ccu_nm.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_frac.h"
 11#include "ccu_gate.h"
 12#include "ccu_nm.h"
 13
 14struct _ccu_nm {
 15	unsigned long	n, min_n, max_n;
 16	unsigned long	m, min_m, max_m;
 17};
 18
 19static unsigned long ccu_nm_calc_rate(unsigned long parent,
 20				      unsigned long n, unsigned long m)
 21{
 22	u64 rate = parent;
 23
 24	rate *= n;
 25	do_div(rate, m);
 26
 27	return rate;
 28}
 29
 30static unsigned long ccu_nm_find_best(struct ccu_common *common, unsigned long parent,
 31				      unsigned long rate, struct _ccu_nm *nm)
 32{
 33	unsigned long best_rate = 0;
 34	unsigned long best_n = 0, best_m = 0;
 35	unsigned long _n, _m;
 36
 37	for (_n = nm->min_n; _n <= nm->max_n; _n++) {
 38		for (_m = nm->min_m; _m <= nm->max_m; _m++) {
 39			unsigned long tmp_rate = ccu_nm_calc_rate(parent,
 40								  _n, _m);
 41
 42			if (ccu_is_better_rate(common, rate, tmp_rate, best_rate)) {
 43				best_rate = tmp_rate;
 44				best_n = _n;
 45				best_m = _m;
 46			}
 47		}
 48	}
 49
 50	nm->n = best_n;
 51	nm->m = best_m;
 52
 53	return best_rate;
 54}
 55
 56static void ccu_nm_disable(struct clk_hw *hw)
 57{
 58	struct ccu_nm *nm = hw_to_ccu_nm(hw);
 59
 60	return ccu_gate_helper_disable(&nm->common, nm->enable);
 61}
 62
 63static int ccu_nm_enable(struct clk_hw *hw)
 64{
 65	struct ccu_nm *nm = hw_to_ccu_nm(hw);
 66
 67	return ccu_gate_helper_enable(&nm->common, nm->enable);
 68}
 69
 70static int ccu_nm_is_enabled(struct clk_hw *hw)
 71{
 72	struct ccu_nm *nm = hw_to_ccu_nm(hw);
 73
 74	return ccu_gate_helper_is_enabled(&nm->common, nm->enable);
 75}
 76
 77static unsigned long ccu_nm_recalc_rate(struct clk_hw *hw,
 78					unsigned long parent_rate)
 79{
 80	struct ccu_nm *nm = hw_to_ccu_nm(hw);
 81	unsigned long rate;
 82	unsigned long n, m;
 83	u32 reg;
 84
 85	if (ccu_frac_helper_is_enabled(&nm->common, &nm->frac)) {
 86		rate = ccu_frac_helper_read_rate(&nm->common, &nm->frac);
 87
 88		if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 89			rate /= nm->fixed_post_div;
 90
 91		return rate;
 92	}
 93
 94	reg = readl(nm->common.base + nm->common.reg);
 95
 96	n = reg >> nm->n.shift;
 97	n &= (1 << nm->n.width) - 1;
 98	n += nm->n.offset;
 99	if (!n)
100		n++;
101
102	m = reg >> nm->m.shift;
103	m &= (1 << nm->m.width) - 1;
104	m += nm->m.offset;
105	if (!m)
106		m++;
107
108	if (ccu_sdm_helper_is_enabled(&nm->common, &nm->sdm))
109		rate = ccu_sdm_helper_read_rate(&nm->common, &nm->sdm, m, n);
110	else
111		rate = ccu_nm_calc_rate(parent_rate, n, m);
112
113	if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
114		rate /= nm->fixed_post_div;
115
116	return rate;
117}
118
119static int ccu_nm_determine_rate(struct clk_hw *hw,
120				 struct clk_rate_request *req)
121{
122	struct ccu_nm *nm = hw_to_ccu_nm(hw);
123	struct _ccu_nm _nm;
124
125	if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
126		req->rate *= nm->fixed_post_div;
127
128	if (req->rate < nm->min_rate) {
129		req->rate = nm->min_rate;
130		if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
131			req->rate /= nm->fixed_post_div;
132		return 0;
133	}
134
135	if (nm->max_rate && req->rate > nm->max_rate) {
136		req->rate = nm->max_rate;
137		if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
