[PATCH v2 02/11] ASoC: SDCA: export PM helpers keyed on sdca_class_drv

[Srinivas Kandagatla <srinivas.kandagatla@oss.qualcomm.com>]

The class PM callbacks pull sdca_class_drv out of drvdata, so the
built-in class_sdw_driver owns the drvdata slot.  That works for the
generic case but blocks codec drivers that want to embed
sdca_class_drv in their own private struct -- they need drvdata for
their codec priv.

Split the four callbacks into exported helpers that take a
struct sdca_class_drv * directly:

  sdca_class_system_suspend()
  sdca_class_system_resume()
  sdca_class_runtime_suspend()
  sdca_class_runtime_resume()

Codec drivers can now compose these into their own dev_pm_ops without
going through drvdata.

For the built-in class_sdw_driver, add small dev_pm_ops wrappers that
fetch drv from drvdata, wire them into sdca_class_pm_ops, and export
the ops so any generic SDCA slave can pick them up as-is.

No functional change: the built-in class_sdw_driver keeps the same PM
semantics; only the internal plumbing shifts to operate on
sdca_class_drv instead of struct device *dev.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@oss.qualcomm.com>
---
 .../soc/sdca => include/sound}/sdca_class.h   | 19 +++++
 sound/soc/sdca/sdca_class.c                   | 82 +++++++++++++++----
 sound/soc/sdca/sdca_class_function.c          |  2 +-
 3 files changed, 84 insertions(+), 19 deletions(-)
 rename {sound/soc/sdca => include/sound}/sdca_class.h (50%)

diff --git a/sound/soc/sdca/sdca_class.h b/include/sound/sdca_class.h
similarity index 50%
rename from sound/soc/sdca/sdca_class.h
rename to include/sound/sdca_class.h
index 57f7f8d08f49..15a180385202 100644
--- a/sound/soc/sdca/sdca_class.h
+++ b/include/sound/sdca_class.h
@@ -15,6 +15,7 @@
 #include <linux/workqueue.h>
 
 struct device;
+struct dev_pm_ops;
 struct regmap;
 struct sdw_slave;
 struct sdca_function_data;
@@ -32,4 +33,22 @@ struct sdca_class_drv {
 	struct work_struct boot_work;
 };
 
+/*
+ * PM helpers.  Codec drivers embed sdca_class_drv in their own priv,
+ * own dev_set_drvdata(), and compose these into their own dev_pm_ops:
+ *
+ *	static int wcd_runtime_suspend(struct device *dev) {
+ *		struct wcd_priv *priv = dev_get_drvdata(dev);
+ *		return sdca_class_runtime_suspend(&priv->class);
+ *	}
+ *
+ * The built-in class_sdw_driver in sdca_class.c uses sdca_class_pm_ops
+ * directly because it stashes the sdca_class_drv in drvdata itself.
+ */
+int sdca_class_runtime_suspend(struct sdca_class_drv *drv);
+int sdca_class_runtime_resume(struct sdca_class_drv *drv);
+int sdca_class_system_suspend(struct sdca_class_drv *drv);
+int sdca_class_system_resume(struct sdca_class_drv *drv);
+extern const struct dev_pm_ops sdca_class_pm_ops;
+
 #endif /* __SDCA_CLASS_H__ */
diff --git a/sound/soc/sdca/sdca_class.c b/sound/soc/sdca/sdca_class.c
index d7444f442c71..88a29116a334 100644
--- a/sound/soc/sdca/sdca_class.c
+++ b/sound/soc/sdca/sdca_class.c
@@ -20,7 +20,7 @@
 #include <sound/sdca_function.h>
 #include <sound/sdca_interrupts.h>
 #include <sound/sdca_regmap.h>
-#include "sdca_class.h"
+#include <sound/sdca_class.h>
 
 #define CLASS_SDW_ATTACH_TIMEOUT_MS	5000
 
@@ -194,30 +194,41 @@ static void class_sdw_remove(struct sdw_slave *sdw)
 	cancel_work_sync(&drv->boot_work);
 }
 
-static int class_suspend(struct device *dev)
+/**
+ * sdca_class_system_suspend - SDCA class system suspend helper
+ * @drv: caller-owned sdca_class_drv.
+ *
+ * Codec drivers compose this into their own dev_pm_ops.  Disables the
+ * SoundWire interrupt and forces runtime suspend of the underlying
+ * class regmap.
+ */
+int sdca_class_system_suspend(struct sdca_class_drv *drv)
 {
-	struct sdca_class_drv *drv = dev_get_drvdata(dev);
 	int ret;
 
 	disable_irq(drv->sdw->irq);
 
-	ret = pm_runtime_force_suspend(dev);
+	ret = pm_runtime_force_suspend(drv->dev);
 	if (ret) {
-		dev_err(dev, "failed to force suspend: %d\n", ret);
+		dev_err(drv->dev, "failed to force suspend: %d\n", ret);
 		return ret;
 	}
 
 	return 0;
 }
+EXPORT_SYMBOL_NS_GPL(sdca_class_system_suspend, "SND_SOC_SDCA_CLASS");
 
