[PATCH] clk: imx: imx8mp: Add pm_runtime support for power saving

[Marco Felsch]

On 24-03-18, Peng Fan wrote:
> > Subject: [PATCH] clk: imx: imx8mp: Add pm_runtime support for power
> > saving
> > 
> > Add pm_runtime support for power saving. In pm runtime suspend state the
> > registers will be reseted, so add registers save in pm runtime suspend and
> > restore them in pm runtime resume.

We had similar patches in our downstream repo but didn't upstream yet
since there was an clk-handing issue. IIRC the issue was regarding the
global clock-prepare lock and a circular dependency on it. Is this
resolved now?

Regards,
  Marco

> > Signed-off-by: Shengjiu Wang <shengjiu.wang at nxp.com>
> 
> Reviewed-by: Peng Fan <peng.fan at nxp.com>
> > ---
> >  drivers/clk/imx/clk-imx8mp-audiomix.c | 99 ++++++++++++++++++++++++++-
> >  1 file changed, 96 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/clk/imx/clk-imx8mp-audiomix.c b/drivers/clk/imx/clk-
> > imx8mp-audiomix.c
> > index 55ed211a5e0b..d2bf53e2aacf 100644
> > --- a/drivers/clk/imx/clk-imx8mp-audiomix.c
> > +++ b/drivers/clk/imx/clk-imx8mp-audiomix.c
> > @@ -7,10 +7,12 @@
> > 
> >  #include <linux/clk-provider.h>
> >  #include <linux/device.h>
> > +#include <linux/io.h>
> >  #include <linux/mod_devicetable.h>
> >  #include <linux/module.h>
> >  #include <linux/of.h>
> >  #include <linux/platform_device.h>
> > +#include <linux/pm_runtime.h>
> > 
> >  #include <dt-bindings/clock/imx8mp-clock.h>
> > 
> > @@ -18,6 +20,7 @@
> > 
> >  #define CLKEN0			0x000
> >  #define CLKEN1			0x004
> > +#define EARC			0x200
> >  #define SAI1_MCLK_SEL		0x300
> >  #define SAI2_MCLK_SEL		0x304
> >  #define SAI3_MCLK_SEL		0x308
> > @@ -26,6 +29,12 @@
> >  #define SAI7_MCLK_SEL		0x314
> >  #define PDM_SEL			0x318
> >  #define SAI_PLL_GNRL_CTL	0x400
> > +#define SAI_PLL_FDIVL_CTL0	0x404
> > +#define SAI_PLL_FDIVL_CTL1	0x408
> > +#define SAI_PLL_SSCG_CTL	0x40C
> > +#define SAI_PLL_MNIT_CTL	0x410
> > +#define IPG_LP_CTRL		0x504
> > +#define REGS_NUM		16
> > 
> >  #define SAIn_MCLK1_PARENT(n)						\
> >  static const struct clk_parent_data					\
> > @@ -182,13 +191,65 @@ static struct clk_imx8mp_audiomix_sel sels[] = {
> >  	CLK_SAIn(7)
> >  };
> > 
> > +struct clk_imx8mp_audiomix_regs {
> > +	u32 regs_num;
> > +	u32 regs_off[];
> > +};
> > +
> > +static const struct clk_imx8mp_audiomix_regs audiomix_regs = {
> > +	.regs_num = REGS_NUM,
> > +	.regs_off = {
> > +		CLKEN0,
> > +		CLKEN1,
> > +		EARC,
> > +		SAI1_MCLK_SEL,
> > +		SAI2_MCLK_SEL,
> > +		SAI3_MCLK_SEL,
> > +		SAI5_MCLK_SEL,
> > +		SAI6_MCLK_SEL,
> > +		SAI7_MCLK_SEL,
> > +		PDM_SEL,
> > +		SAI_PLL_GNRL_CTL,
> > +		SAI_PLL_FDIVL_CTL0,
> > +		SAI_PLL_FDIVL_CTL1,
> > +		SAI_PLL_SSCG_CTL,
> > +		SAI_PLL_MNIT_CTL,
> > +		IPG_LP_CTRL
> > +	},
> > +};
> > +
> > +struct clk_imx8mp_audiomix_drvdata {
> > +	void __iomem *base;
> > +	u32 regs_save[REGS_NUM];
> > +};
> > +
