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