drivers/gpu/drm/sun4i/sun6i_drc.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2016 Free Electrons
   4  *
   5  * Maxime Ripard <maxime.ripard@free-electrons.com>
   6  */
   7
   8 #include <linux/clk.h>
   9 #include <linux/component.h>
  10 #include <linux/module.h>
  11 #include <linux/mod_devicetable.h>
  12 #include <linux/platform_device.h>
  13 #include <linux/regmap.h>
  14 #include <linux/reset.h>
  15
  16 struct sun6i_drc {
  17         struct clk              *bus_clk;
  18         struct clk              *mod_clk;
  19         struct reset_control    *reset;
  20 };
  21
  22 static int sun6i_drc_bind(struct device *dev, struct device *master,
  23                          void *data)
  24 {
  25         struct sun6i_drc *drc;
  26         int ret;
  27
  28         drc = devm_kzalloc(dev, sizeof(*drc), GFP_KERNEL);
  29         if (!drc)
  30                 return -ENOMEM;
  31         dev_set_drvdata(dev, drc);
  32
  33         drc->reset = devm_reset_control_get(dev, NULL);
  34         if (IS_ERR(drc->reset)) {
  35                 dev_err(dev, "Couldn't get our reset line\n");
  36                 return PTR_ERR(drc->reset);
  37         }
  38
  39         ret = reset_control_deassert(drc->reset);
  40         if (ret) {
  41                 dev_err(dev, "Couldn't deassert our reset line\n");
  42                 return ret;
  43         }
  44
  45         drc->bus_clk = devm_clk_get(dev, "ahb");
  46         if (IS_ERR(drc->bus_clk)) {
  47                 dev_err(dev, "Couldn't get our bus clock\n");
  48                 ret = PTR_ERR(drc->bus_clk);
  49                 goto err_assert_reset;
  50         }
  51         clk_prepare_enable(drc->bus_clk);
  52
  53         drc->mod_clk = devm_clk_get(dev, "mod");
  54         if (IS_ERR(drc->mod_clk)) {
  55                 dev_err(dev, "Couldn't get our mod clock\n");
  56                 ret = PTR_ERR(drc->mod_clk);
  57                 goto err_disable_bus_clk;
  58         }
  59
  60         ret = clk_set_rate_exclusive(drc->mod_clk, 300000000);
  61         if (ret) {
  62                 dev_err(dev, "Couldn't set the module clock frequency\n");
  63                 goto err_disable_bus_clk;
  64         }
  65
  66         clk_prepare_enable(drc->mod_clk);
  67
  68         return 0;
  69
  70 err_disable_bus_clk:
  71         clk_disable_unprepare(drc->bus_clk);
  72 err_assert_reset:
  73         reset_control_assert(drc->reset);
  74         return ret;
  75 }
  76
  77 static void sun6i_drc_unbind(struct device *dev, struct device *master,
  78                             void *data)
  79 {
  80         struct sun6i_drc *drc = dev_get_drvdata(dev);
  81
  82         clk_rate_exclusive_put(drc->mod_clk);
  83         clk_disable_unprepare(drc->mod_clk);
  84         clk_disable_unprepare(drc->bus_clk);
  85         reset_control_assert(drc->reset);
  86 }
  87
  88 static const struct component_ops sun6i_drc_ops = {
  89         .bind   = sun6i_drc_bind,
  90         .unbind = sun6i_drc_unbind,
  91 };
  92
  93 static int sun6i_drc_probe(struct platform_device *pdev)
  94 {
  95         return component_add(&pdev->dev, &sun6i_drc_ops);
  96 }
  97
  98 static int sun6i_drc_remove(struct platform_device *pdev)
  99 {
 100         component_del(&pdev->dev, &sun6i_drc_ops);
 101
 102         return 0;
 103 }
 104
 105 static const struct of_device_id sun6i_drc_of_table[] = {
 106         { .compatible = "allwinner,sun6i-a31-drc" },
 107         { .compatible = "allwinner,sun6i-a31s-drc" },
 108         { .compatible = "allwinner,sun8i-a23-drc" },
 109         { .compatible = "allwinner,sun8i-a33-drc" },
 110         { .compatible = "allwinner,sun9i-a80-drc" },
 111         { }
 112 };
 113 MODULE_DEVICE_TABLE(of, sun6i_drc_of_table);
 114
 115 static struct platform_driver sun6i_drc_platform_driver = {
 116         .probe          = sun6i_drc_probe,
 117         .remove         = sun6i_drc_remove,
 118         .driver         = {
 119                 .name           = "sun6i-drc",
 120                 .of_match_table = sun6i_drc_of_table,
 121         },
 122 };
 123 module_platform_driver(sun6i_drc_platform_driver);
 124
 125 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
 126 MODULE_DESCRIPTION("Allwinner A31 Dynamic Range Control (DRC) Driver");
 127 MODULE_LICENSE("GPL");