drivers/cpufreq/tegra124-cpufreq.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Tegra 124 cpufreq driver
   4  */
   5
   6 #define pr_fmt(fmt)     KBUILD_MODNAME ": " fmt
   7
   8 #include <linux/clk.h>
   9 #include <linux/cpufreq.h>
  10 #include <linux/err.h>
  11 #include <linux/init.h>
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/of.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/pm_opp.h>
  17 #include <linux/types.h>
  18
  19 struct tegra124_cpufreq_priv {
  20         struct clk *cpu_clk;
  21         struct clk *pllp_clk;
  22         struct clk *pllx_clk;
  23         struct clk *dfll_clk;
  24         struct platform_device *cpufreq_dt_pdev;
  25 };
  26
  27 static int tegra124_cpu_switch_to_dfll(struct tegra124_cpufreq_priv *priv)
  28 {
  29         struct clk *orig_parent;
  30         int ret;
  31
  32         ret = clk_set_rate(priv->dfll_clk, clk_get_rate(priv->cpu_clk));
  33         if (ret)
  34                 return ret;
  35
  36         orig_parent = clk_get_parent(priv->cpu_clk);
  37         clk_set_parent(priv->cpu_clk, priv->pllp_clk);
  38
  39         ret = clk_prepare_enable(priv->dfll_clk);
  40         if (ret)
  41                 goto out;
  42
  43         clk_set_parent(priv->cpu_clk, priv->dfll_clk);
  44
  45         return 0;
  46
  47 out:
  48         clk_set_parent(priv->cpu_clk, orig_parent);
  49
  50         return ret;
  51 }
  52
  53 static int tegra124_cpufreq_probe(struct platform_device *pdev)
  54 {
  55         struct device_node *np __free(device_node) = of_cpu_device_node_get(0);
  56         struct tegra124_cpufreq_priv *priv;
  57         struct device *cpu_dev;
  58         struct platform_device_info cpufreq_dt_devinfo = {};
  59         int ret;
  60
  61         if (!np)
  62                 return -ENODEV;
  63
  64         priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
  65         if (!priv)
  66                 return -ENOMEM;
  67
  68         cpu_dev = get_cpu_device(0);
  69         if (!cpu_dev)
  70                 return -ENODEV;
  71
  72         priv->cpu_clk = of_clk_get_by_name(np, "cpu_g");
  73         if (IS_ERR(priv->cpu_clk))
  74                 return PTR_ERR(priv->cpu_clk);
  75
  76         priv->dfll_clk = of_clk_get_by_name(np, "dfll");
  77         if (IS_ERR(priv->dfll_clk)) {
  78                 ret = PTR_ERR(priv->dfll_clk);
  79                 goto out_put_cpu_clk;
  80         }
  81
  82         priv->pllx_clk = of_clk_get_by_name(np, "pll_x");
  83         if (IS_ERR(priv->pllx_clk)) {
  84                 ret = PTR_ERR(priv->pllx_clk);
  85                 goto out_put_dfll_clk;
  86         }
  87
  88         priv->pllp_clk = of_clk_get_by_name(np, "pll_p");
  89         if (IS_ERR(priv->pllp_clk)) {
  90                 ret = PTR_ERR(priv->pllp_clk);
  91                 goto out_put_pllx_clk;
  92         }
  93
  94         ret = tegra124_cpu_switch_to_dfll(priv);
  95         if (ret)
  96                 goto out_put_pllp_clk;
  97
  98         cpufreq_dt_devinfo.name = "cpufreq-dt";
  99         cpufreq_dt_devinfo.parent = &pdev->dev;
 100
 101         priv->cpufreq_dt_pdev =
 102                 platform_device_register_full(&cpufreq_dt_devinfo);
 103         if (IS_ERR(priv->cpufreq_dt_pdev)) {
 104                 ret = PTR_ERR(priv->cpufreq_dt_pdev);
 105                 goto out_put_pllp_clk;
 106         }
 107
 108         platform_set_drvdata(pdev, priv);
 109
 110         return 0;
 111
 112 out_put_pllp_clk:
 113         clk_put(priv->pllp_clk);
 114 out_put_pllx_clk:
 115         clk_put(priv->pllx_clk);
 116 out_put_dfll_clk:
 117         clk_put(priv->dfll_clk);
 118 out_put_cpu_clk:
 119         clk_put(priv->cpu_clk);
 120
 121         return ret;
 122 }
 123
 124 static int __maybe_unused tegra124_cpufreq_suspend(struct device *dev)
 125 {
 126         struct tegra124_cpufreq_priv *priv = dev_get_drvdata(dev);
 127         int err;
 128
 129         /*
 130          * PLLP rate 408Mhz is below the CPU Fmax at Vmin and is safe to
 131          * use during suspend and resume. So, switch the CPU clock source
 132          * to PLLP and disable DFLL.
