drivers/reset/reset-axs10x.c

   1 /*
   2  * Copyright (C) 2017 Synopsys.
   3  *
   4  * Synopsys AXS10x reset driver.
   5  *
   6  * This file is licensed under the terms of the GNU General Public
   7  * License version 2. This program is licensed "as is" without any
   8  * warranty of any kind, whether express or implied.
   9  */
  10
  11 #include <linux/io.h>
  12 #include <linux/module.h>
  13 #include <linux/mod_devicetable.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/reset-controller.h>
  16
  17 #define to_axs10x_rst(p)        container_of((p), struct axs10x_rst, rcdev)
  18
  19 #define AXS10X_MAX_RESETS       32
  20
  21 struct axs10x_rst {
  22         void __iomem                    *regs_rst;
  23         spinlock_t                      lock;
  24         struct reset_controller_dev     rcdev;
  25 };
  26
  27 static int axs10x_reset_reset(struct reset_controller_dev *rcdev,
  28                               unsigned long id)
  29 {
  30         struct axs10x_rst *rst = to_axs10x_rst(rcdev);
  31         unsigned long flags;
  32
  33         spin_lock_irqsave(&rst->lock, flags);
  34         writel(BIT(id), rst->regs_rst);
  35         spin_unlock_irqrestore(&rst->lock, flags);
  36
  37         return 0;
  38 }
  39
  40 static const struct reset_control_ops axs10x_reset_ops = {
  41         .reset  = axs10x_reset_reset,
  42 };
  43
  44 static int axs10x_reset_probe(struct platform_device *pdev)
  45 {
  46         struct axs10x_rst *rst;
  47         struct resource *mem;
  48
  49         rst = devm_kzalloc(&pdev->dev, sizeof(*rst), GFP_KERNEL);
  50         if (!rst)
  51                 return -ENOMEM;
  52
  53         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  54         rst->regs_rst = devm_ioremap_resource(&pdev->dev, mem);
  55         if (IS_ERR(rst->regs_rst))
  56                 return PTR_ERR(rst->regs_rst);
  57
  58         spin_lock_init(&rst->lock);
  59
  60         rst->rcdev.owner = THIS_MODULE;
  61         rst->rcdev.ops = &axs10x_reset_ops;
  62         rst->rcdev.of_node = pdev->dev.of_node;
  63         rst->rcdev.nr_resets = AXS10X_MAX_RESETS;
  64
  65         return devm_reset_controller_register(&pdev->dev, &rst->rcdev);
  66 }
  67
  68 static const struct of_device_id axs10x_reset_dt_match[] = {
  69         { .compatible = "snps,axs10x-reset" },
  70         { },
  71 };
  72
  73 static struct platform_driver axs10x_reset_driver = {
  74         .probe  = axs10x_reset_probe,
  75         .driver = {
  76                 .name = "axs10x-reset",
  77                 .of_match_table = axs10x_reset_dt_match,
  78         },
  79 };
  80 builtin_platform_driver(axs10x_reset_driver);
  81
  82 MODULE_AUTHOR("Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>");
  83 MODULE_DESCRIPTION("Synopsys AXS10x reset driver");
  84 MODULE_LICENSE("GPL v2");