[PATCH v6 4/4] clk: samsung: exynos-audss: Use runtime PM

[Marek Szyprowski <m.szyprowski@samsung.com>]

This patch adds support for runtime PM to Exynos Audio SubSystem driver to
enable full support for audio power domain on Exynos5 SoCs. The main change
is moving register saving and restoring code from system sleep PM ops to
runtime PM ops and implementing system sleep PM ops with generic
pm_runtime_force_suspend/resume helpers. Runtime PM of the Exynos AudSS
device is managed from clock core depending on the preparation status
of the provided clocks.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 .../devicetree/bindings/clock/clk-exynos-audss.txt |  6 ++
 drivers/clk/samsung/clk-exynos-audss.c             | 68 +++++++++++++---------
 2 files changed, 45 insertions(+), 29 deletions(-)

diff --git a/Documentation/devicetree/bindings/clock/clk-exynos-audss.txt b/Documentation/devicetree/bindings/clock/clk-exynos-audss.txt
index 0c3d6015868d..f3635d5aeba4 100644
--- a/Documentation/devicetree/bindings/clock/clk-exynos-audss.txt
+++ b/Documentation/devicetree/bindings/clock/clk-exynos-audss.txt
@@ -33,6 +33,12 @@ Required Properties:
 - clock-names: Aliases for the above clocks. They should be "pll_ref",
   "pll_in", "cdclk", "sclk_audio", and "sclk_pcm_in" respectively.
 
+Optional Properties:
+
+  - power-domains: a phandle to respective power domain node as described by
+    generic PM domain bindings (see power/power_domain.txt for more
+    information).
+
 The following is the list of clocks generated by the controller. Each clock is
 assigned an identifier and client nodes use this identifier to specify the
 clock which they consume. Some of the clocks are available only on a particular
diff --git a/drivers/clk/samsung/clk-exynos-audss.c b/drivers/clk/samsung/clk-exynos-audss.c
index cb7df358a27d..2af07e159538 100644
--- a/drivers/clk/samsung/clk-exynos-audss.c
+++ b/drivers/clk/samsung/clk-exynos-audss.c
@@ -18,6 +18,7 @@
 #include <linux/syscore_ops.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
 
 #include <dt-bindings/clock/exynos-audss-clk.h>
 
@@ -37,14 +38,13 @@
 #define ASS_CLK_DIV 0x4
 #define ASS_CLK_GATE 0x8
 
-#ifdef CONFIG_PM_SLEEP
 static unsigned long reg_save[][2] = {
 	{ ASS_CLK_SRC,  0 },
 	{ ASS_CLK_DIV,  0 },
 	{ ASS_CLK_GATE, 0 },
 };
 
-static int exynos_audss_clk_suspend(struct device *dev)
+static int __maybe_unused exynos_audss_clk_suspend(struct device *dev)
 {
 	int i;
 
@@ -54,7 +54,7 @@ static int exynos_audss_clk_suspend(struct device *dev)
 	return 0;
 }
 
-static int exynos_audss_clk_resume(struct device *dev)
+static int __maybe_unused exynos_audss_clk_resume(struct device *dev)
 {
 	int i;
 
@@ -63,7 +63,6 @@ static int exynos_audss_clk_resume(struct device *dev)
 
 	return 0;
 }
-#endif /* CONFIG_PM_SLEEP */
 
 struct exynos_audss_clk_drvdata {
 	unsigned int has_adma_clk:1;
@@ -134,6 +133,7 @@ static int exynos_audss_clk_probe(struct platform_device *pdev)
 	struct clk *pll_ref, *pll_in, *cdclk, *sclk_audio, *sclk_pcm_in;
 	const struct exynos_audss_clk_drvdata *variant;
 	struct resource *res;
+	struct device *dev = &pdev->dev;
 	int i, ret = 0;
 
 	variant = of_device_get_match_data(&pdev->dev);
@@ -141,15 +141,15 @@ static int exynos_audss_clk_probe(struct platform_device *pdev)
 		return -EINVAL;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	reg_base = devm_ioremap_resource(&pdev->dev, res);
+	reg_base = devm_ioremap_resource(dev, res);
 	if (IS_ERR(reg_base)) {
-		dev_err(&pdev->dev, "failed to map audss registers\n");
+		dev_err(dev, "failed to map audss registers\n");
 		return PTR_ERR(reg_base);
 	}
 
 	epll = ERR_PTR(-ENODEV);
 
