soundwire: intel: move to auxiliary bus

Now that the auxiliary_bus exists, there's no reason to use platform
devices as children of a PCI device any longer.

This patch refactors the code by extending a basic auxiliary device
with Intel link-specific structures that need to be passed between
controller and link levels. This refactoring is much cleaner with no
need for cross-pointers between device and link structures.

Note that the auxiliary bus API has separate init and add steps, which
requires more attention in the error unwinding paths. The main loop
needs to deal with kfree() and auxiliary_device_uninit() for the
current iteration before jumping to the common label which releases
everything allocated in prior iterations.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20210511052132.28150-1-yung-chuan.liao@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

Author: plbossart

drivers/soundwire/Kconfig

@@ -25,6 +25,7 @@ config SOUNDWIRE_INTEL
 	tristate "Intel SoundWire Master driver"
 	select SOUNDWIRE_CADENCE
 	select SOUNDWIRE_GENERIC_ALLOCATION
+	select AUXILIARY_BUS
 	depends on ACPI && SND_SOC
 	help
 	  SoundWire Intel Master driver.

drivers/soundwire/intel.c

@@ -11,7 +11,7 @@
 #include <linux/module.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
-#include <linux/platform_device.h>
+#include <linux/auxiliary_bus.h>
 #include <sound/pcm_params.h>
 #include <linux/pm_runtime.h>
 #include <sound/soc.h>
@@ -1327,11 +1327,14 @@ static int intel_init(struct sdw_intel *sdw)
 }
 
 /*
- * probe and init
+ * probe and init (aux_dev_id argument is required by function prototype but not used)
  */
-static int intel_master_probe(struct platform_device *pdev)
+static int intel_link_probe(struct auxiliary_device *auxdev,
+			    const struct auxiliary_device_id *aux_dev_id)
+
 {
-	struct device *dev = &pdev->dev;
+	struct device *dev = &auxdev->dev;
+	struct sdw_intel_link_dev *ldev = auxiliary_dev_to_sdw_intel_link_dev(auxdev);
 	struct sdw_intel *sdw;
 	struct sdw_cdns *cdns;
 	struct sdw_bus *bus;
@@ -1344,14 +1347,14 @@ static int intel_master_probe(struct platform_device *pdev)
 	cdns = &sdw->cdns;
 	bus = &cdns->bus;
 
-	sdw->instance = pdev->id;
-	sdw->link_res = dev_get_platdata(dev);
+	sdw->instance = auxdev->id;
+	sdw->link_res = &ldev->link_res;
 	cdns->dev = dev;
 	cdns->registers = sdw->link_res->registers;
 	cdns->instance = sdw->instance;
 	cdns->msg_count = 0;
 
-	bus->link_id = pdev->id;
+	bus->link_id = auxdev->id;
 
 	sdw_cdns_probe(cdns);
 
@@ -1384,10 +1387,10 @@ static int intel_master_probe(struct platform_device *pdev)
 	return 0;
 }
 
-int intel_master_startup(struct platform_device *pdev)
+int intel_link_startup(struct auxiliary_device *auxdev)
 {
 	struct sdw_cdns_stream_config config;
-	struct device *dev = &pdev->dev;
+	struct device *dev = &auxdev->dev;
 	struct sdw_cdns *cdns = dev_get_drvdata(dev);
 	struct sdw_intel *sdw = cdns_to_intel(cdns);
 	struct sdw_bus *bus = &cdns->bus;
@@ -1524,9 +1527,9 @@ int intel_master_startup(struct platform_device *pdev)
 	return ret;
 }
 
-static int intel_master_remove(struct platform_device *pdev)
+static void intel_link_remove(struct auxiliary_device *auxdev)
 {
-	struct device *dev = &pdev->dev;
+	struct device *dev = &auxdev->dev;
 	struct sdw_cdns *cdns = dev_get_drvdata(dev);
 	struct sdw_intel *sdw = cdns_to_intel(cdns);
 	struct sdw_bus *bus = &cdns->bus;
@@ -1542,19 +1545,17 @@ static int intel_master_remove(struct platform_device *pdev)
 		snd_soc_unregister_component(dev);
 	}
 	sdw_bus_master_delete(bus);
-
-	return 0;
 }
 
-int intel_master_process_wakeen_event(struct platform_device *pdev)
+int intel_link_process_wakeen_event(struct auxiliary_device *auxdev)
 {
-	struct device *dev = &pdev->dev;
+	struct device *dev = &auxdev->dev;
 	struct sdw_intel *sdw;
 	struct sdw_bus *bus;
 	void __iomem *shim;
 	u16 wake_sts;
 
-	sdw = platform_get_drvdata(pdev);
+	sdw = dev_get_drvdata(dev);
 	bus = &sdw->cdns.bus;
 
 	if (bus->prop.hw_disabled) {
@@ -1976,17 +1977,22 @@ static const struct dev_pm_ops intel_pm = {
 	SET_RUNTIME_PM_OPS(intel_suspend_runtime, intel_resume_runtime, NULL)
 };
 
-static struct platform_driver sdw_intel_drv = {
-	.probe = intel_master_probe,
-	.remove = intel_master_remove,
+static const struct auxiliary_device_id intel_link_id_table[] = {
+	{ .name = "soundwire_intel.link" },
+	{},
+};
+MODULE_DEVICE_TABLE(auxiliary, intel_link_id_table);
+
+static struct auxiliary_driver sdw_intel_drv = {
+	.probe = intel_link_probe,
+	.remove = intel_link_remove,
 	.driver = {
-		.name = "intel-sdw",
+		/* auxiliary_driver_register() sets .name to be the modname */
 		.pm = &intel_pm,
-	}
+	},
+	.id_table = intel_link_id_table
 };
-
-module_platform_driver(sdw_intel_drv);
+module_auxiliary_driver(sdw_intel_drv);
 
 MODULE_LICENSE("Dual BSD/GPL");
-MODULE_ALIAS("platform:intel-sdw");
-MODULE_DESCRIPTION("Intel Soundwire Master Driver");
+MODULE_DESCRIPTION("Intel Soundwire Link Driver");

drivers/soundwire/intel.h

@@ -7,7 +7,6 @@
 /**
  * struct sdw_intel_link_res - Soundwire Intel link resource structure,
  * typically populated by the controller driver.
- * @pdev: platform_device
  * @mmio_base: mmio base of SoundWire registers
  * @registers: Link IO registers base
  * @shim: Audio shim pointer
@@ -23,7 +22,6 @@
  * @list: used to walk-through all masters exposed by the same controller
  */
 struct sdw_intel_link_res {
-	struct platform_device *pdev;
 	void __iomem *mmio_base; /* not strictly needed, useful for debug */
 	void __iomem *registers;
 	void __iomem *shim;
@@ -48,7 +46,15 @@ struct sdw_intel {
 #endif
 };
 
-int intel_master_startup(struct platform_device *pdev);
-int intel_master_process_wakeen_event(struct platform_device *pdev);
+int intel_link_startup(struct auxiliary_device *auxdev);
+int intel_link_process_wakeen_event(struct auxiliary_device *auxdev);
+
+struct sdw_intel_link_dev {
+	struct auxiliary_device auxdev;
+	struct sdw_intel_link_res link_res;
+};
+
+#define auxiliary_dev_to_sdw_intel_link_dev(auxiliary_dev) \
+	container_of(auxiliary_dev, struct sdw_intel_link_dev, auxdev)
 
 #endif /* __SDW_INTEL_LOCAL_H */