drivers/reset/reset-k210.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * Copyright (c) 2020 Western Digital Corporation or its affiliates.
0004  */
0005 #include <linux/of.h>
0006 #include <linux/of_device.h>
0007 #include <linux/platform_device.h>
0008 #include <linux/reset-controller.h>
0009 #include <linux/delay.h>
0010 #include <linux/mfd/syscon.h>
0011 #include <linux/regmap.h>
0012 #include <soc/canaan/k210-sysctl.h>
0013
0014 #include <dt-bindings/reset/k210-rst.h>
0015
0016 #define K210_RST_MASK   0x27FFFFFF
0017
0018 struct k210_rst {
0019     struct regmap *map;
0020     struct reset_controller_dev rcdev;
0021 };
0022
0023 static inline struct k210_rst *
0024 to_k210_rst(struct reset_controller_dev *rcdev)
0025 {
0026     return container_of(rcdev, struct k210_rst, rcdev);
0027 }
0028
0029 static inline int k210_rst_assert(struct reset_controller_dev *rcdev,
0030                   unsigned long id)
0031 {
0032     struct k210_rst *ksr = to_k210_rst(rcdev);
0033
0034     return regmap_update_bits(ksr->map, K210_SYSCTL_PERI_RESET, BIT(id), 1);
0035 }
0036
0037 static inline int k210_rst_deassert(struct reset_controller_dev *rcdev,
0038                     unsigned long id)
0039 {
0040     struct k210_rst *ksr = to_k210_rst(rcdev);
0041
0042     return regmap_update_bits(ksr->map, K210_SYSCTL_PERI_RESET, BIT(id), 0);
0043 }
0044
0045 static int k210_rst_reset(struct reset_controller_dev *rcdev,
0046               unsigned long id)
0047 {
0048     int ret;
0049
0050     ret = k210_rst_assert(rcdev, id);
0051     if (ret == 0) {
0052         udelay(10);
0053         ret = k210_rst_deassert(rcdev, id);
0054     }
0055
0056     return ret;
0057 }
0058
0059 static int k210_rst_status(struct reset_controller_dev *rcdev,
0060                unsigned long id)
0061 {
0062     struct k210_rst *ksr = to_k210_rst(rcdev);
0063     u32 reg, bit = BIT(id);
0064     int ret;
0065
0066     ret = regmap_read(ksr->map, K210_SYSCTL_PERI_RESET, &reg);
0067     if (ret)
0068         return ret;
0069
0070     return reg & bit;
0071 }
0072
0073 static int k210_rst_xlate(struct reset_controller_dev *rcdev,
0074               const struct of_phandle_args *reset_spec)
0075 {
0076     unsigned long id = reset_spec->args[0];
0077
0078     if (!(BIT(id) & K210_RST_MASK))
0079         return -EINVAL;
0080
0081     return id;
0082 }
0083
0084 static const struct reset_control_ops k210_rst_ops = {
0085     .assert     = k210_rst_assert,
0086     .deassert   = k210_rst_deassert,
0087     .reset      = k210_rst_reset,
0088     .status     = k210_rst_status,
0089 };
0090
0091 static int k210_rst_probe(struct platform_device *pdev)
0092 {
0093     struct device *dev = &pdev->dev;
0094     struct device_node *parent_np = of_get_parent(dev->of_node);
0095     struct k210_rst *ksr;
0096
0097     dev_info(dev, "K210 reset controller\n");
0098
0099     ksr = devm_kzalloc(dev, sizeof(*ksr), GFP_KERNEL);
0100     if (!ksr)
0101         return -ENOMEM;
0102
0103     ksr->map = syscon_node_to_regmap(parent_np);
0104     of_node_put(parent_np);
0105     if (IS_ERR(ksr->map))
0106         return PTR_ERR(ksr->map);
0107
0108     ksr->rcdev.owner = THIS_MODULE;
0109     ksr->rcdev.dev = dev;
0110     ksr->rcdev.of_node = dev->of_node;
0111     ksr->rcdev.ops = &k210_rst_ops;
0112     ksr->rcdev.nr_resets = fls(K210_RST_MASK);
0113     ksr->rcdev.of_reset_n_cells = 1;
0114     ksr->rcdev.of_xlate = k210_rst_xlate;
0115
0116     return devm_reset_controller_register(dev, &ksr->rcdev);
0117 }
0118
0119 static const struct of_device_id k210_rst_dt_ids[] = {
0120     { .compatible = "canaan,k210-rst" },
0121     { /* sentinel */ },
0122 };
0123
0124 static struct platform_driver k210_rst_driver = {
0125     .probe  = k210_rst_probe,
0126     .driver = {
0127         .name       = "k210-rst",
0128         .of_match_table = k210_rst_dt_ids,
0129     },
0130 };
0131 builtin_platform_driver(k210_rst_driver);