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 000000000..c58beaf8a
--- /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);