xref: /linux/drivers/clk/baikal-t1/clk-ccu-pll.c (revision be239684b18e1cdcafcf8c7face4a2f562c745ad) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
4  *
5  * Authors:
6  *   Serge Semin <Sergey.Semin@baikalelectronics.ru>
7  *   Dmitry Dunaev <dmitry.dunaev@baikalelectronics.ru>
8  *
9  * Baikal-T1 CCU PLL clocks driver
10  */
11 
12 #define pr_fmt(fmt) "bt1-ccu-pll: " fmt
13 
14 #include <linux/kernel.h>
15 #include <linux/platform_device.h>
16 #include <linux/printk.h>
17 #include <linux/slab.h>
18 #include <linux/clk-provider.h>
19 #include <linux/mfd/syscon.h>
20 #include <linux/of.h>
21 #include <linux/of_address.h>
22 #include <linux/ioport.h>
23 #include <linux/regmap.h>
24 
25 #include <dt-bindings/clock/bt1-ccu.h>
26 
27 #include "ccu-pll.h"
28 
29 #define CCU_CPU_PLL_BASE		0x000
30 #define CCU_SATA_PLL_BASE		0x008
31 #define CCU_DDR_PLL_BASE		0x010
32 #define CCU_PCIE_PLL_BASE		0x018
33 #define CCU_ETH_PLL_BASE		0x020
34 
35 #define CCU_PLL_INFO(_id, _name, _pname, _base, _flags, _features)	\
36 	{								\
37 		.id = _id,						\
38 		.name = _name,						\
39 		.parent_name = _pname,					\
40 		.base = _base,						\
41 		.flags = _flags,					\
42 		.features = _features,					\
43 	}
44 
45 #define CCU_PLL_NUM			ARRAY_SIZE(pll_info)
46 
47 struct ccu_pll_info {
48 	unsigned int id;
49 	const char *name;
50 	const char *parent_name;
51 	unsigned int base;
52 	unsigned long flags;
53 	unsigned long features;
54 };
55 
56 /*
57  * Alas we have to mark all PLLs as critical. CPU and DDR PLLs are sources of
58  * CPU cores and DDR controller reference clocks, due to which they obviously
59  * shouldn't be ever gated. SATA and PCIe PLLs are the parents of APB-bus and
60  * DDR controller AXI-bus clocks. If they are gated the system will be
61  * unusable. Moreover disabling SATA and Ethernet PLLs causes automatic reset
62  * of the corresponding subsystems. So until we aren't ready to re-initialize
63  * all the devices consuming those PLLs, they will be marked as critical too.
64  */
65 static const struct ccu_pll_info pll_info[] = {
66 	CCU_PLL_INFO(CCU_CPU_PLL, "cpu_pll", "ref_clk", CCU_CPU_PLL_BASE,
67 		     CLK_IS_CRITICAL, CCU_PLL_BASIC),
68 	CCU_PLL_INFO(CCU_SATA_PLL, "sata_pll", "ref_clk", CCU_SATA_PLL_BASE,
69 		     CLK_IS_CRITICAL | CLK_SET_RATE_GATE, 0),
70 	CCU_PLL_INFO(CCU_DDR_PLL, "ddr_pll", "ref_clk", CCU_DDR_PLL_BASE,
71 		     CLK_IS_CRITICAL | CLK_SET_RATE_GATE, 0),
72 	CCU_PLL_INFO(CCU_PCIE_PLL, "pcie_pll", "ref_clk", CCU_PCIE_PLL_BASE,
73 		     CLK_IS_CRITICAL, CCU_PLL_BASIC),
74 	CCU_PLL_INFO(CCU_ETH_PLL, "eth_pll", "ref_clk", CCU_ETH_PLL_BASE,
75 		     CLK_IS_CRITICAL | CLK_SET_RATE_GATE, 0)
76 };
77 
78 struct ccu_pll_data {
79 	struct device_node *np;
80 	struct regmap *sys_regs;
81 	struct ccu_pll *plls[CCU_PLL_NUM];
82 };
83 
84 static struct ccu_pll_data *pll_data;
85 
86 static struct ccu_pll *ccu_pll_find_desc(struct ccu_pll_data *data,
87 					 unsigned int clk_id)
88 {
89 	int idx;
90 
91 	for (idx = 0; idx < CCU_PLL_NUM; ++idx) {
92 		if (pll_info[idx].id == clk_id)
93 			return data->plls[idx];
94 	}
95 
96 	return ERR_PTR(-EINVAL);
97 }
98 
99 static struct ccu_pll_data *ccu_pll_create_data(struct device_node *np)
100 {
101 	struct ccu_pll_data *data;
102 
103 	data = kzalloc(sizeof(*data), GFP_KERNEL);
104 	if (!data)
105 		return ERR_PTR(-ENOMEM);
106 
107 	data->np = np;
108 
109 	return data;
110 }
111 
112 static void ccu_pll_free_data(struct ccu_pll_data *data)
113 {
114 	kfree(data);
115 }
116 
117 static int ccu_pll_find_sys_regs(struct ccu_pll_data *data)
118 {
119 	data->sys_regs = syscon_node_to_regmap(data->np->parent);
120 	if (IS_ERR(data->sys_regs)) {
121 		pr_err("Failed to find syscon regs for '%s'\n",
122 			of_node_full_name(data->np));
123 		return PTR_ERR(data->sys_regs);