-	clk_table = devm_kzalloc(&pdev->dev,
+	clk_table = devm_kzalloc(dev,
 				sizeof(struct clk *) * EXYNOS_AUDSS_MAX_CLKS,
 				GFP_KERNEL);
 	if (!clk_table)
@@ -158,8 +158,8 @@ static int exynos_audss_clk_probe(struct platform_device *pdev)
 	clk_data.clks = clk_table;
 	clk_data.clk_num = variant->num_clks;
 
-	pll_ref = devm_clk_get(&pdev->dev, "pll_ref");
-	pll_in = devm_clk_get(&pdev->dev, "pll_in");
+	pll_ref = devm_clk_get(dev, "pll_ref");
+	pll_in = devm_clk_get(dev, "pll_in");
 	if (!IS_ERR(pll_ref))
 		mout_audss_p[0] = __clk_get_name(pll_ref);
 	if (!IS_ERR(pll_in)) {
@@ -170,81 +170,89 @@ static int exynos_audss_clk_probe(struct platform_device *pdev)
 
 			ret = clk_prepare_enable(epll);
 			if (ret) {
-				dev_err(&pdev->dev,
+				dev_err(dev,
 					"failed to prepare the epll clock\n");
 				return ret;
 			}
 		}
 	}
-	clk_table[EXYNOS_MOUT_AUDSS] = clk_register_mux(NULL, "mout_audss",
+
+	/*
+	 * Enable runtime PM here, so clock core with use runtime PM for all
+	 * registered clocks.
+	 */
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+
+	clk_table[EXYNOS_MOUT_AUDSS] = clk_register_mux(dev, "mout_audss",
 				mout_audss_p, ARRAY_SIZE(mout_audss_p),
 				CLK_SET_RATE_NO_REPARENT,
 				reg_base + ASS_CLK_SRC, 0, 1, 0, &lock);
 
-	cdclk = devm_clk_get(&pdev->dev, "cdclk");
-	sclk_audio = devm_clk_get(&pdev->dev, "sclk_audio");
+	cdclk = devm_clk_get(dev, "cdclk");
+	sclk_audio = devm_clk_get(dev, "sclk_audio");
 	if (!IS_ERR(cdclk))
 		mout_i2s_p[1] = __clk_get_name(cdclk);
 	if (!IS_ERR(sclk_audio))
 		mout_i2s_p[2] = __clk_get_name(sclk_audio);
-	clk_table[EXYNOS_MOUT_I2S] = clk_register_mux(NULL, "mout_i2s",
+	clk_table[EXYNOS_MOUT_I2S] = clk_register_mux(dev, "mout_i2s",
 				mout_i2s_p, ARRAY_SIZE(mout_i2s_p),
 				CLK_SET_RATE_NO_REPARENT,
 				reg_base + ASS_CLK_SRC, 2, 2, 0, &lock);
 
-	clk_table[EXYNOS_DOUT_SRP] = clk_register_divider(NULL, "dout_srp",
+	clk_table[EXYNOS_DOUT_SRP] = clk_register_divider(dev, "dout_srp",
 				"mout_audss", 0, reg_base + ASS_CLK_DIV, 0, 4,
 				0, &lock);
 
-	clk_table[EXYNOS_DOUT_AUD_BUS] = clk_register_divider(NULL,
+	clk_table[EXYNOS_DOUT_AUD_BUS] = clk_register_divider(dev,
 				"dout_aud_bus", "dout_srp", 0,
 				reg_base + ASS_CLK_DIV, 4, 4, 0, &lock);
 
-	clk_table[EXYNOS_DOUT_I2S] = clk_register_divider(NULL, "dout_i2s",
+	clk_table[EXYNOS_DOUT_I2S] = clk_register_divider(dev, "dout_i2s",
 				"mout_i2s", 0, reg_base + ASS_CLK_DIV, 8, 4, 0,
 				&lock);
 
