1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (c) 2018, The Linux Foundation. All rights reserved.
4 #include <linux/kernel.h>
5 #include <linux/export.h>
6 #include <linux/regmap.h>
7 #include <linux/delay.h>
9 #include <linux/clk-provider.h>
10 #include <linux/spinlock.h>
12 #include "clk-regmap.h"
13 #include "clk-hfpll.h"
15 #define PLL_OUTCTRL BIT(0)
16 #define PLL_BYPASSNL BIT(1)
17 #define PLL_RESET_N BIT(2)
19 /* Initialize a HFPLL at a given rate and enable it. */
20 static void __clk_hfpll_init_once(struct clk_hw *hw)
22 struct clk_hfpll *h = to_clk_hfpll(hw);
23 struct hfpll_data const *hd = h->d;
24 struct regmap *regmap = h->clkr.regmap;
26 if (likely(h->init_done))
29 /* Configure PLL parameters for integer mode. */
31 regmap_write(regmap, hd->config_reg, hd->config_val);
32 regmap_write(regmap, hd->m_reg, 0);
33 regmap_write(regmap, hd->n_reg, 1);
36 u32 regval = hd->user_val;
39 rate = clk_hw_get_rate(hw);
41 /* Pick the right VCO. */
42 if (hd->user_vco_mask && rate > hd->low_vco_max_rate)
43 regval |= hd->user_vco_mask;
44 regmap_write(regmap, hd->user_reg, regval);
48 regmap_write(regmap, hd->droop_reg, hd->droop_val);
53 static void __clk_hfpll_enable(struct clk_hw *hw)
55 struct clk_hfpll *h = to_clk_hfpll(hw);
56 struct hfpll_data const *hd = h->d;
57 struct regmap *regmap = h->clkr.regmap;
60 __clk_hfpll_init_once(hw);
62 /* Disable PLL bypass mode. */
63 regmap_update_bits(regmap, hd->mode_reg, PLL_BYPASSNL, PLL_BYPASSNL);
66 * H/W requires a 5us delay between disabling the bypass and
67 * de-asserting the reset. Delay 10us just to be safe.
71 /* De-assert active-low PLL reset. */
72 regmap_update_bits(regmap, hd->mode_reg, PLL_RESET_N, PLL_RESET_N);
74 /* Wait for PLL to lock. */
77 * Busy wait. Should never timeout, we add a timeout to
78 * prevent any sort of stall.
80 regmap_read_poll_timeout(regmap, hd->status_reg, val,
81 !(val & BIT(hd->lock_bit)), 0,
86 /* Enable PLL output. */
87 regmap_update_bits(regmap, hd->mode_reg, PLL_OUTCTRL, PLL_OUTCTRL);
90 /* Enable an already-configured HFPLL. */
91 static int clk_hfpll_enable(struct clk_hw *hw)
94 struct clk_hfpll *h = to_clk_hfpll(hw);
95 struct hfpll_data const *hd = h->d;
96 struct regmap *regmap = h->clkr.regmap;
99 spin_lock_irqsave(&h->lock, flags);
100 regmap_read(regmap, hd->mode_reg, &mode);
101 if (!(mode & (PLL_BYPASSNL | PLL_RESET_N | PLL_OUTCTRL)))
102 __clk_hfpll_enable(hw);
103 spin_unlock_irqrestore(&h->lock, flags);
108 static void __clk_hfpll_disable(struct clk_hfpll *h)
110 struct hfpll_data const *hd = h->d;
111 struct regmap *regmap = h->clkr.regmap;
114 * Disable the PLL output, disable test mode, enable the bypass mode,
115 * and assert the reset.
