| Linus Walleij | 2acb037 | 2017-05-24 10:19:20 +0200 | [diff] [blame] | 1 | /* |
| 2 | * Cortina Gemini Reset controller driver |
| 3 | * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org> |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or modify |
| 6 | * it under the terms of the GNU General Public License version 2 as |
| 7 | * published by the Free Software Foundation. |
| 8 | */ |
| 9 | |
| 10 | #include <linux/err.h> |
| 11 | #include <linux/init.h> |
| 12 | #include <linux/mfd/syscon.h> |
| 13 | #include <linux/regmap.h> |
| 14 | #include <linux/of.h> |
| 15 | #include <linux/platform_device.h> |
| 16 | #include <linux/reset-controller.h> |
| 17 | #include <dt-bindings/reset/cortina,gemini-reset.h> |
| 18 | |
| 19 | /** |
| 20 | * struct gemini_reset - gemini reset controller |
| 21 | * @map: regmap to access the containing system controller |
| 22 | * @rcdev: reset controller device |
| 23 | */ |
| 24 | struct gemini_reset { |
| 25 | struct regmap *map; |
| 26 | struct reset_controller_dev rcdev; |
| 27 | }; |
| 28 | |
| 29 | #define GEMINI_GLOBAL_SOFT_RESET 0x0c |
| 30 | |
| 31 | #define to_gemini_reset(p) \ |
| 32 | container_of((p), struct gemini_reset, rcdev) |
| 33 | |
| 34 | /* |
| 35 | * This is a self-deasserting reset controller. |
| 36 | */ |
| 37 | static int gemini_reset(struct reset_controller_dev *rcdev, |
| 38 | unsigned long id) |
| 39 | { |
| 40 | struct gemini_reset *gr = to_gemini_reset(rcdev); |
| 41 | |
| 42 | /* Manual says to always set BIT 30 (CPU1) to 1 */ |
| 43 | return regmap_write(gr->map, |
| 44 | GEMINI_GLOBAL_SOFT_RESET, |
| 45 | BIT(GEMINI_RESET_CPU1) | BIT(id)); |
| 46 | } |
| 47 | |
| 48 | static int gemini_reset_status(struct reset_controller_dev *rcdev, |
| 49 | unsigned long id) |
| 50 | { |
| 51 | struct gemini_reset *gr = to_gemini_reset(rcdev); |
| 52 | u32 val; |
| 53 | int ret; |
| 54 | |
| 55 | ret = regmap_read(gr->map, GEMINI_GLOBAL_SOFT_RESET, &val); |
| 56 | if (ret) |
| 57 | return ret; |
| 58 | |
| 59 | return !!(val & BIT(id)); |
| 60 | } |
| 61 | |
| 62 | static const struct reset_control_ops gemini_reset_ops = { |
| 63 | .reset = gemini_reset, |
| 64 | .status = gemini_reset_status, |
| 65 | }; |
| 66 | |
| 67 | static int gemini_reset_probe(struct platform_device *pdev) |
| 68 | { |
| 69 | struct gemini_reset *gr; |
| 70 | struct device *dev = &pdev->dev; |
| 71 | struct device_node *np = dev->of_node; |
| 72 | int ret; |
| 73 | |
| 74 | gr = devm_kzalloc(dev, sizeof(*gr), GFP_KERNEL); |
| 75 | if (!gr) |
| 76 | return -ENOMEM; |
| 77 | |
| 78 | gr->map = syscon_node_to_regmap(np); |
| 79 | if (IS_ERR(gr->map)) { |
| 80 | ret = PTR_ERR(gr->map); |
| 81 | dev_err(dev, "unable to get regmap (%d)", ret); |
| 82 | return ret; |
| 83 | } |
| 84 | gr->rcdev.owner = THIS_MODULE; |
| 85 | gr->rcdev.nr_resets = 32; |
| 86 | gr->rcdev.ops = &gemini_reset_ops; |
| 87 | gr->rcdev.of_node = pdev->dev.of_node; |
| 88 | |
| 89 | ret = devm_reset_controller_register(&pdev->dev, &gr->rcdev); |
| 90 | if (ret) |
| 91 | return ret; |
| 92 | |
| 93 | dev_info(dev, "registered Gemini reset controller\n"); |
| 94 | return 0; |
| 95 | } |
| 96 | |
| 97 | static const struct of_device_id gemini_reset_dt_ids[] = { |
| 98 | { .compatible = "cortina,gemini-syscon", }, |
| 99 | { /* sentinel */ }, |
| 100 | }; |
| 101 | |
| 102 | static struct platform_driver gemini_reset_driver = { |
| 103 | .probe = gemini_reset_probe, |
| 104 | .driver = { |
| 105 | .name = "gemini-reset", |
| 106 | .of_match_table = gemini_reset_dt_ids, |
| 107 | .suppress_bind_attrs = true, |
| 108 | }, |
| 109 | }; |
| 110 | builtin_platform_driver(gemini_reset_driver); |