Merge tag 'nfs-for-5.3-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs
[linux-2.6-microblaze.git] / drivers / cpufreq / tegra20-cpufreq.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2010 Google, Inc.
4  *
5  * Author:
6  *      Colin Cross <ccross@google.com>
7  *      Based on arch/arm/plat-omap/cpu-omap.c, (C) 2005 Nokia Corporation
8  */
9
10 #include <linux/clk.h>
11 #include <linux/cpufreq.h>
12 #include <linux/err.h>
13 #include <linux/init.h>
14 #include <linux/module.h>
15 #include <linux/platform_device.h>
16 #include <linux/types.h>
17
18 static struct cpufreq_frequency_table freq_table[] = {
19         { .frequency = 216000 },
20         { .frequency = 312000 },
21         { .frequency = 456000 },
22         { .frequency = 608000 },
23         { .frequency = 760000 },
24         { .frequency = 816000 },
25         { .frequency = 912000 },
26         { .frequency = 1000000 },
27         { .frequency = CPUFREQ_TABLE_END },
28 };
29
30 struct tegra20_cpufreq {
31         struct device *dev;
32         struct cpufreq_driver driver;
33         struct clk *cpu_clk;
34         struct clk *pll_x_clk;
35         struct clk *pll_p_clk;
36         bool pll_x_prepared;
37 };
38
39 static unsigned int tegra_get_intermediate(struct cpufreq_policy *policy,
40                                            unsigned int index)
41 {
42         struct tegra20_cpufreq *cpufreq = cpufreq_get_driver_data();
43         unsigned int ifreq = clk_get_rate(cpufreq->pll_p_clk) / 1000;
44
45         /*
46          * Don't switch to intermediate freq if:
47          * - we are already at it, i.e. policy->cur == ifreq
48          * - index corresponds to ifreq
49          */
50         if (freq_table[index].frequency == ifreq || policy->cur == ifreq)
51                 return 0;
52
53         return ifreq;
54 }
55
56 static int tegra_target_intermediate(struct cpufreq_policy *policy,
57                                      unsigned int index)
58 {
59         struct tegra20_cpufreq *cpufreq = cpufreq_get_driver_data();
60         int ret;
61
62         /*
63          * Take an extra reference to the main pll so it doesn't turn
64          * off when we move the cpu off of it as enabling it again while we
65          * switch to it from tegra_target() would take additional time.
66          *
67          * When target-freq is equal to intermediate freq we don't need to
68          * switch to an intermediate freq and so this routine isn't called.
69          * Also, we wouldn't be using pll_x anymore and must not take extra
70          * reference to it, as it can be disabled now to save some power.
71          */
72         clk_prepare_enable(cpufreq->pll_x_clk);
73
74         ret = clk_set_parent(cpufreq->cpu_clk, cpufreq->pll_p_clk);
75         if (ret)
76                 clk_disable_unprepare(cpufreq->pll_x_clk);
77         else
78                 cpufreq->pll_x_prepared = true;
79
80         return ret;
81 }
82
83 static int tegra_target(struct cpufreq_policy *policy, unsigned int index)
84 {
85         struct tegra20_cpufreq *cpufreq = cpufreq_get_driver_data();
86         unsigned long rate = freq_table[index].frequency;
87         unsigned int ifreq = clk_get_rate(cpufreq->pll_p_clk) / 1000;
88         int ret;
89
90         /*
91          * target freq == pll_p, don't need to take extra reference to pll_x_clk
92          * as it isn't used anymore.
93          */
94         if (rate == ifreq)
95                 return clk_set_parent(cpufreq->cpu_clk, cpufreq->pll_p_clk);
96
97         ret = clk_set_rate(cpufreq->pll_x_clk, rate * 1000);
98         /* Restore to earlier frequency on error, i.e. pll_x */
99         if (ret)
100                 dev_err(cpufreq->dev, "Failed to change pll_x to %lu\n", rate);
101
102         ret = clk_set_parent(cpufreq->cpu_clk, cpufreq->pll_x_clk);
103         /* This shouldn't fail while changing or restoring */
104         WARN_ON(ret);
105
106         /*
107          * Drop count to pll_x clock only if we switched to intermediate freq
108          * earlier while transitioning to a target frequency.
