soundwire: bus: Add internal slave ID and use for IRQs

Currently the SoundWire IRQ code uses the dev_num to create an IRQ
mapping for each slave. However, there is an issue there, the dev_num
is only allocated when the slave enumerates on the bus and enumeration
may happen before or after probe of the slave driver. In the case
enumeration happens after probe of the slave driver then the IRQ
mapping will use dev_num before it is set. This could cause multiple
slaves to use zero as their IRQ mapping.

It is very desirable to have the IRQ mapped before the slave probe
is called, so drivers can do resource allocation in probe as normal. To
solve these issues add an internal ID created for each slave when it is
probed and use that for mapping the IRQ.

Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.dev>
Link: https://lore.kernel.org/r/20250429101808.348462-3-ckeepax@opensource.cirrus.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

3 files changed, 15 insertions, 3 deletions

diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c
index 6cfec4a2af33..377ab21c9cf0 100644
--- a/drivers/soundwire/bus.c
+++ b/drivers/soundwire/bus.c
@@ -56,6 +56,8 @@ int sdw_bus_master_add(struct sdw_bus *bus, struct device *parent,
 		return ret;
 	}
 
+	ida_init(&bus->slave_ida);
+
 	ret = sdw_master_device_add(bus, parent, fwnode);
 	if (ret < 0) {
 		dev_err(parent, "Failed to add master device at link %d\n",
diff --git a/drivers/soundwire/bus_type.c b/drivers/soundwire/bus_type.c
index e98d5db81b1c..75d6f16efced 100644
--- a/drivers/soundwire/bus_type.c
+++ b/drivers/soundwire/bus_type.c
@@ -105,9 +105,17 @@ static int sdw_drv_probe(struct device *dev)
 	if (ret)
 		return ret;
 
+	ret = ida_alloc_max(&slave->bus->slave_ida, SDW_FW_MAX_DEVICES, GFP_KERNEL);
+	if (ret < 0) {
+		dev_err(dev, "Failed to allocated ID: %d\n", ret);
+		return ret;
+	}
+	slave->index = ret;
+
 	ret = drv->probe(slave, id);
 	if (ret) {
 		dev_pm_domain_detach(dev, false);
+		ida_free(&slave->bus->slave_ida, slave->index);
 		return ret;
 	}
 
@@ -174,6 +182,8 @@ static int sdw_drv_remove(struct device *dev)
 
 	dev_pm_domain_detach(dev, false);
 
+	ida_free(&slave->bus->slave_ida, slave->index);
+
 	return ret;
 }
 
diff --git a/drivers/soundwire/irq.c b/drivers/soundwire/irq.c
index c237e6d0766b..f18be37efef8 100644
--- a/drivers/soundwire/irq.c
+++ b/drivers/soundwire/irq.c
@@ -31,7 +31,7 @@ int sdw_irq_create(struct sdw_bus *bus,
 {
 	bus->irq_chip.name = dev_name(bus->dev);
 
-	bus->domain = irq_domain_create_linear(fwnode, SDW_MAX_DEVICES,
+	bus->domain = irq_domain_create_linear(fwnode, SDW_FW_MAX_DEVICES,
 					       &sdw_domain_ops, bus);
 	if (!bus->domain) {
 		dev_err(bus->dev, "Failed to add IRQ domain\n");
@@ -50,12 +50,12 @@ static void sdw_irq_dispose_mapping(void *data)
 {
 	struct sdw_slave *slave = data;
 
-	irq_dispose_mapping(irq_find_mapping(slave->bus->domain, slave->dev_num));
+	irq_dispose_mapping(slave->irq);
 }
 
 void sdw_irq_create_mapping(struct sdw_slave *slave)
 {
-	slave->irq = irq_create_mapping(slave->bus->domain, slave->dev_num);
+	slave->irq = irq_create_mapping(slave->bus->domain, slave->index);
 	if (!slave->irq)
 		dev_warn(&slave->dev, "Failed to map IRQ\n");