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
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", 0))
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,imx8m-noc", },
149 { .compatible = "fsl,imx8m-nic", },
150 { /* sentinel */ },
151 };
152 MODULE_DEVICE_TABLE(of, imx_bus_of_match);
153
154 static struct platform_driver imx_bus_platdrv = {
155 .probe = imx_bus_probe,
156 .driver = {
157 .name = "imx-bus-devfreq",
158 .of_match_table = imx_bus_of_match,
159 },
160 };
161 module_platform_driver(imx_bus_platdrv);
162
163 MODULE_DESCRIPTION("Generic i.MX bus frequency scaling driver");
164 MODULE_AUTHOR("Leonard Crestez <leonard.crestez@nxp.com>");
165 MODULE_LICENSE("GPL v2");
166
