| Maxime Coquelin | b70b009 | 2016-07-22 11:37:49 +0200 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) Maxime Coquelin 2015 |
| 3 | * Author: Maxime Coquelin <mcoquelin.stm32@gmail.com> |
| 4 | * License terms: GNU General Public License (GPL), version 2 |
| 5 | * |
| 6 | * Heavily based on sunxi driver from Maxime Ripard. |
| 7 | */ |
| 8 | |
| 9 | #include <linux/err.h> |
| 10 | #include <linux/io.h> |
| 11 | #include <linux/of.h> |
| 12 | #include <linux/of_address.h> |
| 13 | #include <linux/platform_device.h> |
| 14 | #include <linux/reset-controller.h> |
| 15 | #include <linux/slab.h> |
| 16 | #include <linux/spinlock.h> |
| 17 | #include <linux/types.h> |
| 18 | |
| 19 | struct stm32_reset_data { |
| 20 | spinlock_t lock; |
| 21 | void __iomem *membase; |
| 22 | struct reset_controller_dev rcdev; |
| 23 | }; |
| 24 | |
| 25 | static int stm32_reset_assert(struct reset_controller_dev *rcdev, |
| 26 | unsigned long id) |
| 27 | { |
| 28 | struct stm32_reset_data *data = container_of(rcdev, |
| 29 | struct stm32_reset_data, |
| 30 | rcdev); |
| 31 | int bank = id / BITS_PER_LONG; |
| 32 | int offset = id % BITS_PER_LONG; |
| 33 | unsigned long flags; |
| 34 | u32 reg; |
| 35 | |
| 36 | spin_lock_irqsave(&data->lock, flags); |
| 37 | |
| 38 | reg = readl(data->membase + (bank * 4)); |
| 39 | writel(reg | BIT(offset), data->membase + (bank * 4)); |
| 40 | |
| 41 | spin_unlock_irqrestore(&data->lock, flags); |
| 42 | |
| 43 | return 0; |
| 44 | } |
| 45 | |
| 46 | static int stm32_reset_deassert(struct reset_controller_dev *rcdev, |
| 47 | unsigned long id) |
| 48 | { |
| 49 | struct stm32_reset_data *data = container_of(rcdev, |
| 50 | struct stm32_reset_data, |
| 51 | rcdev); |
| 52 | int bank = id / BITS_PER_LONG; |
| 53 | int offset = id % BITS_PER_LONG; |
| 54 | unsigned long flags; |
| 55 | u32 reg; |
| 56 | |
| 57 | spin_lock_irqsave(&data->lock, flags); |
| 58 | |
| 59 | reg = readl(data->membase + (bank * 4)); |
| 60 | writel(reg & ~BIT(offset), data->membase + (bank * 4)); |
| 61 | |
| 62 | spin_unlock_irqrestore(&data->lock, flags); |
| 63 | |
| 64 | return 0; |
| 65 | } |
| 66 | |
| 67 | static const struct reset_control_ops stm32_reset_ops = { |
| 68 | .assert = stm32_reset_assert, |
| 69 | .deassert = stm32_reset_deassert, |
| 70 | }; |
| 71 | |
| 72 | static const struct of_device_id stm32_reset_dt_ids[] = { |
| 73 | { .compatible = "st,stm32-rcc", }, |
| 74 | { /* sentinel */ }, |
| 75 | }; |
| 76 | |
| 77 | static int stm32_reset_probe(struct platform_device *pdev) |
| 78 | { |
| 79 | struct stm32_reset_data *data; |
| 80 | struct resource *res; |
| 81 | |
| 82 | data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); |
| 83 | if (!data) |
| 84 | return -ENOMEM; |
| 85 | |
| 86 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| 87 | data->membase = devm_ioremap_resource(&pdev->dev, res); |
| 88 | if (IS_ERR(data->membase)) |
| 89 | return PTR_ERR(data->membase); |
| 90 | |
| 91 | spin_lock_init(&data->lock); |
| 92 | |
| 93 | data->rcdev.owner = THIS_MODULE; |
| 94 | data->rcdev.nr_resets = resource_size(res) * 8; |
| 95 | data->rcdev.ops = &stm32_reset_ops; |
| 96 | data->rcdev.of_node = pdev->dev.of_node; |
| 97 | |
| 98 | return devm_reset_controller_register(&pdev->dev, &data->rcdev); |
| 99 | } |
| 100 | |
| 101 | static struct platform_driver stm32_reset_driver = { |
| 102 | .probe = stm32_reset_probe, |
| 103 | .driver = { |
| 104 | .name = "stm32-rcc-reset", |
| 105 | .of_match_table = stm32_reset_dt_ids, |
| 106 | }, |
| 107 | }; |
| 108 | builtin_platform_driver(stm32_reset_driver); |