8500: wmt: Fix checking return value of pinctrl_register() irqchip: vt8500: Convert arch-vt8500 to new irqchip infrastructure reset: NULL deref on allocation failure reset: Add reset controller API dt: describe base reset signal binding ARM: EXYNOS: Add arm-pmu DT binding for exynos421x ARM: EXYNOS: Add arm-pmu DT binding for exynos5250 ARM: EXYNOS: Enable PMUs for exynos4 irqchip: exynos-combiner: Correct combined IRQs for exynos4 irqchip: exynos-combiner: Add set_irq_affinity function for combiner_irq ARM: EXYNOS: fix compilation error introduced due to common clock migration clk: exynos5250: Fix divider values for sclk_mmc{0,1,2,3} clk: exynos4: export clocks required for fimc-is clk: samsung: Fix compilation error clk: tegra: fix enum tegra114_clk to match binding ...
Diffstat (limited to 'drivers/reset')
-rw-r--r--drivers/reset/Kconfig13
-rw-r--r--drivers/reset/Makefile1
-rw-r--r--drivers/reset/core.c297
3 files changed, 311 insertions, 0 deletions
diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
new file mode 100644
index 000000000000..c9d04f797862
--- /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 000000000000..1e2d83f2b995
--- /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 000000000000..d1b6089a0ef8
--- /dev/null
+++ b/drivers/reset/core.c
@@ -0,0 +1,297 @@
+/*
+ * 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 <linux/device.h>
+#include <linux/err.h>
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/reset.h>
+#include <linux/reset-controller.h>
+#include <linux/slab.h>
+
+static DEFINE_MUTEX(reset_controller_list_mutex);
+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 *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.
+ */
+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];
+}
+EXPORT_SYMBOL_GPL(of_reset_simple_xlate);
+
+/**
+ * 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;
+ }
+
+ mutex_lock(&reset_controller_list_mutex);
+ list_add(&rcdev->list, &reset_controller_list);
+ mutex_unlock(&reset_controller_list_mutex);
+
+ 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)
+{
+ mutex_lock(&reset_controller_list_mutex);
+ list_del(&rcdev->list);
+ mutex_unlock(&reset_controller_list_mutex);
+}
+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);
+
+/**
+ * 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 *dev, const char *id)
+{
+ struct reset_control *rstc = ERR_PTR(-EPROBE_DEFER);
+ struct reset_controller_dev *r, *rcdev;
+ struct of_phandle_args args;
+ int index = 0;
+ int rstc_id;
+ int ret;
+
+ if (!dev)
+ return ERR_PTR(-EINVAL);
+
+ if (id)
+ index = of_property_match_string(dev->of_node,
+ "reset-names", id);
+ ret = of_parse_phandle_with_args(dev->of_node, "resets", "#reset-cells",
+ index, &args);
+ if (ret)
+ return ERR_PTR(ret);
+
+ mutex_lock(&reset_controller_list_mutex);
+ rcdev = NULL;
+ list_for_each_entry(r, &reset_controller_list, list) {
+ if (args.np == r->of_node) {
+ rcdev = r;
+ break;
+ }
+ }
+ of_node_put(args.np);
+
+ if (!rcdev) {
+ mutex_unlock(&reset_controller_list_mutex);
+ return ERR_PTR(-ENODEV);
+ }
+
+ rstc_id = rcdev->of_xlate(rcdev, &args);
+ if (rstc_id < 0) {
+ mutex_unlock(&reset_controller_list_mutex);
+ return ERR_PTR(rstc_id);
+ }
+
+ try_module_get(rcdev->owner);
+ mutex_unlock(&reset_controller_list_mutex);
+
+ rstc = kzalloc(sizeof(*rstc), GFP_KERNEL);
+ if (!rstc) {
+ module_put(rcdev->owner);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ rstc->dev = dev;
+ rstc->rcdev = rcdev;
+ rstc->id = rstc_id;
+
+ 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;
+
+ module_put(rstc->rcdev->owner);
+ kfree(rstc);
+}
+EXPORT_SYMBOL_GPL(reset_control_put);
+
+static void devm_reset_control_release(struct device *dev, void *res)
+{
+ reset_control_put(*(struct reset_control **)res);
+}
+
+/**
+ * devm_reset_control_get - resource managed reset_control_get()
+ * @dev: device to be reset by the controller
+ * @id: reset line name
+ *
+ * Managed reset_control_get(). For reset controllers returned from this
+ * function, reset_control_put() is called automatically on driver detach.
+ * See reset_control_get() for more information.
+ */
+struct reset_control *devm_reset_control_get(struct device *dev, const char *id)
+{
+ struct reset_control **ptr, *rstc;
+
+ ptr = devres_alloc(devm_reset_control_release, sizeof(*ptr),
+ GFP_KERNEL);
+ if (!ptr)
+ return ERR_PTR(-ENOMEM);
+
+ rstc = reset_control_get(dev, id);
+ if (!IS_ERR(rstc)) {
+ *ptr = rstc;
+ devres_add(dev, ptr);
+ } else {
+ devres_free(ptr);
+ }
+
+ return rstc;
+}
+EXPORT_SYMBOL_GPL(devm_reset_control_get);
+
+static int devm_reset_control_match(struct device *dev, void *res, void *data)
+{
+ struct reset_control **rstc = res;
+ if (WARN_ON(!rstc || !*rstc))
+ return 0;
+ return *rstc == data;
+}
+
+/**
+ * devm_reset_control_put - resource managed reset_control_put()
+ * @rstc: reset controller to free
+ *
+ * Deallocate a reset control allocated withd devm_reset_control_get().
+ * This function will not need to be called normally, as devres will take
+ * care of freeing the resource.
+ */
+void devm_reset_control_put(struct reset_control *rstc)
+{
+ int ret;
+
+ ret = devres_release(rstc->dev, devm_reset_control_release,
+ devm_reset_control_match, rstc);
+ if (ret)
+ WARN_ON(ret);
+}
+EXPORT_SYMBOL_GPL(devm_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 *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);