drivers/reset/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_platform.h>
   9 #include <linux/reset-controller.h>
  10 #include <linux/spinlock.h>
  11
  12 #include <dt-bindings/reset/amlogic,meson-axg-audio-arb.h>
  13
  14 struct meson_audio_arb_data {
  15         struct reset_controller_dev rstc;
  16         void __iomem *regs;
  17         struct clk *clk;
  18         const unsigned int *reset_bits;
  19         spinlock_t lock;
  20 };
  21
  22 struct meson_audio_arb_match_data {
  23         const unsigned int *reset_bits;
  24         unsigned int reset_num;
  25 };
  26
  27 #define ARB_GENERAL_BIT 31
  28
  29 static const unsigned int axg_audio_arb_reset_bits[] = {
  30         [AXG_ARB_TODDR_A]       = 0,
  31         [AXG_ARB_TODDR_B]       = 1,
  32         [AXG_ARB_TODDR_C]       = 2,
  33         [AXG_ARB_FRDDR_A]       = 4,
  34         [AXG_ARB_FRDDR_B]       = 5,
  35         [AXG_ARB_FRDDR_C]       = 6,
  36 };
  37
  38 static const struct meson_audio_arb_match_data axg_audio_arb_match = {
  39         .reset_bits = axg_audio_arb_reset_bits,
  40         .reset_num = ARRAY_SIZE(axg_audio_arb_reset_bits),
  41 };
  42
  43 static const unsigned int sm1_audio_arb_reset_bits[] = {
  44         [AXG_ARB_TODDR_A]       = 0,
  45         [AXG_ARB_TODDR_B]       = 1,
  46         [AXG_ARB_TODDR_C]       = 2,
  47         [AXG_ARB_FRDDR_A]       = 4,
  48         [AXG_ARB_FRDDR_B]       = 5,
  49         [AXG_ARB_FRDDR_C]       = 6,
  50         [AXG_ARB_TODDR_D]       = 3,
  51         [AXG_ARB_FRDDR_D]       = 7,
  52 };
  53
  54 static const struct meson_audio_arb_match_data sm1_audio_arb_match = {
  55         .reset_bits = sm1_audio_arb_reset_bits,
  56         .reset_num = ARRAY_SIZE(sm1_audio_arb_reset_bits),
  57 };
  58
  59 static int meson_audio_arb_update(struct reset_controller_dev *rcdev,
  60                                   unsigned long id, bool assert)
  61 {
  62         u32 val;
  63         struct meson_audio_arb_data *arb =
  64                 container_of(rcdev, struct meson_audio_arb_data, rstc);
  65
  66         spin_lock(&arb->lock);
  67         val = readl(arb->regs);
  68
  69         if (assert)
  70                 val &= ~BIT(arb->reset_bits[id]);
  71         else
  72                 val |= BIT(arb->reset_bits[id]);
  73
  74         writel(val, arb->regs);
  75         spin_unlock(&arb->lock);
  76
  77         return 0;
  78 }
  79
  80 static int meson_audio_arb_status(struct reset_controller_dev *rcdev,
  81                                   unsigned long id)
  82 {
  83         u32 val;
  84         struct meson_audio_arb_data *arb =
  85                 container_of(rcdev, struct meson_audio_arb_data, rstc);
  86
  87         val = readl(arb->regs);
  88
  89         return !(val & BIT(arb->reset_bits[id]));
  90 }
  91
  92 static int meson_audio_arb_assert(struct reset_controller_dev *rcdev,
  93                                   unsigned long id)
  94 {
  95         return meson_audio_arb_update(rcdev, id, true);
  96 }
  97
  98 static int meson_audio_arb_deassert(struct reset_controller_dev *rcdev,
  99                                     unsigned long id)
 100 {
 101         return meson_audio_arb_update(rcdev, id, false);
 102 }
 103
 104 static const struct reset_control_ops meson_audio_arb_rstc_ops = {
 105         .assert = meson_audio_arb_assert,
 106         .deassert = meson_audio_arb_deassert,
 107         .status = meson_audio_arb_status,
 108 };
