diff options
Diffstat (limited to 'drivers/clk/tegra/clk-device.c')
| -rw-r--r-- | drivers/clk/tegra/clk-device.c | 199 |
1 files changed, 199 insertions, 0 deletions
diff --git a/drivers/clk/tegra/clk-device.c b/drivers/clk/tegra/clk-device.c new file mode 100644 index 000000000000..c58beaf8afbc --- /dev/null +++ b/drivers/clk/tegra/clk-device.c @@ -0,0 +1,199 @@ +// SPDX-License-Identifier: GPL-2.0-only + +#include <linux/clk.h> +#include <linux/clk-provider.h> +#include <linux/mutex.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> +#include <linux/pm_domain.h> +#include <linux/pm_opp.h> +#include <linux/pm_runtime.h> +#include <linux/slab.h> + +#include <soc/tegra/common.h> + +#include "clk.h" + +/* + * This driver manages performance state of the core power domain for the + * independent PLLs and system clocks. We created a virtual clock device + * for such clocks, see tegra_clk_dev_register(). + */ + +struct tegra_clk_device { + struct notifier_block clk_nb; + struct device *dev; + struct clk_hw *hw; + struct mutex lock; +}; + +static int tegra_clock_set_pd_state(struct tegra_clk_device *clk_dev, + unsigned long rate) +{ + struct device *dev = clk_dev->dev; + struct dev_pm_opp *opp; + unsigned int pstate; + + opp = dev_pm_opp_find_freq_ceil(dev, &rate); + if (opp == ERR_PTR(-ERANGE)) { + /* + * Some clocks may be unused by a particular board and they + * may have uninitiated clock rate that is overly high. In + * this case clock is expected to be disabled, but still we + * need to set up performance state of the power domain and + * not error out clk initialization. A typical example is + * a PCIe clock on Android tablets. + */ + dev_dbg(dev, "failed to find ceil OPP for %luHz\n", rate); + opp = dev_pm_opp_find_freq_floor(dev, &rate); + } + + if (IS_ERR(opp)) { + dev_err(dev, "failed to find OPP for %luHz: %pe\n", rate, opp); + return PTR_ERR(opp); + } + + pstate = dev_pm_opp_get_required_pstate(opp, 0); + dev_pm_opp_put(opp); + + return dev_pm_genpd_set_performance_state(dev, pstate); +} + +static int tegra_clock_change_notify(struct notifier_block *nb, + unsigned long msg, void *data) +{ + struct clk_notifier_data *cnd = data; + struct tegra_clk_device *clk_dev; + int err = 0; + + clk_dev = container_of(nb, struct tegra_clk_device, clk_nb); + + mutex_lock(&clk_dev->lock); + switch (msg) { + case PRE_RATE_CHANGE: + if (cnd->new_rate > cnd->old_rate) + err = tegra_clock_set_pd_state(clk_dev, cnd->new_rate); + break; + + case ABORT_RATE_CHANGE: + err = tegra_clock_set_pd_state(clk_dev, cnd->old_rate); + break; + + case POST_RATE_CHANGE: + if (cnd->new_rate < cnd->old_rate) + err = tegra_clock_set_pd_state(clk_dev, cnd->new_rate); + break; + + default: + break; + } + mutex_unlock(&clk_dev->lock); + + return notifier_from_errno(err); +} + +static int tegra_clock_sync_pd_state(struct tegra_clk_device *clk_dev) +{ + unsigned long rate; + int ret; + + mutex_lock(&clk_dev->lock); + + rate = clk_hw_get_rate(clk_dev->hw); + ret = tegra_clock_set_pd_state(clk_dev, rate); + + mutex_unlock(&clk_dev->lock); + + return ret; +} + +static int tegra_clock_probe(struct platform_device *pdev) +{ + struct tegra_core_opp_params opp_params = {}; + struct tegra_clk_device *clk_dev; + struct device *dev = &pdev->dev; + struct clk *clk; + int err; + + if (!dev->pm_domain) + return -EINVAL; + + clk_dev = devm_kzalloc(dev, sizeof(*clk_dev), GFP_KERNEL); + if (!clk_dev) + return -ENOMEM; + + clk = devm_clk_get(dev, NULL); + if (IS_ERR(clk)) + return PTR_ERR(clk); + + clk_dev->dev = dev; + clk_dev->hw = __clk_get_hw(clk); + clk_dev->clk_nb.notifier_call = tegra_clock_change_notify; + mutex_init(&clk_dev->lock); + + platform_set_drvdata(pdev, clk_dev); + + /* + * Runtime PM was already enabled for this device by the parent clk + * driver and power domain state should be synced under clk_dev lock, + * hence we don't use the common OPP helper that initializes OPP + * state. For some clocks common OPP helper may fail to find ceil + * rate, it's handled by this driver. + */ + err = devm_tegra_core_dev_init_opp_table(dev, &opp_params); + if (err) + return err; + + err = clk_notifier_register(clk, &clk_dev->clk_nb); + if (err) { + dev_err(dev, "failed to register clk notifier: %d\n", err); + return err; + } + + /* + * The driver is attaching to a potentially active/resumed clock, hence + * we need to sync the power domain performance state in a accordance to + * the clock rate if clock is resumed. + */ + err = tegra_clock_sync_pd_state(clk_dev); + if (err) + goto unreg_clk; + + return 0; + +unreg_clk: + clk_notifier_unregister(clk, &clk_dev->clk_nb); + + return err; +} + +/* + * Tegra GENPD driver enables clocks during NOIRQ phase. It can't be done + * for clocks served by this driver because runtime PM is unavailable in + * NOIRQ phase. We will keep clocks resumed during suspend to mitigate this + * problem. In practice this makes no difference from a power management + * perspective since voltage is kept at a nominal level during suspend anyways. + */ +static const struct dev_pm_ops tegra_clock_pm = { + SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_resume_and_get, pm_runtime_put) +}; + +static const struct of_device_id tegra_clock_match[] = { + { .compatible = "nvidia,tegra20-sclk" }, + { .compatible = "nvidia,tegra30-sclk" }, + { .compatible = "nvidia,tegra30-pllc" }, + { .compatible = "nvidia,tegra30-plle" }, + { .compatible = "nvidia,tegra30-pllm" }, + { } +}; + +static struct platform_driver tegra_clock_driver = { + .driver = { + .name = "tegra-clock", + .of_match_table = tegra_clock_match, + .pm = &tegra_clock_pm, + .suppress_bind_attrs = true, + }, + .probe = tegra_clock_probe, +}; +builtin_platform_driver(tegra_clock_driver); |