LXR linux/drivers/reset/reset-pistachio.c

   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/init.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 devm_reset_controller_register(dev, &rd->rcdev);
 125}
 126
 127static const struct of_device_id pistachio_reset_dt_ids[] = {
 128         { .compatible = "img,pistachio-reset", },
 129         { /* sentinel */ },
 130};
 131
 132static struct platform_driver pistachio_reset_driver = {
 133        .probe  = pistachio_reset_probe,
 134        .driver = {
 135                .name           = "pistachio-reset",
 136                .of_match_table = pistachio_reset_dt_ids,
 137        },
 138};
 139builtin_platform_driver(pistachio_reset_driver);
 140