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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * TI SYSCON regmap reset driver4 *5 * Copyright (C) 2015-2016 Texas Instruments Incorporated - https://www.ti.com/6 * Andrew F. Davis <afd@ti.com>7 * Suman Anna <afd@ti.com>8 */9 10#include <linux/mfd/syscon.h>11#include <linux/module.h>12#include <linux/of.h>13#include <linux/platform_device.h>14#include <linux/regmap.h>15#include <linux/reset-controller.h>16 17#include <dt-bindings/reset/ti-syscon.h>18 19/**20 * struct ti_syscon_reset_control - reset control structure21 * @assert_offset: reset assert control register offset from syscon base22 * @assert_bit: reset assert bit in the reset assert control register23 * @deassert_offset: reset deassert control register offset from syscon base24 * @deassert_bit: reset deassert bit in the reset deassert control register25 * @status_offset: reset status register offset from syscon base26 * @status_bit: reset status bit in the reset status register27 * @flags: reset flag indicating how the (de)assert and status are handled28 */29struct ti_syscon_reset_control {30 unsigned int assert_offset;31 unsigned int assert_bit;32 unsigned int deassert_offset;33 unsigned int deassert_bit;34 unsigned int status_offset;35 unsigned int status_bit;36 u32 flags;37};38 39/**40 * struct ti_syscon_reset_data - reset controller information structure41 * @rcdev: reset controller entity42 * @regmap: regmap handle containing the memory-mapped reset registers43 * @controls: array of reset controls44 * @nr_controls: number of controls in control array45 */46struct ti_syscon_reset_data {47 struct reset_controller_dev rcdev;48 struct regmap *regmap;49 struct ti_syscon_reset_control *controls;50 unsigned int nr_controls;51};52 53#define to_ti_syscon_reset_data(_rcdev) \54 container_of(_rcdev, struct ti_syscon_reset_data, rcdev)55 56/**57 * ti_syscon_reset_assert() - assert device reset58 * @rcdev: reset controller entity59 * @id: ID of the reset to be asserted60 *61 * This function implements the reset driver op to assert a device's reset.62 * This asserts the reset in a manner prescribed by the reset flags.63 *64 * Return: 0 for successful request, else a corresponding error value65 */66static int ti_syscon_reset_assert(struct reset_controller_dev *rcdev,67 unsigned long id)68{69 struct ti_syscon_reset_data *data = to_ti_syscon_reset_data(rcdev);70 struct ti_syscon_reset_control *control;71 unsigned int mask, value;72 73 if (id >= data->nr_controls)74 return -EINVAL;75 76 control = &data->controls[id];77 78 if (control->flags & ASSERT_NONE)79 return -ENOTSUPP; /* assert not supported for this reset */80 81 mask = BIT(control->assert_bit);82 value = (control->flags & ASSERT_SET) ? mask : 0x0;83 84 return regmap_write_bits(data->regmap, control->assert_offset, mask, value);85}86 87/**88 * ti_syscon_reset_deassert() - deassert device reset89 * @rcdev: reset controller entity90 * @id: ID of reset to be deasserted91 *92 * This function implements the reset driver op to deassert a device's reset.93 * This deasserts the reset in a manner prescribed by the reset flags.94 *95 * Return: 0 for successful request, else a corresponding error value96 */97static int ti_syscon_reset_deassert(struct reset_controller_dev *rcdev,98 unsigned long id)99{100 struct ti_syscon_reset_data *data = to_ti_syscon_reset_data(rcdev);101 struct ti_syscon_reset_control *control;102 unsigned int mask, value;103 104 if (id >= data->nr_controls)105 return -EINVAL;106 107 control = &data->controls[id];108 109 if (control->flags & DEASSERT_NONE)110 return -ENOTSUPP; /* deassert not supported