// SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) STMicroelectronics 2018 - All Rights Reserved * Author: Gabriel Fernandez <gabriel.fernandez@st.com> for STMicroelectronics. */ #include <linux/device.h> #include <linux/err.h> #include <linux/io.h> #include <linux/of.h> #include <linux/platform_device.h> #include <linux/reset-controller.h> #define CLR_OFFSET 0x4 struct stm32_reset_data { struct reset_controller_dev rcdev; void __iomem *membase; }; static inline struct stm32_reset_data * to_stm32_reset_data(struct reset_controller_dev *rcdev) { return container_of(rcdev, struct stm32_reset_data, rcdev); } static int stm32_reset_update(struct reset_controller_dev *rcdev, unsigned long id, bool assert) { struct stm32_reset_data *data = to_stm32_reset_data(rcdev); int reg_width = sizeof(u32); int bank = id / (reg_width * BITS_PER_BYTE); int offset = id % (reg_width * BITS_PER_BYTE); void __iomem *addr; addr = data->membase + (bank * reg_width); if (!assert) addr += CLR_OFFSET; writel(BIT(offset), addr); return 0; } static int stm32_reset_assert(struct reset_controller_dev *rcdev, unsigned long id) { return stm32_reset_update(rcdev, id, true); } static int stm32_reset_deassert(struct reset_controller_dev *rcdev, unsigned long id) { return stm32_reset_update(rcdev, id, false); } static int stm32_reset_status(struct reset_controller_dev *rcdev, unsigned long id) { struct stm32_reset_data *data = to_stm32_reset_data(rcdev); int reg_width = sizeof(u32); int bank = id / (reg_width * BITS_PER_BYTE); int offset = id % (reg_width * BITS_PER_BYTE); u32 reg; reg = readl(data->membase + (bank * reg_width)); return !!(reg & BIT(offset)); } static const struct reset_control_ops stm32_reset_ops = { .assert = stm32_reset_assert, .deassert = stm32_reset_deassert, .status = stm32_reset_status, }; static const struct of_device_id stm32_reset_dt_ids[] = { { .compatible = "st,stm32mp1-rcc"}, { /* sentinel */ }, }; static int stm32_reset_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct stm32_reset_data *data; void __iomem *membase; struct resource *res; data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); if (!data) return -ENOMEM; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); membase = devm_ioremap_resource(dev, res); if (IS_ERR(membase)) return PTR_ERR(membase); data->membase = membase; data->rcdev.owner = THIS_MODULE; data->rcdev.nr_resets = resource_size(res) * BITS_PER_BYTE; data->rcdev.ops = &stm32_reset_ops; data->rcdev.of_node = dev->of_node; return devm_reset_controller_register(dev, &data->rcdev); } static struct platform_driver stm32_reset_driver = { .probe = stm32_reset_probe, .driver = { .name = "stm32mp1-reset", .of_match_table = stm32_reset_dt_ids, }, }; builtin_platform_driver(stm32_reset_driver);