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 arb->rstc.owner = THIS_MODULE; 134 135 /* 136 * Enable general : 137 * In the initial state, all memory interfaces are disabled 138 * and the general bit is on 139 */ 140 ret = clk_prepare_enable(arb->clk); 141 if (ret) { 142 dev_err(dev, "failed to enable arb clock\n"); 143 return ret; 144 } 145 writel(BIT(ARB_GENERAL_BIT), arb->regs); 146 147 /* Register reset controller */ 148 ret = devm_reset_controller_register(dev, &arb->rstc); 149 if (ret) { 150 dev_err(dev, "failed to register arb reset controller\n"); 151 meson_audio_arb_remove(pdev); 152 } 153 154 return ret; 155 } 156 157 static struct platform_driver meson_audio_arb_pdrv = { 158 .probe = meson_audio_arb_probe, 159 .remove = meson_audio_arb_remove, 160 .driver = { 161 .name = "meson-audio-arb-reset", 162 .of_match_table = meson_audio_arb_of_match, 163 }, 164 }; 165 module_platform_driver(meson_audio_arb_pdrv); 166 167 MODULE_DESCRIPTION("Amlogic A113 Audio Memory Arbiter"); 168 MODULE_AUTHOR("Jerome Brunet <jbrunet@baylibre.com>"); 169 MODULE_LICENSE("GPL v2"); 170