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Subject[PATCH V1 06/12] clk: tegra: add suspend resume support for DFLL clock
Date
This patch adds support for suspend and resume for DFLL clock.

Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
---
drivers/clk/tegra/clk-dfll.c | 82 ++++++++++++++++++++++++++++++++++++++++++++
drivers/clk/tegra/clk-dfll.h | 2 ++
2 files changed, 84 insertions(+)

diff --git a/drivers/clk/tegra/clk-dfll.c b/drivers/clk/tegra/clk-dfll.c
index 1fc71baae13b..d92a5a05fbbc 100644
--- a/drivers/clk/tegra/clk-dfll.c
+++ b/drivers/clk/tegra/clk-dfll.c
@@ -286,6 +286,7 @@ struct tegra_dfll {
unsigned long dvco_rate_min;

enum dfll_ctrl_mode mode;
+ enum dfll_ctrl_mode resume_mode;
enum dfll_tune_range tune_range;
struct dentry *debugfs_dir;
struct clk_hw dfll_clk_hw;
@@ -1873,6 +1874,87 @@ static int dfll_fetch_common_params(struct tegra_dfll *td)
}

/*
+ * tegra_dfll_suspend
+ * @pdev: DFLL instance
+ *
+ * dfll controls clock/voltage to other devices, including CPU. Therefore,
+ * dfll driver pm suspend callback does not stop cl-dvfs operations. It is
+ * only used to enforce cold voltage limit, since SoC may cool down during
+ * suspend without waking up. The correct temperature zone after suspend will
+ * be updated via dfll cooling device interface during resume of temperature
+ * sensor.
+ */
+void tegra_dfll_suspend(struct platform_device *pdev)
+{
+ struct tegra_dfll *td = dev_get_drvdata(&pdev->dev);
+
+ if (!td)
+ return;
+
+ if (td->mode <= DFLL_DISABLED)
+ return;
+
+ td->resume_mode = td->mode;
+ switch (td->mode) {
+ case DFLL_CLOSED_LOOP:
+ dfll_set_mode(td, DFLL_CLOSED_LOOP);
+ dfll_set_frequency_request(td, &td->last_req);
+
+ dfll_unlock(td);
+ break;
+ default:
+ break;
+ }
+}
+
+/**
+ * tegra_dfll_resume - reprogram the DFLL after context-loss
+ * @pdev: DFLL instance
+ *
+ * Re-initialize and enable target device clock in open loop mode. Called
+ * directly from SoC clock resume syscore operation. Closed loop will be
+ * re-entered in platform syscore ops as well after CPU clock source is
+ * switched to DFLL in open loop.
+ */
+void tegra_dfll_resume(struct platform_device *pdev, bool on_dfll)
+{
+ struct tegra_dfll *td = dev_get_drvdata(&pdev->dev);
+
+ if (!td)
+ return;
+
+ if (on_dfll) {
+ if (td->resume_mode == DFLL_CLOSED_LOOP)
+ dfll_lock(td);
+ td->resume_mode = DFLL_DISABLED;
+ return;
+ }
+
+ reset_control_deassert(td->dvco_rst);
+
+ pm_runtime_get(td->dev);
+
+ /* Re-init DFLL */
+ dfll_init_out_if(td);
+ dfll_set_default_params(td);
+ dfll_set_open_loop_config(td);
+
+ pm_runtime_put(td->dev);
+
+ /* Restore last request and mode up to open loop */
+ switch (td->resume_mode) {
+ case DFLL_CLOSED_LOOP:
+ case DFLL_OPEN_LOOP:
+ dfll_set_mode(td, DFLL_OPEN_LOOP);
+ if (td->pmu_if == TEGRA_DFLL_PMU_I2C)
+ dfll_i2c_set_output_enabled(td, false);
+ break;
+ default:
+ break;
+ }
+}
+
+/*
* API exported to per-SoC platform drivers
*/

diff --git a/drivers/clk/tegra/clk-dfll.h b/drivers/clk/tegra/clk-dfll.h
index 85d0d95223f3..44160b0495fe 100644
--- a/drivers/clk/tegra/clk-dfll.h
+++ b/drivers/clk/tegra/clk-dfll.h
@@ -48,6 +48,8 @@ struct tegra_dfll_soc_data {
int tegra_dfll_register(struct platform_device *pdev,
struct tegra_dfll_soc_data *soc);
struct tegra_dfll_soc_data *tegra_dfll_unregister(struct platform_device *pdev);
+void tegra_dfll_suspend(struct platform_device *pdev);
+void tegra_dfll_resume(struct platform_device *pdev, bool on_dfll);
int tegra_dfll_runtime_suspend(struct device *dev);
int tegra_dfll_runtime_resume(struct device *dev);

--
2.7.4
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