xref: /openbmc/linux/drivers/clk/mvebu/dove-divider.c (revision c19edff6)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Marvell Dove PMU Core PLL divider driver
4  *
5  * Cleaned up by substantially rewriting, and converted to DT by
6  * Russell King.  Origin is not known.
7  */
8 #include <linux/clk-provider.h>
9 #include <linux/delay.h>
10 #include <linux/io.h>
11 #include <linux/kernel.h>
12 #include <linux/of.h>
13 #include <linux/of_address.h>
14 
15 #include "dove-divider.h"
16 
17 struct dove_clk {
18 	const char *name;
19 	struct clk_hw hw;
20 	void __iomem *base;
21 	spinlock_t *lock;
22 	u8 div_bit_start;
23 	u8 div_bit_end;
24 	u8 div_bit_load;
25 	u8 div_bit_size;
26 	u32 *divider_table;
27 };
28 
29 enum {
30 	DIV_CTRL0 = 0,
31 	DIV_CTRL1 = 4,
32 	DIV_CTRL1_N_RESET_MASK = BIT(10),
33 };
34 
35 #define to_dove_clk(hw) container_of(hw, struct dove_clk, hw)
36 
dove_load_divider(void __iomem * base,u32 val,u32 mask,u32 load)37 static void dove_load_divider(void __iomem *base, u32 val, u32 mask, u32 load)
38 {
39 	u32 v;
40 
41 	v = readl_relaxed(base + DIV_CTRL1) | DIV_CTRL1_N_RESET_MASK;
42 	writel_relaxed(v, base + DIV_CTRL1);
43 
44 	v = (readl_relaxed(base + DIV_CTRL0) & ~(mask | load)) | val;
45 	writel_relaxed(v, base + DIV_CTRL0);
46 	writel_relaxed(v | load, base + DIV_CTRL0);
47 	ndelay(250);
48 	writel_relaxed(v, base + DIV_CTRL0);
49 }
50 
dove_get_divider(struct dove_clk * dc)51 static unsigned int dove_get_divider(struct dove_clk *dc)
52 {
53 	unsigned int divider;
54 	u32 val;
55 
56 	val = readl_relaxed(dc->base + DIV_CTRL0);
57 	val >>= dc->div_bit_start;
58 
59 	divider = val & ~(~0 << dc->div_bit_size);
60 
61 	if (dc->divider_table)
62 		divider = dc->divider_table[divider];
63 
64 	return divider;
65 }
66 
dove_calc_divider(const struct dove_clk * dc,unsigned long rate,unsigned long parent_rate,bool set)67 static int dove_calc_divider(const struct dove_clk *dc, unsigned long rate,
68 			     unsigned long parent_rate, bool set)
69 {
70 	unsigned int divider, max;
71 
72 	divider = DIV_ROUND_CLOSEST(parent_rate, rate);
73 
74 	if (dc->divider_table) {
75 		unsigned int i;
76 
77 		for (i = 0; dc->divider_table[i]; i++)
78 			if (divider == dc->divider_table[i]) {
79 				divider = i;
80 				break;
81 			}
82 
83 		if (!dc->divider_table[i])
84 			return -EINVAL;
85 	} else {
86 		max = 1 << dc->div_bit_size;
87 
88 		if (set && (divider == 0 || divider >= max))
89 			return -EINVAL;
90 		if (divider >= max)
91 			divider = max - 1;
92 		else if (divider == 0)
93 			divider = 1;
94 	}
95 
96 	return divider;
97 }
98 
dove_recalc_rate(struct clk_hw * hw,unsigned long parent)99 static unsigned long dove_recalc_rate(struct clk_hw *hw, unsigned long parent)
100 {
101 	struct dove_clk *dc = to_dove_clk(hw);
102 	unsigned int divider = dove_get_divider(dc);
103 	unsigned long rate = DIV_ROUND_CLOSEST(parent, divider);
104 
105 	pr_debug("%s(): %s divider=%u parent=%lu rate=%lu\n",
106 		 __func__, dc->name, divider, parent, rate);
107 
108 	return rate;
109 }
110 
dove_round_rate(struct clk_hw * hw,unsigned long rate,unsigned long * parent)111 static long dove_round_rate(struct clk_hw *hw, unsigned long rate,
112 			    unsigned long *parent)
113 {
114 	struct dove_clk *dc = to_dove_clk(hw);
115 	unsigned long parent_rate = *parent;
116 	int divider;
117 
118 	divider = dove_calc_divider(dc, rate, parent_rate, false);
119 	if (divider < 0)
120 		return divider;
121 
122 	rate = DIV_ROUND_CLOSEST(parent_rate, divider);
123 
124 	pr_debug("%s(): %s divider=%u parent=%lu rate=%lu\n",
125 		 __func__, dc->name, divider, parent_rate, rate);
126 
127 	return rate;
128 }
129 
dove_set_clock(struct clk_hw * hw,unsigned long rate,unsigned long parent_rate)130 static int dove_set_clock(struct clk_hw *hw, unsigned long rate,
