1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright 2018 NXP
4  */
5 
6 #include <linux/clk-provider.h>
7 #include <linux/errno.h>
8 #include <linux/export.h>
9 #include <linux/io.h>
10 #include <linux/slab.h>
11 
12 #include "clk.h"
13 
14 #define PCG_PREDIV_SHIFT	16
15 #define PCG_PREDIV_WIDTH	3
16 #define PCG_PREDIV_MAX		8
17 
18 #define PCG_DIV_SHIFT		0
19 #define PCG_CORE_DIV_WIDTH	3
20 #define PCG_DIV_WIDTH		6
21 #define PCG_DIV_MAX		64
22 
23 #define PCG_PCS_SHIFT		24
24 #define PCG_PCS_MASK		0x7
25 
26 #define PCG_CGC_SHIFT		28
27 
28 static unsigned long imx8m_clk_composite_divider_recalc_rate(struct clk_hw *hw,
29 						unsigned long parent_rate)
30 {
31 	struct clk_divider *divider = to_clk_divider(hw);
32 	unsigned long prediv_rate;
33 	unsigned int prediv_value;
34 	unsigned int div_value;
35 
36 	prediv_value = readl(divider->reg) >> divider->shift;
37 	prediv_value &= clk_div_mask(divider->width);
38 
39 	prediv_rate = divider_recalc_rate(hw, parent_rate, prediv_value,
40 						NULL, divider->flags,
41 						divider->width);
42 
43 	div_value = readl(divider->reg) >> PCG_DIV_SHIFT;
44 	div_value &= clk_div_mask(PCG_DIV_WIDTH);
45 
46 	return divider_recalc_rate(hw, prediv_rate, div_value, NULL,
47 				   divider->flags, PCG_DIV_WIDTH);
48 }
49 
50 static int imx8m_clk_composite_compute_dividers(unsigned long rate,
51 						unsigned long parent_rate,
52 						int *prediv, int *postdiv)
53 {
54 	int div1, div2;
55 	int error = INT_MAX;
56 	int ret = -EINVAL;
57 
58 	*prediv = 1;
59 	*postdiv = 1;
60 
61 	for (div1 = 1; div1 <= PCG_PREDIV_MAX; div1++) {
62 		for (div2 = 1; div2 <= PCG_DIV_MAX; div2++) {
63 			int new_error = ((parent_rate / div1) / div2) - rate;
64 
65 			if (abs(new_error) < abs(error)) {
66 				*prediv = div1;
67 				*postdiv = div2;
68 				error = new_error;
69 				ret = 0;
70 			}
71 		}
72 	}
73 	return ret;
74 }
75 
76 static long imx8m_clk_composite_divider_round_rate(struct clk_hw *hw,
77 						unsigned long rate,
78 						unsigned long *prate)
79 {
80 	int prediv_value;
81 	int div_value;
82 
83 	imx8m_clk_composite_compute_dividers(rate, *prate,
84 						&prediv_value, &div_value);
85 	rate = DIV_ROUND_UP(*prate, prediv_value);
86 
87 	return DIV_ROUND_UP(rate, div_value);
88 
89 }
90 
91 static int imx8m_clk_composite_divider_set_rate(struct clk_hw *hw,
92 					unsigned long rate,
93 					unsigned long parent_rate)
94 {
95 	struct clk_divider *divider = to_clk_divider(hw);
96 	unsigned long flags;
97 	int prediv_value;
98 	int div_value;
99 	int ret;
100 	u32 val;
101 
102 	ret = imx8m_clk_composite_compute_dividers(rate, parent_rate,
103 						&prediv_value, &div_value);
104 	if (ret)
105 		return -EINVAL;
106 
107 	spin_lock_irqsave(divider->lock, flags);
108 
109 	val = readl(divider->reg);
110 	val &= ~((clk_div_mask(divider->width) << divider->shift) |
111 			(clk_div_mask(PCG_DIV_WIDTH) << PCG_DIV_SHIFT));
112 
113 	val |= (u32)(prediv_value  - 1) << divider->shift;
114 	val |= (u32)(div_value - 1) << PCG_DIV_SHIFT;
115 	writel(val, divider->reg);
116 
117 	spin_unlock_irqrestore(divider->lock, flags);
118 
119 	return ret;
120 }
121 
122 static const struct clk_ops imx8m_clk_composite_divider_ops = {
123 	.recalc_rate = imx8m_clk_composite_divider_recalc_rate,
124 	.round_rate = imx8m_clk_composite_divider_round_rate,
125 	.set_rate = imx8m_clk_composite_divider_set_rate,
126 };
127 
128 static u8 imx8m_clk_composite_mux_get_parent(struct clk_hw *hw)
129 {
130 	return clk_mux_ops.get_parent(hw);
131 }
132 
133 static int imx8m_clk_composite_mux_set_parent(struct clk_hw *hw, u8 index)
134 {
135 	struct clk_mux *mux = to_clk_mux(hw);
136 	u32 val = clk_mux_index_to_val(mux->table, mux->flags, index);
137 	unsigned long flags = 0;
138 	u32 reg;
139 
140 	if (mux->lock)
141 		spin_lock_irqsave(mux->lock, flags);
142 
143 	reg = readl(mux->reg);
144 	reg &= ~(mux->mask << mux->shift);
145 	val = val << mux->shift;
146 	reg |= val;
147 	/*
148 	 * write twice to make sure non-target interface
149 	 * SEL_A/B point the same clk input.
