1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright 2019 NXP
4 */
5
6#include <linux/clk.h>
7#include <linux/devfreq.h>
8#include <linux/device.h>
9#include <linux/module.h>
10#include <linux/of_device.h>
11#include <linux/pm_opp.h>
12#include <linux/platform_device.h>
13#include <linux/slab.h>
14
15struct imx_bus {
16	struct devfreq_dev_profile profile;
17	struct devfreq *devfreq;
18	struct clk *clk;
19	struct platform_device *icc_pdev;
20};
21
22static int imx_bus_target(struct device *dev,
23		unsigned long *freq, u32 flags)
24{
25	struct dev_pm_opp *new_opp;
26	int ret;
27
28	new_opp = devfreq_recommended_opp(dev, freq, flags);
29	if (IS_ERR(new_opp)) {
30		ret = PTR_ERR(new_opp);
31		dev_err(dev, "failed to get recommended opp: %d\n", ret);
32		return ret;
33	}
34	dev_pm_opp_put(new_opp);
35
36	return dev_pm_opp_set_rate(dev, *freq);
37}
38
39static int imx_bus_get_cur_freq(struct device *dev, unsigned long *freq)
40{
41	struct imx_bus *priv = dev_get_drvdata(dev);
42
43	*freq = clk_get_rate(priv->clk);
44
45	return 0;
46}
47
48static int imx_bus_get_dev_status(struct device *dev,
49		struct devfreq_dev_status *stat)
50{
51	struct imx_bus *priv = dev_get_drvdata(dev);
52
53	stat->busy_time = 0;
54	stat->total_time = 0;
55	stat->current_frequency = clk_get_rate(priv->clk);
56
57	return 0;
58}
59
60static void imx_bus_exit(struct device *dev)
61{
62	struct imx_bus *priv = dev_get_drvdata(dev);
63
64	dev_pm_opp_of_remove_table(dev);
65	platform_device_unregister(priv->icc_pdev);
66}
67
68/* imx_bus_init_icc() - register matching icc provider if required */
69static int imx_bus_init_icc(struct device *dev)
70{
71	struct imx_bus *priv = dev_get_drvdata(dev);
72	const char *icc_driver_name;
73
74	if (!of_get_property(dev->of_node, "#interconnect-cells", 0))
75		return 0;
76	if (!IS_ENABLED(CONFIG_INTERCONNECT_IMX)) {
77		dev_warn(dev, "imx interconnect drivers disabled\n");
78		return 0;
79	}
80
81	icc_driver_name = of_device_get_match_data(dev);
82	if (!icc_driver_name) {
83		dev_err(dev, "unknown interconnect driver\n");
84		return 0;
85	}
86
87	priv->icc_pdev = platform_device_register_data(
88			dev, icc_driver_name, -1, NULL, 0);
89	if (IS_ERR(priv->icc_pdev)) {
90		dev_err(dev, "failed to register icc provider %s: %ld\n",
91				icc_driver_name, PTR_ERR(priv->icc_pdev));
92		return PTR_ERR(priv->icc_pdev);
93	}
94
95	return 0;
96}
97
98static int imx_bus_probe(struct platform_device *pdev)
99{
100	struct device *dev = &pdev->dev;
101	struct imx_bus *priv;
102	const char *gov = DEVFREQ_GOV_USERSPACE;
103	int ret;
104
105	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
106	if (!priv)
107		return -ENOMEM;
108
109	/*
110	 * Fetch the clock to adjust but don't explicitly enable.
111	 *
112	 * For imx bus clock clk_set_rate is safe no matter if the clock is on
113	 * or off and some peripheral side-buses might be off unless enabled by
114	 * drivers for devices on those specific buses.
115	 *
116	 * Rate adjustment on a disabled bus clock just takes effect later.
117	 */
118	priv->clk = devm_clk_get(dev, NULL);
119	if (IS_ERR(priv->clk)) {
120		ret = PTR_ERR(priv->clk);
121		dev_err(dev, "failed to fetch clk: %d\n", ret);
122		return ret;
123	}
124	platform_set_drvdata(pdev, priv);
125
126	ret = dev_pm_opp_of_add_table(dev);
127	if (ret < 0) {
128		dev_err(dev, "failed to get OPP table\n");
129		return ret;
130	}
131
132	priv->profile.polling_ms = 1000;
133	priv->profile.target = imx_bus_target;
134	priv->profile.get_dev_status = imx_bus_get_dev_status;
135	priv->profile.exit = imx_bus_exit;
136	priv->profile.get_cur_freq = imx_bus_get_cur_freq;
137	priv->profile.initial_freq = clk_get_rate(priv->clk);
138
139	priv->devfreq = devm_devfreq_add_device(dev, &priv->profile,
140						gov, NULL);
141	if (IS_ERR(priv->devfreq)) {
142		ret = PTR_ERR(priv->devfreq);
143		dev_err(dev, "failed to add devfreq device: %d\n", ret);
144		goto err;
145	}
146
147	ret = imx_bus_init_icc(dev);
148	if (ret)
149		goto err;
150
151	return 0;
152
153err:
154	dev_pm_opp_of_remove_table(dev);
155	return ret;
156}
157
158static const struct of_device_id imx_bus_of_match[] = {
159	{ .compatible = "fsl,imx8mq-noc", .data = "imx8mq-interconnect", },
160	{ .compatible = "fsl,imx8mm-noc", .data = "imx8mm-interconnect", },
161	{ .compatible = "fsl,imx8mn-noc", .data = "imx8mn-interconnect", },
162	{ .compatible = "fsl,imx8m-noc", },
163	{ .compatible = "fsl,imx8m-nic", },
164	{ /* sentinel */ },
165};
166MODULE_DEVICE_TABLE(of, imx_bus_of_match);
167
168static struct platform_driver imx_bus_platdrv = {
169	.probe		= imx_bus_probe,
170	.driver = {
171		.name	= "imx-bus-devfreq",
172		.of_match_table = of_match_ptr(imx_bus_of_match),
173	},
174};
175module_platform_driver(imx_bus_platdrv);
176
177MODULE_DESCRIPTION("Generic i.MX bus frequency scaling driver");
178MODULE_AUTHOR("Leonard Crestez <leonard.crestez@nxp.com>");
179MODULE_LICENSE("GPL v2");
180