138			req->rate /= nm->fixed_post_div;
139		return 0;
140	}
141
142	if (ccu_frac_helper_has_rate(&nm->common, &nm->frac, req->rate)) {
143		if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
144			req->rate /= nm->fixed_post_div;
145		return 0;
146	}
147
148	if (ccu_sdm_helper_has_rate(&nm->common, &nm->sdm, req->rate)) {
149		if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
150			req->rate /= nm->fixed_post_div;
151		return 0;
152	}
153
154	_nm.min_n = nm->n.min ?: 1;
155	_nm.max_n = nm->n.max ?: 1 << nm->n.width;
156	_nm.min_m = 1;
157	_nm.max_m = nm->m.max ?: 1 << nm->m.width;
158
159	req->rate = ccu_nm_find_best(&nm->common, req->best_parent_rate,
160				     req->rate, &_nm);
161
162	if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
163		req->rate /= nm->fixed_post_div;
164
165	return 0;
166}
167
168static int ccu_nm_set_rate(struct clk_hw *hw, unsigned long rate,
169			   unsigned long parent_rate)
170{
171	struct ccu_nm *nm = hw_to_ccu_nm(hw);
172	struct _ccu_nm _nm;
173	unsigned long flags;
174	u32 reg;
175
176	/* Adjust target rate according to post-dividers */
177	if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
178		rate = rate * nm->fixed_post_div;
179
180	if (ccu_frac_helper_has_rate(&nm->common, &nm->frac, rate)) {
181		spin_lock_irqsave(nm->common.lock, flags);
182
183		/* most SoCs require M to be 0 if fractional mode is used */
184		reg = readl(nm->common.base + nm->common.reg);
185		reg &= ~GENMASK(nm->m.width + nm->m.shift - 1, nm->m.shift);
186		writel(reg, nm->common.base + nm->common.reg);
187
188		spin_unlock_irqrestore(nm->common.lock, flags);
189
190		ccu_frac_helper_enable(&nm->common, &nm->frac);
191
192		return ccu_frac_helper_set_rate(&nm->common, &nm->frac,
193						rate, nm->lock);
194	} else {
195		ccu_frac_helper_disable(&nm->common, &nm->frac);
196	}
197
198	_nm.min_n = nm->n.min ?: 1;
199	_nm.max_n = nm->n.max ?: 1 << nm->n.width;
200	_nm.min_m = 1;
201	_nm.max_m = nm->m.max ?: 1 << nm->m.width;
202
203	if (ccu_sdm_helper_has_rate(&nm->common, &nm->sdm, rate)) {
204		ccu_sdm_helper_enable(&nm->common, &nm->sdm, rate);
205
206		/* Sigma delta modulation requires specific N and M factors */
207		ccu_sdm_helper_get_factors(&nm->common, &nm->sdm, rate,
208					   &_nm.m, &_nm.n);
209	} else {
210		ccu_sdm_helper_disable(&nm->common, &nm->sdm);
211		ccu_nm_find_best(&nm->common, parent_rate, rate, &_nm);
212	}
213
214	spin_lock_irqsave(nm->common.lock, flags);
215
216	reg = readl(nm->common.base + nm->common.reg);
217	reg &= ~GENMASK(nm->n.width + nm->n.shift - 1, nm->n.shift);
218	reg &= ~GENMASK(nm->m.width + nm->m.shift - 1, nm->m.shift);
219
220	reg |= (_nm.n - nm->n.offset) << nm->n.shift;
221	reg |= (_nm.m - nm->m.offset) << nm->m.shift;
222	writel(reg, nm->common.base + nm->common.reg);
223
224	spin_unlock_irqrestore(nm->common.lock, flags);
225
226	ccu_helper_wait_for_lock(&nm->common, nm->lock);
227
228	return 0;
229}
230
231const struct clk_ops ccu_nm_ops = {
232	.disable	= ccu_nm_disable,
233	.enable		= ccu_nm_enable,
234	.is_enabled	= ccu_nm_is_enabled,
235
236	.recalc_rate	= ccu_nm_recalc_rate,
237	.determine_rate = ccu_nm_determine_rate,
238	.set_rate	= ccu_nm_set_rate,
239};
240EXPORT_SYMBOL_NS_GPL(ccu_nm_ops, "SUNXI_CCU");