1/*
2 * Copyright (c) 2013, The Linux Foundation. All rights reserved.
3 *
4 * This software is licensed under the terms of the GNU General Public
5 * License version 2, as published by the Free Software Foundation, and
6 * may be copied, distributed, and modified under those terms.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11 * GNU General Public License for more details.
12 */
13
14#include <linux/kernel.h>
15#include <linux/bitops.h>
16#include <linux/err.h>
17#include <linux/bug.h>
18#include <linux/delay.h>
19#include <linux/export.h>
20#include <linux/clk-provider.h>
21#include <linux/regmap.h>
22
23#include <asm/div64.h>
24
25#include "clk-pll.h"
26
27#define PLL_OUTCTRL		BIT(0)
28#define PLL_BYPASSNL		BIT(1)
29#define PLL_RESET_N		BIT(2)
30#define PLL_LOCK_COUNT_SHIFT	8
31#define PLL_LOCK_COUNT_MASK	0x3f
32#define PLL_BIAS_COUNT_SHIFT	14
33#define PLL_BIAS_COUNT_MASK	0x3f
34#define PLL_VOTE_FSM_ENA	BIT(20)
35#define PLL_VOTE_FSM_RESET	BIT(21)
36
37static int clk_pll_enable(struct clk_hw *hw)
38{
39	struct clk_pll *pll = to_clk_pll(hw);
40	int ret;
41	u32 mask, val;
42
43	mask = PLL_OUTCTRL | PLL_RESET_N | PLL_BYPASSNL;
44	ret = regmap_read(pll->clkr.regmap, pll->mode_reg, &val);
45	if (ret)
46		return ret;
47
48	/* Skip if already enabled or in FSM mode */
49	if ((val & mask) == mask || val & PLL_VOTE_FSM_ENA)
50		return 0;
51
52	/* Disable PLL bypass mode. */
53	ret = regmap_update_bits(pll->clkr.regmap, pll->mode_reg, PLL_BYPASSNL,
54				 PLL_BYPASSNL);
55	if (ret)
56		return ret;
57
58	/*
59	 * H/W requires a 5us delay between disabling the bypass and
60	 * de-asserting the reset. Delay 10us just to be safe.
61	 */
62	udelay(10);
63
64	/* De-assert active-low PLL reset. */
65	ret = regmap_update_bits(pll->clkr.regmap, pll->mode_reg, PLL_RESET_N,
66				 PLL_RESET_N);
67	if (ret)
68		return ret;
69
70	/* Wait until PLL is locked. */
71	udelay(50);
72
73	/* Enable PLL output. */
74	return regmap_update_bits(pll->clkr.regmap, pll->mode_reg, PLL_OUTCTRL,
75				 PLL_OUTCTRL);
76}
77
78static void clk_pll_disable(struct clk_hw *hw)
79{
80	struct clk_pll *pll = to_clk_pll(hw);
81	u32 mask;
82	u32 val;
83
84	regmap_read(pll->clkr.regmap, pll->mode_reg, &val);
85	/* Skip if in FSM mode */
86	if (val & PLL_VOTE_FSM_ENA)
87		return;
88	mask = PLL_OUTCTRL | PLL_RESET_N | PLL_BYPASSNL;
89	regmap_update_bits(pll->clkr.regmap, pll->mode_reg, mask, 0);
90}
91
92static unsigned long
93clk_pll_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
94{
95	struct clk_pll *pll = to_clk_pll(hw);
96	u32 l, m, n, config;
97	unsigned long rate;
98	u64 tmp;
99
100	regmap_read(pll->clkr.regmap, pll->l_reg, &l);
101	regmap_read(pll->clkr.regmap, pll->m_reg, &m);
102	regmap_read(pll->clkr.regmap, pll->n_reg, &n);
103
104	l &= 0x3ff;
105	m &= 0x7ffff;
106	n &= 0x7ffff;
107
108	rate = parent_rate * l;
109	if (n) {
110		tmp = parent_rate;
111		tmp *= m;
112		do_div(tmp, n);
113		rate += tmp;
114	}
115	if (pll->post_div_width) {
116		regmap_read(pll->clkr.regmap, pll->config_reg, &config);
117		config >>= pll->post_div_shift;
118		config &= BIT(pll->post_div_width) - 1;
119		rate /= config + 1;
120	}
121
122	return rate;
123}
124
125static const
126struct pll_freq_tbl *find_freq(const struct pll_freq_tbl *f, unsigned long rate)
127{
128	if (!f)
129		return NULL;
130
131	for (; f->freq; f++)
132		if (rate <= f->freq)
133			return f;
134
135	return NULL;
136}
137
138static long
139clk_pll_determine_rate(struct clk_hw *hw, unsigned long rate,
140		       unsigned long min_rate, unsigned long max_rate,
141		       unsigned long *p_rate, struct clk_hw **p)
142{
143	struct clk_pll *pll = to_clk_pll(hw);
144	const struct pll_freq_tbl *f;
145
146	f = find_freq(pll->freq_tbl, rate);
147	if (!f)
148		return clk_pll_recalc_rate(hw, *p_rate);
149
150	return f->freq;
151}
152
153static int
154clk_pll_set_rate(struct clk_hw *hw, unsigned long rate, unsigned long p_rate)
155{
156	struct clk_pll *pll = to_clk_pll(hw);
