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Diffstat (limited to '')
| -rw-r--r-- | drivers/reset/reset-meson.c | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/drivers/reset/reset-meson.c b/drivers/reset/reset-meson.c new file mode 100644 index 000000000..26dc54778 --- /dev/null +++ b/drivers/reset/reset-meson.c @@ -0,0 +1,157 @@ +// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause +/* + * Amlogic Meson Reset Controller driver + * + * Copyright (c) 2016 BayLibre, SAS. + * Author: Neil Armstrong <narmstrong@baylibre.com> + */ +#include <linux/err.h> +#include <linux/init.h> +#include <linux/io.h> +#include <linux/of.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/reset-controller.h> +#include <linux/slab.h> +#include <linux/types.h> +#include <linux/of_device.h> + +#define BITS_PER_REG 32 + +struct meson_reset_param { + int reg_count; + int level_offset; +}; + +struct meson_reset { + void __iomem *reg_base; + const struct meson_reset_param *param; + struct reset_controller_dev rcdev; + spinlock_t lock; +}; + +static int meson_reset_reset(struct reset_controller_dev *rcdev, + unsigned long id) +{ + struct meson_reset *data = + container_of(rcdev, struct meson_reset, rcdev); + unsigned int bank = id / BITS_PER_REG; + unsigned int offset = id % BITS_PER_REG; + void __iomem *reg_addr = data->reg_base + (bank << 2); + + writel(BIT(offset), reg_addr); + + return 0; +} + +static int meson_reset_level(struct reset_controller_dev *rcdev, + unsigned long id, bool assert) +{ + struct meson_reset *data = + container_of(rcdev, struct meson_reset, rcdev); + unsigned int bank = id / BITS_PER_REG; + unsigned int offset = id % BITS_PER_REG; + void __iomem *reg_addr; + unsigned long flags; + u32 reg; + + reg_addr = data->reg_base + data->param->level_offset + (bank << 2); + + spin_lock_irqsave(&data->lock, flags); + + reg = readl(reg_addr); + if (assert) + writel(reg & ~BIT(offset), reg_addr); + else + writel(reg | BIT(offset), reg_addr); + + spin_unlock_irqrestore(&data->lock, flags); + + return 0; +} + +static int meson_reset_assert(struct reset_controller_dev *rcdev, + unsigned long id) +{ + return meson_reset_level(rcdev, id, true); +} + +static int meson_reset_deassert(struct reset_controller_dev *rcdev, + unsigned long id) +{ + return meson_reset_level(rcdev, id, false); +} + +static const struct reset_control_ops meson_reset_ops = { + .reset = meson_reset_reset, + .assert = meson_reset_assert, + .deassert = meson_reset_deassert, +}; + +static const struct meson_reset_param meson8b_param = { + .reg_count = 8, + .level_offset = 0x7c, +}; + +static const struct meson_reset_param meson_a1_param = { + .reg_count = 3, + .level_offset = 0x40, +}; + +static const struct meson_reset_param meson_s4_param = { + .reg_count = 6, + .level_offset = 0x40, +}; + +static const struct of_device_id meson_reset_dt_ids[] = { + { .compatible = "amlogic,meson8b-reset", .data = &meson8b_param}, + { .compatible = "amlogic,meson-gxbb-reset", .data = &meson8b_param}, + { .compatible = "amlogic,meson-axg-reset", .data = &meson8b_param}, + { .compatible = "amlogic,meson-a1-reset", .data = &meson_a1_param}, + { .compatible = "amlogic,meson-s4-reset", .data = &meson_s4_param}, + { /* sentinel */ }, +}; +MODULE_DEVICE_TABLE(of, meson_reset_dt_ids); + +static int meson_reset_probe(struct platform_device *pdev) +{ + struct meson_reset *data; + struct resource *res; + + data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + data->reg_base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(data->reg_base)) + return PTR_ERR(data->reg_base); + + data->param = of_device_get_match_data(&pdev->dev); + if (!data->param) + return -ENODEV; + + platform_set_drvdata(pdev, data); + + spin_lock_init(&data->lock); + + data->rcdev.owner = THIS_MODULE; + data->rcdev.nr_resets = data->param->reg_count * BITS_PER_REG; + data->rcdev.ops = &meson_reset_ops; + data->rcdev.of_node = pdev->dev.of_node; + + return devm_reset_controller_register(&pdev->dev, &data->rcdev); +} + +static struct platform_driver meson_reset_driver = { + .probe = meson_reset_probe, + .driver = { + .name = "meson_reset", + .of_match_table = meson_reset_dt_ids, + }, +}; +module_platform_driver(meson_reset_driver); + +MODULE_DESCRIPTION("Amlogic Meson Reset Controller driver"); +MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>"); +MODULE_LICENSE("Dual BSD/GPL"); |