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.

Signed-off-by: Shengjiu Wang <[e-mail]>
Reviewed-by: Peng Fan <[e-mail]>
Reviewed-by: Marc Kleine-Budde <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Abel Vesa <[e-mail]>

drivers/clk/imx/clk-imx8mp-audiomix.c

···
 
 #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>
 
···
 
 #define CLKEN0			0x000
 #define CLKEN1			0x004
+#define EARC			0x200
 #define SAI1_MCLK_SEL		0x300
 #define SAI2_MCLK_SEL		0x304
 #define SAI3_MCLK_SEL		0x308
···
 #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 SAIn_MCLK1_PARENT(n)						\
 static const struct clk_parent_data					\
···
 	CLK_SAIn(7)
 };
 
+static const u16 audiomix_regs[] = {
+	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_priv {
+	void __iomem *base;
+	u32 regs_save[ARRAY_SIZE(audiomix_regs)];
+
+	/* Must be last */
+	struct clk_hw_onecell_data clk_data;
+};
+
+static void clk_imx8mp_audiomix_save_restore(struct device *dev, bool save)
+{
+	struct clk_imx8mp_audiomix_priv *priv = dev_get_drvdata(dev);
+	void __iomem *base = priv->base;
+	int i;
+
+	if (save) {
+		for (i = 0; i < ARRAY_SIZE(audiomix_regs); i++)
+			priv->regs_save[i] = readl(base + audiomix_regs[i]);
+	} else {
+		for (i = 0; i < ARRAY_SIZE(audiomix_regs); i++)
+			writel(priv->regs_save[i], base + audiomix_regs[i]);
+	}
+}
+
 static int clk_imx8mp_audiomix_probe(struct platform_device *pdev)
 {
-	struct clk_hw_onecell_data *priv;
+	struct clk_imx8mp_audiomix_priv *priv;
+	struct clk_hw_onecell_data *clk_hw_data;
 	struct device *dev = &pdev->dev;
 	void __iomem *base;
 	struct clk_hw *hw;
-	int i;
+	int i, ret;
 
 	priv = devm_kzalloc(dev,
-			    struct_size(priv, hws, IMX8MP_CLK_AUDIOMIX_END),
+			    struct_size(priv, clk_data.hws, IMX8MP_CLK_AUDIOMIX_END),
 			    GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
 
-	priv->num = IMX8MP_CLK_AUDIOMIX_END;
+	clk_hw_data = &priv->clk_data;
+	clk_hw_data->num = IMX8MP_CLK_AUDIOMIX_END;
 
 	base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(base))
 		return PTR_ERR(base);
+
+	priv->base = base;
+	dev_set_drvdata(dev, priv);
+
+	/*
+	 * pm_runtime_enable needs to be called before clk register.
+	 * That is to make core->rpm_enabled to be true for clock
+	 * usage.
+	 */
+	pm_runtime_get_noresume(dev);
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
 
 	for (i = 0; i < ARRAY_SIZE(sels); i++) {
 		if (sels[i].num_parents == 1) {
···
 				0, NULL, NULL);
 		}
 
-		if (IS_ERR(hw))
-			return PTR_ERR(hw);
+		if (IS_ERR(hw)) {
+			ret = PTR_ERR(hw);
+			goto err_clk_register;
+		}
 
-		priv->hws[sels[i].clkid] = hw;
+		clk_hw_data->hws[sels[i].clkid] = hw;
 	}
 
 	/* SAI PLL */
···
 		ARRAY_SIZE(clk_imx8mp_audiomix_pll_parents),
 		CLK_SET_RATE_NO_REPARENT, base + SAI_PLL_GNRL_CTL,
 		0, 2, 0, NULL, NULL);
-	priv->hws[IMX8MP_CLK_AUDIOMIX_SAI_PLL_REF_SEL] = hw;
+	clk_hw_data->hws[IMX8MP_CLK_AUDIOMIX_SAI_PLL_REF_SEL] = hw;
 
 	hw = imx_dev_clk_hw_pll14xx(dev, "sai_pll", "sai_pll_ref_sel",
 				    base + 0x400, &imx_1443x_pll);
-	if (IS_ERR(hw))
-		return PTR_ERR(hw);
-	priv->hws[IMX8MP_CLK_AUDIOMIX_SAI_PLL] = hw;
+	if (IS_ERR(hw)) {
+		ret = PTR_ERR(hw);
+		goto err_clk_register;
+	}
+	clk_hw_data->hws[IMX8MP_CLK_AUDIOMIX_SAI_PLL] = hw;
 
 	hw = devm_clk_hw_register_mux_parent_data_table(dev,
 		"sai_pll_bypass", clk_imx8mp_audiomix_pll_bypass_sels,
 		ARRAY_SIZE(clk_imx8mp_audiomix_pll_bypass_sels),
 		CLK_SET_RATE_NO_REPARENT | CLK_SET_RATE_PARENT,
 		base + SAI_PLL_GNRL_CTL, 16, 1, 0, NULL, NULL);
-	if (IS_ERR(hw))
-		return PTR_ERR(hw);
-	priv->hws[IMX8MP_CLK_AUDIOMIX_SAI_PLL_BYPASS] = hw;
+	if (IS_ERR(hw)) {
+		ret = PTR_ERR(hw);
+		goto err_clk_register;
+	}
+
+	clk_hw_data->hws[IMX8MP_CLK_AUDIOMIX_SAI_PLL_BYPASS] = hw;
 
 	hw = devm_clk_hw_register_gate(dev, "sai_pll_out", "sai_pll_bypass",
 				       0, base + SAI_PLL_GNRL_CTL, 13,
 				       0, NULL);
-	if (IS_ERR(hw))
-		return PTR_ERR(hw);
-	priv->hws[IMX8MP_CLK_AUDIOMIX_SAI_PLL_OUT] = hw;
+	if (IS_ERR(hw)) {
+		ret = PTR_ERR(hw);
+		goto err_clk_register;
+	}
+	clk_hw_data->hws[IMX8MP_CLK_AUDIOMIX_SAI_PLL_OUT] = hw;
 
 	hw = devm_clk_hw_register_fixed_factor(dev, "sai_pll_out_div2",
 					       "sai_pll_out", 0, 1, 2);
-	if (IS_ERR(hw))
-		return PTR_ERR(hw);
+	if (IS_ERR(hw)) {
+		ret = PTR_ERR(hw);
+		goto err_clk_register;
+	}
 
-	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,
+					  clk_hw_data);
+	if (ret)
+		goto err_clk_register;
+
+	pm_runtime_put_sync(dev);
+	return 0;
+
+err_clk_register:
+	pm_runtime_put_sync(dev);
+	pm_runtime_disable(dev);
+	return ret;
 }
+
+static int clk_imx8mp_audiomix_remove(struct platform_device *pdev)
+{
+	pm_runtime_disable(&pdev->dev);
+
+	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" },
···
 
 static struct platform_driver clk_imx8mp_audiomix_driver = {
 	.probe	= clk_imx8mp_audiomix_probe,
+	.remove = clk_imx8mp_audiomix_remove,
 	.driver = {
 		.name = "imx8mp-audio-blk-ctrl",
 		.of_match_table = clk_imx8mp_audiomix_of_match,
+		.pm = &clk_imx8mp_audiomix_pm_ops,
 	},
 };