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");