1 /* 2 * Copyright (C) 2014 Marvell Technology Group Ltd. 3 * 4 * Marvell Berlin reset driver 5 * 6 * Antoine Tenart <antoine.tenart@free-electrons.com> 7 * Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com> 8 * 9 * This file is licensed under the terms of the GNU General Public 10 * License version 2. This program is licensed "as is" without any 11 * warranty of any kind, whether express or implied. 12 */ 13 14 #include <linux/delay.h> 15 #include <linux/io.h> 16 #include <linux/mfd/syscon.h> 17 #include <linux/init.h> 18 #include <linux/of.h> 19 #include <linux/of_address.h> 20 #include <linux/platform_device.h> 21 #include <linux/regmap.h> 22 #include <linux/reset-controller.h> 23 #include <linux/slab.h> 24 #include <linux/types.h> 25 26 #define BERLIN_MAX_RESETS 32 27 28 #define to_berlin_reset_priv(p) \ 29 container_of((p), struct berlin_reset_priv, rcdev) 30 31 struct berlin_reset_priv { 32 struct regmap *regmap; 33 struct reset_controller_dev rcdev; 34 }; 35 36 static int berlin_reset_reset(struct reset_controller_dev *rcdev, 37 unsigned long id) 38 { 39 struct berlin_reset_priv *priv = to_berlin_reset_priv(rcdev); 40 int offset = id >> 8; 41 int mask = BIT(id & 0x1f); 42 43 regmap_write(priv->regmap, offset, mask); 44 45 /* let the reset be effective */ 46 udelay(10); 47 48 return 0; 49 } 50 51 static const struct reset_control_ops berlin_reset_ops = { 52 .reset = berlin_reset_reset, 53 }; 54 55 static int berlin_reset_xlate(struct reset_controller_dev *rcdev, 56 const struct of_phandle_args *reset_spec) 57 { 58 unsigned offset, bit; 59 60 offset = reset_spec->args[0]; 61 bit = reset_spec->args[1]; 62 63 if (bit >= BERLIN_MAX_RESETS) 64 return -EINVAL; 65 66 return (offset << 8) | bit; 67 } 68 69 static int berlin2_reset_probe(struct platform_device *pdev) 70 { 71 struct device_node *parent_np = of_get_parent(pdev->dev.of_node); 72 struct berlin_reset_priv *priv; 73 74 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); 75 if (!priv) 76 return -ENOMEM; 77 78 priv->regmap = syscon_node_to_regmap(parent_np); 79 of_node_put(parent_np); 80 if (IS_ERR(priv->regmap)) 81 return PTR_ERR(priv->regmap); 82 83 priv->rcdev.owner = THIS_MODULE; 84 priv->rcdev.ops = &berlin_reset_ops; 85 priv->rcdev.of_node = pdev->dev.of_node; 86 priv->rcdev.of_reset_n_cells = 2; 87 priv->rcdev.of_xlate = berlin_reset_xlate; 88 89 return reset_controller_register(&priv->rcdev); 90 } 91 92 static const struct of_device_id berlin_reset_dt_match[] = { 93 { .compatible = "marvell,berlin2-reset" }, 94 { }, 95 }; 96 97 static struct platform_driver berlin_reset_driver = { 98 .probe = berlin2_reset_probe, 99 .driver = { 100 .name = "berlin2-reset", 101 .of_match_table = berlin_reset_dt_match, 102 }, 103 }; 104 builtin_platform_driver(berlin_reset_driver); 105