131 			  unsigned long parent_rate)
132 {
133 	struct dove_clk *dc = to_dove_clk(hw);
134 	u32 mask, load, div;
135 	int divider;
136 
137 	divider = dove_calc_divider(dc, rate, parent_rate, true);
138 	if (divider < 0)
139 		return divider;
140 
141 	pr_debug("%s(): %s divider=%u parent=%lu rate=%lu\n",
142 		 __func__, dc->name, divider, parent_rate, rate);
143 
144 	div = (u32)divider << dc->div_bit_start;
145 	mask = ~(~0 << dc->div_bit_size) << dc->div_bit_start;
146 	load = BIT(dc->div_bit_load);
147 
148 	spin_lock(dc->lock);
149 	dove_load_divider(dc->base, div, mask, load);
150 	spin_unlock(dc->lock);
151 
152 	return 0;
153 }
154 
155 static const struct clk_ops dove_divider_ops = {
156 	.set_rate	= dove_set_clock,
157 	.round_rate	= dove_round_rate,
158 	.recalc_rate	= dove_recalc_rate,
159 };
160 
clk_register_dove_divider(struct device * dev,struct dove_clk * dc,const char ** parent_names,size_t num_parents,void __iomem * base)161 static struct clk *clk_register_dove_divider(struct device *dev,
162 	struct dove_clk *dc, const char **parent_names, size_t num_parents,
163 	void __iomem *base)
164 {
165 	char name[32];
166 	struct clk_init_data init = {
167 		.name = name,
168 		.ops = &dove_divider_ops,
169 		.parent_names = parent_names,
170 		.num_parents = num_parents,
171 	};
172 
173 	strscpy(name, dc->name, sizeof(name));
174 
175 	dc->hw.init = &init;
176 	dc->base = base;
177 	dc->div_bit_size = dc->div_bit_end - dc->div_bit_start + 1;
178 
179 	return clk_register(dev, &dc->hw);
180 }
181 
182 static DEFINE_SPINLOCK(dove_divider_lock);
183 
184 static u32 axi_divider[] = {-1, 2, 1, 3, 4, 6, 5, 7, 8, 10, 9, 0};
185 
186 static struct dove_clk dove_hw_clocks[4] = {
187 	{
188 		.name = "axi",
189 		.lock = &dove_divider_lock,
190 		.div_bit_start = 1,
191 		.div_bit_end = 6,
192 		.div_bit_load = 7,
193 		.divider_table = axi_divider,
194 	}, {
195 		.name = "gpu",
196 		.lock = &dove_divider_lock,
197 		.div_bit_start = 8,
198 		.div_bit_end = 13,
199 		.div_bit_load = 14,
200 	}, {
201 		.name = "vmeta",
202 		.lock = &dove_divider_lock,
203 		.div_bit_start = 15,
204 		.div_bit_end = 20,
205 		.div_bit_load = 21,
206 	}, {
207 		.name = "lcd",
208 		.lock = &dove_divider_lock,
209 		.div_bit_start = 22,
210 		.div_bit_end = 27,
211 		.div_bit_load = 28,
212 	},
213 };
214 
215 static const char *core_pll[] = {
216 	"core-pll",
217 };
218 
dove_divider_init(struct device * dev,void __iomem * base,struct clk ** clks)219 static int dove_divider_init(struct device *dev, void __iomem *base,
220 	struct clk **clks)
221 {
222 	struct clk *clk;
223 	int i;
224 
225 	/*
226 	 * Create the core PLL clock.  We treat this as a fixed rate
227 	 * clock as we don't know any better, and documentation is sparse.
228 	 */
229 	clk = clk_register_fixed_rate(dev, core_pll[0], NULL, 0, 2000000000UL);
230 	if (IS_ERR(clk))
231 		return PTR_ERR(clk);
232 
233 	for (i = 0; i < ARRAY_SIZE(dove_hw_clocks); i++)
234 		clks[i] = clk_register_dove_divider(dev, &dove_hw_clocks[i],
235 						    core_pll,
236 						    ARRAY_SIZE(core_pll), base);
237 
238 	return 0;
239 }
240 
241 static struct clk *dove_divider_clocks[4];
242 
243 static struct clk_onecell_data dove_divider_data = {
244 	.clks = dove_divider_clocks,
245 	.clk_num = ARRAY_SIZE(dove_divider_clocks),
246 };
247 
dove_divider_clk_init(struct device_node * np)248 void __init dove_divider_clk_init(struct device_node *np)
249 {
250 	void __iomem *base;
251 
252 	base = of_iomap(np, 0);
253 	if (WARN_ON(!base))
254 		return;
255 
256 	if (WARN_ON(dove_divider_init(NULL, base, dove_divider_clocks))) {
257 		iounmap(base);
258 		return;
259 	}
260 
261 	of_clk_add_provider(np, of_clk_src_onecell_get, &dove_divider_data);
262 }
263