1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (C) 2016 Freescale Semiconductor, Inc.
4  * Copyright 2017~2018 NXP
5  *
6  * Author: Dong Aisheng <aisheng.dong@nxp.com>
7  *
8  */
9 
10 #include <linux/clk-provider.h>
11 #include <linux/err.h>
12 #include <linux/io.h>
13 #include <linux/iopoll.h>
14 #include <linux/slab.h>
15 
16 #include "clk.h"
17 
18 /**
19  * struct clk_pfdv2 - IMX PFD clock
20  * @hw:		clock source
21  * @reg:	PFD register address
22  * @gate_bit:	Gate bit offset
23  * @vld_bit:	Valid bit offset
24  * @frac_off:	PLL Fractional Divider offset
25  */
26 
27 struct clk_pfdv2 {
28 	struct clk_hw	hw;
29 	void __iomem	*reg;
30 	u8		gate_bit;
31 	u8		vld_bit;
32 	u8		frac_off;
33 };
34 
35 #define to_clk_pfdv2(_hw) container_of(_hw, struct clk_pfdv2, hw)
36 
37 #define CLK_PFDV2_FRAC_MASK 0x3f
38 
39 #define LOCK_TIMEOUT_US		USEC_PER_MSEC
40 
41 static DEFINE_SPINLOCK(pfd_lock);
42 
clk_pfdv2_wait(struct clk_pfdv2 * pfd)43 static int clk_pfdv2_wait(struct clk_pfdv2 *pfd)
44 {
45 	u32 val;
46 
47 	return readl_poll_timeout(pfd->reg, val, val & (1 << pfd->vld_bit),
48 				  0, LOCK_TIMEOUT_US);
49 }
50 
clk_pfdv2_enable(struct clk_hw * hw)51 static int clk_pfdv2_enable(struct clk_hw *hw)
52 {
53 	struct clk_pfdv2 *pfd = to_clk_pfdv2(hw);
54 	unsigned long flags;
55 	u32 val;
56 
57 	spin_lock_irqsave(&pfd_lock, flags);
58 	val = readl_relaxed(pfd->reg);
59 	val &= ~(1 << pfd->gate_bit);
60 	writel_relaxed(val, pfd->reg);
61 	spin_unlock_irqrestore(&pfd_lock, flags);
62 
63 	return clk_pfdv2_wait(pfd);
64 }
65 
clk_pfdv2_disable(struct clk_hw * hw)66 static void clk_pfdv2_disable(struct clk_hw *hw)
67 {
68 	struct clk_pfdv2 *pfd = to_clk_pfdv2(hw);
69 	unsigned long flags;
70 	u32 val;
71 
72 	spin_lock_irqsave(&pfd_lock, flags);
73 	val = readl_relaxed(pfd->reg);
74 	val |= (1 << pfd->gate_bit);
75 	writel_relaxed(val, pfd->reg);
76 	spin_unlock_irqrestore(&pfd_lock, flags);
77 }
78 
clk_pfdv2_recalc_rate(struct clk_hw * hw,unsigned long parent_rate)79 static unsigned long clk_pfdv2_recalc_rate(struct clk_hw *hw,
80 					   unsigned long parent_rate)
81 {
82 	struct clk_pfdv2 *pfd = to_clk_pfdv2(hw);
83 	u64 tmp = parent_rate;
84 	u8 frac;
85 
86 	frac = (readl_relaxed(pfd->reg) >> pfd->frac_off)
87 		& CLK_PFDV2_FRAC_MASK;
88 
89 	if (!frac) {
90 		pr_debug("clk_pfdv2: %s invalid pfd frac value 0\n",
91 			 clk_hw_get_name(hw));
92 		return 0;
93 	}
94 
95 	tmp *= 18;
96 	do_div(tmp, frac);
97 
98 	return tmp;
99 }
100 
clk_pfdv2_determine_rate(struct clk_hw * hw,struct clk_rate_request * req)101 static int clk_pfdv2_determine_rate(struct clk_hw *hw,
102 				    struct clk_rate_request *req)
103 {
104 	unsigned long parent_rates[] = {
105 					480000000,
106 					528000000,
107 					req->best_parent_rate
108 				       };
109 	unsigned long best_rate = -1UL, rate = req->rate;
110 	unsigned long best_parent_rate = req->best_parent_rate;
111 	u64 tmp;
112 	u8 frac;
113 	int i;
114 
115 	for (i = 0; i < ARRAY_SIZE(parent_rates); i++) {
116 		tmp = parent_rates[i];
117 		tmp = tmp * 18 + rate / 2;
118 		do_div(tmp, rate);
119 		frac = tmp;
120 
121 		if (frac < 12)
122 			frac = 12;
123 		else if (frac > 35)
124 			frac = 35;
125 
126 		tmp = parent_rates[i];
127 		tmp *= 18;
128 		do_div(tmp, frac);
129 
130 		if (abs(tmp - req->rate) < abs(best_rate - req->rate)) {
131 			best_rate = tmp;
132 			best_parent_rate = parent_rates[i];
133 		}
134 	}
135 
136 	req->best_parent_rate = best_parent_rate;
137 	req->rate = best_rate;
138 
139 	return 0;
140 }
141 
clk_pfdv2_is_enabled(struct clk_hw * hw)142 static int clk_pfdv2_is_enabled(struct clk_hw *hw)
143 {
144 	struct clk_pfdv2 *pfd = to_clk_pfdv2(hw);
145 
146 	if (readl_relaxed(pfd->reg) & (1 << pfd->gate_bit))
147 		return 0;
148 
149 	return 1;
150 }
151 
clk_pfdv2_set_rate(struct clk_hw * hw,unsigned long rate,unsigned long parent_rate)152 static int clk_pfdv2_set_rate(struct clk_hw *hw, unsigned long rate,
153 			      unsigned long parent_rate)
154 {
155 	struct clk_pfdv2 *pfd = to_clk_pfdv2(hw);
156 	unsigned long flags;
157 	u64 tmp = parent_rate;
158 	u32 val;
159 	u8 frac;
160 
161 	if (!rate)
162 		return -EINVAL;
163 
164 	/*
165 	 * PFD can NOT change rate without gating.
