drivers/gpu/drm/sun4i/sun6i_drc.c

   1 /*
   2  * Copyright (C) 2016 Free Electrons
   3  *
   4  * Maxime Ripard <maxime.ripard@free-electrons.com>
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License as
   8  * published by the Free Software Foundation; either version 2 of
   9  * the License, or (at your option) any later version.
  10  */
  11
  12 #include <linux/clk.h>
  13 #include <linux/component.h>
  14 #include <linux/module.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/regmap.h>
  17 #include <linux/reset.h>
  18
  19 struct sun6i_drc {
  20         struct clk              *bus_clk;
  21         struct clk              *mod_clk;
  22         struct reset_control    *reset;
  23 };
  24
  25 static int sun6i_drc_bind(struct device *dev, struct device *master,
  26                          void *data)
  27 {
  28         struct sun6i_drc *drc;
  29         int ret;
  30
  31         drc = devm_kzalloc(dev, sizeof(*drc), GFP_KERNEL);
  32         if (!drc)
  33                 return -ENOMEM;
  34         dev_set_drvdata(dev, drc);
  35
  36         drc->reset = devm_reset_control_get(dev, NULL);
  37         if (IS_ERR(drc->reset)) {
  38                 dev_err(dev, "Couldn't get our reset line\n");
  39                 return PTR_ERR(drc->reset);
  40         }
  41
  42         ret = reset_control_deassert(drc->reset);
  43         if (ret) {
  44                 dev_err(dev, "Couldn't deassert our reset line\n");
  45                 return ret;
  46         }
  47
  48         drc->bus_clk = devm_clk_get(dev, "ahb");
  49         if (IS_ERR(drc->bus_clk)) {
  50                 dev_err(dev, "Couldn't get our bus clock\n");
  51                 ret = PTR_ERR(drc->bus_clk);
  52                 goto err_assert_reset;
  53         }
  54         clk_prepare_enable(drc->bus_clk);
  55
  56         drc->mod_clk = devm_clk_get(dev, "mod");
  57         if (IS_ERR(drc->mod_clk)) {
  58                 dev_err(dev, "Couldn't get our mod clock\n");
  59                 ret = PTR_ERR(drc->mod_clk);
  60                 goto err_disable_bus_clk;
  61         }
  62         clk_prepare_enable(drc->mod_clk);
  63
  64         return 0;
  65
  66 err_disable_bus_clk:
  67         clk_disable_unprepare(drc->bus_clk);
  68 err_assert_reset:
  69         reset_control_assert(drc->reset);
  70         return ret;
  71 }
  72
  73 static void sun6i_drc_unbind(struct device *dev, struct device *master,
  74                             void *data)
  75 {
  76         struct sun6i_drc *drc = dev_get_drvdata(dev);
  77
  78         clk_disable_unprepare(drc->mod_clk);
  79         clk_disable_unprepare(drc->bus_clk);
  80         reset_control_assert(drc->reset);
  81 }
  82
  83 static const struct component_ops sun6i_drc_ops = {
  84         .bind   = sun6i_drc_bind,
  85         .unbind = sun6i_drc_unbind,
  86 };
  87
  88 static int sun6i_drc_probe(struct platform_device *pdev)
  89 {
  90         return component_add(&pdev->dev, &sun6i_drc_ops);
  91 }
  92
  93 static int sun6i_drc_remove(struct platform_device *pdev)
  94 {
  95         component_del(&pdev->dev, &sun6i_drc_ops);
  96
  97         return 0;
  98 }
  99
 100 static const struct of_device_id sun6i_drc_of_table[] = {
 101         { .compatible = "allwinner,sun6i-a31-drc" },
 102         { .compatible = "allwinner,sun6i-a31s-drc" },
 103         { .compatible = "allwinner,sun8i-a33-drc" },
 104         { }
 105 };
 106 MODULE_DEVICE_TABLE(of, sun6i_drc_of_table);
 107
 108 static struct platform_driver sun6i_drc_platform_driver = {
 109         .probe          = sun6i_drc_probe,
 110         .remove         = sun6i_drc_remove,
 111         .driver         = {
 112                 .name           = "sun6i-drc",
 113                 .of_match_table = sun6i_drc_of_table,
 114         },
 115 };
 116 module_platform_driver(sun6i_drc_platform_driver);
 117
 118 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
 119 MODULE_DESCRIPTION("Allwinner A31 Dynamic Range Control (DRC) Driver");
 120 MODULE_LICENSE("GPL");