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| 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 | +#define ARB_GENERAL_BIT 31 |
| 23 | + |
| 24 | +static const unsigned int axg_audio_arb_reset_bits[] = { |
| 25 | + [AXG_ARB_TODDR_A] = 0, |
| 26 | + [AXG_ARB_TODDR_B] = 1, |
| 27 | + [AXG_ARB_TODDR_C] = 2, |
| 28 | + [AXG_ARB_FRDDR_A] = 4, |
| 29 | + [AXG_ARB_FRDDR_B] = 5, |
| 30 | + [AXG_ARB_FRDDR_C] = 6, |
| 31 | +}; |
| 32 | + |
| 33 | +static int meson_audio_arb_update(struct reset_controller_dev *rcdev, |
| 34 | + unsigned long id, bool assert) |
| 35 | +{ |
| 36 | + u32 val; |
| 37 | + struct meson_audio_arb_data *arb = |
| 38 | + container_of(rcdev, struct meson_audio_arb_data, rstc); |
| 39 | + |
| 40 | + spin_lock(&arb->lock); |
| 41 | + val = readl(arb->regs); |
| 42 | + |
| 43 | + if (assert) |
| 44 | + val &= ~BIT(arb->reset_bits[id]); |
| 45 | + else |
| 46 | + val |= BIT(arb->reset_bits[id]); |
| 47 | + |
| 48 | + writel(val, arb->regs); |
| 49 | + spin_unlock(&arb->lock); |
| 50 | + |
| 51 | + return 0; |
| 52 | +} |
| 53 | + |
| 54 | +static int meson_audio_arb_status(struct reset_controller_dev *rcdev, |
| 55 | + unsigned long id) |
| 56 | +{ |
| 57 | + u32 val; |
| 58 | + struct meson_audio_arb_data *arb = |
| 59 | + container_of(rcdev, struct meson_audio_arb_data, rstc); |
| 60 | + |
| 61 | + val = readl(arb->regs); |
| 62 | + |
| 63 | + return !(val & BIT(arb->reset_bits[id])); |
| 64 | +} |
| 65 | + |
| 66 | +static int meson_audio_arb_assert(struct reset_controller_dev *rcdev, |
| 67 | + unsigned long id) |
| 68 | +{ |
| 69 | + return meson_audio_arb_update(rcdev, id, true); |
| 70 | +} |
| 71 | + |
| 72 | +static int meson_audio_arb_deassert(struct reset_controller_dev *rcdev, |
| 73 | + unsigned long id) |
| 74 | +{ |
| 75 | + return meson_audio_arb_update(rcdev, id, false); |
| 76 | +} |
| 77 | + |
| 78 | +static const struct reset_control_ops meson_audio_arb_rstc_ops = { |
| 79 | + .assert = meson_audio_arb_assert, |
| 80 | + .deassert = meson_audio_arb_deassert, |
| 81 | + .status = meson_audio_arb_status, |
| 82 | +}; |
| 83 | + |
| 84 | +static const struct of_device_id meson_audio_arb_of_match[] = { |
| 85 | + { .compatible = "amlogic,meson-axg-audio-arb", }, |
| 86 | + {} |
| 87 | +}; |
| 88 | +MODULE_DEVICE_TABLE(of, meson_audio_arb_of_match); |
| 89 | + |
| 90 | +static int meson_audio_arb_remove(struct platform_device *pdev) |
| 91 | +{ |
| 92 | + struct meson_audio_arb_data *arb = platform_get_drvdata(pdev); |
| 93 | + |
| 94 | + /* Disable all access */ |
| 95 | + spin_lock(&arb->lock); |
| 96 | + writel(0, arb->regs); |
| 97 | + spin_unlock(&arb->lock); |
| 98 | + |
| 99 | + clk_disable_unprepare(arb->clk); |
| 100 | + |
| 101 | + return 0; |
| 102 | +} |
| 103 | + |
| 104 | +static int meson_audio_arb_probe(struct platform_device *pdev) |
| 105 | +{ |
| 106 | + struct device *dev = &pdev->dev; |
| 107 | + struct meson_audio_arb_data *arb; |
| 108 | + struct resource *res; |
| 109 | + int ret; |
| 110 | + |
| 111 | + arb = devm_kzalloc(dev, sizeof(*arb), GFP_KERNEL); |
| 112 | + if (!arb) |
| 113 | + return -ENOMEM; |
| 114 | + platform_set_drvdata(pdev, arb); |
| 115 | + |
| 116 | + arb->clk = devm_clk_get(dev, NULL); |
| 117 | + if (IS_ERR(arb->clk)) { |
| 118 | + if (PTR_ERR(arb->clk) != -EPROBE_DEFER) |
| 119 | + dev_err(dev, "failed to get clock\n"); |
| 120 | + return PTR_ERR(arb->clk); |
| 121 | + } |
| 122 | + |
| 123 | + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| 124 | + arb->regs = devm_ioremap_resource(dev, res); |
| 125 | + if (IS_ERR(arb->regs)) |
| 126 | + return PTR_ERR(arb->regs); |
| 127 | + |
| 128 | + spin_lock_init(&arb->lock); |
| 129 | + arb->reset_bits = axg_audio_arb_reset_bits; |
| 130 | + arb->rstc.nr_resets = ARRAY_SIZE(axg_audio_arb_reset_bits); |
| 131 | + arb->rstc.ops = &meson_audio_arb_rstc_ops; |
| 132 | + arb->rstc.of_node = dev->of_node; |
| 133 | + |
| 134 | + /* |
| 135 | + * Enable general : |
| 136 | + * In the initial state, all memory interfaces are disabled |
| 137 | + * and the general bit is on |
| 138 | + */ |
| 139 | + ret = clk_prepare_enable(arb->clk); |
| 140 | + if (ret) { |
| 141 | + dev_err(dev, "failed to enable arb clock\n"); |
| 142 | + return ret; |
| 143 | + } |
| 144 | + writel(BIT(ARB_GENERAL_BIT), arb->regs); |
| 145 | + |
| 146 | + /* Register reset controller */ |
| 147 | + ret = devm_reset_controller_register(dev, &arb->rstc); |
| 148 | + if (ret) { |
| 149 | + dev_err(dev, "failed to register arb reset controller\n"); |
| 150 | + meson_audio_arb_remove(pdev); |
| 151 | + } |
| 152 | + |
| 153 | + return ret; |
| 154 | +} |
| 155 | + |
| 156 | +static struct platform_driver meson_audio_arb_pdrv = { |
| 157 | + .probe = meson_audio_arb_probe, |
| 158 | + .remove = meson_audio_arb_remove, |
| 159 | + .driver = { |
| 160 | + .name = "meson-audio-arb-reset", |
| 161 | + .of_match_table = meson_audio_arb_of_match, |
| 162 | + }, |
| 163 | +}; |
| 164 | +module_platform_driver(meson_audio_arb_pdrv); |
| 165 | + |
| 166 | +MODULE_DESCRIPTION("Amlogic A113 Audio Memory Arbiter"); |
| 167 | +MODULE_AUTHOR("Jerome Brunet <jbrunet@baylibre.com>"); |
| 168 | +MODULE_LICENSE("GPL v2"); |
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