1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * CPU frequency scaling for DaVinci
4 *
5 * Copyright (C) 2009 Texas Instruments Incorporated - https://www.ti.com/
6 *
7 * Based on linux/arch/arm/plat-omap/cpu-omap.c. Original Copyright follows:
8 *
9 *  Copyright (C) 2005 Nokia Corporation
10 *  Written by Tony Lindgren <tony@atomide.com>
11 *
12 *  Based on cpu-sa1110.c, Copyright (C) 2001 Russell King
13 *
14 * Copyright (C) 2007-2008 Texas Instruments, Inc.
15 * Updated to support OMAP3
16 * Rajendra Nayak <rnayak@ti.com>
17 */
18#include <linux/types.h>
19#include <linux/cpufreq.h>
20#include <linux/init.h>
21#include <linux/err.h>
22#include <linux/clk.h>
23#include <linux/platform_data/davinci-cpufreq.h>
24#include <linux/platform_device.h>
25#include <linux/export.h>
26
27struct davinci_cpufreq {
28	struct device *dev;
29	struct clk *armclk;
30	struct clk *asyncclk;
31	unsigned long asyncrate;
32};
33static struct davinci_cpufreq cpufreq;
34
35static int davinci_target(struct cpufreq_policy *policy, unsigned int idx)
36{
37	struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data;
38	struct clk *armclk = cpufreq.armclk;
39	unsigned int old_freq, new_freq;
40	int ret = 0;
41
42	old_freq = policy->cur;
43	new_freq = pdata->freq_table[idx].frequency;
44
45	/* if moving to higher frequency, up the voltage beforehand */
46	if (pdata->set_voltage && new_freq > old_freq) {
47		ret = pdata->set_voltage(idx);
48		if (ret)
49			return ret;
50	}
51
52	ret = clk_set_rate(armclk, new_freq * 1000);
53	if (ret)
54		return ret;
55
56	if (cpufreq.asyncclk) {
57		ret = clk_set_rate(cpufreq.asyncclk, cpufreq.asyncrate);
58		if (ret)
59			return ret;
60	}
61
62	/* if moving to lower freq, lower the voltage after lowering freq */
63	if (pdata->set_voltage && new_freq < old_freq)
64		pdata->set_voltage(idx);
65
66	return 0;
67}
68
69static int davinci_cpu_init(struct cpufreq_policy *policy)
70{
71	int result = 0;
72	struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data;
73	struct cpufreq_frequency_table *freq_table = pdata->freq_table;
74
75	if (policy->cpu != 0)
76		return -EINVAL;
77
78	/* Finish platform specific initialization */
79	if (pdata->init) {
80		result = pdata->init();
81		if (result)
82			return result;
83	}
84
85	policy->clk = cpufreq.armclk;
86
87	/*
88	 * Time measurement across the target() function yields ~1500-1800us
89	 * time taken with no drivers on notification list.
90	 * Setting the latency to 2000 us to accommodate addition of drivers
91	 * to pre/post change notification list.
92	 */
93	cpufreq_generic_init(policy, freq_table, 2000 * 1000);
94	return 0;
95}
96
97static struct cpufreq_driver davinci_driver = {
98	.flags		= CPUFREQ_NEED_INITIAL_FREQ_CHECK,
99	.verify		= cpufreq_generic_frequency_table_verify,
100	.target_index	= davinci_target,
101	.get		= cpufreq_generic_get,
102	.init		= davinci_cpu_init,
103	.name		= "davinci",
104	.attr		= cpufreq_generic_attr,
105};
106
107static int __init davinci_cpufreq_probe(struct platform_device *pdev)
108{
109	struct davinci_cpufreq_config *pdata = pdev->dev.platform_data;
110	struct clk *asyncclk;
111
112	if (!pdata)
113		return -EINVAL;
114	if (!pdata->freq_table)
115		return -EINVAL;
116
117	cpufreq.dev = &pdev->dev;
118
119	cpufreq.armclk = clk_get(NULL, "arm");
120	if (IS_ERR(cpufreq.armclk)) {
121		dev_err(cpufreq.dev, "Unable to get ARM clock\n");
122		return PTR_ERR(cpufreq.armclk);
123	}
124
125	asyncclk = clk_get(cpufreq.dev, "async");
126	if (!IS_ERR(asyncclk)) {
127		cpufreq.asyncclk = asyncclk;
128		cpufreq.asyncrate = clk_get_rate(asyncclk);
129	}
130
131	return cpufreq_register_driver(&davinci_driver);
132}
133
134static void __exit davinci_cpufreq_remove(struct platform_device *pdev)
135{
136	cpufreq_unregister_driver(&davinci_driver);
137
138	clk_put(cpufreq.armclk);
139
140	if (cpufreq.asyncclk)
141		clk_put(cpufreq.asyncclk);
142}
143
144static struct platform_driver davinci_cpufreq_driver = {
145	.driver = {
146		.name	 = "cpufreq-davinci",
147	},
148	.remove_new = __exit_p(davinci_cpufreq_remove),
149};
150
151int __init davinci_cpufreq_init(void)
152{
153	return platform_driver_probe(&davinci_cpufreq_driver,
154							davinci_cpufreq_probe);
155}
156
157