1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * BCM63268 Timer Clock and Reset Controller Driver
4  *
5  * Copyright (C) 2023 Álvaro Fernández Rojas <noltari@gmail.com>
6  */
7 
8 #include <linux/clk-provider.h>
9 #include <linux/container_of.h>
10 #include <linux/delay.h>
11 #include <linux/device.h>
12 #include <linux/io.h>
13 #include <linux/platform_device.h>
14 #include <linux/reset-controller.h>
15 #include <linux/spinlock.h>
16 
17 #include <dt-bindings/clock/bcm63268-clock.h>
18 
19 #define BCM63268_TIMER_RESET_SLEEP_MIN_US	10000
20 #define BCM63268_TIMER_RESET_SLEEP_MAX_US	20000
21 
22 struct bcm63268_tclkrst_hw {
23 	void __iomem *regs;
24 	spinlock_t lock;
25 
26 	struct reset_controller_dev rcdev;
27 	struct clk_hw_onecell_data data;
28 };
29 
30 struct bcm63268_tclk_table_entry {
31 	const char * const name;
32 	u8 bit;
33 };
34 
35 static const struct bcm63268_tclk_table_entry bcm63268_timer_clocks[] = {
36 	{
37 		.name = "ephy1",
38 		.bit = BCM63268_TCLK_EPHY1,
39 	}, {
40 		.name = "ephy2",
41 		.bit = BCM63268_TCLK_EPHY2,
42 	}, {
43 		.name = "ephy3",
44 		.bit = BCM63268_TCLK_EPHY3,
45 	}, {
46 		.name = "gphy1",
47 		.bit = BCM63268_TCLK_GPHY1,
48 	}, {
49 		.name = "dsl",
50 		.bit = BCM63268_TCLK_DSL,
51 	}, {
52 		.name = "wakeon_ephy",
53 		.bit = BCM63268_TCLK_WAKEON_EPHY,
54 	}, {
55 		.name = "wakeon_dsl",
56 		.bit = BCM63268_TCLK_WAKEON_DSL,
57 	}, {
58 		.name = "fap1_pll",
59 		.bit = BCM63268_TCLK_FAP1,
60 	}, {
61 		.name = "fap2_pll",
62 		.bit = BCM63268_TCLK_FAP2,
63 	}, {
64 		.name = "uto_50",
65 		.bit = BCM63268_TCLK_UTO_50,
66 	}, {
67 		.name = "uto_extin",
68 		.bit = BCM63268_TCLK_UTO_EXTIN,
69 	}, {
70 		.name = "usb_ref",
71 		.bit = BCM63268_TCLK_USB_REF,
72 	}, {
73 		/* sentinel */
74 	}
75 };
76 
77 static inline struct bcm63268_tclkrst_hw *
to_bcm63268_timer_reset(struct reset_controller_dev * rcdev)78 to_bcm63268_timer_reset(struct reset_controller_dev *rcdev)
79 {
80 	return container_of(rcdev, struct bcm63268_tclkrst_hw, rcdev);
81 }
82 
bcm63268_timer_reset_update(struct reset_controller_dev * rcdev,unsigned long id,bool assert)83 static int bcm63268_timer_reset_update(struct reset_controller_dev *rcdev,
84 				unsigned long id, bool assert)
85 {
86 	struct bcm63268_tclkrst_hw *reset = to_bcm63268_timer_reset(rcdev);
87 	unsigned long flags;
88 	uint32_t val;
89 
90 	spin_lock_irqsave(&reset->lock, flags);
91 	val = __raw_readl(reset->regs);
92 	if (assert)
93 		val &= ~BIT(id);
94 	else
95 		val |= BIT(id);
96 	__raw_writel(val, reset->regs);
97 	spin_unlock_irqrestore(&reset->lock, flags);
98 
99 	return 0;
100 }
101 
bcm63268_timer_reset_assert(struct reset_controller_dev * rcdev,unsigned long id)102 static int bcm63268_timer_reset_assert(struct reset_controller_dev *rcdev,
103 				unsigned long id)
104 {
105 	return bcm63268_timer_reset_update(rcdev, id, true);
106 }
107 
bcm63268_timer_reset_deassert(struct reset_controller_dev * rcdev,unsigned long id)108 static int bcm63268_timer_reset_deassert(struct reset_controller_dev *rcdev,
109 				  unsigned long id)
110 {
111 	return bcm63268_timer_reset_update(rcdev, id, false);
112 }
113 
bcm63268_timer_reset_reset(struct reset_controller_dev * rcdev,unsigned long id)114 static int bcm63268_timer_reset_reset(struct reset_controller_dev *rcdev,
115 			       unsigned long id)
116 {
117 	bcm63268_timer_reset_update(rcdev, id, true);
118 	usleep_range(BCM63268_TIMER_RESET_SLEEP_MIN_US,
119 		     BCM63268_TIMER_RESET_SLEEP_MAX_US);
120 
121 	bcm63268_timer_reset_update(rcdev, id, false);
122 	/*
123 	 * Ensure component is taken out reset state by sleeping also after
124 	 * deasserting the reset. Otherwise, the component may not be ready
125 	 * for operation.
