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path: root/drivers/cpufreq/tegra124-cpufreq.c
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Diffstat (limited to 'drivers/cpufreq/tegra124-cpufreq.c')
-rw-r--r--drivers/cpufreq/tegra124-cpufreq.c222
1 files changed, 222 insertions, 0 deletions
diff --git a/drivers/cpufreq/tegra124-cpufreq.c b/drivers/cpufreq/tegra124-cpufreq.c
new file mode 100644
index 0000000000..aae951d4e7
--- /dev/null
+++ b/drivers/cpufreq/tegra124-cpufreq.c
@@ -0,0 +1,222 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Tegra 124 cpufreq driver
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/clk.h>
+#include <linux/cpufreq.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_opp.h>
+#include <linux/types.h>
+
+struct tegra124_cpufreq_priv {
+ struct clk *cpu_clk;
+ struct clk *pllp_clk;
+ struct clk *pllx_clk;
+ struct clk *dfll_clk;
+ struct platform_device *cpufreq_dt_pdev;
+};
+
+static int tegra124_cpu_switch_to_dfll(struct tegra124_cpufreq_priv *priv)
+{
+ struct clk *orig_parent;
+ int ret;
+
+ ret = clk_set_rate(priv->dfll_clk, clk_get_rate(priv->cpu_clk));
+ if (ret)
+ return ret;
+
+ orig_parent = clk_get_parent(priv->cpu_clk);
+ clk_set_parent(priv->cpu_clk, priv->pllp_clk);
+
+ ret = clk_prepare_enable(priv->dfll_clk);
+ if (ret)
+ goto out;
+
+ clk_set_parent(priv->cpu_clk, priv->dfll_clk);
+
+ return 0;
+
+out:
+ clk_set_parent(priv->cpu_clk, orig_parent);
+
+ return ret;
+}
+
+static int tegra124_cpufreq_probe(struct platform_device *pdev)
+{
+ struct tegra124_cpufreq_priv *priv;
+ struct device_node *np;
+ struct device *cpu_dev;
+ struct platform_device_info cpufreq_dt_devinfo = {};
+ int ret;
+
+ priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ cpu_dev = get_cpu_device(0);
+ if (!cpu_dev)
+ return -ENODEV;
+
+ np = of_cpu_device_node_get(0);
+ if (!np)
+ return -ENODEV;
+
+ priv->cpu_clk = of_clk_get_by_name(np, "cpu_g");
+ if (IS_ERR(priv->cpu_clk)) {
+ ret = PTR_ERR(priv->cpu_clk);
+ goto out_put_np;
+ }
+
+ priv->dfll_clk = of_clk_get_by_name(np, "dfll");
+ if (IS_ERR(priv->dfll_clk)) {
+ ret = PTR_ERR(priv->dfll_clk);
+ goto out_put_cpu_clk;
+ }
+
+ priv->pllx_clk = of_clk_get_by_name(np, "pll_x");
+ if (IS_ERR(priv->pllx_clk)) {
+ ret = PTR_ERR(priv->pllx_clk);
+ goto out_put_dfll_clk;
+ }
+
+ priv->pllp_clk = of_clk_get_by_name(np, "pll_p");
+ if (IS_ERR(priv->pllp_clk)) {
+ ret = PTR_ERR(priv->pllp_clk);
+ goto out_put_pllx_clk;
+ }
+
+ ret = tegra124_cpu_switch_to_dfll(priv);
+ if (ret)
+ goto out_put_pllp_clk;
+
+ cpufreq_dt_devinfo.name = "cpufreq-dt";
+ cpufreq_dt_devinfo.parent = &pdev->dev;
+
+ priv->cpufreq_dt_pdev =
+ platform_device_register_full(&cpufreq_dt_devinfo);
+ if (IS_ERR(priv->cpufreq_dt_pdev)) {
+ ret = PTR_ERR(priv->cpufreq_dt_pdev);
+ goto out_put_pllp_clk;
+ }
+
+ platform_set_drvdata(pdev, priv);
+
+ of_node_put(np);
+
+ return 0;
+
+out_put_pllp_clk:
+ clk_put(priv->pllp_clk);
+out_put_pllx_clk:
+ clk_put(priv->pllx_clk);
+out_put_dfll_clk:
+ clk_put(priv->dfll_clk);
+out_put_cpu_clk:
+ clk_put(priv->cpu_clk);
+out_put_np:
+ of_node_put(np);
+
+ return ret;
+}
+
+static int __maybe_unused tegra124_cpufreq_suspend(struct device *dev)
+{
+ struct tegra124_cpufreq_priv *priv = dev_get_drvdata(dev);
+ int err;
+
+ /*
+ * PLLP rate 408Mhz is below the CPU Fmax at Vmin and is safe to
+ * use during suspend and resume. So, switch the CPU clock source
+ * to PLLP and disable DFLL.
