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.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 void imx_bus_exit(struct device *dev)
49{
50	struct imx_bus *priv = dev_get_drvdata(dev);
51
52	dev_pm_opp_of_remove_table(dev);
53	platform_device_unregister(priv->icc_pdev);
54}
55
56/* imx_bus_init_icc() - register matching icc provider if required */
57static int imx_bus_init_icc(struct device *dev)
58{
59	struct imx_bus *priv = dev_get_drvdata(dev);
60	const char *icc_driver_name;
61
62	if (!of_get_property(dev->of_node, "#interconnect-cells", NULL))
63		return 0;
64	if (!IS_ENABLED(CONFIG_INTERCONNECT_IMX)) {
65		dev_warn(dev, "imx interconnect drivers disabled\n");
66		return 0;
67	}
68
69	icc_driver_name = of_device_get_match_data(dev);
70	if (!icc_driver_name) {
71		dev_err(dev, "unknown interconnect driver\n");
72		return 0;
73	}
74
75	priv->icc_pdev = platform_device_register_data(
76			dev, icc_driver_name, -1, NULL, 0);
77	if (IS_ERR(priv->icc_pdev)) {
78		dev_err(dev, "failed to register icc provider %s: %ld\n",
79				icc_driver_name, PTR_ERR(priv->icc_pdev));
80		return PTR_ERR(priv->icc_pdev);
81	}
82
83	return 0;
84}
85
86static int imx_bus_probe(struct platform_device *pdev)
87{
88	struct device *dev = &pdev->dev;
89	struct imx_bus *priv;
90	const char *gov = DEVFREQ_GOV_USERSPACE;
91	int ret;
92
93	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
94	if (!priv)
95		return -ENOMEM;
96
97	/*
98	 * Fetch the clock to adjust but don't explicitly enable.
99	 *
100	 * For imx bus clock clk_set_rate is safe no matter if the clock is on
101	 * or off and some peripheral side-buses might be off unless enabled by
102	 * drivers for devices on those specific buses.
103	 *
104	 * Rate adjustment on a disabled bus clock just takes effect later.
105	 */
106	priv->clk = devm_clk_get(dev, NULL);
107	if (IS_ERR(priv->clk)) {
108		ret = PTR_ERR(priv->clk);
109		dev_err(dev, "failed to fetch clk: %d\n", ret);
110		return ret;
111	}
112	platform_set_drvdata(pdev, priv);
113
114	ret = dev_pm_opp_of_add_table(dev);
115	if (ret < 0) {
116		dev_err(dev, "failed to get OPP table\n");
117		return ret;
118	}
119
120	priv->profile.target = imx_bus_target;
121	priv->profile.exit = imx_bus_exit;
122	priv->profile.get_cur_freq = imx_bus_get_cur_freq;
123	priv->profile.initial_freq = clk_get_rate(priv->clk);
124
125	priv->devfreq = devm_devfreq_add_device(dev, &priv->profile,
126						gov, NULL);
127	if (IS_ERR(priv->devfreq)) {
128		ret = PTR_ERR(priv->devfreq);
129		dev_err(dev, "failed to add devfreq device: %d\n", ret);
130		goto err;
131	}
132
133	ret = imx_bus_init_icc(dev);
134	if (ret)
135		goto err;
136
137	return 0;
138
139err:
140	dev_pm_opp_of_remove_table(dev);
141	return ret;
142}
143
144static const struct of_device_id imx_bus_of_match[] = {
145	{ .compatible = "fsl,imx8mq-noc", .data = "imx8mq-interconnect", },
146	{ .compatible = "fsl,imx8mm-noc", .data = "imx8mm-interconnect", },
147	{ .compatible = "fsl,imx8mn-noc", .data = "imx8mn-interconnect", },
148	{ .compatible = "fsl,imx8mp-noc", .data = "imx8mp-interconnect", },
149	{ .compatible = "fsl,imx8m-noc", },
150	{ .compatible = "fsl,imx8m-nic", },
151	{ /* sentinel */ },
152};
153MODULE_DEVICE_TABLE(of, imx_bus_of_match);
154
155static struct platform_driver imx_bus_platdrv = {
156	.probe		= imx_bus_probe,
157	.driver = {
158		.name	= "imx-bus-devfreq",
159		.of_match_table = imx_bus_of_match,
160	},
161};
162module_platform_driver(imx_bus_platdrv);
163
164MODULE_DESCRIPTION("Generic i.MX bus frequency scaling driver");
165MODULE_AUTHOR("Leonard Crestez <leonard.crestez@nxp.com>");
166MODULE_LICENSE("GPL v2");
167