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