drivers/reset/amlogic/reset-meson-audio-arb.c

   1 // SPDX-License-Identifier: (GPL-2.0 OR MIT)
   2 // Copyright (c) 2018 BayLibre, SAS.
   3 // Author: Jerome Brunet <jbrunet@baylibre.com>
   4
   5 #include <linux/clk.h>
   6 #include <linux/io.h>
   7 #include <linux/module.h>
   8 #include <linux/of.h>
   9 #include <linux/platform_device.h>
  10 #include <linux/reset-controller.h>
  11 #include <linux/spinlock.h>
  12
  13 #include <dt-bindings/reset/amlogic,meson-axg-audio-arb.h>
  14
  15 struct meson_audio_arb_data {
  16         struct reset_controller_dev rstc;
  17         void __iomem *regs;
  18         struct clk *clk;
  19         const unsigned int *reset_bits;
  20         spinlock_t lock;
  21 };
  22
  23 struct meson_audio_arb_match_data {
  24         const unsigned int *reset_bits;
  25         unsigned int reset_num;
  26 };
  27
  28 #define ARB_GENERAL_BIT 31
  29
  30 static const unsigned int axg_audio_arb_reset_bits[] = {
  31         [AXG_ARB_TODDR_A]       = 0,
  32         [AXG_ARB_TODDR_B]       = 1,
  33         [AXG_ARB_TODDR_C]       = 2,
  34         [AXG_ARB_FRDDR_A]       = 4,
  35         [AXG_ARB_FRDDR_B]       = 5,
  36         [AXG_ARB_FRDDR_C]       = 6,
  37 };
  38
  39 static const struct meson_audio_arb_match_data axg_audio_arb_match = {
  40         .reset_bits = axg_audio_arb_reset_bits,
  41         .reset_num = ARRAY_SIZE(axg_audio_arb_reset_bits),
  42 };
  43
  44 static const unsigned int sm1_audio_arb_reset_bits[] = {
  45         [AXG_ARB_TODDR_A]       = 0,
  46         [AXG_ARB_TODDR_B]       = 1,
  47         [AXG_ARB_TODDR_C]       = 2,
  48         [AXG_ARB_FRDDR_A]       = 4,
  49         [AXG_ARB_FRDDR_B]       = 5,
  50         [AXG_ARB_FRDDR_C]       = 6,
  51         [AXG_ARB_TODDR_D]       = 3,
  52         [AXG_ARB_FRDDR_D]       = 7,
  53 };
  54
  55 static const struct meson_audio_arb_match_data sm1_audio_arb_match = {
  56         .reset_bits = sm1_audio_arb_reset_bits,
  57         .reset_num = ARRAY_SIZE(sm1_audio_arb_reset_bits),
  58 };
  59
  60 static int meson_audio_arb_update(struct reset_controller_dev *rcdev,
  61                                   unsigned long id, bool assert)
  62 {
  63         u32 val;
  64         struct meson_audio_arb_data *arb =
  65                 container_of(rcdev, struct meson_audio_arb_data, rstc);
  66
  67         spin_lock(&arb->lock);
  68         val = readl(arb->regs);
  69
  70         if (assert)
  71                 val &= ~BIT(arb->reset_bits[id]);
  72         else
  73                 val |= BIT(arb->reset_bits[id]);
  74
  75         writel(val, arb->regs);
  76         spin_unlock(&arb->lock);
  77
  78         return 0;
  79 }
  80
  81 static int meson_audio_arb_status(struct reset_controller_dev *rcdev,
  82                                   unsigned long id)
  83 {
  84         u32 val;
  85         struct meson_audio_arb_data *arb =
  86                 container_of(rcdev, struct meson_audio_arb_data, rstc);
  87
  88         val = readl(arb->regs);
  89
  90         return !(val & BIT(arb->reset_bits[id]));
  91 }
  92
  93 static int meson_audio_arb_assert(struct reset_controller_dev *rcdev,
  94                                   unsigned long id)
  95 {
  96         return meson_audio_arb_update(rcdev, id, true);
  97 }
  98
  99 static int meson_audio_arb_deassert(struct reset_controller_dev *rcdev,
