GNU Linux-libre 5.19-rc6-gnu
[releases.git] / drivers / cpufreq / davinci-cpufreq.c
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
27 struct davinci_cpufreq {
28         struct device *dev;
29         struct clk *armclk;
30         struct clk *asyncclk;
31         unsigned long asyncrate;
32 };
33 static struct davinci_cpufreq cpufreq;
34
35 static 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
69 static 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
97 static 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
107 static 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
134 static int __exit davinci_cpufreq_remove(struct platform_device *pdev)
135 {
136         clk_put(cpufreq.armclk);
137
138         if (cpufreq.asyncclk)
139                 clk_put(cpufreq.asyncclk);
140
141         return cpufreq_unregister_driver(&davinci_driver);
142 }
143
144 static struct platform_driver davinci_cpufreq_driver = {
145         .driver = {
146                 .name    = "cpufreq-davinci",
147         },
148         .remove = __exit_p(davinci_cpufreq_remove),
149 };
150
151 int __init davinci_cpufreq_init(void)
152 {
153         return platform_driver_probe(&davinci_cpufreq_driver,
154                                                         davinci_cpufreq_probe);
155 }
156