 109
 110 static const struct of_device_id meson_audio_arb_of_match[] = {
 111         {
 112                 .compatible = "amlogic,meson-axg-audio-arb",
 113                 .data = &axg_audio_arb_match,
 114         }, {
 115                 .compatible = "amlogic,meson-sm1-audio-arb",
 116                 .data = &sm1_audio_arb_match,
 117         },
 118         {}
 119 };
 120 MODULE_DEVICE_TABLE(of, meson_audio_arb_of_match);
 121
 122 static int meson_audio_arb_remove(struct platform_device *pdev)
 123 {
 124         struct meson_audio_arb_data *arb = platform_get_drvdata(pdev);
 125
 126         /* Disable all access */
 127         spin_lock(&arb->lock);
 128         writel(0, arb->regs);
 129         spin_unlock(&arb->lock);
 130
 131         clk_disable_unprepare(arb->clk);
 132
 133         return 0;
 134 }
 135
 136 static int meson_audio_arb_probe(struct platform_device *pdev)
 137 {
 138         struct device *dev = &pdev->dev;
 139         const struct meson_audio_arb_match_data *data;
 140         struct meson_audio_arb_data *arb;
 141         struct resource *res;
 142         int ret;
 143
 144         data = of_device_get_match_data(dev);
 145         if (!data)
 146                 return -EINVAL;
 147
 148         arb = devm_kzalloc(dev, sizeof(*arb), GFP_KERNEL);
 149         if (!arb)
 150                 return -ENOMEM;
 151         platform_set_drvdata(pdev, arb);
 152
 153         arb->clk = devm_clk_get(dev, NULL);
 154         if (IS_ERR(arb->clk)) {
 155                 if (PTR_ERR(arb->clk) != -EPROBE_DEFER)
 156                         dev_err(dev, "failed to get clock\n");
 157                 return PTR_ERR(arb->clk);
 158         }
 159
 160         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 161         arb->regs = devm_ioremap_resource(dev, res);
 162         if (IS_ERR(arb->regs))
 163                 return PTR_ERR(arb->regs);
 164
 165         spin_lock_init(&arb->lock);
 166         arb->reset_bits = data->reset_bits;
 167         arb->rstc.nr_resets = data->reset_num;
 168         arb->rstc.ops = &meson_audio_arb_rstc_ops;
 169         arb->rstc.of_node = dev->of_node;
 170         arb->rstc.owner = THIS_MODULE;
 171
 172         /*
 173          * Enable general :
 174          * In the initial state, all memory interfaces are disabled
 175          * and the general bit is on
 176          */
 177         ret = clk_prepare_enable(arb->clk);
 178         if (ret) {
 179                 dev_err(dev, "failed to enable arb clock\n");
 180                 return ret;
 181         }
 182         writel(BIT(ARB_GENERAL_BIT), arb->regs);
 183
 184         /* Register reset controller */
 185         ret = devm_reset_controller_register(dev, &arb->rstc);
 186         if (ret) {
 187                 dev_err(dev, "failed to register arb reset controller\n");
 188                 meson_audio_arb_remove(pdev);
 189         }
 190
 191         return ret;
 192 }
 193
 194 static struct platform_driver meson_audio_arb_pdrv = {
 195         .probe = meson_audio_arb_probe,
 196         .remove = meson_audio_arb_remove,
 197         .driver = {
 198                 .name = "meson-audio-arb-reset",
 199                 .of_match_table = meson_audio_arb_of_match,
 200         },
 201 };
 202 module_platform_driver(meson_audio_arb_pdrv);
 203
 204 MODULE_DESCRIPTION("Amlogic A113 Audio Memory Arbiter");
 205 MODULE_AUTHOR("Jerome Brunet <jbrunet@baylibre.com>");
 206 MODULE_LICENSE("GPL v2");