109          */
110         if (cpufreq->pll_x_prepared) {
111                 clk_disable_unprepare(cpufreq->pll_x_clk);
112                 cpufreq->pll_x_prepared = false;
113         }
114
115         return ret;
116 }
117
118 static int tegra_cpu_init(struct cpufreq_policy *policy)
119 {
120         struct tegra20_cpufreq *cpufreq = cpufreq_get_driver_data();
121
122         clk_prepare_enable(cpufreq->cpu_clk);
123
124         /* FIXME: what's the actual transition time? */
125         cpufreq_generic_init(policy, freq_table, 300 * 1000);
126         policy->clk = cpufreq->cpu_clk;
127         policy->suspend_freq = freq_table[0].frequency;
128         return 0;
129 }
130
131 static int tegra_cpu_exit(struct cpufreq_policy *policy)
132 {
133         struct tegra20_cpufreq *cpufreq = cpufreq_get_driver_data();
134
135         clk_disable_unprepare(cpufreq->cpu_clk);
136         return 0;
137 }
138
139 static int tegra20_cpufreq_probe(struct platform_device *pdev)
140 {
141         struct tegra20_cpufreq *cpufreq;
142         int err;
143
144         cpufreq = devm_kzalloc(&pdev->dev, sizeof(*cpufreq), GFP_KERNEL);
145         if (!cpufreq)
146                 return -ENOMEM;
147
148         cpufreq->cpu_clk = clk_get_sys(NULL, "cclk");
149         if (IS_ERR(cpufreq->cpu_clk))
150                 return PTR_ERR(cpufreq->cpu_clk);
151
152         cpufreq->pll_x_clk = clk_get_sys(NULL, "pll_x");
153         if (IS_ERR(cpufreq->pll_x_clk)) {
154                 err = PTR_ERR(cpufreq->pll_x_clk);
155                 goto put_cpu;
156         }
157
158         cpufreq->pll_p_clk = clk_get_sys(NULL, "pll_p");
159         if (IS_ERR(cpufreq->pll_p_clk)) {
160                 err = PTR_ERR(cpufreq->pll_p_clk);
161                 goto put_pll_x;
162         }
163
164         cpufreq->dev = &pdev->dev;
165         cpufreq->driver.get = cpufreq_generic_get;
166         cpufreq->driver.attr = cpufreq_generic_attr;
167         cpufreq->driver.init = tegra_cpu_init;
168         cpufreq->driver.exit = tegra_cpu_exit;
169         cpufreq->driver.flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK;
170         cpufreq->driver.verify = cpufreq_generic_frequency_table_verify;
171         cpufreq->driver.suspend = cpufreq_generic_suspend;
172         cpufreq->driver.driver_data = cpufreq;
173         cpufreq->driver.target_index = tegra_target;
174         cpufreq->driver.get_intermediate = tegra_get_intermediate;
175         cpufreq->driver.target_intermediate = tegra_target_intermediate;
176         snprintf(cpufreq->driver.name, CPUFREQ_NAME_LEN, "tegra");
177
178         err = cpufreq_register_driver(&cpufreq->driver);
179         if (err)
180                 goto put_pll_p;
181
182         platform_set_drvdata(pdev, cpufreq);
183
184         return 0;
185
186 put_pll_p:
187         clk_put(cpufreq->pll_p_clk);
188 put_pll_x:
189         clk_put(cpufreq->pll_x_clk);
190 put_cpu:
191         clk_put(cpufreq->cpu_clk);
192
193         return err;
194 }
195
196 static int tegra20_cpufreq_remove(struct platform_device *pdev)
197 {
198         struct tegra20_cpufreq *cpufreq = platform_get_drvdata(pdev);
199
200         cpufreq_unregister_driver(&cpufreq->driver);
201
202         clk_put(cpufreq->pll_p_clk);
203         clk_put(cpufreq->pll_x_clk);
204         clk_put(cpufreq->cpu_clk);
205
206         return 0;
207 }
208
209 static struct platform_driver tegra20_cpufreq_driver = {
210         .probe          = tegra20_cpufreq_probe,
211         .remove         = tegra20_cpufreq_remove,
212         .driver         = {
213                 .name   = "tegra20-cpufreq",
214         },
215 };
216 module_platform_driver(tegra20_cpufreq_driver);
217
218 MODULE_ALIAS("platform:tegra20-cpufreq");
219 MODULE_AUTHOR("Colin Cross <ccross@android.com>");
220 MODULE_DESCRIPTION("NVIDIA Tegra20 cpufreq driver");
221 MODULE_LICENSE("GPL");