166 	 * as the PFDs may enabled in HW by default but no
167 	 * consumer used it, the enable count is '0', so the
168 	 * 'SET_RATE_GATE' can NOT help on blocking the set_rate
169 	 * ops especially for 'assigned-clock-xxx'. In order
170 	 * to simplify the case, just disable the PFD if it is
171 	 * enabled in HW but not in SW.
172 	 */
173 	if (clk_pfdv2_is_enabled(hw))
174 		clk_pfdv2_disable(hw);
175 
176 	tmp = tmp * 18 + rate / 2;
177 	do_div(tmp, rate);
178 	frac = tmp;
179 	if (frac < 12)
180 		frac = 12;
181 	else if (frac > 35)
182 		frac = 35;
183 
184 	spin_lock_irqsave(&pfd_lock, flags);
185 	val = readl_relaxed(pfd->reg);
186 	val &= ~(CLK_PFDV2_FRAC_MASK << pfd->frac_off);
187 	val |= frac << pfd->frac_off;
188 	writel_relaxed(val, pfd->reg);
189 	spin_unlock_irqrestore(&pfd_lock, flags);
190 
191 	return 0;
192 }
193 
194 static const struct clk_ops clk_pfdv2_ops = {
195 	.enable		= clk_pfdv2_enable,
196 	.disable	= clk_pfdv2_disable,
197 	.recalc_rate	= clk_pfdv2_recalc_rate,
198 	.determine_rate	= clk_pfdv2_determine_rate,
199 	.set_rate	= clk_pfdv2_set_rate,
200 	.is_enabled     = clk_pfdv2_is_enabled,
201 };
202 
imx_clk_hw_pfdv2(enum imx_pfdv2_type type,const char * name,const char * parent_name,void __iomem * reg,u8 idx)203 struct clk_hw *imx_clk_hw_pfdv2(enum imx_pfdv2_type type, const char *name,
204 			     const char *parent_name, void __iomem *reg, u8 idx)
205 {
206 	struct clk_init_data init;
207 	struct clk_pfdv2 *pfd;
208 	struct clk_hw *hw;
209 	int ret;
210 
211 	WARN_ON(idx > 3);
212 
213 	pfd = kzalloc(sizeof(*pfd), GFP_KERNEL);
214 	if (!pfd)
215 		return ERR_PTR(-ENOMEM);
216 
217 	pfd->reg = reg;
218 	pfd->gate_bit = (idx + 1) * 8 - 1;
219 	pfd->vld_bit = pfd->gate_bit - 1;
220 	pfd->frac_off = idx * 8;
221 
222 	init.name = name;
223 	init.ops = &clk_pfdv2_ops;
224 	init.parent_names = &parent_name;
225 	init.num_parents = 1;
226 	if (type == IMX_PFDV2_IMX7ULP)
227 		init.flags = CLK_SET_RATE_GATE | CLK_SET_RATE_PARENT;
228 	else
229 		init.flags = CLK_SET_RATE_GATE;
230 
231 	pfd->hw.init = &init;
232 
233 	hw = &pfd->hw;
234 	ret = clk_hw_register(NULL, hw);
235 	if (ret) {
236 		kfree(pfd);
237 		hw = ERR_PTR(ret);
238 	}
239 
240 	return hw;
241 }
242 EXPORT_SYMBOL_GPL(imx_clk_hw_pfdv2);
243