157	const struct pll_freq_tbl *f;
158	bool enabled;
159	u32 mode;
160	u32 enable_mask = PLL_OUTCTRL | PLL_BYPASSNL | PLL_RESET_N;
161
162	f = find_freq(pll->freq_tbl, rate);
163	if (!f)
164		return -EINVAL;
165
166	regmap_read(pll->clkr.regmap, pll->mode_reg, &mode);
167	enabled = (mode & enable_mask) == enable_mask;
168
169	if (enabled)
170		clk_pll_disable(hw);
171
172	regmap_update_bits(pll->clkr.regmap, pll->l_reg, 0x3ff, f->l);
173	regmap_update_bits(pll->clkr.regmap, pll->m_reg, 0x7ffff, f->m);
174	regmap_update_bits(pll->clkr.regmap, pll->n_reg, 0x7ffff, f->n);
175	regmap_write(pll->clkr.regmap, pll->config_reg, f->ibits);
176
177	if (enabled)
178		clk_pll_enable(hw);
179
180	return 0;
181}
182
183const struct clk_ops clk_pll_ops = {
184	.enable = clk_pll_enable,
185	.disable = clk_pll_disable,
186	.recalc_rate = clk_pll_recalc_rate,
187	.determine_rate = clk_pll_determine_rate,
188	.set_rate = clk_pll_set_rate,
189};
190EXPORT_SYMBOL_GPL(clk_pll_ops);
191
192static int wait_for_pll(struct clk_pll *pll)
193{
194	u32 val;
195	int count;
196	int ret;
197	const char *name = __clk_get_name(pll->clkr.hw.clk);
198
199	/* Wait for pll to enable. */
200	for (count = 200; count > 0; count--) {
201		ret = regmap_read(pll->clkr.regmap, pll->status_reg, &val);
202		if (ret)
203			return ret;
204		if (val & BIT(pll->status_bit))
205			return 0;
206		udelay(1);
207	}
208
209	WARN(1, "%s didn't enable after voting for it!\n", name);
210	return -ETIMEDOUT;
211}
212
213static int clk_pll_vote_enable(struct clk_hw *hw)
214{
215	int ret;
216	struct clk_pll *p = to_clk_pll(__clk_get_hw(__clk_get_parent(hw->clk)));
217
218	ret = clk_enable_regmap(hw);
219	if (ret)
220		return ret;
221
222	return wait_for_pll(p);
223}
224
225const struct clk_ops clk_pll_vote_ops = {
226	.enable = clk_pll_vote_enable,
227	.disable = clk_disable_regmap,
228};
229EXPORT_SYMBOL_GPL(clk_pll_vote_ops);
230
231static void
232clk_pll_set_fsm_mode(struct clk_pll *pll, struct regmap *regmap, u8 lock_count)
233{
234	u32 val;
235	u32 mask;
236
237	/* De-assert reset to FSM */
238	regmap_update_bits(regmap, pll->mode_reg, PLL_VOTE_FSM_RESET, 0);
239
240	/* Program bias count and lock count */
241	val = 1 << PLL_BIAS_COUNT_SHIFT | lock_count << PLL_LOCK_COUNT_SHIFT;
242	mask = PLL_BIAS_COUNT_MASK << PLL_BIAS_COUNT_SHIFT;
243	mask |= PLL_LOCK_COUNT_MASK << PLL_LOCK_COUNT_SHIFT;
244	regmap_update_bits(regmap, pll->mode_reg, mask, val);
245
246	/* Enable PLL FSM voting */
247	regmap_update_bits(regmap, pll->mode_reg, PLL_VOTE_FSM_ENA,
248		PLL_VOTE_FSM_ENA);
249}
250
251static void clk_pll_configure(struct clk_pll *pll, struct regmap *regmap,
252	const struct pll_config *config)
253{
254	u32 val;
255	u32 mask;
256
257	regmap_write(regmap, pll->l_reg, config->l);
258	regmap_write(regmap, pll->m_reg, config->m);
259	regmap_write(regmap, pll->n_reg, config->n);
260
261	val = config->vco_val;
262	val |= config->pre_div_val;
263	val |= config->post_div_val;
264	val |= config->mn_ena_mask;
265	val |= config->main_output_mask;
266	val |= config->aux_output_mask;
267
268	mask = config->vco_mask;
269	mask |= config->pre_div_mask;
270	mask |= config->post_div_mask;
271	mask |= config->mn_ena_mask;
272	mask |= config->main_output_mask;
273	mask |= config->aux_output_mask;
274
275	regmap_update_bits(regmap, pll->config_reg, mask, val);
276}
277
278void clk_pll_configure_sr(struct clk_pll *pll, struct regmap *regmap,
279		const struct pll_config *config, bool fsm_mode)
280{
281	clk_pll_configure(pll, regmap, config);
282	if (fsm_mode)
283		clk_pll_set_fsm_mode(pll, regmap, 8);
284}
285EXPORT_SYMBOL_GPL(clk_pll_configure_sr);
286
287void clk_pll_configure_sr_hpm_lp(struct clk_pll *pll, struct regmap *regmap,
288		const struct pll_config *config, bool fsm_mode)
289{
290	clk_pll_configure(pll, regmap, config);
291	if (fsm_mode)
292		clk_pll_set_fsm_mode(pll, regmap, 0);
293}
294EXPORT_SYMBOL_GPL(clk_pll_configure_sr_hpm_lp);
295