[PATCH] soundwire: debugfs: add root-level peripherals table

From: Bard Liao

Date: Wed Sep 02 2026 - 04:29:35 EST


The table will let user know what peripherals are listed and get the
detected status by the dev_num.

Signed-off-by: Bard Liao <yung-chuan.liao@xxxxxxxxxxxxxxx>
---
drivers/soundwire/debugfs.c | 72 +++++++++++++++++++++++++++++++++++++
1 file changed, 72 insertions(+)

diff --git a/drivers/soundwire/debugfs.c b/drivers/soundwire/debugfs.c
index 2905ec19b838..3cc3428df6a4 100644
--- a/drivers/soundwire/debugfs.c
+++ b/drivers/soundwire/debugfs.c
@@ -9,12 +9,82 @@
#include <linux/pm_runtime.h>
#include <linux/slab.h>
#include <linux/soundwire/sdw.h>
+#include <linux/soundwire/sdw_type.h>
#include <linux/soundwire/sdw_registers.h>
#include <linux/string_choices.h>
#include "bus.h"

static struct dentry *sdw_debugfs_root;

+#define SDW_PERIPH_HEADER_FMT "%-28s %-7s %-16s %-6s %-7s %-8s %-9s %-11s\n"
+#define SDW_PERIPH_ENTRY_FMT "%-28s %-7u %#016llx %-6.4x %-7.4x %-8.2x %-9.2x %-11.1x\n"
+
+static u64 sdw_slave_addr_from_id(struct sdw_bus *bus,
+ const struct sdw_slave_id *id)
+{
+ u64 addr = 0;
+ u8 unique_id = id->unique_id;
+
+ if (unique_id == SDW_IGNORED_UNIQUE_ID)
+ unique_id = 0;
+
+ addr |= FIELD_PREP(SDW_DISCO_LINK_ID_MASK, bus->link_id);
+ addr |= FIELD_PREP(SDW_VERSION_MASK, id->sdw_version);
+ addr |= FIELD_PREP(SDW_UNIQUE_ID_MASK, unique_id);
+ addr |= FIELD_PREP(SDW_MFG_ID_MASK, id->mfg_id);
+ addr |= FIELD_PREP(SDW_PART_ID_MASK, id->part_id);
+ addr |= FIELD_PREP(SDW_CLASS_ID_MASK, id->class_id);
+
+ return addr;
+}
+
+static void sdw_dump_bus_peripherals(struct seq_file *s_file, struct sdw_bus *bus)
+{
+ struct sdw_slave *slave;
+ u64 addr;
+
+ seq_printf(s_file, "master-%d-%d\n",
+ bus->controller_id, bus->link_id);
+ seq_printf(s_file, SDW_PERIPH_HEADER_FMT,
+ "name", "dev_num", "addr", "mfg_id", "part_id",
+ "class_id", "unique_id", "sdw_version");
+
+ mutex_lock(&bus->bus_lock);
+ list_for_each_entry(slave, &bus->slaves, node) {
+ addr = sdw_slave_addr_from_id(bus, &slave->id);
+ seq_printf(s_file, SDW_PERIPH_ENTRY_FMT,
+ dev_name(&slave->dev), slave->dev_num,
+ addr,
+ slave->id.mfg_id, slave->id.part_id,
+ slave->id.class_id, slave->id.unique_id,
+ slave->id.sdw_version);
+ }
+ mutex_unlock(&bus->bus_lock);
+
+ seq_putc(s_file, '\n');
+}
+
+static int sdw_root_peripherals_dump(struct device *dev, void *data)
+{
+ struct sdw_master_device *md;
+ struct seq_file *s_file = data;
+
+ if (dev->type != &sdw_master_type)
+ return 0;
+
+ md = dev_to_sdw_master_device(dev);
+ sdw_dump_bus_peripherals(s_file, md->bus);
+
+ return 0;
+}
+
+static int sdw_root_peripherals_show(struct seq_file *s_file, void *data)
+{
+ return bus_for_each_dev(&sdw_bus_type, NULL, s_file,
+ sdw_root_peripherals_dump);
+}
+DEFINE_SHOW_ATTRIBUTE(sdw_root_peripherals);
+
void sdw_bus_debugfs_init(struct sdw_bus *bus)
{
char name[16];
@@ -375,6 +445,8 @@ void sdw_debugfs_init(void)
firmware_file = kstrdup("", GFP_KERNEL);

sdw_debugfs_root = debugfs_create_dir("soundwire", NULL);
+ debugfs_create_file("peripherals", 0400, sdw_debugfs_root, NULL,
+ &sdw_root_peripherals_fops);
}

void sdw_debugfs_exit(void)
--
2.43.0