drivers/reset/reset-tps380x.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * TI TPS380x Supply Voltage Supervisor and Reset Controller Driver
   4  *
   5  * Copyright (C) 2022 Pengutronix, Marco Felsch <kernel@pengutronix.de>
   6  *
   7  * Based on Simple Reset Controller Driver
   8  *
   9  * Copyright (C) 2017 Pengutronix, Philipp Zabel <kernel@pengutronix.de>
  10  */
  11
  12 #include <linux/delay.h>
  13 #include <linux/gpio/consumer.h>
  14 #include <linux/module.h>
  15 #include <linux/of.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/property.h>
  18 #include <linux/reset-controller.h>
  19
  20 struct tps380x_reset {
  21         struct reset_controller_dev     rcdev;
  22         struct gpio_desc                *reset_gpio;
  23         unsigned int                    reset_ms;
  24 };
  25
  26 struct tps380x_reset_devdata {
  27         unsigned int min_reset_ms;
  28         unsigned int typ_reset_ms;
  29         unsigned int max_reset_ms;
  30 };
  31
  32 static inline
  33 struct tps380x_reset *to_tps380x_reset(struct reset_controller_dev *rcdev)
  34 {
  35         return container_of(rcdev, struct tps380x_reset, rcdev);
  36 }
  37
  38 static int
  39 tps380x_reset_assert(struct reset_controller_dev *rcdev, unsigned long id)
  40 {
  41         struct tps380x_reset *tps380x = to_tps380x_reset(rcdev);
  42
  43         gpiod_set_value_cansleep(tps380x->reset_gpio, 1);
  44
  45         return 0;
  46 }
  47
  48 static int
  49 tps380x_reset_deassert(struct reset_controller_dev *rcdev, unsigned long id)
  50 {
  51         struct tps380x_reset *tps380x = to_tps380x_reset(rcdev);
  52
  53         gpiod_set_value_cansleep(tps380x->reset_gpio, 0);
  54         msleep(tps380x->reset_ms);
  55
  56         return 0;
  57 }
  58
  59 static const struct reset_control_ops reset_tps380x_ops = {
  60         .assert         = tps380x_reset_assert,
  61         .deassert       = tps380x_reset_deassert,
  62 };
  63
  64 static int tps380x_reset_of_xlate(struct reset_controller_dev *rcdev,
  65                                   const struct of_phandle_args *reset_spec)
  66 {
  67         /* No special handling needed, we have only one reset line per device */
  68         return 0;
  69 }
  70
  71 static int tps380x_reset_probe(struct platform_device *pdev)
  72 {
  73         struct device *dev = &pdev->dev;
  74         const struct tps380x_reset_devdata *devdata;
  75         struct tps380x_reset *tps380x;
  76
  77         devdata = device_get_match_data(dev);
  78         if (!devdata)
  79                 return -EINVAL;
  80
  81         tps380x = devm_kzalloc(dev, sizeof(*tps380x), GFP_KERNEL);
  82         if (!tps380x)
  83                 return -ENOMEM;
  84
  85         tps380x->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
  86         if (IS_ERR(tps380x->reset_gpio))
  87                 return dev_err_probe(dev, PTR_ERR(tps380x->reset_gpio),
  88                                      "Failed to get GPIO\n");
  89
  90         tps380x->reset_ms = devdata->max_reset_ms;
  91
  92         tps380x->rcdev.ops = &reset_tps380x_ops;
  93         tps380x->rcdev.owner = THIS_MODULE;
  94         tps380x->rcdev.dev = dev;
  95         tps380x->rcdev.of_node = dev->of_node;
  96         tps380x->rcdev.of_reset_n_cells = 0;
  97         tps380x->rcdev.of_xlate = tps380x_reset_of_xlate;
  98         tps380x->rcdev.nr_resets = 1;
  99
 100         return devm_reset_controller_register(dev, &tps380x->rcdev);
 101 }
 102
 103 static const struct tps380x_reset_devdata tps3801_reset_data = {
 104         .min_reset_ms = 120,
 105         .typ_reset_ms = 200,
 106         .max_reset_ms = 280,
 107 };
 108
 109 static const struct of_device_id tps380x_reset_dt_ids[] = {
 110         { .compatible = "ti,tps3801", .data = &tps3801_reset_data },
 111         { /* sentinel */ },
 112 };
 113 MODULE_DEVICE_TABLE(of, tps380x_reset_dt_ids);
 114
 115 static struct platform_driver tps380x_reset_driver = {
 116         .probe  = tps380x_reset_probe,
 117         .driver = {
 118                 .name           = "tps380x-reset",
 119                 .of_match_table = tps380x_reset_dt_ids,
 120         },
 121 };
 122 module_platform_driver(tps380x_reset_driver);
 123
 124 MODULE_AUTHOR("Marco Felsch <kernel@pengutronix.de>");
 125 MODULE_DESCRIPTION("TI TPS380x Supply Voltage Supervisor and Reset Driver");
 126 MODULE_LICENSE("GPL v2");