1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Pistachio SoC Reset Controller driver
  4 *
  5 * Copyright (C) 2015 Imagination Technologies Ltd.
  6 *
  7 * Author: Damien Horsley <Damien.Horsley@imgtec.com>
  8 */
  9
 10#include <linux/init.h>
 11#include <linux/of.h>
 12#include <linux/platform_device.h>
 13#include <linux/regmap.h>
 14#include <linux/reset-controller.h>
 15#include <linux/slab.h>
 16#include <linux/mfd/syscon.h>
 17
 18#include <dt-bindings/reset/pistachio-resets.h>
 19
 20#define	PISTACHIO_SOFT_RESET		0
 21
 22struct pistachio_reset_data {
 23	struct reset_controller_dev	rcdev;
 24	struct regmap			*periph_regs;
 25};
 26
 27static inline int pistachio_reset_shift(unsigned long id)
 28{
 29	switch (id) {
 30	case PISTACHIO_RESET_I2C0:
 31	case PISTACHIO_RESET_I2C1:
 32	case PISTACHIO_RESET_I2C2:
 33	case PISTACHIO_RESET_I2C3:
 34	case PISTACHIO_RESET_I2S_IN:
 35	case PISTACHIO_RESET_PRL_OUT:
 36	case PISTACHIO_RESET_SPDIF_OUT:
 37	case PISTACHIO_RESET_SPI:
 38	case PISTACHIO_RESET_PWM_PDM:
 39	case PISTACHIO_RESET_UART0:
 40	case PISTACHIO_RESET_UART1:
 41	case PISTACHIO_RESET_QSPI:
 42	case PISTACHIO_RESET_MDC:
 43	case PISTACHIO_RESET_SDHOST:
 44	case PISTACHIO_RESET_ETHERNET:
 45	case PISTACHIO_RESET_IR:
 46	case PISTACHIO_RESET_HASH:
 47	case PISTACHIO_RESET_TIMER:
 48		return id;
 49	case PISTACHIO_RESET_I2S_OUT:
 50	case PISTACHIO_RESET_SPDIF_IN:
 51	case PISTACHIO_RESET_EVT:
 52		return id + 6;
 53	case PISTACHIO_RESET_USB_H:
 54	case PISTACHIO_RESET_USB_PR:
 55	case PISTACHIO_RESET_USB_PHY_PR:
 56	case PISTACHIO_RESET_USB_PHY_PON:
 57		return id + 7;
 58	default:
 59		return -EINVAL;
 60	}
 61}
 62
 63static int pistachio_reset_assert(struct reset_controller_dev *rcdev,
 64				  unsigned long id)
 65{
 66	struct pistachio_reset_data *rd;
 67	u32 mask;
 68	int shift;
 69
 70	rd = container_of(rcdev, struct pistachio_reset_data, rcdev);
 71	shift = pistachio_reset_shift(id);
 72	if (shift < 0)
 73		return shift;
 74	mask = BIT(shift);
 75
 76	return regmap_update_bits(rd->periph_regs, PISTACHIO_SOFT_RESET,
 77				  mask, mask);
 78}
 79
 80static int pistachio_reset_deassert(struct reset_controller_dev *rcdev,
 81				    unsigned long id)
 82{
 83	struct pistachio_reset_data *rd;
 84	u32 mask;
 85	int shift;
 86
 87	rd = container_of(rcdev, struct pistachio_reset_data, rcdev);
 88	shift = pistachio_reset_shift(id);
 89	if (shift < 0)
 90		return shift;
 91	mask = BIT(shift);
 92
 93	return regmap_update_bits(rd->periph_regs, PISTACHIO_SOFT_RESET,
 94				  mask, 0);
 95}
 96
 97static const struct reset_control_ops pistachio_reset_ops = {
 98	.assert		= pistachio_reset_assert,
 99	.deassert	= pistachio_reset_deassert,
100};
101
102static int pistachio_reset_probe(struct platform_device *pdev)
103{
104	struct pistachio_reset_data *rd;
105	struct device *dev = &pdev->dev;
106	struct device_node *np = pdev->dev.of_node;
107
108	rd = devm_kzalloc(dev, sizeof(*rd), GFP_KERNEL);
109	if (!rd)
110		return -ENOMEM;
111
112	rd->periph_regs = syscon_node_to_regmap(np->parent);
113	if (IS_ERR(rd->periph_regs))
114		return PTR_ERR(rd->periph_regs);
115
116	rd->rcdev.owner = THIS_MODULE;
117	rd->rcdev.nr_resets = PISTACHIO_RESET_MAX + 1;
118	rd->rcdev.ops = &pistachio_reset_ops;
119	rd->rcdev.of_node = np;
120
121	return devm_reset_controller_register(dev, &rd->rcdev);
122}
123
124static const struct of_device_id pistachio_reset_dt_ids[] = {
125	 { .compatible = "img,pistachio-reset", },
126	 { /* sentinel */ },
127};
128
129static struct platform_driver pistachio_reset_driver = {
130	.probe	= pistachio_reset_probe,
131	.driver = {
132		.name		= "pistachio-reset",
133		.of_match_table	= pistachio_reset_dt_ids,
134	},
135};
136builtin_platform_driver(pistachio_reset_driver);