Commit ea0c5cba authored by Dong Aisheng's avatar Dong Aisheng Committed by Shawn Guo
Browse files

clk: imx: lpcg: add suspend/resume support 



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: default avatarStephen Boyd <sboyd@kernel.org>
Signed-off-by: default avatarDong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: default avatarShawn Guo <shawnguo@kernel.org>
parent 18cdbad4

drivers/clk/imx/clk-imx8qxp-lpcg.c

+1 −0
Original line number Diff line number Diff line
@@ -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,

drivers/clk/imx/clk-lpcg-scu.c

+37 −0
Original line number Diff line number Diff line
@@ -34,6 +34,9 @@ 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)
@@ -113,6 +116,9 @@ 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;

}
@@ -123,3 +129,34 @@ 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)

};

drivers/clk/imx/clk-scu.h

+1 −0
Original line number Diff line number Diff line
@@ -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,

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