[PATCH 09/18] soundwire: bus: add helper to reset Slave status to UNATTACHED

From: Pierre-Louis Bossart
Date: Wed Oct 23 2019 - 17:47:12 EST


When resuming, we need to re-enumerate and restart from UNATTACHED.

This will help implement a more robust state machine avoiding race
conditions on resume.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
---
drivers/soundwire/bus.c | 24 ++++++++++++++++++++++++
drivers/soundwire/bus.h | 2 ++
2 files changed, 26 insertions(+)

diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c
index 0e761efd32f9..17c744c0ff4c 100644
--- a/drivers/soundwire/bus.c
+++ b/drivers/soundwire/bus.c
@@ -1107,3 +1107,27 @@ int sdw_handle_slave_status(struct sdw_bus *bus,
return ret;
}
EXPORT_SYMBOL(sdw_handle_slave_status);
+
+void sdw_clear_slave_status(struct sdw_bus *bus)
+{
+ struct sdw_slave *slave;
+ int i;
+
+ /* Check all non-zero devices */
+ for (i = 1; i <= SDW_MAX_DEVICES; i++) {
+ mutex_lock(&bus->bus_lock);
+ if (test_bit(i, bus->assigned) == false) {
+ mutex_unlock(&bus->bus_lock);
+ continue;
+ }
+ mutex_unlock(&bus->bus_lock);
+
+ slave = sdw_get_slave(bus, i);
+ if (!slave)
+ continue;
+
+ if (slave->status != SDW_SLAVE_UNATTACHED)
+ sdw_modify_slave_status(slave, SDW_SLAVE_UNATTACHED);
+ }
+}
+EXPORT_SYMBOL(sdw_clear_slave_status);
diff --git a/drivers/soundwire/bus.h b/drivers/soundwire/bus.h
index acb8d11a4c84..cdbd11292cc3 100644
--- a/drivers/soundwire/bus.h
+++ b/drivers/soundwire/bus.h
@@ -165,4 +165,6 @@ sdw_update(struct sdw_slave *slave, u32 addr, u8 mask, u8 val)
return sdw_write(slave, addr, tmp);
}

+void sdw_clear_slave_status(struct sdw_bus *bus);
+
#endif /* __SDW_BUS_H */
--
2.20.1