1/*
  2 * Pistachio SoC Reset Controller driver
  3 *
  4 * Copyright (C) 2015 Imagination Technologies Ltd.
  5 *
  6 * Author: Damien Horsley <Damien.Horsley@imgtec.com>
  7 *
  8 * This program is free software; you can redistribute it and/or modify it
  9 * under the terms and conditions of the GNU General Public License,
 10 * version 2, as published by the Free Software Foundation.
 11 */
 12
 13#include <linux/module.h>
 14#include <linux/of.h>
 15#include <linux/platform_device.h>
 16#include <linux/regmap.h>
 17#include <linux/reset-controller.h>
 18#include <linux/slab.h>
 19#include <linux/mfd/syscon.h>
 20
 21#include <dt-bindings/reset/pistachio-resets.h>
 22
 23#define	PISTACHIO_SOFT_RESET		0
 24
 25struct pistachio_reset_data {
 26	struct reset_controller_dev	rcdev;
 27	struct regmap			*periph_regs;
 28};
 29
 30static inline int pistachio_reset_shift(unsigned long id)
 31{
 32	switch (id) {
 33	case PISTACHIO_RESET_I2C0:
 34	case PISTACHIO_RESET_I2C1:
 35	case PISTACHIO_RESET_I2C2:
 36	case PISTACHIO_RESET_I2C3:
 37	case PISTACHIO_RESET_I2S_IN:
 38	case PISTACHIO_RESET_PRL_OUT:
 39	case PISTACHIO_RESET_SPDIF_OUT:
 40	case PISTACHIO_RESET_SPI:
 41	case PISTACHIO_RESET_PWM_PDM:
 42	case PISTACHIO_RESET_UART0:
 43	case PISTACHIO_RESET_UART1:
 44	case PISTACHIO_RESET_QSPI:
 45	case PISTACHIO_RESET_MDC:
 46	case PISTACHIO_RESET_SDHOST:
 47	case PISTACHIO_RESET_ETHERNET:
 48	case PISTACHIO_RESET_IR:
 49	case PISTACHIO_RESET_HASH:
 50	case PISTACHIO_RESET_TIMER:
 51		return id;
 52	case PISTACHIO_RESET_I2S_OUT:
 53	case PISTACHIO_RESET_SPDIF_IN:
 54	case PISTACHIO_RESET_EVT:
 55		return id + 6;
 56	case PISTACHIO_RESET_USB_H:
 57	case PISTACHIO_RESET_USB_PR:
 58	case PISTACHIO_RESET_USB_PHY_PR:
 59	case PISTACHIO_RESET_USB_PHY_PON:
 60		return id + 7;
 61	default:
 62		return -EINVAL;
 63	}
 64}
 65
 66static int pistachio_reset_assert(struct reset_controller_dev *rcdev,
 67				  unsigned long id)
 68{
 69	struct pistachio_reset_data *rd;
 70	u32 mask;
 71	int shift;
 72
 73	rd = container_of(rcdev, struct pistachio_reset_data, rcdev);
 74	shift = pistachio_reset_shift(id);
 75	if (shift < 0)
 76		return shift;
 77	mask = BIT(shift);
 78
 79	return regmap_update_bits(rd->periph_regs, PISTACHIO_SOFT_RESET,
 80				  mask, mask);
 81}
 82
 83static int pistachio_reset_deassert(struct reset_controller_dev *rcdev,
 84				    unsigned long id)
 85{
 86	struct pistachio_reset_data *rd;
 87	u32 mask;
 88	int shift;
 89
 90	rd = container_of(rcdev, struct pistachio_reset_data, rcdev);
 91	shift = pistachio_reset_shift(id);
 92	if (shift < 0)
 93		return shift;
 94	mask = BIT(shift);
 95
 96	return regmap_update_bits(rd->periph_regs, PISTACHIO_SOFT_RESET,
 97				  mask, 0);
 98}
 99
100static const struct reset_control_ops pistachio_reset_ops = {
101	.assert		= pistachio_reset_assert,
102	.deassert	= pistachio_reset_deassert,
103};
104
105static int pistachio_reset_probe(struct platform_device *pdev)
106{
107	struct pistachio_reset_data *rd;
108	struct device *dev = &pdev->dev;
109	struct device_node *np = pdev->dev.of_node;
110
111	rd = devm_kzalloc(dev, sizeof(*rd), GFP_KERNEL);
112	if (!rd)
113		return -ENOMEM;
114
115	rd->periph_regs = syscon_node_to_regmap(np->parent);
116	if (IS_ERR(rd->periph_regs))
117		return PTR_ERR(rd->periph_regs);
118
119	rd->rcdev.owner = THIS_MODULE;
120	rd->rcdev.nr_resets = PISTACHIO_RESET_MAX + 1;
121	rd->rcdev.ops = &pistachio_reset_ops;
122	rd->rcdev.of_node = np;
123
124	return reset_controller_register(&rd->rcdev);
125}
126
127static int pistachio_reset_remove(struct platform_device *pdev)
128{
129	struct pistachio_reset_data *data = platform_get_drvdata(pdev);
130
131	reset_controller_unregister(&data->rcdev);
132
133	return 0;
134}
135
136static const struct of_device_id pistachio_reset_dt_ids[] = {
137	 { .compatible = "img,pistachio-reset", },
138	 { /* sentinel */ },
139};
140MODULE_DEVICE_TABLE(of, pistachio_reset_dt_ids);
141
142static struct platform_driver pistachio_reset_driver = {
143	.probe	= pistachio_reset_probe,
144	.remove	= pistachio_reset_remove,
145	.driver = {
146		.name		= "pistachio-reset",
147		.of_match_table	= pistachio_reset_dt_ids,
148	},
149};
150module_platform_driver(pistachio_reset_driver);
151
152MODULE_AUTHOR("Damien Horsley <Damien.Horsley@imgtec.com>");
153MODULE_DESCRIPTION("Pistacho Reset Controller Driver");
154MODULE_LICENSE("GPL v2");