-	clk_table[EXYNOS_SRP_CLK] = clk_register_gate(NULL, "srp_clk",
+	clk_table[EXYNOS_SRP_CLK] = clk_register_gate(dev, "srp_clk",
 				"dout_srp", CLK_SET_RATE_PARENT,
 				reg_base + ASS_CLK_GATE, 0, 0, &lock);
 
-	clk_table[EXYNOS_I2S_BUS] = clk_register_gate(NULL, "i2s_bus",
+	clk_table[EXYNOS_I2S_BUS] = clk_register_gate(dev, "i2s_bus",
 				"dout_aud_bus", CLK_SET_RATE_PARENT,
 				reg_base + ASS_CLK_GATE, 2, 0, &lock);
 
-	clk_table[EXYNOS_SCLK_I2S] = clk_register_gate(NULL, "sclk_i2s",
+	clk_table[EXYNOS_SCLK_I2S] = clk_register_gate(dev, "sclk_i2s",
 				"dout_i2s", CLK_SET_RATE_PARENT,
 				reg_base + ASS_CLK_GATE, 3, 0, &lock);
 
-	clk_table[EXYNOS_PCM_BUS] = clk_register_gate(NULL, "pcm_bus",
+	clk_table[EXYNOS_PCM_BUS] = clk_register_gate(dev, "pcm_bus",
 				 "sclk_pcm", CLK_SET_RATE_PARENT,
 				reg_base + ASS_CLK_GATE, 4, 0, &lock);
 
-	sclk_pcm_in = devm_clk_get(&pdev->dev, "sclk_pcm_in");
+	sclk_pcm_in = devm_clk_get(dev, "sclk_pcm_in");
 	if (!IS_ERR(sclk_pcm_in))
 		sclk_pcm_p = __clk_get_name(sclk_pcm_in);
-	clk_table[EXYNOS_SCLK_PCM] = clk_register_gate(NULL, "sclk_pcm",
+	clk_table[EXYNOS_SCLK_PCM] = clk_register_gate(dev, "sclk_pcm",
 				sclk_pcm_p, CLK_SET_RATE_PARENT,
 				reg_base + ASS_CLK_GATE, 5, 0, &lock);
 
 	if (variant->has_adma_clk) {
-		clk_table[EXYNOS_ADMA] = clk_register_gate(NULL, "adma",
+		clk_table[EXYNOS_ADMA] = clk_register_gate(dev, "adma",
 				"dout_srp", CLK_SET_RATE_PARENT,
 				reg_base + ASS_CLK_GATE, 9, 0, &lock);
 	}
 
 	for (i = 0; i < clk_data.clk_num; i++) {
 		if (IS_ERR(clk_table[i])) {
-			dev_err(&pdev->dev, "failed to register clock %d\n", i);
+			dev_err(dev, "failed to register clock %d\n", i);
 			ret = PTR_ERR(clk_table[i]);
 			goto unregister;
 		}
 	}
 
-	ret = of_clk_add_provider(pdev->dev.of_node, of_clk_src_onecell_get,
+	ret = of_clk_add_provider(dev->of_node, of_clk_src_onecell_get,
 					&clk_data);
 	if (ret) {
-		dev_err(&pdev->dev, "failed to add clock provider\n");
+		dev_err(dev, "failed to add clock provider\n");
 		goto unregister;
 	}
 
@@ -272,8 +280,10 @@ static int exynos_audss_clk_remove(struct platform_device *pdev)
 }
 
 static const struct dev_pm_ops exynos_audss_clk_pm_ops = {
-	SET_LATE_SYSTEM_SLEEP_PM_OPS(exynos_audss_clk_suspend,
-				     exynos_audss_clk_resume)
+	SET_RUNTIME_PM_OPS(exynos_audss_clk_suspend, exynos_audss_clk_resume,
+			   NULL)
+	SET_LATE_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+				     pm_runtime_force_resume)
 };
 
 static struct platform_driver exynos_audss_clk_driver = {
-- 
1.9.1