1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * BCM6345 Reset Controller Driver 4 * 5 * Copyright (C) 2020 Álvaro Fernández Rojas <noltari@gmail.com> 6 */ 7 8 #include <linux/delay.h> 9 #include <linux/init.h> 10 #include <linux/io.h> 11 #include <linux/mod_devicetable.h> 12 #include <linux/platform_device.h> 13 #include <linux/reset-controller.h> 14 15 #define BCM6345_RESET_NUM 32 16 #define BCM6345_RESET_SLEEP_MIN_US 10000 17 #define BCM6345_RESET_SLEEP_MAX_US 20000 18 19 struct bcm6345_reset { 20 struct reset_controller_dev rcdev; 21 void __iomem *base; 22 spinlock_t lock; 23 }; 24 25 static inline struct bcm6345_reset * 26 to_bcm6345_reset(struct reset_controller_dev *rcdev) 27 { 28 return container_of(rcdev, struct bcm6345_reset, rcdev); 29 } 30 31 static int bcm6345_reset_update(struct reset_controller_dev *rcdev, 32 unsigned long id, bool assert) 33 { 34 struct bcm6345_reset *bcm6345_reset = to_bcm6345_reset(rcdev); 35 unsigned long flags; 36 uint32_t val; 37 38 spin_lock_irqsave(&bcm6345_reset->lock, flags); 39 val = __raw_readl(bcm6345_reset->base); 40 if (assert) 41 val &= ~BIT(id); 42 else 43 val |= BIT(id); 44 __raw_writel(val, bcm6345_reset->base); 45 spin_unlock_irqrestore(&bcm6345_reset->lock, flags); 46 47 return 0; 48 } 49 50 static int bcm6345_reset_assert(struct reset_controller_dev *rcdev, 51 unsigned long id) 52 { 53 return bcm6345_reset_update(rcdev, id, true); 54 } 55 56 static int bcm6345_reset_deassert(struct reset_controller_dev *rcdev, 57 unsigned long id) 58 { 59 return bcm6345_reset_update(rcdev, id, false); 60 } 61 62 static int bcm6345_reset_reset(struct reset_controller_dev *rcdev, 63 unsigned long id) 64 { 65 bcm6345_reset_update(rcdev, id, true); 66 usleep_range(BCM6345_RESET_SLEEP_MIN_US, 67 BCM6345_RESET_SLEEP_MAX_US); 68 69 bcm6345_reset_update(rcdev, id, false); 70 /* 71 * Ensure component is taken out reset state by sleeping also after 72 * deasserting the reset. Otherwise, the component may not be ready 73 * for operation. 74 */ 75 usleep_range(BCM6345_RESET_SLEEP_MIN_US, 76 BCM6345_RESET_SLEEP_MAX_US); 77 78 return 0; 79 } 80 81 static int bcm6345_reset_status(struct reset_controller_dev *rcdev, 82 unsigned long id) 83 { 84 struct bcm6345_reset *bcm6345_reset = to_bcm6345_reset(rcdev); 85 86 return !(__raw_readl(bcm6345_reset->base) & BIT(id)); 87 } 88 89 static const struct reset_control_ops bcm6345_reset_ops = { 90 .assert = bcm6345_reset_assert, 91 .deassert = bcm6345_reset_deassert, 92 .reset = bcm6345_reset_reset, 93 .status = bcm6345_reset_status, 94 }; 95 96 static int bcm6345_reset_probe(struct platform_device *pdev) 97 { 98 struct bcm6345_reset *bcm6345_reset; 99 100 bcm6345_reset = devm_kzalloc(&pdev->dev, 101 sizeof(*bcm6345_reset), GFP_KERNEL); 102 if (!bcm6345_reset) 103 return -ENOMEM; 104 105 platform_set_drvdata(pdev, bcm6345_reset); 106 107 bcm6345_reset->base = devm_platform_ioremap_resource(pdev, 0); 108 if (IS_ERR(bcm6345_reset->base)) 109 return PTR_ERR(bcm6345_reset->base); 110 111 spin_lock_init(&bcm6345_reset->lock); 112 bcm6345_reset->rcdev.ops = &bcm6345_reset_ops; 113 bcm6345_reset->rcdev.owner = THIS_MODULE; 114 bcm6345_reset->rcdev.of_node = pdev->dev.of_node; 115 bcm6345_reset->rcdev.of_reset_n_cells = 1; 116 bcm6345_reset->rcdev.nr_resets = BCM6345_RESET_NUM; 117 118 return devm_reset_controller_register(&pdev->dev, 119 &bcm6345_reset->rcdev); 120 } 121 122 static const struct of_device_id bcm6345_reset_of_match[] = { 123 { .compatible = "brcm,bcm6345-reset" }, 124 { /* sentinel */ }, 125 }; 126 127 static struct platform_driver bcm6345_reset_driver = { 128 .probe = bcm6345_reset_probe, 129 .driver = { 130 .name = "bcm6345-reset", 131 .of_match_table = bcm6345_reset_of_match, 132 .suppress_bind_attrs = true, 133 }, 134 }; 135 builtin_platform_driver(bcm6345_reset_driver); 136