kernel/drivers/cpufreq/tegra124-cpufreq.c

   1 /*
   2  * Tegra 124 cpufreq driver
   3  *
   4  * This software is licensed under the terms of the GNU General Public
   5  * License version 2, as published by the Free Software Foundation, and
   6  * may be copied, distributed, and modified under those terms.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  */
  13
  14 #define pr_fmt(fmt)     KBUILD_MODNAME ": " fmt
  15
  16 #include <linux/clk.h>
  17 #include <linux/cpufreq-dt.h>
  18 #include <linux/err.h>
  19 #include <linux/init.h>
  20 #include <linux/kernel.h>
  21 #include <linux/module.h>
  22 #include <linux/of_device.h>
  23 #include <linux/of.h>
  24 #include <linux/platform_device.h>
  25 #include <linux/pm_opp.h>
  26 #include <linux/regulator/consumer.h>
  27 #include <linux/types.h>
  28
  29 struct tegra124_cpufreq_priv {
  30         struct regulator *vdd_cpu_reg;
  31         struct clk *cpu_clk;
  32         struct clk *pllp_clk;
  33         struct clk *pllx_clk;
  34         struct clk *dfll_clk;
  35         struct platform_device *cpufreq_dt_pdev;
  36 };
  37
  38 static int tegra124_cpu_switch_to_dfll(struct tegra124_cpufreq_priv *priv)
  39 {
  40         struct clk *orig_parent;
  41         int ret;
  42
  43         ret = clk_set_rate(priv->dfll_clk, clk_get_rate(priv->cpu_clk));
  44         if (ret)
  45                 return ret;
  46
  47         orig_parent = clk_get_parent(priv->cpu_clk);
  48         clk_set_parent(priv->cpu_clk, priv->pllp_clk);
  49
  50         ret = clk_prepare_enable(priv->dfll_clk);
  51         if (ret)
  52                 goto out;
  53
  54         clk_set_parent(priv->cpu_clk, priv->dfll_clk);
  55
  56         return 0;
  57
  58 out:
  59         clk_set_parent(priv->cpu_clk, orig_parent);
  60
  61         return ret;
  62 }
  63
  64 static void tegra124_cpu_switch_to_pllx(struct tegra124_cpufreq_priv *priv)
  65 {
  66         clk_set_parent(priv->cpu_clk, priv->pllp_clk);
  67         clk_disable_unprepare(priv->dfll_clk);
  68         regulator_sync_voltage(priv->vdd_cpu_reg);
  69         clk_set_parent(priv->cpu_clk, priv->pllx_clk);
  70 }
  71
  72 static struct cpufreq_dt_platform_data cpufreq_dt_pd = {
  73         .independent_clocks = false,
  74 };
  75
  76 static int tegra124_cpufreq_probe(struct platform_device *pdev)
  77 {
  78         struct tegra124_cpufreq_priv *priv;
  79         struct device_node *np;
  80         struct device *cpu_dev;
  81         struct platform_device_info cpufreq_dt_devinfo = {};
  82         int ret;
  83
  84         priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
  85         if (!priv)
  86                 return -ENOMEM;
  87
  88         cpu_dev = get_cpu_device(0);
  89         if (!cpu_dev)
  90                 return -ENODEV;
  91
  92         np = of_cpu_device_node_get(0);
  93         if (!np)
  94                 return -ENODEV;
  95
  96         priv->vdd_cpu_reg = regulator_get(cpu_dev, "vdd-cpu");
  97         if (IS_ERR(priv->vdd_cpu_reg)) {
  98                 ret = PTR_ERR(priv->vdd_cpu_reg);
  99                 goto out_put_np;
 100         }
 101
 102         priv->cpu_clk = of_clk_get_by_name(np, "cpu_g");
 103         if (IS_ERR(priv->cpu_clk)) {
 104                 ret = PTR_ERR(priv->cpu_clk);
 105                 goto out_put_vdd_cpu_reg;
 106         }
 107
 108         priv->dfll_clk = of_clk_get_by_name(np, "dfll");
 109         if (IS_ERR(priv->dfll_clk)) {
