xref: /openbmc/linux/drivers/devfreq/imx-bus.c (revision 9027f2e7)
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 
15 struct imx_bus {
16 	struct devfreq_dev_profile profile;
17 	struct devfreq *devfreq;
18 	struct clk *clk;
19 	struct platform_device *icc_pdev;
20 };
21 
imx_bus_target(struct device * dev,unsigned long * freq,u32 flags)22 static 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 
imx_bus_get_cur_freq(struct device * dev,unsigned long * freq)39 static 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 
imx_bus_exit(struct device * dev)48 static 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 */
imx_bus_init_icc(struct device * dev)57 static 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 
imx_bus_probe(struct platform_device * pdev)86 static 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 
139 err:
140 	dev_pm_opp_of_remove_table(dev);
141 	return ret;
142 }
143 
144 static 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 };
153 MODULE_DEVICE_TABLE(of, imx_bus_of_match);
154 
155 static 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 };
162 module_platform_driver(imx_bus_platdrv);
163 
164 MODULE_DESCRIPTION("Generic i.MX bus frequency scaling driver");
165 MODULE_AUTHOR("Leonard Crestez <leonard.crestez@nxp.com>");
166 MODULE_LICENSE("GPL v2");
167