 133          */
 134         err = clk_set_parent(priv->cpu_clk, priv->pllp_clk);
 135         if (err < 0) {
 136                 dev_err(dev, "failed to reparent to PLLP: %d\n", err);
 137                 return err;
 138         }
 139
 140         clk_disable_unprepare(priv->dfll_clk);
 141
 142         return 0;
 143 }
 144
 145 static int __maybe_unused tegra124_cpufreq_resume(struct device *dev)
 146 {
 147         struct tegra124_cpufreq_priv *priv = dev_get_drvdata(dev);
 148         int err;
 149
 150         /*
 151          * Warmboot code powers up the CPU with PLLP clock source.
 152          * Enable DFLL clock and switch CPU clock source back to DFLL.
 153          */
 154         err = clk_prepare_enable(priv->dfll_clk);
 155         if (err < 0) {
 156                 dev_err(dev, "failed to enable DFLL clock for CPU: %d\n", err);
 157                 goto disable_cpufreq;
 158         }
 159
 160         err = clk_set_parent(priv->cpu_clk, priv->dfll_clk);
 161         if (err < 0) {
 162                 dev_err(dev, "failed to reparent to DFLL clock: %d\n", err);
 163                 goto disable_dfll;
 164         }
 165
 166         return 0;
 167
 168 disable_dfll:
 169         clk_disable_unprepare(priv->dfll_clk);
 170 disable_cpufreq:
 171         disable_cpufreq();
 172
 173         return err;
 174 }
 175
 176 static const struct dev_pm_ops tegra124_cpufreq_pm_ops = {
 177         SET_SYSTEM_SLEEP_PM_OPS(tegra124_cpufreq_suspend,
 178                                 tegra124_cpufreq_resume)
 179 };
 180
 181 static struct platform_driver tegra124_cpufreq_platdrv = {
 182         .driver.name    = "cpufreq-tegra124",
 183         .driver.pm      = &tegra124_cpufreq_pm_ops,
 184         .probe          = tegra124_cpufreq_probe,
 185 };
 186
 187 static int __init tegra_cpufreq_init(void)
 188 {
 189         int ret;
 190         struct platform_device *pdev;
 191
 192         if (!(of_machine_is_compatible("nvidia,tegra124") ||
 193                 of_machine_is_compatible("nvidia,tegra210")))
 194                 return -ENODEV;
 195
 196         /*
 197          * Platform driver+device required for handling EPROBE_DEFER with
 198          * the regulator and the DFLL clock
 199          */
 200         ret = platform_driver_register(&tegra124_cpufreq_platdrv);
 201         if (ret)
 202                 return ret;
 203
 204         pdev = platform_device_register_simple("cpufreq-tegra124", -1, NULL, 0);
 205         if (IS_ERR(pdev)) {
 206                 platform_driver_unregister(&tegra124_cpufreq_platdrv);
 207                 return PTR_ERR(pdev);
 208         }
 209
 210         return 0;
 211 }
 212 module_init(tegra_cpufreq_init);
 213
 214 MODULE_AUTHOR("Tuomas Tynkkynen <[email protected]>");
 215 MODULE_DESCRIPTION("cpufreq driver for NVIDIA Tegra124");