 100                                     unsigned long id)
 101 {
 102         return meson_audio_arb_update(rcdev, id, false);
 103 }
 104
 105 static const struct reset_control_ops meson_audio_arb_rstc_ops = {
 106         .assert = meson_audio_arb_assert,
 107         .deassert = meson_audio_arb_deassert,
 108         .status = meson_audio_arb_status,
 109 };
 110
 111 static const struct of_device_id meson_audio_arb_of_match[] = {
 112         {
 113                 .compatible = "amlogic,meson-axg-audio-arb",
 114                 .data = &axg_audio_arb_match,
 115         }, {
 116                 .compatible = "amlogic,meson-sm1-audio-arb",
 117                 .data = &sm1_audio_arb_match,
 118         },
 119         {}
 120 };
 121 MODULE_DEVICE_TABLE(of, meson_audio_arb_of_match);
 122
 123 static void meson_audio_arb_remove(struct platform_device *pdev)
 124 {
 125         struct meson_audio_arb_data *arb = platform_get_drvdata(pdev);
 126
 127         /* Disable all access */
 128         spin_lock(&arb->lock);
 129         writel(0, arb->regs);
 130         spin_unlock(&arb->lock);
 131 }
 132
 133 static int meson_audio_arb_probe(struct platform_device *pdev)
 134 {
 135         struct device *dev = &pdev->dev;
 136         const struct meson_audio_arb_match_data *data;
 137         struct meson_audio_arb_data *arb;
 138         int ret;
 139
 140         data = of_device_get_match_data(dev);
 141         if (!data)
 142                 return -EINVAL;
 143
 144         arb = devm_kzalloc(dev, sizeof(*arb), GFP_KERNEL);
 145         if (!arb)
 146                 return -ENOMEM;
 147         platform_set_drvdata(pdev, arb);
 148
 149         arb->clk = devm_clk_get_enabled(dev, NULL);
 150         if (IS_ERR(arb->clk))
 151                 return dev_err_probe(dev, PTR_ERR(arb->clk), "failed to get clock\n");
 152
 153         arb->regs = devm_platform_ioremap_resource(pdev, 0);
 154         if (IS_ERR(arb->regs))
 155                 return PTR_ERR(arb->regs);
 156
 157         spin_lock_init(&arb->lock);
 158         arb->reset_bits = data->reset_bits;
 159         arb->rstc.nr_resets = data->reset_num;
 160         arb->rstc.ops = &meson_audio_arb_rstc_ops;
 161         arb->rstc.of_node = dev->of_node;
 162         arb->rstc.owner = THIS_MODULE;
 163
 164         /*
 165          * Enable general :
 166          * In the initial state, all memory interfaces are disabled
 167          * and the general bit is on
 168          */
 169         writel(BIT(ARB_GENERAL_BIT), arb->regs);
 170
 171         /* Register reset controller */
 172         ret = devm_reset_controller_register(dev, &arb->rstc);
 173         if (ret) {
 174                 dev_err(dev, "failed to register arb reset controller\n");
 175                 meson_audio_arb_remove(pdev);
 176         }
 177
 178         return ret;
 179 }
 180
 181 static struct platform_driver meson_audio_arb_pdrv = {
 182         .probe = meson_audio_arb_probe,
 183         .remove_new = meson_audio_arb_remove,
 184         .driver = {
 185                 .name = "meson-audio-arb-reset",
 186                 .of_match_table = meson_audio_arb_of_match,
 187         },
 188 };
 189 module_platform_driver(meson_audio_arb_pdrv);
 190
 191 MODULE_DESCRIPTION("Amlogic A113 Audio Memory Arbiter");
 192 MODULE_AUTHOR("Jerome Brunet <jbrunet@baylibre.com>");
 193 MODULE_LICENSE("GPL v2");