* Copyright 2013 Philipp Zabel, Pengutronix
*/
#include <linux/atomic.h>
+#include <linux/cleanup.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/kref.h>
+#include <linux/gpio/driver.h>
+#include <linux/gpio/machine.h>
+#include <linux/idr.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/acpi.h>
+#include <linux/platform_device.h>
#include <linux/reset.h>
#include <linux/reset-controller.h>
#include <linux/slab.h>
static DEFINE_MUTEX(reset_lookup_mutex);
static LIST_HEAD(reset_lookup_list);
+/* Protects reset_gpio_lookup_list */
+static DEFINE_MUTEX(reset_gpio_lookup_mutex);
+static LIST_HEAD(reset_gpio_lookup_list);
+static DEFINE_IDA(reset_gpio_ida);
+
/**
* struct reset_control - a reset control
* @rcdev: a pointer to the reset controller device
struct reset_control *rstc[] __counted_by(num_rstcs);
};
+/**
+ * struct reset_gpio_lookup - lookup key for ad-hoc created reset-gpio devices
+ * @of_args: phandle to the reset controller with all the args like GPIO number
+ * @list: list entry for the reset_gpio_lookup_list
+ */
+struct reset_gpio_lookup {
+ struct of_phandle_args of_args;
+ struct list_head list;
+};
+
static const char *rcdev_name(struct reset_controller_dev *rcdev)
{
if (rcdev->dev)
if (rcdev->of_node)
return rcdev->of_node->full_name;
+ if (rcdev->of_args)
+ return rcdev->of_args->np->full_name;
+
return NULL;
}
*/
int reset_controller_register(struct reset_controller_dev *rcdev)
{
+ if (rcdev->of_node && rcdev->of_args)
+ return -EINVAL;
+
if (!rcdev->of_xlate) {
rcdev->of_reset_n_cells = 1;
rcdev->of_xlate = of_reset_simple_xlate;
kref_put(&rstc->refcnt, __reset_control_release);
}
+static int __reset_add_reset_gpio_lookup(int id, struct device_node *np,
+ unsigned int gpio,
+ unsigned int of_flags)
+{
+ const struct fwnode_handle *fwnode = of_fwnode_handle(np);
+ unsigned int lookup_flags;
+ const char *label_tmp;
+
+ /*
+ * Later we map GPIO flags between OF and Linux, however not all
+ * constants from include/dt-bindings/gpio/gpio.h and
+ * include/linux/gpio/machine.h match each other.
+ */
+ if (of_flags > GPIO_ACTIVE_LOW) {
+ pr_err("reset-gpio code does not support GPIO flags %u for GPIO %u\n",
+ of_flags, gpio);
+ return -EINVAL;
+ }
+
+ struct gpio_device *gdev __free(gpio_device_put) = gpio_device_find_by_fwnode(fwnode);
+ if (!gdev)
+ return -EPROBE_DEFER;
+
+ label_tmp = gpio_device_get_label(gdev);
+ if (!label_tmp)
+ return -EINVAL;
+
+ char *label __free(kfree) = kstrdup(label_tmp, GFP_KERNEL);
+ if (!label)
+ return -ENOMEM;
+
+ /* Size: one lookup entry plus sentinel */
+ struct gpiod_lookup_table *lookup __free(kfree) = kzalloc(struct_size(lookup, table, 2),
+ GFP_KERNEL);
+ if (!lookup)
+ return -ENOMEM;
+
+ lookup->dev_id = kasprintf(GFP_KERNEL, "reset-gpio.%d", id);
+ if (!lookup->dev_id)
+ return -ENOMEM;
+
+ lookup_flags = GPIO_PERSISTENT;
+ lookup_flags |= of_flags & GPIO_ACTIVE_LOW;
+ lookup->table[0] = GPIO_LOOKUP(no_free_ptr(label), gpio, "reset",
+ lookup_flags);
+
+ /* Not freed on success, because it is persisent subsystem data. */
+ gpiod_add_lookup_table(no_free_ptr(lookup));
+
+ return 0;
+}
+
+/*
+ * @args: phandle to the GPIO provider with all the args like GPIO number
+ */
+static int __reset_add_reset_gpio_device(const struct of_phandle_args *args)
+{
+ struct reset_gpio_lookup *rgpio_dev;
+ struct platform_device *pdev;
+ int id, ret;
+
+ /*
+ * Currently only #gpio-cells=2 is supported with the meaning of:
+ * args[0]: GPIO number
+ * args[1]: GPIO flags
+ * TODO: Handle other cases.
+ */
+ if (args->args_count != 2)
+ return -ENOENT;
+
+ /*
+ * Registering reset-gpio device might cause immediate
+ * bind, resulting in its probe() registering new reset controller thus
+ * taking reset_list_mutex lock via reset_controller_register().
