xref: /openbmc/linux/drivers/clk/clk-lan966x.c (revision 0a94608f) 
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Microchip LAN966x SoC Clock driver.
4  *
5  * Copyright (C) 2021 Microchip Technology, Inc. and its subsidiaries
6  *
7  * Author: Kavyasree Kotagiri <kavyasree.kotagiri@microchip.com>
8  */
9 
10 #include <linux/bitfield.h>
11 #include <linux/clk-provider.h>
12 #include <linux/io.h>
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/of.h>
16 #include <linux/platform_device.h>
17 #include <linux/slab.h>
18 
19 #include <dt-bindings/clock/microchip,lan966x.h>
20 
21 #define GCK_ENA         BIT(0)
22 #define GCK_SRC_SEL     GENMASK(9, 8)
23 #define GCK_PRESCALER   GENMASK(23, 16)
24 
25 #define DIV_MAX		255
26 
27 static const char *clk_names[N_CLOCKS] = {
28 	"qspi0", "qspi1", "qspi2", "sdmmc0",
29 	"pi", "mcan0", "mcan1", "flexcom0",
30 	"flexcom1", "flexcom2", "flexcom3",
31 	"flexcom4", "timer1", "usb_refclk",
32 };
33 
34 struct lan966x_gck {
35 	struct clk_hw hw;
36 	void __iomem *reg;
37 };
38 #define to_lan966x_gck(hw) container_of(hw, struct lan966x_gck, hw)
39 
40 static const struct clk_parent_data lan966x_gck_pdata[] = {
41 	{ .fw_name = "cpu", },
42 	{ .fw_name = "ddr", },
43 	{ .fw_name = "sys", },
44 };
45 
46 static struct clk_init_data init = {
47 	.parent_data = lan966x_gck_pdata,
48 	.num_parents = ARRAY_SIZE(lan966x_gck_pdata),
49 };
50 
51 struct clk_gate_soc_desc {
52 	const char *name;
53 	int bit_idx;
54 };
55 
56 static const struct clk_gate_soc_desc clk_gate_desc[] = {
57 	{ "uhphs", 11 },
58 	{ "udphs", 10 },
59 	{ "mcramc", 9 },
60 	{ "hmatrix", 8 },
61 	{ }
62 };
63 
64 static DEFINE_SPINLOCK(clk_gate_lock);
65 static void __iomem *base;
66 
67 static int lan966x_gck_enable(struct clk_hw *hw)
68 {
69 	struct lan966x_gck *gck = to_lan966x_gck(hw);
70 	u32 val = readl(gck->reg);
71 
72 	val |= GCK_ENA;
73 	writel(val, gck->reg);
74 
75 	return 0;
76 }
77 
78 static void lan966x_gck_disable(struct clk_hw *hw)
79 {
80 	struct lan966x_gck *gck = to_lan966x_gck(hw);
81 	u32 val = readl(gck->reg);
82 
83 	val &= ~GCK_ENA;
84 	writel(val, gck->reg);
85 }
86 
87 static int lan966x_gck_set_rate(struct clk_hw *hw,
88 				unsigned long rate,
89 				unsigned long parent_rate)
90 {
91 	struct lan966x_gck *gck = to_lan966x_gck(hw);
92 	u32 div, val = readl(gck->reg);
93 
94 	if (rate == 0 || parent_rate == 0)
95 		return -EINVAL;
96 
97 	/* Set Prescalar */
98 	div = parent_rate / rate;
99 	val &= ~GCK_PRESCALER;
100 	val |= FIELD_PREP(GCK_PRESCALER, (div - 1));
101 	writel(val, gck->reg);
102 
103 	return 0;
104 }
105 
106 static long lan966x_gck_round_rate(struct clk_hw *hw, unsigned long rate,
107 				   unsigned long *parent_rate)
108 {
109 	unsigned int div;
110 
111 	if (rate == 0 || *parent_rate == 0)
112 		return -EINVAL;
113 
114 	if (rate >= *parent_rate)
115 		return *parent_rate;
116 
117 	div = DIV_ROUND_CLOSEST(*parent_rate, rate);
118 
119 	return *parent_rate / div;
120 }
121 
122 static unsigned long lan966x_gck_recalc_rate(struct clk_hw *hw,
123 					     unsigned long parent_rate)
124 {
125 	struct lan966x_gck *gck = to_lan966x_gck(hw);
126 	u32 div, val = readl(gck->reg);
127 
128 	div = FIELD_GET(GCK_PRESCALER, val);
129 
130 	return parent_rate / (div + 1);
131 }
132 
133 static int lan966x_gck_determine_rate(struct clk_hw *hw,
134 				      struct clk_rate_request *req)
135 {
136 	struct clk_hw *parent;
137 	int i;
138 
139 	for (i = 0; i < clk_hw_get_num_parents(hw); ++i) {
140 		parent = clk_hw_get_parent_by_index(hw, i);
141 		if (!parent)
142 			continue;
143 
144 		/* Allowed prescaler divider range is 0-255 */
145 		if (clk_hw_get_rate(parent) / req->rate <= DIV_MAX) {
146 			req->best_parent_hw = parent;
147 			req->best_parent_rate = clk_hw_get_rate(parent);
148 
149 			return 0;
150 		}
151 	}
152 
153 	return -EINVAL;
154 }
155 
156 static u8 lan966x_gck_get_parent(struct clk_hw *hw)
