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path: root/drivers/reset/reset-sunxi.c
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Diffstat (limited to 'drivers/reset/reset-sunxi.c')
-rw-r--r--drivers/reset/reset-sunxi.c175
1 files changed, 175 insertions, 0 deletions
diff --git a/drivers/reset/reset-sunxi.c b/drivers/reset/reset-sunxi.c
new file mode 100644
index 000000000000..695bd3496eba
--- /dev/null
+++ b/drivers/reset/reset-sunxi.c
@@ -0,0 +1,175 @@
+/*
+ * Allwinner SoCs Reset Controller driver
+ *
+ * Copyright 2013 Maxime Ripard
+ *
+ * Maxime Ripard <maxime.ripard@free-electrons.com>
+ *
+ * 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/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/reset-controller.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+
+struct sunxi_reset_data {
+ spinlock_t lock;
+ void __iomem *membase;
+ struct reset_controller_dev rcdev;
+};
+
+static int sunxi_reset_assert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ struct sunxi_reset_data *data = container_of(rcdev,
+ struct sunxi_reset_data,
+ rcdev);
+ int bank = id / BITS_PER_LONG;
+ int offset = id % BITS_PER_LONG;
+ unsigned long flags;
+ u32 reg;
+
+ spin_lock_irqsave(&data->lock, flags);
+
+ reg = readl(data->membase + (bank * 4));
+ writel(reg & ~BIT(offset), data->membase + (bank * 4));
+
+ spin_unlock_irqrestore(&data->lock, flags);
+
+ return 0;
+}
+
+static int sunxi_reset_deassert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ struct sunxi_reset_data *data = container_of(rcdev,
+ struct sunxi_reset_data,
+ rcdev);
+ int bank = id / BITS_PER_LONG;
+ int offset = id % BITS_PER_LONG;
+ unsigned long flags;
+ u32 reg;
+
+ spin_lock_irqsave(&data->lock, flags);
+
+ reg = readl(data->membase + (bank * 4));
+ writel(reg | BIT(offset), data->membase + (bank * 4));
+
+ spin_unlock_irqrestore(&data->lock, flags);
+
+ return 0;
+}
+
+static struct reset_control_ops sunxi_reset_ops = {
+ .assert = sunxi_reset_assert,
+ .deassert = sunxi_reset_deassert,
+};
+
+static int sunxi_reset_init(struct device_node *np)
+{
+ struct sunxi_reset_data *data;
+ struct resource res;
+ resource_size_t size;
+ int ret;
+
+ data = kzalloc(sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ ret = of_address_to_resource(np, 0, &res);
+ if (ret)
+ goto err_alloc;
+
+ size = resource_size(&res);
+ if (!request_mem_region(res.start, size, np->name)) {
+ ret = -EBUSY;
+ goto err_alloc;
+ }
+
+ data->membase = ioremap(res.start, size);
+ if (!data->membase) {
+ ret = -ENOMEM;
+ goto err_alloc;
+ }
+
+ data->rcdev.owner = THIS_MODULE;
+ data->rcdev.nr_resets = size * 32;
+ data->rcdev.ops = &sunxi_reset_ops;
+ data->rcdev.of_node = np;
+ reset_controller_register(&data->rcdev);
+
+ return 0;
+
+err_alloc:
+ kfree(data);
+ return ret;
+};
+
+/*
+ * These are the reset controller we need to initialize early on in
+ * our system, before we can even think of using a regular device
+ * driver for it.
+ */
+static const struct of_device_id sunxi_early_reset_dt_ids[] __initdata = {
+ { .compatible = "allwinner,sun6i-a31-ahb1-reset", },
+ { /* sentinel */ },
+};
+
+void __init sun6i_reset_init(void)
+{
+ struct device_node *np;
+
+ for_each_matching_node(np, sunxi_early_reset_dt_ids)
+ sunxi_reset_init(np);
+}
+
+/*
+ * And these are the controllers we can register through the regular
+ * device model.
+ */
+static const struct of_device_id sunxi_reset_dt_ids[] = {
+ { .compatible = "allwinner,sun6i-a31-clock-reset", },
+ { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, sunxi_reset_dt_ids);
+
+static int sunxi_reset_probe(struct platform_device *pdev)
+{
+ return sunxi_reset_init(pdev->dev.of_node);
+}
+
+static int sunxi_reset_remove(struct platform_device *pdev)
+{
+ struct sunxi_reset_data *data = platform_get_drvdata(pdev);
+
+ reset_controller_unregister(&data->rcdev);
+ iounmap(data->membase);
+ kfree(data);
+
+ return 0;
+}
+
+static struct platform_driver sunxi_reset_driver = {
+ .probe = sunxi_reset_probe,
+ .remove = sunxi_reset_remove,
+ .driver = {
+ .name = "sunxi-reset",
+ .owner = THIS_MODULE,
+ .of_match_table = sunxi_reset_dt_ids,
+ },
+};
+module_platform_driver(sunxi_reset_driver);
+
+MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com");
+MODULE_DESCRIPTION("Allwinner SoCs Reset Controller Driver");
+MODULE_LICENSE("GPL");