+ */
+ lockdep_assert_not_held(&reset_list_mutex);
+
+ mutex_lock(&reset_gpio_lookup_mutex);
+
+ list_for_each_entry(rgpio_dev, &reset_gpio_lookup_list, list) {
+ if (args->np == rgpio_dev->of_args.np) {
+ if (of_phandle_args_equal(args, &rgpio_dev->of_args))
+ goto out; /* Already on the list, done */
+ }
+ }
+
+ id = ida_alloc(&reset_gpio_ida, GFP_KERNEL);
+ if (id < 0) {
+ ret = id;
+ goto err_unlock;
+ }
+
+ /* Not freed on success, because it is persisent subsystem data. */
+ rgpio_dev = kzalloc(sizeof(*rgpio_dev), GFP_KERNEL);
+ if (!rgpio_dev) {
+ ret = -ENOMEM;
+ goto err_ida_free;
+ }
+
+ ret = __reset_add_reset_gpio_lookup(id, args->np, args->args[0],
+ args->args[1]);
+ if (ret < 0)
+ goto err_kfree;
+
+ rgpio_dev->of_args = *args;
+ /*
+ * We keep the device_node reference, but of_args.np is put at the end
+ * of __of_reset_control_get(), so get it one more time.
+ * Hold reference as long as rgpio_dev memory is valid.
+ */
+ of_node_get(rgpio_dev->of_args.np);
+ pdev = platform_device_register_data(NULL, "reset-gpio", id,
+ &rgpio_dev->of_args,
+ sizeof(rgpio_dev->of_args));
+ ret = PTR_ERR_OR_ZERO(pdev);
+ if (ret)
+ goto err_put;
+
+ list_add(&rgpio_dev->list, &reset_gpio_lookup_list);
+
+out:
+ mutex_unlock(&reset_gpio_lookup_mutex);
+
+ return 0;
+
+err_put:
+ of_node_put(rgpio_dev->of_args.np);
+err_kfree:
+ kfree(rgpio_dev);
+err_ida_free:
+ ida_free(&reset_gpio_ida, id);
+err_unlock:
+ mutex_unlock(&reset_gpio_lookup_mutex);
+
+ return ret;
+}
+
+static struct reset_controller_dev *__reset_find_rcdev(const struct of_phandle_args *args,
+ bool gpio_fallback)
+{
+ struct reset_controller_dev *rcdev;
+
+ lockdep_assert_held(&reset_list_mutex);
+
+ list_for_each_entry(rcdev, &reset_controller_list, list) {
+ if (gpio_fallback) {
+ if (rcdev->of_args && of_phandle_args_equal(args,
+ rcdev->of_args))
+ return rcdev;
+ } else {
+ if (args->np == rcdev->of_node)
+ return rcdev;
+ }
+ }
+
+ return NULL;
+}
+
struct reset_control *
__of_reset_control_get(struct device_node *node, const char *id, int index,
bool shared, bool optional, bool acquired)
{
+ bool gpio_fallback = false;
struct reset_control *rstc;
- struct reset_controller_dev *r, *rcdev;
+ struct reset_controller_dev *rcdev;
struct of_phandle_args args;
int rstc_id;
int ret;
index, &args);
if (ret == -EINVAL)
return ERR_PTR(ret);
- if (ret)
- return optional ? NULL : ERR_PTR(ret);
+ if (ret) {
+ if (!IS_ENABLED(CONFIG_RESET_GPIO))
+ return optional ? NULL : ERR_PTR(ret);
- mutex_lock(&reset_list_mutex);
- rcdev = NULL;
- list_for_each_entry(r, &reset_controller_list, list) {
- if (args.np == r->of_node) {
- rcdev = r;
- break;
+ /*
+ * There can be only one reset-gpio for regular devices, so
+ * don't bother with the "reset-gpios" phandle index.
+ */
+ ret = of_parse_phandle_with_args(node, "reset-gpios", "#gpio-cells",
+ 0, &args);
+ if (ret)
+ return optional ? NULL : ERR_PTR(ret);
+
+ gpio_fallback = true;
+
+ ret = __reset_add_reset_gpio_device(&args);
+ if (ret) {
+ rstc = ERR_PTR(ret);
+ goto out_put;
}
}
+ mutex_lock(&reset_list_mutex);
+ rcdev = __reset_find_rcdev(&args, gpio_fallback);
if (!rcdev) {
rstc = ERR_PTR(-EPROBE_DEFER);
- goto out;
+ goto out_unlock;
}
if (WARN_ON(args.args_count != rcdev->of_reset_n_cells)) {
rstc = ERR_PTR(-EINVAL);
- goto out;
+ goto out_unlock;
}
rstc_id = rcdev->of_xlate(rcdev, &args);
if (rstc_id < 0) {
rstc = ERR_PTR(rstc_id);
- goto out;
+ goto out_unlock;
}
/* reset_list_mutex also protects the rcdev's reset_control list */
rstc = __reset_control_get_internal(rcdev, rstc_id, shared, acquired);
-out:
+out_unlock:
mutex_unlock(&reset_list_mutex);
+out_put:
of_node_put(args.np);
return rstc;
projects / users / hch / block.git / commitdiff