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 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 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 48 static 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 60 static 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 */ 69 static 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 98 static 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; 152 153 err: 154 dev_pm_opp_of_remove_table(dev); 155 return ret; 156 } 157 158 static 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 }; 166 MODULE_DEVICE_TABLE(of, imx_bus_of_match); 167 168 static 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 }; 175 module_platform_driver(imx_bus_platdrv); 176 177 MODULE_DESCRIPTION("Generic i.MX bus frequency scaling driver"); 178 MODULE_AUTHOR("Leonard Crestez <leonard.crestez@nxp.com>"); 179 MODULE_LICENSE("GPL v2"); 180