On Sat, Sep 7, 2019 at 5:32 PM Stephen Boyd [off-list ref] wrote:

Quoting Dong Aisheng (2019-08-20 04:13:21)

quoted

Clock state will be lost when its power domain is completely off
during system suspend/resume. So we save and restore the state
accordingly in suspend/resume callback.

And this doesn't need any coordination with other clks in the clk tree
right?

AFAIK no as SC firmware may have handled it properly.

quoted

diff --git a/drivers/clk/imx/clk-scu.c b/drivers/clk/imx/clk-scu.c
index edc39d7..8d9cfa2 100644
--- a/drivers/clk/imx/clk-scu.c
+++ b/drivers/clk/imx/clk-scu.c

@@ -46,6 +46,10 @@ struct clk_scu {
        struct clk_hw hw;
        u16 rsrc_id;
        u8 clk_type;
+
+       /* for state save&restore */
+       bool is_enabled;
+       u32 rate;
 };

 /*

@@ -425,6 +429,9 @@ struct clk_hw *__imx_clk_scu(struct device *dev, const char *name,
                hw = ERR_PTR(ret);
        }

+       if (dev)
+               dev_set_drvdata(dev, clk);
+
        return hw;
 }

@@ -481,10 +488,52 @@ static int imx_clk_scu_probe(struct platform_device *pdev)
        return 0;
 }

+int __maybe_unused imx_clk_scu_suspend(struct device *dev)

static?

quoted

+{
+       struct clk_scu *clk = dev_get_drvdata(dev);
+
+       clk->rate = clk_hw_get_rate(&clk->hw);
+       clk->is_enabled = clk_hw_is_enabled(&clk->hw);
+
+       if (clk->rate)
+               dev_dbg(dev, "save rate %d\n", clk->rate);
+
+       if (clk->is_enabled)
+               dev_dbg(dev, "save enabled state\n");
+
+       return 0;
+}
+
+int __maybe_unused imx_clk_scu_resume(struct device *dev)

static?

quoted

+{
+       struct clk_scu *clk = dev_get_drvdata(dev);
+       int ret = 0;
+
+       if (clk->rate) {
+               ret = clk_scu_set_rate(&clk->hw, clk->rate, 0);
+               dev_dbg(dev, "restore rate %d %s\n", clk->rate,
+                       !ret ? "success" : "failed");
+       }
+
+       if (clk->is_enabled) {
+               ret = clk_scu_prepare(&clk->hw);
+               dev_dbg(dev, "restore enabled state %s\n",
+                       !ret ? "success" : "failed");
+       }
+
+       return ret;
+}
+
+const struct dev_pm_ops imx_clk_scu_pm_ops = {

static?

Sorry that i missed to update here as those function are changed to be
used within
this file now.
Will fix.

Regards
Aisheng

quoted

+       SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(imx_clk_scu_suspend,
+                                     imx_clk_scu_resume)
+};
+

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