soundwire: add sdw_show_ping_status() helper

This helper provides an optional delay parameter to wait for devices
to resync in case of errors, and checks that devices are indeed
attached on the bus.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Acked-By: Vinod Koul <vkoul@kernel.org>
Link: https://lore.kernel.org/r/20220714011043.46059-4-yung-chuan.liao@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c
index 8d4000664fa34f712fa60a3f4b7d985bb90f94b6..d95b07896a3e6838acbf7076bc1d0b103ca265b2 100644 (file)
--- a/drivers/soundwire/bus.c
+++ b/drivers/soundwire/bus.c
@@ -297,6 +297,38 @@ int sdw_transfer(struct sdw_bus *bus, struct sdw_msg *msg)
        return ret;
 }
 
+/**
+ * sdw_show_ping_status() - Direct report of PING status, to be used by Peripheral drivers
+ * @bus: SDW bus
+ * @sync_delay: Delay before reading status
+ */
+void sdw_show_ping_status(struct sdw_bus *bus, bool sync_delay)
+{
+       u32 status;
+
+       if (!bus->ops->read_ping_status)
+               return;
+
+       /*
+        * wait for peripheral to sync if desired. 10-15ms should be more than
+        * enough in most cases.
+        */
+       if (sync_delay)
+               usleep_range(10000, 15000);
+
+       mutex_lock(&bus->msg_lock);
+
+       status = bus->ops->read_ping_status(bus);
+
+       mutex_unlock(&bus->msg_lock);
+
+       if (!status)
+               dev_warn(bus->dev, "%s: no peripherals attached\n", __func__);
+       else
+               dev_dbg(bus->dev, "PING status: %#x\n", status);
+}
+EXPORT_SYMBOL(sdw_show_ping_status);
+
 /**
  * sdw_transfer_defer() - Asynchronously transfer message to a SDW Slave device
  * @bus: SDW bus

diff --git a/include/linux/soundwire/sdw.h b/include/linux/soundwire/sdw.h
index eb840a07c25c3cd779f2d17e4dfe621574b51f5b..822599957b3531855e4484cb359599393dcae1f1 100644 (file)
--- a/include/linux/soundwire/sdw.h
+++ b/include/linux/soundwire/sdw.h
@@ -922,6 +922,8 @@ int sdw_bus_master_add(struct sdw_bus *bus, struct device *parent,
                       struct fwnode_handle *fwnode);
 void sdw_bus_master_delete(struct sdw_bus *bus);
 
+void sdw_show_ping_status(struct sdw_bus *bus, bool sync_delay);
+
 /**
  * sdw_port_config: Master or Slave Port configuration
  *