[PATCH v7 11/11] clk: imx: lpcg: add suspend/resume support
From: Dong Aisheng <aisheng.dong@nxp.com>
Date: 2020-07-29 08:04:53
Also in:
linux-clk
Subsystem:
common clk framework, nxp i.mx clock drivers, the rest · Maintainers:
Michael Turquette, Stephen Boyd, Abel Vesa, Linus Torvalds
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@kernel.org> Signed-off-by: Dong Aisheng <aisheng.dong@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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