126 	 */
127 	usleep_range(BCM63268_TIMER_RESET_SLEEP_MIN_US,
128 		     BCM63268_TIMER_RESET_SLEEP_MAX_US);
129 
130 	return 0;
131 }
132 
bcm63268_timer_reset_status(struct reset_controller_dev * rcdev,unsigned long id)133 static int bcm63268_timer_reset_status(struct reset_controller_dev *rcdev,
134 				unsigned long id)
135 {
136 	struct bcm63268_tclkrst_hw *reset = to_bcm63268_timer_reset(rcdev);
137 
138 	return !(__raw_readl(reset->regs) & BIT(id));
139 }
140 
141 static const struct reset_control_ops bcm63268_timer_reset_ops = {
142 	.assert = bcm63268_timer_reset_assert,
143 	.deassert = bcm63268_timer_reset_deassert,
144 	.reset = bcm63268_timer_reset_reset,
145 	.status = bcm63268_timer_reset_status,
146 };
147 
bcm63268_tclk_probe(struct platform_device * pdev)148 static int bcm63268_tclk_probe(struct platform_device *pdev)
149 {
150 	struct device *dev = &pdev->dev;
151 	const struct bcm63268_tclk_table_entry *entry;
152 	struct bcm63268_tclkrst_hw *hw;
153 	struct clk_hw *clk;
154 	u8 maxbit = 0;
155 	int i, ret;
156 
157 	for (entry = bcm63268_timer_clocks; entry->name; entry++)
158 		maxbit = max(maxbit, entry->bit);
159 	maxbit++;
160 
161 	hw = devm_kzalloc(&pdev->dev, struct_size(hw, data.hws, maxbit),
162 			  GFP_KERNEL);
163 	if (!hw)
164 		return -ENOMEM;
165 
166 	platform_set_drvdata(pdev, hw);
167 
168 	spin_lock_init(&hw->lock);
169 
170 	hw->data.num = maxbit;
171 	for (i = 0; i < maxbit; i++)
172 		hw->data.hws[i] = ERR_PTR(-ENODEV);
173 
174 	hw->regs = devm_platform_ioremap_resource(pdev, 0);
175 	if (IS_ERR(hw->regs))
176 		return PTR_ERR(hw->regs);
177 
178 	for (entry = bcm63268_timer_clocks; entry->name; entry++) {
179 		clk = devm_clk_hw_register_gate(dev, entry->name, NULL, 0,
180 						hw->regs, entry->bit,
181 						CLK_GATE_BIG_ENDIAN,
182 						&hw->lock);
183 		if (IS_ERR(clk))
184 			return PTR_ERR(clk);
185 
186 		hw->data.hws[entry->bit] = clk;
187 	}
188 
189 	ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get,
190 					  &hw->data);
191 	if (ret)
192 		return ret;
193 
194 	hw->rcdev.of_node = dev->of_node;
195 	hw->rcdev.ops = &bcm63268_timer_reset_ops;
196 
197 	ret = devm_reset_controller_register(dev, &hw->rcdev);
198 	if (ret)
199 		dev_err(dev, "Failed to register reset controller\n");
200 
201 	return 0;
202 }
203 
204 static const struct of_device_id bcm63268_tclk_dt_ids[] = {
205 	{ .compatible = "brcm,bcm63268-timer-clocks" },
206 	{ /* sentinel */ }
207 };
208 
209 static struct platform_driver bcm63268_tclk = {
210 	.probe = bcm63268_tclk_probe,
211 	.driver = {
212 		.name = "bcm63268-timer-clock",
213 		.of_match_table = bcm63268_tclk_dt_ids,
214 	},
215 };
216 builtin_platform_driver(bcm63268_tclk);
217