drivers/reset/reset-pistachio.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Pistachio SoC Reset Controller driver
0004  *
0005  * Copyright (C) 2015 Imagination Technologies Ltd.
0006  *
0007  * Author: Damien Horsley <Damien.Horsley@imgtec.com>
0008  */
0009
0010 #include <linux/init.h>
0011 #include <linux/of.h>
0012 #include <linux/platform_device.h>
0013 #include <linux/regmap.h>
0014 #include <linux/reset-controller.h>
0015 #include <linux/slab.h>
0016 #include <linux/mfd/syscon.h>
0017
0018 #include <dt-bindings/reset/pistachio-resets.h>
0019
0020 #define PISTACHIO_SOFT_RESET        0
0021
0022 struct pistachio_reset_data {
0023     struct reset_controller_dev rcdev;
0024     struct regmap           *periph_regs;
0025 };
0026
0027 static inline int pistachio_reset_shift(unsigned long id)
0028 {
0029     switch (id) {
0030     case PISTACHIO_RESET_I2C0:
0031     case PISTACHIO_RESET_I2C1:
0032     case PISTACHIO_RESET_I2C2:
0033     case PISTACHIO_RESET_I2C3:
0034     case PISTACHIO_RESET_I2S_IN:
0035     case PISTACHIO_RESET_PRL_OUT:
0036     case PISTACHIO_RESET_SPDIF_OUT:
0037     case PISTACHIO_RESET_SPI:
0038     case PISTACHIO_RESET_PWM_PDM:
0039     case PISTACHIO_RESET_UART0:
0040     case PISTACHIO_RESET_UART1:
0041     case PISTACHIO_RESET_QSPI:
0042     case PISTACHIO_RESET_MDC:
0043     case PISTACHIO_RESET_SDHOST:
0044     case PISTACHIO_RESET_ETHERNET:
0045     case PISTACHIO_RESET_IR:
0046     case PISTACHIO_RESET_HASH:
0047     case PISTACHIO_RESET_TIMER:
0048         return id;
0049     case PISTACHIO_RESET_I2S_OUT:
0050     case PISTACHIO_RESET_SPDIF_IN:
0051     case PISTACHIO_RESET_EVT:
0052         return id + 6;
0053     case PISTACHIO_RESET_USB_H:
0054     case PISTACHIO_RESET_USB_PR:
0055     case PISTACHIO_RESET_USB_PHY_PR:
0056     case PISTACHIO_RESET_USB_PHY_PON:
0057         return id + 7;
0058     default:
0059         return -EINVAL;
0060     }
0061 }
0062
0063 static int pistachio_reset_assert(struct reset_controller_dev *rcdev,
0064                   unsigned long id)
0065 {
0066     struct pistachio_reset_data *rd;
0067     u32 mask;
0068     int shift;
0069
0070     rd = container_of(rcdev, struct pistachio_reset_data, rcdev);
0071     shift = pistachio_reset_shift(id);
0072     if (shift < 0)
0073         return shift;
0074     mask = BIT(shift);
0075
0076     return regmap_update_bits(rd->periph_regs, PISTACHIO_SOFT_RESET,
0077                   mask, mask);
0078 }
0079
0080 static int pistachio_reset_deassert(struct reset_controller_dev *rcdev,
0081                     unsigned long id)
0082 {
0083     struct pistachio_reset_data *rd;
0084     u32 mask;
0085     int shift;
0086
0087     rd = container_of(rcdev, struct pistachio_reset_data, rcdev);
0088     shift = pistachio_reset_shift(id);
0089     if (shift < 0)
0090         return shift;
0091     mask = BIT(shift);
0092
0093     return regmap_update_bits(rd->periph_regs, PISTACHIO_SOFT_RESET,
0094                   mask, 0);
0095 }
0096
0097 static const struct reset_control_ops pistachio_reset_ops = {
0098     .assert     = pistachio_reset_assert,
0099     .deassert   = pistachio_reset_deassert,
0100 };
0101
0102 static int pistachio_reset_probe(struct platform_device *pdev)
0103 {
0104     struct pistachio_reset_data *rd;
0105     struct device *dev = &pdev->dev;
0106     struct device_node *np = pdev->dev.of_node;
0107
0108     rd = devm_kzalloc(dev, sizeof(*rd), GFP_KERNEL);
0109     if (!rd)
0110         return -ENOMEM;
0111
0112     rd->periph_regs = syscon_node_to_regmap(np->parent);
0113     if (IS_ERR(rd->periph_regs))
0114         return PTR_ERR(rd->periph_regs);
0115
0116     rd->rcdev.owner = THIS_MODULE;
0117     rd->rcdev.nr_resets = PISTACHIO_RESET_MAX + 1;
0118     rd->rcdev.ops = &pistachio_reset_ops;
0119     rd->rcdev.of_node = np;
0120
0121     return devm_reset_controller_register(dev, &rd->rcdev);
0122 }
0123
0124 static const struct of_device_id pistachio_reset_dt_ids[] = {
0125      { .compatible = "img,pistachio-reset", },
0126      { /* sentinel */ },
0127 };
0128
0129 static struct platform_driver pistachio_reset_driver = {
0130     .probe  = pistachio_reset_probe,
0131     .driver = {
0132         .name       = "pistachio-reset",
0133         .of_match_table = pistachio_reset_dt_ids,
0134     },
0135 };
0136 builtin_platform_driver(pistachio_reset_driver);