 110                 ret = PTR_ERR(priv->dfll_clk);
 111                 goto out_put_cpu_clk;
 112         }
 113
 114         priv->pllx_clk = of_clk_get_by_name(np, "pll_x");
 115         if (IS_ERR(priv->pllx_clk)) {
 116                 ret = PTR_ERR(priv->pllx_clk);
 117                 goto out_put_dfll_clk;
 118         }
 119
 120         priv->pllp_clk = of_clk_get_by_name(np, "pll_p");
 121         if (IS_ERR(priv->pllp_clk)) {
 122                 ret = PTR_ERR(priv->pllp_clk);
 123                 goto out_put_pllx_clk;
 124         }
 125
 126         ret = tegra124_cpu_switch_to_dfll(priv);
 127         if (ret)
 128                 goto out_put_pllp_clk;
 129
 130         cpufreq_dt_devinfo.name = "cpufreq-dt";
 131         cpufreq_dt_devinfo.parent = &pdev->dev;
 132         cpufreq_dt_devinfo.data = &cpufreq_dt_pd;
 133         cpufreq_dt_devinfo.size_data = sizeof(cpufreq_dt_pd);
 134
 135         priv->cpufreq_dt_pdev =
 136                 platform_device_register_full(&cpufreq_dt_devinfo);
 137         if (IS_ERR(priv->cpufreq_dt_pdev)) {
 138                 ret = PTR_ERR(priv->cpufreq_dt_pdev);
 139                 goto out_switch_to_pllx;
 140         }
 141
 142         platform_set_drvdata(pdev, priv);
 143
 144         return 0;
 145
 146 out_switch_to_pllx:
 147         tegra124_cpu_switch_to_pllx(priv);
 148 out_put_pllp_clk:
 149         clk_put(priv->pllp_clk);
 150 out_put_pllx_clk:
 151         clk_put(priv->pllx_clk);
 152 out_put_dfll_clk:
 153         clk_put(priv->dfll_clk);
 154 out_put_cpu_clk:
 155         clk_put(priv->cpu_clk);
 156 out_put_vdd_cpu_reg:
 157         regulator_put(priv->vdd_cpu_reg);
 158 out_put_np:
 159         of_node_put(np);
 160
 161         return ret;
 162 }
 163
 164 static int tegra124_cpufreq_remove(struct platform_device *pdev)
 165 {
 166         struct tegra124_cpufreq_priv *priv = platform_get_drvdata(pdev);
 167
 168         platform_device_unregister(priv->cpufreq_dt_pdev);
 169         tegra124_cpu_switch_to_pllx(priv);
 170
 171         clk_put(priv->pllp_clk);
 172         clk_put(priv->pllx_clk);
 173         clk_put(priv->dfll_clk);
 174         clk_put(priv->cpu_clk);
 175         regulator_put(priv->vdd_cpu_reg);
 176
 177         return 0;
 178 }
 179
 180 static struct platform_driver tegra124_cpufreq_platdrv = {
 181         .driver.name    = "cpufreq-tegra124",
 182         .probe          = tegra124_cpufreq_probe,
 183         .remove         = tegra124_cpufreq_remove,
 184 };
 185
 186 static int __init tegra_cpufreq_init(void)
 187 {
 188         int ret;
 189         struct platform_device *pdev;
 190
 191         if (!of_machine_is_compatible("nvidia,tegra124"))
 192                 return -ENODEV;
 193
 194         /*
 195          * Platform driver+device required for handling EPROBE_DEFER with
 196          * the regulator and the DFLL clock
 197          */
 198         ret = platform_driver_register(&tegra124_cpufreq_platdrv);
 199         if (ret)
 200                 return ret;
 201
 202         pdev = platform_device_register_simple("cpufreq-tegra124", -1, NULL, 0);
 203         if (IS_ERR(pdev)) {
 204                 platform_driver_unregister(&tegra124_cpufreq_platdrv);
 205                 return PTR_ERR(pdev);
 206         }
 207
 208         return 0;
 209 }
 210 module_init(tegra_cpufreq_init);
 211
 212 MODULE_AUTHOR("Tuomas Tynkkynen <ttynkkynen@nvidia.com>");
 213 MODULE_DESCRIPTION("cpufreq driver for NVIDIA Tegra124");
 214 MODULE_LICENSE("GPL v2");