> > +static void clk_imx8mp_audiomix_save_restore(struct device *dev, bool
> > +save) {
> > +	struct clk_imx8mp_audiomix_drvdata *drvdata =
> > dev_get_drvdata(dev);
> > +	void __iomem *base = drvdata->base;
> > +	int i;
> > +
> > +	if (save) {
> > +		for (i = 0; i < audiomix_regs.regs_num; i++)
> > +			drvdata->regs_save[i] = readl(base +
> > audiomix_regs.regs_off[i]);
> > +	} else {
> > +		for (i = 0; i < audiomix_regs.regs_num; i++)
> > +			writel(drvdata->regs_save[i], base +
> > audiomix_regs.regs_off[i]);
> > +	}
> > +}
> > +
> >  static int clk_imx8mp_audiomix_probe(struct platform_device *pdev)  {
> > +	struct clk_imx8mp_audiomix_drvdata *drvdata;
> >  	struct clk_hw_onecell_data *priv;
> >  	struct device *dev = &pdev->dev;
> >  	void __iomem *base;
> >  	struct clk_hw *hw;
> > -	int i;
> > +	int i, ret;
> > +
> > +	drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
> > +	if (!drvdata)
> > +		return -ENOMEM;
> > 
> >  	priv = devm_kzalloc(dev,
> >  			    struct_size(priv, hws,
> > IMX8MP_CLK_AUDIOMIX_END), @@ -202,6 +263,9 @@ static int
> > clk_imx8mp_audiomix_probe(struct platform_device *pdev)
> >  	if (IS_ERR(base))
> >  		return PTR_ERR(base);
> > 
> > +	drvdata->base = base;
> > +	dev_set_drvdata(dev, drvdata);
> > +
> >  	for (i = 0; i < ARRAY_SIZE(sels); i++) {
> >  		if (sels[i].num_parents == 1) {
> >  			hw = devm_clk_hw_register_gate_parent_data(dev,
> > @@ -257,10 +321,38 @@ static int clk_imx8mp_audiomix_probe(struct
> > platform_device *pdev)
> >  	if (IS_ERR(hw))
> >  		return PTR_ERR(hw);
> > 
> > -	return devm_of_clk_add_hw_provider(&pdev->dev,
> > of_clk_hw_onecell_get,
> > -					   priv);
> > +	ret = devm_of_clk_add_hw_provider(&pdev->dev,
> > of_clk_hw_onecell_get,
> > +					  priv);
> > +	if (ret)
> > +		return ret;
> > +
> > +	pm_runtime_enable(&pdev->dev);
> > +	clk_imx8mp_audiomix_save_restore(&pdev->dev, true);
> > +
> > +	return 0;
> >  }
> > 
> > +static int clk_imx8mp_audiomix_runtime_suspend(struct device *dev) {
> > +	clk_imx8mp_audiomix_save_restore(dev, true);
> > +
> > +	return 0;
> > +}
> > +
> > +static int clk_imx8mp_audiomix_runtime_resume(struct device *dev) {
> > +	clk_imx8mp_audiomix_save_restore(dev, false);
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct dev_pm_ops clk_imx8mp_audiomix_pm_ops = {
> > +	SET_RUNTIME_PM_OPS(clk_imx8mp_audiomix_runtime_suspend,
> > +			   clk_imx8mp_audiomix_runtime_resume, NULL)
> > +	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
> > +				      pm_runtime_force_resume)
> > +};
> > +
> >  static const struct of_device_id clk_imx8mp_audiomix_of_match[] = {
> >  	{ .compatible = "fsl,imx8mp-audio-blk-ctrl" },
> >  	{ /* sentinel */ }
> > @@ -272,6 +364,7 @@ static struct platform_driver
> > clk_imx8mp_audiomix_driver = {
> >  	.driver = {
> >  		.name = "imx8mp-audio-blk-ctrl",
> >  		.of_match_table = clk_imx8mp_audiomix_of_match,
> > +		.pm = &clk_imx8mp_audiomix_pm_ops,
> >  	},
> >  };
> > 
> > --
> > 2.34.1
> 
> 
>