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// 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_device.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");
MODULE_LICENSE("GPL v2");
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