150 	 */
151 	writel(reg, mux->reg);
152 	writel(reg, mux->reg);
153 
154 	if (mux->lock)
155 		spin_unlock_irqrestore(mux->lock, flags);
156 
157 	return 0;
158 }
159 
160 static int
161 imx8m_clk_composite_mux_determine_rate(struct clk_hw *hw,
162 				       struct clk_rate_request *req)
163 {
164 	return clk_mux_ops.determine_rate(hw, req);
165 }
166 
167 
168 static const struct clk_ops imx8m_clk_composite_mux_ops = {
169 	.get_parent = imx8m_clk_composite_mux_get_parent,
170 	.set_parent = imx8m_clk_composite_mux_set_parent,
171 	.determine_rate = imx8m_clk_composite_mux_determine_rate,
172 };
173 
174 struct clk_hw *imx8m_clk_hw_composite_flags(const char *name,
175 					const char * const *parent_names,
176 					int num_parents, void __iomem *reg,
177 					u32 composite_flags,
178 					unsigned long flags)
179 {
180 	struct clk_hw *hw = ERR_PTR(-ENOMEM), *mux_hw;
181 	struct clk_hw *div_hw, *gate_hw;
182 	struct clk_divider *div = NULL;
183 	struct clk_gate *gate = NULL;
184 	struct clk_mux *mux = NULL;
185 	const struct clk_ops *divider_ops;
186 	const struct clk_ops *mux_ops;
187 
188 	mux = kzalloc(sizeof(*mux), GFP_KERNEL);
189 	if (!mux)
190 		goto fail;
191 
192 	mux_hw = &mux->hw;
193 	mux->reg = reg;
194 	mux->shift = PCG_PCS_SHIFT;
195 	mux->mask = PCG_PCS_MASK;
196 	mux->lock = &imx_ccm_lock;
197 
198 	div = kzalloc(sizeof(*div), GFP_KERNEL);
199 	if (!div)
200 		goto fail;
201 
202 	div_hw = &div->hw;
203 	div->reg = reg;
204 	if (composite_flags & IMX_COMPOSITE_CORE) {
205 		div->shift = PCG_DIV_SHIFT;
206 		div->width = PCG_CORE_DIV_WIDTH;
207 		divider_ops = &clk_divider_ops;
208 		mux_ops = &imx8m_clk_composite_mux_ops;
209 	} else if (composite_flags & IMX_COMPOSITE_BUS) {
210 		div->shift = PCG_PREDIV_SHIFT;
211 		div->width = PCG_PREDIV_WIDTH;
212 		divider_ops = &imx8m_clk_composite_divider_ops;
213 		mux_ops = &imx8m_clk_composite_mux_ops;
214 	} else {
215 		div->shift = PCG_PREDIV_SHIFT;
216 		div->width = PCG_PREDIV_WIDTH;
217 		divider_ops = &imx8m_clk_composite_divider_ops;
218 		mux_ops = &clk_mux_ops;
219 		flags |= CLK_SET_PARENT_GATE;
220 	}
221 
222 	div->lock = &imx_ccm_lock;
223 	div->flags = CLK_DIVIDER_ROUND_CLOSEST;
224 
225 	gate = kzalloc(sizeof(*gate), GFP_KERNEL);
226 	if (!gate)
227 		goto fail;
228 
229 	gate_hw = &gate->hw;
230 	gate->reg = reg;
231 	gate->bit_idx = PCG_CGC_SHIFT;
232 	gate->lock = &imx_ccm_lock;
233 
234 	hw = clk_hw_register_composite(NULL, name, parent_names, num_parents,
235 			mux_hw, mux_ops, div_hw,
236 			divider_ops, gate_hw, &clk_gate_ops, flags);
237 	if (IS_ERR(hw))
238 		goto fail;
239 
240 	return hw;
241 
242 fail:
243 	kfree(gate);
244 	kfree(div);
245 	kfree(mux);
246 	return ERR_CAST(hw);
247 }
248 EXPORT_SYMBOL_GPL(imx8m_clk_hw_composite_flags);
249