124 	}
125 
126 	return 0;
127 }
128 
129 static struct clk_hw *ccu_pll_of_clk_hw_get(struct of_phandle_args *clkspec,
130 					    void *priv)
131 {
132 	struct ccu_pll_data *data = priv;
133 	struct ccu_pll *pll;
134 	unsigned int clk_id;
135 
136 	clk_id = clkspec->args[0];
137 	pll = ccu_pll_find_desc(data, clk_id);
138 	if (IS_ERR(pll)) {
139 		if (pll != ERR_PTR(-EPROBE_DEFER))
140 			pr_info("Invalid PLL clock ID %d specified\n", clk_id);
141 
142 		return ERR_CAST(pll);
143 	}
144 
145 	return ccu_pll_get_clk_hw(pll);
146 }
147 
148 static int ccu_pll_clk_register(struct ccu_pll_data *data, bool defer)
149 {
150 	int idx, ret;
151 
152 	for (idx = 0; idx < CCU_PLL_NUM; ++idx) {
153 		const struct ccu_pll_info *info = &pll_info[idx];
154 		struct ccu_pll_init_data init = {0};
155 
156 		/* Defer non-basic PLLs allocation for the probe stage */
157 		if (!!(info->features & CCU_PLL_BASIC) ^ defer) {
158 			if (!data->plls[idx])
159 				data->plls[idx] = ERR_PTR(-EPROBE_DEFER);
160 
161 			continue;
162 		}
163 
164 		init.id = info->id;
165 		init.name = info->name;
166 		init.parent_name = info->parent_name;
167 		init.base = info->base;
168 		init.sys_regs = data->sys_regs;
169 		init.np = data->np;
170 		init.flags = info->flags;
171 		init.features = info->features;
172 
173 		data->plls[idx] = ccu_pll_hw_register(&init);
174 		if (IS_ERR(data->plls[idx])) {
175 			ret = PTR_ERR(data->plls[idx]);
176 			pr_err("Couldn't register PLL hw '%s'\n",
177 				init.name);
178 			goto err_hw_unregister;
179 		}
180 	}
181 
182 	return 0;
183 
184 err_hw_unregister:
185 	for (--idx; idx >= 0; --idx) {
186 		if (!!(pll_info[idx].features & CCU_PLL_BASIC) ^ defer)
187 			continue;
188 
189 		ccu_pll_hw_unregister(data->plls[idx]);
190 	}
191 
192 	return ret;
193 }
194 
195 static void ccu_pll_clk_unregister(struct ccu_pll_data *data, bool defer)
196 {
197 	int idx;
198 
199 	/* Uninstall only the clocks registered on the specfied stage */
200 	for (idx = 0; idx < CCU_PLL_NUM; ++idx) {
201 		if (!!(pll_info[idx].features & CCU_PLL_BASIC) ^ defer)
202 			continue;
203 
204 		ccu_pll_hw_unregister(data->plls[idx]);
205 	}
206 }
207 
208 static int ccu_pll_of_register(struct ccu_pll_data *data)
209 {
210 	int ret;
211 
212 	ret = of_clk_add_hw_provider(data->np, ccu_pll_of_clk_hw_get, data);
213 	if (ret) {
214 		pr_err("Couldn't register PLL provider of '%s'\n",
215 			of_node_full_name(data->np));
216 	}
217 
218 	return ret;
219 }
220 
221 static int ccu_pll_probe(struct platform_device *pdev)
222 {
223 	struct ccu_pll_data *data = pll_data;
224 
225 	if (!data)
226 		return -EINVAL;
227 
228 	return ccu_pll_clk_register(data, false);
229 }
230 
231 static const struct of_device_id ccu_pll_of_match[] = {
232 	{ .compatible = "baikal,bt1-ccu-pll" },
233 	{ }
234 };
235 
236 static struct platform_driver ccu_pll_driver = {
237 	.probe  = ccu_pll_probe,
238 	.driver = {
239 		.name = "clk-ccu-pll",
240 		.of_match_table = ccu_pll_of_match,
241 		.suppress_bind_attrs = true,
242 	},
243 };
244 builtin_platform_driver(ccu_pll_driver);
245 
246 static __init void ccu_pll_init(struct device_node *np)
247 {
248 	struct ccu_pll_data *data;
249 	int ret;
250 
251 	data = ccu_pll_create_data(np);
252 	if (IS_ERR(data))
253 		return;
254 
255 	ret = ccu_pll_find_sys_regs(data);
256 	if (ret)
257 		goto err_free_data;
258 
259 	ret = ccu_pll_clk_register(data, true);
260 	if (ret)
261 		goto err_free_data;
262 
263 	ret = ccu_pll_of_register(data);
264 	if (ret)
265 		goto err_clk_unregister;
266 
267 	pll_data = data;
268 
269 	return;
270 
271 err_clk_unregister:
272 	ccu_pll_clk_unregister(data, true);
273 
274 err_free_data:
275 	ccu_pll_free_data(data);
276 }
277 CLK_OF_DECLARE_DRIVER(ccu_pll, "baikal,bt1-ccu-pll", ccu_pll_init);
278