diff options
Diffstat (limited to 'drivers/reset/reset-sunxi.c')
| -rw-r--r-- | drivers/reset/reset-sunxi.c | 175 |
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 00000000000..695bd3496eb --- /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"); |