157 {
158 	struct lan966x_gck *gck = to_lan966x_gck(hw);
159 	u32 val = readl(gck->reg);
160 
161 	return FIELD_GET(GCK_SRC_SEL, val);
162 }
163 
164 static int lan966x_gck_set_parent(struct clk_hw *hw, u8 index)
165 {
166 	struct lan966x_gck *gck = to_lan966x_gck(hw);
167 	u32 val = readl(gck->reg);
168 
169 	val &= ~GCK_SRC_SEL;
170 	val |= FIELD_PREP(GCK_SRC_SEL, index);
171 	writel(val, gck->reg);
172 
173 	return 0;
174 }
175 
176 static const struct clk_ops lan966x_gck_ops = {
177 	.enable         = lan966x_gck_enable,
178 	.disable        = lan966x_gck_disable,
179 	.set_rate       = lan966x_gck_set_rate,
180 	.round_rate     = lan966x_gck_round_rate,
181 	.recalc_rate    = lan966x_gck_recalc_rate,
182 	.determine_rate = lan966x_gck_determine_rate,
183 	.set_parent     = lan966x_gck_set_parent,
184 	.get_parent     = lan966x_gck_get_parent,
185 };
186 
187 static struct clk_hw *lan966x_gck_clk_register(struct device *dev, int i)
188 {
189 	struct lan966x_gck *priv;
190 	int ret;
191 
192 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
193 	if (!priv)
194 		return ERR_PTR(-ENOMEM);
195 
196 	priv->reg = base + (i * 4);
197 	priv->hw.init = &init;
198 	ret = devm_clk_hw_register(dev, &priv->hw);
199 	if (ret)
200 		return ERR_PTR(ret);
201 
202 	return &priv->hw;
203 };
204 
205 static int lan966x_gate_clk_register(struct device *dev,
206 				     struct clk_hw_onecell_data *hw_data,
207 				     void __iomem *gate_base)
208 {
209 	int i;
210 
211 	for (i = GCK_GATE_UHPHS; i < N_CLOCKS; ++i) {
212 		int idx = i - GCK_GATE_UHPHS;
213 
214 		hw_data->hws[i] =
215 			devm_clk_hw_register_gate(dev, clk_gate_desc[idx].name,
216 						  "lan966x", 0, base,
217 						  clk_gate_desc[idx].bit_idx,
218 						  0, &clk_gate_lock);
219 
220 		if (IS_ERR(hw_data->hws[i]))
221 			return dev_err_probe(dev, PTR_ERR(hw_data->hws[i]),
222 					     "failed to register %s clock\n",
223 					     clk_gate_desc[idx].name);
224 	}
225 
226 	return 0;
227 }
228 
229 static int lan966x_clk_probe(struct platform_device *pdev)
230 {
231 	struct clk_hw_onecell_data *hw_data;
232 	struct device *dev = &pdev->dev;
233 	void __iomem *gate_base;
234 	struct resource *res;
235 	int i, ret;
236 
237 	hw_data = devm_kzalloc(dev, struct_size(hw_data, hws, N_CLOCKS),
238 			       GFP_KERNEL);
239 	if (!hw_data)
240 		return -ENOMEM;
241 
242 	base = devm_platform_ioremap_resource(pdev, 0);
243 	if (IS_ERR(base))
244 		return PTR_ERR(base);
245 
246 	init.ops = &lan966x_gck_ops;
247 
248 	hw_data->num = GCK_GATE_UHPHS;
249 
250 	for (i = 0; i < GCK_GATE_UHPHS; i++) {
251 		init.name = clk_names[i];
252 		hw_data->hws[i] = lan966x_gck_clk_register(dev, i);
253 		if (IS_ERR(hw_data->hws[i])) {
254 			dev_err(dev, "failed to register %s clock\n",
255 				init.name);
256 			return PTR_ERR(hw_data->hws[i]);
257 		}
258 	}
259 
260 	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
261 	if (res) {
262 		gate_base = devm_ioremap_resource(&pdev->dev, res);
263 		if (IS_ERR(gate_base))
264 			return PTR_ERR(gate_base);
265 
266 		hw_data->num = N_CLOCKS;
267 
268 		ret = lan966x_gate_clk_register(dev, hw_data, gate_base);
269 		if (ret)
270 			return ret;
271 	}
272 
273 	return devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get, hw_data);
274 }
275 
276 static const struct of_device_id lan966x_clk_dt_ids[] = {
277 	{ .compatible = "microchip,lan966x-gck", },
278 	{ }
279 };
280 MODULE_DEVICE_TABLE(of, lan966x_clk_dt_ids);
281 
282 static struct platform_driver lan966x_clk_driver = {
283 	.probe  = lan966x_clk_probe,
284 	.driver = {
285 		.name = "lan966x-clk",
286 		.of_match_table = lan966x_clk_dt_ids,
287 	},
288 };
289 builtin_platform_driver(lan966x_clk_driver);
290 
291 MODULE_AUTHOR("Kavyasree Kotagiri <kavyasree.kotagiri@microchip.com>");
292 MODULE_DESCRIPTION("LAN966X clock driver");
293 MODULE_LICENSE("GPL v2");
294