diff options
Diffstat (limited to 'drivers/reset/reset-meson.c')
| -rw-r--r-- | drivers/reset/reset-meson.c | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/drivers/reset/reset-meson.c b/drivers/reset/reset-meson.c new file mode 100644 index 000000000..5242e0679 --- /dev/null +++ b/drivers/reset/reset-meson.c @@ -0,0 +1,173 @@ +/* + * Amlogic Meson Reset Controller driver + * + * This file is provided under a dual BSD/GPLv2 license. When using or + * redistributing this file, you may do so under either license. + * + * GPL LICENSE SUMMARY + * + * Copyright (c) 2016 BayLibre, SAS. + * Author: Neil Armstrong <narmstrong@baylibre.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of version 2 of the GNU General Public License as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see <http://www.gnu.org/licenses/>. + * The full GNU General Public License is included in this distribution + * in the file called COPYING. + * + * BSD LICENSE + * + * Copyright (c) 2016 BayLibre, SAS. + * Author: Neil Armstrong <narmstrong@baylibre.com> + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * * Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * * Neither the name of Intel Corporation nor the names of its + * contributors may be used to endorse or promote products derived + * from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ +#include <linux/err.h> +#include <linux/init.h> +#include <linux/io.h> +#include <linux/of.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 REG_COUNT 8 +#define BITS_PER_REG 32 +#define LEVEL_OFFSET 0x7c + +struct meson_reset { + void __iomem *reg_base; + 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 = data->reg_base + LEVEL_OFFSET + (bank << 2); + unsigned long flags; + u32 reg; + + 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 of_device_id meson_reset_dt_ids[] = { + { .compatible = "amlogic,meson8b-reset" }, + { .compatible = "amlogic,meson-gxbb-reset" }, + { .compatible = "amlogic,meson-axg-reset" }, + { /* sentinel */ }, +}; + +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); + + platform_set_drvdata(pdev, data); + + spin_lock_init(&data->lock); + + data->rcdev.owner = THIS_MODULE; + data->rcdev.nr_resets = 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, + }, +}; +builtin_platform_driver(meson_reset_driver); |