-static int class_resume(struct device *dev)
+/**
+ * sdca_class_system_resume - SDCA class system resume helper
+ * @drv: caller-owned sdca_class_drv.
+ */
+int sdca_class_system_resume(struct sdca_class_drv *drv)
 {
-	struct sdca_class_drv *drv = dev_get_drvdata(dev);
 	int ret;
 
-	ret = pm_runtime_force_resume(dev);
+	ret = pm_runtime_force_resume(drv->dev);
 	if (ret) {
-		dev_err(dev, "failed to force resume: %d\n", ret);
+		dev_err(drv->dev, "failed to force resume: %d\n", ret);
 		return ret;
 	}
 
@@ -225,11 +236,14 @@ static int class_resume(struct device *dev)
 
 	return 0;
 }
+EXPORT_SYMBOL_NS_GPL(sdca_class_system_resume, "SND_SOC_SDCA_CLASS");
 
-static int class_runtime_suspend(struct device *dev)
+/**
+ * sdca_class_runtime_suspend - SDCA class runtime suspend helper
+ * @drv: caller-owned sdca_class_drv.
+ */
+int sdca_class_runtime_suspend(struct sdca_class_drv *drv)
 {
-	struct sdca_class_drv *drv = dev_get_drvdata(dev);
-
 	/*
 	 * Whilst the driver doesn't power the chip down here, going into runtime
 	 * suspend lets the SoundWire bus power down, which means the driver
@@ -239,10 +253,14 @@ static int class_runtime_suspend(struct device *dev)
 
 	return 0;
 }
+EXPORT_SYMBOL_NS_GPL(sdca_class_runtime_suspend, "SND_SOC_SDCA_CLASS");
 
-static int class_runtime_resume(struct device *dev)
+/**
+ * sdca_class_runtime_resume - SDCA class runtime resume helper
+ * @drv: caller-owned sdca_class_drv.
+ */
+int sdca_class_runtime_resume(struct sdca_class_drv *drv)
 {
-	struct sdca_class_drv *drv = dev_get_drvdata(dev);
 	int ret;
 
 	ret = sdw_slave_wait_for_init(drv->sdw, CLASS_SDW_ATTACH_TIMEOUT_MS);
@@ -265,11 +283,39 @@ static int class_runtime_resume(struct device *dev)
 
 	return ret;
 }
+EXPORT_SYMBOL_NS_GPL(sdca_class_runtime_resume, "SND_SOC_SDCA_CLASS");
+
+/*
+ * Convenience dev_pm_ops used by the built-in class_sdw_driver, which
+ * stashes its sdca_class_drv in drvdata directly.  Codec drivers that
+ * embed sdca_class_drv in their own priv compose their own dev_pm_ops
+ * using the sdca_class_*_suspend/resume helpers above.
+ */
+static int class_pm_system_suspend(struct device *dev)
+{
+	return sdca_class_system_suspend(dev_get_drvdata(dev));
+}
+
+static int class_pm_system_resume(struct device *dev)
+{
+	return sdca_class_system_resume(dev_get_drvdata(dev));
+}
+
+static int class_pm_runtime_suspend(struct device *dev)
+{
+	return sdca_class_runtime_suspend(dev_get_drvdata(dev));
+}
+
+static int class_pm_runtime_resume(struct device *dev)
+{
+	return sdca_class_runtime_resume(dev_get_drvdata(dev));
+}
 
-static const struct dev_pm_ops class_pm_ops = {
-	SYSTEM_SLEEP_PM_OPS(class_suspend, class_resume)
-	RUNTIME_PM_OPS(class_runtime_suspend, class_runtime_resume, NULL)
+const struct dev_pm_ops sdca_class_pm_ops = {
+	SYSTEM_SLEEP_PM_OPS(class_pm_system_suspend, class_pm_system_resume)
+	RUNTIME_PM_OPS(class_pm_runtime_suspend, class_pm_runtime_resume, NULL)
 };
+EXPORT_SYMBOL_NS_GPL(sdca_class_pm_ops, "SND_SOC_SDCA_CLASS");
 
 static const struct sdw_device_id class_sdw_id[] = {
 	SDW_SLAVE_ENTRY(0x01FA, 0x4245, 0),
@@ -282,7 +328,7 @@ MODULE_DEVICE_TABLE(sdw, class_sdw_id);
 static struct sdw_driver class_sdw_driver = {
 	.driver = {
 		.name		= "sdca_class",
-		.pm		= pm_ptr(&class_pm_ops),
+		.pm		= pm_ptr(&sdca_class_pm_ops),
 	},
 
 	.probe		= class_sdw_probe,
diff --git a/sound/soc/sdca/sdca_class_function.c b/sound/soc/sdca/sdca_class_function.c
index cc7045dc26e6..10a2b031b572 100644
--- a/sound/soc/sdca/sdca_class_function.c
+++ b/sound/soc/sdca/sdca_class_function.c
@@ -26,7 +26,7 @@
 #include <sound/soc-component.h>
 #include <sound/soc-dai.h>
 #include <sound/soc.h>
-#include "sdca_class.h"
+#include <sound/sdca_class.h>
 #include "sdca_function_device.h"
 
 struct class_function_drv {
-- 
2.53.0