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
  25 struct pistachio_reset_data {
  26         struct reset_controller_dev     rcdev;
  27         struct regmap                   *periph_regs;
  28 };
  29
  30 static 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
  66 static 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
  83 static 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
 100 static const struct reset_control_ops pistachio_reset_ops = {
 101         .assert         = pistachio_reset_assert,
 102         .deassert       = pistachio_reset_deassert,
 103 };
 104
 105 static 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
 127 static const struct of_device_id pistachio_reset_dt_ids[] = {
 128          { .compatible = "img,pistachio-reset", },
 129          { /* sentinel */ },
 130 };
 131
 132 static 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 };
 139 builtin_platform_driver(pistachio_reset_driver);