drivers/reset/reset-pistachio.c

   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
  22 struct pistachio_reset_data {
  23         struct reset_controller_dev     rcdev;
  24         struct regmap                   *periph_regs;
  25 };
  26
  27 static 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
  63 static 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
  80 static 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
  97 static const struct reset_control_ops pistachio_reset_ops = {
  98         .assert         = pistachio_reset_assert,
  99         .deassert       = pistachio_reset_deassert,
 100 };
 101
 102 static 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
 124 static const struct of_device_id pistachio_reset_dt_ids[] = {
 125          { .compatible = "img,pistachio-reset", },
 126          { /* sentinel */ },
 127 };
 128
 129 static 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 };
 136 builtin_platform_driver(pistachio_reset_driver);