117 regmap_update_bits(regmap, hd->mode_reg,
118 PLL_BYPASSNL | PLL_RESET_N | PLL_OUTCTRL, 0);
121 static void clk_hfpll_disable(struct clk_hw *hw)
123 struct clk_hfpll *h = to_clk_hfpll(hw);
126 spin_lock_irqsave(&h->lock, flags);
127 __clk_hfpll_disable(h);
128 spin_unlock_irqrestore(&h->lock, flags);
131 static long clk_hfpll_round_rate(struct clk_hw *hw, unsigned long rate,
132 unsigned long *parent_rate)
134 struct clk_hfpll *h = to_clk_hfpll(hw);
135 struct hfpll_data const *hd = h->d;
138 rate = clamp(rate, hd->min_rate, hd->max_rate);
140 rrate = DIV_ROUND_UP(rate, *parent_rate) * *parent_rate;
141 if (rrate > hd->max_rate)
142 rrate -= *parent_rate;
148 * For optimization reasons, assumes no downstream clocks are actively using
151 static int clk_hfpll_set_rate(struct clk_hw *hw, unsigned long rate,
152 unsigned long parent_rate)
154 struct clk_hfpll *h = to_clk_hfpll(hw);
155 struct hfpll_data const *hd = h->d;
156 struct regmap *regmap = h->clkr.regmap;
161 l_val = rate / parent_rate;
163 spin_lock_irqsave(&h->lock, flags);
165 enabled = __clk_is_enabled(hw->clk);
167 __clk_hfpll_disable(h);
169 /* Pick the right VCO. */
170 if (hd->user_reg && hd->user_vco_mask) {
171 regmap_read(regmap, hd->user_reg, &val);
172 if (rate <= hd->low_vco_max_rate)
173 val &= ~hd->user_vco_mask;
175 val |= hd->user_vco_mask;
176 regmap_write(regmap, hd->user_reg, val);
179 regmap_write(regmap, hd->l_reg, l_val);
182 __clk_hfpll_enable(hw);
184 spin_unlock_irqrestore(&h->lock, flags);
189 static unsigned long clk_hfpll_recalc_rate(struct clk_hw *hw,
190 unsigned long parent_rate)
192 struct clk_hfpll *h = to_clk_hfpll(hw);
193 struct hfpll_data const *hd = h->d;
194 struct regmap *regmap = h->clkr.regmap;
197 regmap_read(regmap, hd->l_reg, &l_val);
199 return l_val * parent_rate;
202 static int clk_hfpll_init(struct clk_hw *hw)
204 struct clk_hfpll *h = to_clk_hfpll(hw);
205 struct hfpll_data const *hd = h->d;
206 struct regmap *regmap = h->clkr.regmap;
209 regmap_read(regmap, hd->mode_reg, &mode);
210 if (mode != (PLL_BYPASSNL | PLL_RESET_N | PLL_OUTCTRL)) {
211 __clk_hfpll_init_once(hw);
215 if (hd->status_reg) {
216 regmap_read(regmap, hd->status_reg, &status);
217 if (!(status & BIT(hd->lock_bit))) {
218 WARN(1, "HFPLL %s is ON, but not locked!\n",
219 __clk_get_name(hw->clk));
220 clk_hfpll_disable(hw);
221 __clk_hfpll_init_once(hw);
228 static int hfpll_is_enabled(struct clk_hw *hw)
230 struct clk_hfpll *h = to_clk_hfpll(hw);
231 struct hfpll_data const *hd = h->d;
232 struct regmap *regmap = h->clkr.regmap;
235 regmap_read(regmap, hd->mode_reg, &mode);
237 return mode == (PLL_BYPASSNL | PLL_RESET_N | PLL_OUTCTRL);
240 const struct clk_ops clk_ops_hfpll = {
241 .enable = clk_hfpll_enable,
242 .disable = clk_hfpll_disable,
243 .is_enabled = hfpll_is_enabled,
244 .round_rate = clk_hfpll_round_rate,
245 .set_rate = clk_hfpll_set_rate,
246 .recalc_rate = clk_hfpll_recalc_rate,
247 .init = clk_hfpll_init,
249 EXPORT_SYMBOL_GPL(clk_ops_hfpll);