+ */
+ err = clk_set_parent(priv->cpu_clk, priv->pllp_clk);
+ if (err < 0) {
+ dev_err(dev, "failed to reparent to PLLP: %d\n", err);
+ return err;
+ }
+
+ clk_disable_unprepare(priv->dfll_clk);
+
+ return 0;
+}
+
+static int __maybe_unused tegra124_cpufreq_resume(struct device *dev)
+{
+ struct tegra124_cpufreq_priv *priv = dev_get_drvdata(dev);
+ int err;
+
+ /*
+ * Warmboot code powers up the CPU with PLLP clock source.
+ * Enable DFLL clock and switch CPU clock source back to DFLL.
+ */
+ err = clk_prepare_enable(priv->dfll_clk);
+ if (err < 0) {
+ dev_err(dev, "failed to enable DFLL clock for CPU: %d\n", err);
+ goto disable_cpufreq;
+ }
+
+ err = clk_set_parent(priv->cpu_clk, priv->dfll_clk);
+ if (err < 0) {
+ dev_err(dev, "failed to reparent to DFLL clock: %d\n", err);
+ goto disable_dfll;
+ }
+
+ return 0;
+
+disable_dfll:
+ clk_disable_unprepare(priv->dfll_clk);
+disable_cpufreq:
+ disable_cpufreq();
+
+ return err;
+}
+
+static const struct dev_pm_ops tegra124_cpufreq_pm_ops = {
+ SET_SYSTEM_SLEEP_PM_OPS(tegra124_cpufreq_suspend,
+ tegra124_cpufreq_resume)
+};
+
+static struct platform_driver tegra124_cpufreq_platdrv = {
+ .driver.name = "cpufreq-tegra124",
+ .driver.pm = &tegra124_cpufreq_pm_ops,
+ .probe = tegra124_cpufreq_probe,
+};
+
+static int __init tegra_cpufreq_init(void)
+{
+ int ret;
+ struct platform_device *pdev;
+
+ if (!(of_machine_is_compatible("nvidia,tegra124") ||
+ of_machine_is_compatible("nvidia,tegra210")))
+ return -ENODEV;
+
+ /*
+ * Platform driver+device required for handling EPROBE_DEFER with
+ * the regulator and the DFLL clock
+ */
+ ret = platform_driver_register(&tegra124_cpufreq_platdrv);
+ if (ret)
+ return ret;
+
+ pdev = platform_device_register_simple("cpufreq-tegra124", -1, NULL, 0);
+ if (IS_ERR(pdev)) {
+ platform_driver_unregister(&tegra124_cpufreq_platdrv);
+ return PTR_ERR(pdev);
+ }
+
+ return 0;
+}
+module_init(tegra_cpufreq_init);
+
+MODULE_AUTHOR("Tuomas Tynkkynen <ttynkkynen@nvidia.com>");
+MODULE_DESCRIPTION("cpufreq driver for NVIDIA Tegra124");