diff options
Diffstat (limited to 'drivers/cpufreq/tegra124-cpufreq.c')
| -rw-r--r-- | drivers/cpufreq/tegra124-cpufreq.c | 222 |
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 000000000..aae951d4e --- /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"); |