for this reset */111 112 mask = BIT(control->deassert_bit);113 value = (control->flags & DEASSERT_SET) ? mask : 0x0;114 115 return regmap_write_bits(data->regmap, control->deassert_offset, mask, value);116}117 118/**119 * ti_syscon_reset_status() - check device reset status120 * @rcdev: reset controller entity121 * @id: ID of the reset for which the status is being requested122 *123 * This function implements the reset driver op to return the status of a124 * device's reset.125 *126 * Return: 0 if reset is deasserted, true if reset is asserted, else a127 * corresponding error value128 */129static int ti_syscon_reset_status(struct reset_controller_dev *rcdev,130 unsigned long id)131{132 struct ti_syscon_reset_data *data = to_ti_syscon_reset_data(rcdev);133 struct ti_syscon_reset_control *control;134 unsigned int reset_state;135 int ret;136 137 if (id >= data->nr_controls)138 return -EINVAL;139 140 control = &data->controls[id];141 142 if (control->flags & STATUS_NONE)143 return -ENOTSUPP; /* status not supported for this reset */144 145 ret = regmap_read(data->regmap, control->status_offset, &reset_state);146 if (ret)147 return ret;148 149 return !(reset_state & BIT(control->status_bit)) ==150 !(control->flags & STATUS_SET);151}152 153static const struct reset_control_ops ti_syscon_reset_ops = {154 .assert = ti_syscon_reset_assert,155 .deassert = ti_syscon_reset_deassert,156 .status = ti_syscon_reset_status,157};158 159static int ti_syscon_reset_probe(struct platform_device *pdev)160{161 struct device *dev = &pdev->dev;162 struct device_node *np = dev->of_node;163 struct ti_syscon_reset_data *data;164 struct regmap *regmap;165 const __be32 *list;166 struct ti_syscon_reset_control *controls;167 int size, nr_controls, i;168 169 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);170 if (!data)171 return -ENOMEM;172 173 regmap = syscon_node_to_regmap(np->parent);174 if (IS_ERR(regmap))175 return PTR_ERR(regmap);176 177 list = of_get_property(np, "ti,reset-bits", &size);178 if (!list || (size / sizeof(*list)) % 7 != 0) {179 dev_err(dev, "invalid DT reset description\n");180 return -EINVAL;181 }182 183 nr_controls = (size / sizeof(*list)) / 7;184 controls = devm_kcalloc(dev, nr_controls, sizeof(*controls),185 GFP_KERNEL);186 if (!controls)187 return -ENOMEM;188 189 for (i = 0; i < nr_controls; i++) {190 controls[i].assert_offset = be32_to_cpup(list++);191 controls[i].assert_bit = be32_to_cpup(list++);192 controls[i].deassert_offset = be32_to_cpup(list++);193 controls[i].deassert_bit = be32_to_cpup(list++);194 controls[i].status_offset = be32_to_cpup(list++);195 controls[i].status_bit = be32_to_cpup(list++);196 controls[i].flags = be32_to_cpup(list++);197 }198 199 data->rcdev.ops = &ti_syscon_reset_ops;200 data->rcdev.owner = THIS_MODULE;201 data->rcdev.of_node = np;202 data->rcdev.nr_resets = nr_controls;203 data->regmap = regmap;204 data->controls = controls;205 data->nr_controls = nr_controls;206 207 return devm_reset_controller_register(dev, &data->rcdev);208}209 210static const struct of_device_id ti_syscon_reset_of_match[] = {211 { .compatible = "ti,syscon-reset", },212 { /* sentinel */ },213};214MODULE_DEVICE_TABLE(of, ti_syscon_reset_of_match);215 216static struct platform_driver ti_syscon_reset_driver = {217 .probe = ti_syscon_reset_probe,218 .driver = {219 .name = "ti-syscon-reset",220 .of_match_table = ti_syscon_reset_of_match,221 },222};223module_platform_driver(ti_syscon_reset_driver);224 225MODULE_AUTHOR("Andrew F. Davis <afd@ti.com>");226MODULE_AUTHOR("Suman Anna <s-anna@ti.com>");227MODULE_DESCRIPTION("TI SYSCON Regmap Reset Driver");228MODULE_LICENSE("GPL v2");229