[PATCH v7 11/11] clk: imx: lpcg: add suspend/resume support
Dong Aisheng
aisheng.dong at nxp.com
Wed Jul 29 04:00:18 EDT 2020
LPCG clock state may be lost when it's power domain is completely
off during system suspend/resume and we need save and restore the
state properly.
Reviewed-by: Stephen Boyd <sboyd at kernel.org>
Signed-off-by: Dong Aisheng <aisheng.dong at nxp.com>
---
ChangeLog:
v5->v7:
* no changes
v5:
* make suspend/resume function static
* improve code comments
v4: no changes
v3: new patch
---
drivers/clk/imx/clk-imx8qxp-lpcg.c | 1 +
drivers/clk/imx/clk-lpcg-scu.c | 37 ++++++++++++++++++++++++++++++
drivers/clk/imx/clk-scu.h | 1 +
3 files changed, 39 insertions(+)
diff --git a/drivers/clk/imx/clk-imx8qxp-lpcg.c b/drivers/clk/imx/clk-imx8qxp-lpcg.c
index 3385de76f6c7..4d4a3a65bcec 100644
--- a/drivers/clk/imx/clk-imx8qxp-lpcg.c
+++ b/drivers/clk/imx/clk-imx8qxp-lpcg.c
@@ -364,6 +364,7 @@ static struct platform_driver imx8qxp_lpcg_clk_driver = {
.driver = {
.name = "imx8qxp-lpcg-clk",
.of_match_table = imx8qxp_lpcg_match,
+ .pm = &imx_clk_lpcg_scu_pm_ops,
.suppress_bind_attrs = true,
},
.probe = imx8qxp_lpcg_clk_probe,
diff --git a/drivers/clk/imx/clk-lpcg-scu.c b/drivers/clk/imx/clk-lpcg-scu.c
index 2242e5047a0e..5bd8af371059 100644
--- a/drivers/clk/imx/clk-lpcg-scu.c
+++ b/drivers/clk/imx/clk-lpcg-scu.c
@@ -33,6 +33,9 @@ struct clk_lpcg_scu {
void __iomem *reg;
u8 bit_idx;
bool hw_gate;
+
+ /* for state save&restore */
+ u32 state;
};
#define to_clk_lpcg_scu(_hw) container_of(_hw, struct clk_lpcg_scu, hw)
@@ -112,6 +115,9 @@ struct clk_hw *__imx_clk_lpcg_scu(struct device *dev, const char *name,
hw = ERR_PTR(ret);
}
+ if (dev)
+ dev_set_drvdata(dev, clk);
+
return hw;
}
@@ -122,3 +128,34 @@ void imx_clk_lpcg_scu_unregister(struct clk_hw *hw)
clk_hw_unregister(&clk->hw);
kfree(clk);
}
+
+static int __maybe_unused imx_clk_lpcg_scu_suspend(struct device *dev)
+{
+ struct clk_lpcg_scu *clk = dev_get_drvdata(dev);
+
+ clk->state = readl_relaxed(clk->reg);
+ dev_dbg(dev, "save lpcg state 0x%x\n", clk->state);
+
+ return 0;
+}
+
+static int __maybe_unused imx_clk_lpcg_scu_resume(struct device *dev)
+{
+ struct clk_lpcg_scu *clk = dev_get_drvdata(dev);
+
+ /*
+ * FIXME: Sometimes writes don't work unless the CPU issues
+ * them twice
+ */
+
+ writel(clk->state, clk->reg);
+ writel(clk->state, clk->reg);
+ dev_dbg(dev, "restore lpcg state 0x%x\n", clk->state);
+
+ return 0;
+}
+
+const struct dev_pm_ops imx_clk_lpcg_scu_pm_ops = {
+ SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(imx_clk_lpcg_scu_suspend,
+ imx_clk_lpcg_scu_resume)
+};
diff --git a/drivers/clk/imx/clk-scu.h b/drivers/clk/imx/clk-scu.h
index faee1ba5c4ee..e8352164923e 100644
--- a/drivers/clk/imx/clk-scu.h
+++ b/drivers/clk/imx/clk-scu.h
@@ -11,6 +11,7 @@
#include <linux/of.h>
extern struct list_head imx_scu_clks[];
+extern const struct dev_pm_ops imx_clk_lpcg_scu_pm_ops;
int imx_clk_scu_init(struct device_node *np);
struct clk_hw *imx_scu_of_clk_src_get(struct of_phandle_args *clkspec,
--
2.23.0
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