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");