drivers/devfreq/imx-bus.c

   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 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 */
  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
  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");