tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Tegra 124 cpufreq driver
4 */
5
6#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
7
8#include <linux/clk.h>
9#include <linux/err.h>
10#include <linux/init.h>
11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <linux/of_device.h>
14#include <linux/of.h>
15#include <linux/platform_device.h>
16#include <linux/pm_opp.h>
17#include <linux/types.h>
18
19struct tegra124_cpufreq_priv {
20 struct clk *cpu_clk;
21 struct clk *pllp_clk;
22 struct clk *pllx_clk;
23 struct clk *dfll_clk;
24 struct platform_device *cpufreq_dt_pdev;
25};
26
27static int tegra124_cpu_switch_to_dfll(struct tegra124_cpufreq_priv *priv)
28{
29 struct clk *orig_parent;
30 int ret;
31
32 ret = clk_set_rate(priv->dfll_clk, clk_get_rate(priv->cpu_clk));
33 if (ret)
34 return ret;
35
36 orig_parent = clk_get_parent(priv->cpu_clk);
37 clk_set_parent(priv->cpu_clk, priv->pllp_clk);
38
39 ret = clk_prepare_enable(priv->dfll_clk);
40 if (ret)
41 goto out;
42
43 clk_set_parent(priv->cpu_clk, priv->dfll_clk);
44
45 return 0;
46
47out:
48 clk_set_parent(priv->cpu_clk, orig_parent);
49
50 return ret;
51}
52
53static int tegra124_cpufreq_probe(struct platform_device *pdev)
54{
55 struct tegra124_cpufreq_priv *priv;
56 struct device_node *np;
57 struct device *cpu_dev;
58 struct platform_device_info cpufreq_dt_devinfo = {};
59 int ret;
60
61 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
62 if (!priv)
63 return -ENOMEM;
64
65 cpu_dev = get_cpu_device(0);
66 if (!cpu_dev)
67 return -ENODEV;
68
69 np = of_cpu_device_node_get(0);
70 if (!np)
71 return -ENODEV;
72
73 priv->cpu_clk = of_clk_get_by_name(np, "cpu_g");
74 if (IS_ERR(priv->cpu_clk)) {
75 ret = PTR_ERR(priv->cpu_clk);
76 goto out_put_np;
77 }
78
79 priv->dfll_clk = of_clk_get_by_name(np, "dfll");
80 if (IS_ERR(priv->dfll_clk)) {
81 ret = PTR_ERR(priv->dfll_clk);
82 goto out_put_cpu_clk;
83 }
84
85 priv->pllx_clk = of_clk_get_by_name(np, "pll_x");
86 if (IS_ERR(priv->pllx_clk)) {
87 ret = PTR_ERR(priv->pllx_clk);
88 goto out_put_dfll_clk;
89 }
90
91 priv->pllp_clk = of_clk_get_by_name(np, "pll_p");
92 if (IS_ERR(priv->pllp_clk)) {
93 ret = PTR_ERR(priv->pllp_clk);
94 goto out_put_pllx_clk;
95 }
96
97 ret = tegra124_cpu_switch_to_dfll(priv);
98 if (ret)
99 goto out_put_pllp_clk;
100
101 cpufreq_dt_devinfo.name = "cpufreq-dt";
102 cpufreq_dt_devinfo.parent = &pdev->dev;
103
104 priv->cpufreq_dt_pdev =
105 platform_device_register_full(&cpufreq_dt_devinfo);
106 if (IS_ERR(priv->cpufreq_dt_pdev)) {
107 ret = PTR_ERR(priv->cpufreq_dt_pdev);
108 goto out_put_pllp_clk;
109 }
110
111 platform_set_drvdata(pdev, priv);
112
113 of_node_put(np);
114
115 return 0;
116
117out_put_pllp_clk:
118 clk_put(priv->pllp_clk);
119out_put_pllx_clk:
120 clk_put(priv->pllx_clk);
121out_put_dfll_clk:
122 clk_put(priv->dfll_clk);
123out_put_cpu_clk:
124 clk_put(priv->cpu_clk);
125out_put_np:
126 of_node_put(np);
127
128 return ret;
129}
130
131static struct platform_driver tegra124_cpufreq_platdrv = {
132 .driver.name = "cpufreq-tegra124",
133 .probe = tegra124_cpufreq_probe,
134};
135
136static int __init tegra_cpufreq_init(void)
137{
138 int ret;
139 struct platform_device *pdev;
140
141 if (!(of_machine_is_compatible("nvidia,tegra124") ||
142 of_machine_is_compatible("nvidia,tegra210")))
143 return -ENODEV;
144
145 /*
146 * Platform driver+device required for handling EPROBE_DEFER with
147 * the regulator and the DFLL clock
148 */
149 ret = platform_driver_register(&tegra124_cpufreq_platdrv);
150 if (ret)
151 return ret;
152
153 pdev = platform_device_register_simple("cpufreq-tegra124", -1, NULL, 0);
154 if (IS_ERR(pdev)) {
155 platform_driver_unregister(&tegra124_cpufreq_platdrv);
156 return PTR_ERR(pdev);
157 }
158
159 return 0;
160}
161module_init(tegra_cpufreq_init);
162
163MODULE_AUTHOR("Tuomas Tynkkynen <ttynkkynen@nvidia.com>");
164MODULE_DESCRIPTION("cpufreq driver for NVIDIA Tegra124");
165MODULE_LICENSE("GPL v2");