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
 14struct 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
 22struct 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
 29static 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
 38static 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
 43static 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
 54static 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
 59static 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
 80static 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
 92static 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
 98static 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
104static 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
110static 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};
120MODULE_DEVICE_TABLE(of, meson_audio_arb_of_match);
121
122static 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
136static 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
194static 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};
202module_platform_driver(meson_audio_arb_pdrv);
203
204MODULE_DESCRIPTION("Amlogic A113 Audio Memory Arbiter");
205MODULE_AUTHOR("Jerome Brunet <jbrunet@baylibre.com>");
206MODULE_LICENSE("GPL v2");