ccu_nk.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * Copyright (C) 2016 Maxime Ripard
  4 * Maxime Ripard <maxime.ripard@free-electrons.com>
  5 */
  6
  7#include <linux/clk-provider.h>
  8#include <linux/io.h>
  9
 10#include "ccu_gate.h"
 11#include "ccu_nk.h"
 12
 13struct _ccu_nk {
 14	unsigned long	n, min_n, max_n;
 15	unsigned long	k, min_k, max_k;
 16};
 17
 18static unsigned long ccu_nk_find_best(unsigned long parent, unsigned long rate,
 19				      struct _ccu_nk *nk)
 20{
 21	unsigned long best_rate = 0;
 22	unsigned int best_k = 0, best_n = 0;
 23	unsigned int _k, _n;
 24
 25	for (_k = nk->min_k; _k <= nk->max_k; _k++) {
 26		for (_n = nk->min_n; _n <= nk->max_n; _n++) {
 27			unsigned long tmp_rate = parent * _n * _k;
 28
 29			if (tmp_rate > rate)
 30				continue;
 31
 32			if ((rate - tmp_rate) < (rate - best_rate)) {
 33				best_rate = tmp_rate;
 34				best_k = _k;
 35				best_n = _n;
 36			}
 37		}
 38	}
 39
 40	nk->k = best_k;
 41	nk->n = best_n;
 42
 43	return best_rate;
 44}
 45
 46static void ccu_nk_disable(struct clk_hw *hw)
 47{
 48	struct ccu_nk *nk = hw_to_ccu_nk(hw);
 49
 50	return ccu_gate_helper_disable(&nk->common, nk->enable);
 51}
 52
 53static int ccu_nk_enable(struct clk_hw *hw)
 54{
 55	struct ccu_nk *nk = hw_to_ccu_nk(hw);
 56
 57	return ccu_gate_helper_enable(&nk->common, nk->enable);
 58}
 59
 60static int ccu_nk_is_enabled(struct clk_hw *hw)
 61{
 62	struct ccu_nk *nk = hw_to_ccu_nk(hw);
 63
 64	return ccu_gate_helper_is_enabled(&nk->common, nk->enable);
 65}
 66
 67static unsigned long ccu_nk_recalc_rate(struct clk_hw *hw,
 68					unsigned long parent_rate)
 69{
 70	struct ccu_nk *nk = hw_to_ccu_nk(hw);
 71	unsigned long rate, n, k;
 72	u32 reg;
 73
 74	reg = readl(nk->common.base + nk->common.reg);
 75
 76	n = reg >> nk->n.shift;
 77	n &= (1 << nk->n.width) - 1;
 78	n += nk->n.offset;
 79	if (!n)
 80		n++;
 81
 82	k = reg >> nk->k.shift;
 83	k &= (1 << nk->k.width) - 1;
 84	k += nk->k.offset;
 85	if (!k)
 86		k++;
 87
 88	rate = parent_rate * n * k;
 89	if (nk->common.features & CCU_FEATURE_FIXED_POSTDIV)
 90		rate /= nk->fixed_post_div;
 91
 92	return rate;
 93}
 94
 95static int ccu_nk_determine_rate(struct clk_hw *hw,
 96				 struct clk_rate_request *req)
 97{
 98	struct ccu_nk *nk = hw_to_ccu_nk(hw);
 99	struct _ccu_nk _nk;
100
101	if (nk->common.features & CCU_FEATURE_FIXED_POSTDIV)
102		req->rate *= nk->fixed_post_div;
103
104	_nk.min_n = nk->n.min ?: 1;
105	_nk.max_n = nk->n.max ?: 1 << nk->n.width;
106	_nk.min_k = nk->k.min ?: 1;
107	_nk.max_k = nk->k.max ?: 1 << nk->k.width;
108
109	req->rate = ccu_nk_find_best(req->best_parent_rate, req->rate, &_nk);
110
111	if (nk->common.features & CCU_FEATURE_FIXED_POSTDIV)
112		req->rate = req->rate / nk->fixed_post_div;
113
114	return 0;
115}
116
117static int ccu_nk_set_rate(struct clk_hw *hw, unsigned long rate,
118			   unsigned long parent_rate)
119{
120	struct ccu_nk *nk = hw_to_ccu_nk(hw);
121	unsigned long flags;
122	struct _ccu_nk _nk;
123	u32 reg;
124
125	if (nk->common.features & CCU_FEATURE_FIXED_POSTDIV)
126		rate = rate * nk->fixed_post_div;
127
128	_nk.min_n = nk->n.min ?: 1;
129	_nk.max_n = nk->n.max ?: 1 << nk->n.width;
130	_nk.min_k = nk->k.min ?: 1;
131	_nk.max_k = nk->k.max ?: 1 << nk->k.width;
132
133	ccu_nk_find_best(parent_rate, rate, &_nk);
134
135	spin_lock_irqsave(nk->common.lock, flags);
136
137	reg = readl(nk->common.base + nk->common.reg);
138	reg &= ~GENMASK(nk->n.width + nk->n.shift - 1, nk->n.shift);
139	reg &= ~GENMASK(nk->k.width + nk->k.shift - 1, nk->k.shift);
140
141	reg |= (_nk.k - nk->k.offset) << nk->k.shift;
142	reg |= (_nk.n - nk->n.offset) << nk->n.shift;
143	writel(reg, nk->common.base + nk->common.reg);
144
145	spin_unlock_irqrestore(nk->common.lock, flags);
146
147	ccu_helper_wait_for_lock(&nk->common, nk->lock);
148
149	return 0;
150}
151
152const struct clk_ops ccu_nk_ops = {
153	.disable	= ccu_nk_disable,
154	.enable		= ccu_nk_enable,
155	.is_enabled	= ccu_nk_is_enabled,
156
157	.recalc_rate	= ccu_nk_recalc_rate,
158	.determine_rate = ccu_nk_determine_rate,
159	.set_rate	= ccu_nk_set_rate,
160};
161EXPORT_SYMBOL_NS_GPL(ccu_nk_ops, "SUNXI_CCU");