soundwire: bus: clock_stop: don't deal with UNATTACHED Slave devices

We don't need to do anything for the slave if it is unattached during
clock stop prepare and exit sequences.

Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20200531151806.25951-1-yung-chuan.liao@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c
index 24ba772..fcfba1c 100644 (file)
--- a/drivers/soundwire/bus.c
+++ b/drivers/soundwire/bus.c
@@ -863,13 +863,13 @@ int sdw_bus_prep_clk_stop(struct sdw_bus *bus)
                if (!slave->dev_num)
                        continue;
 
-               /* Identify if Slave(s) are available on Bus */
-               is_slave = true;
-
                if (slave->status != SDW_SLAVE_ATTACHED &&
                    slave->status != SDW_SLAVE_ALERT)
                        continue;
 
+               /* Identify if Slave(s) are available on Bus */
+               is_slave = true;
+
                slave_mode = sdw_get_clk_stop_mode(slave);
                slave->curr_clk_stop_mode = slave_mode;
 
@@ -900,6 +900,10 @@ int sdw_bus_prep_clk_stop(struct sdw_bus *bus)
                        return ret;
        }
 
+       /* Don't need to inform slaves if there is no slave attached */
+       if (!is_slave)
+               return ret;
+
        /* Inform slaves that prep is done */
        list_for_each_entry(slave, &bus->slaves, node) {
                if (!slave->dev_num)
@@ -985,13 +989,13 @@ int sdw_bus_exit_clk_stop(struct sdw_bus *bus)
                if (!slave->dev_num)
                        continue;
 
-               /* Identify if Slave(s) are available on Bus */
-               is_slave = true;
-
                if (slave->status != SDW_SLAVE_ATTACHED &&
                    slave->status != SDW_SLAVE_ALERT)
                        continue;
 
+               /* Identify if Slave(s) are available on Bus */
+               is_slave = true;
+
                mode = slave->curr_clk_stop_mode;
 
                if (mode == SDW_CLK_STOP_MODE1) {
@@ -1016,6 +1020,13 @@ int sdw_bus_exit_clk_stop(struct sdw_bus *bus)
        if (is_slave && !simple_clk_stop)
                sdw_bus_wait_for_clk_prep_deprep(bus, SDW_BROADCAST_DEV_NUM);
 
+       /*
+        * Don't need to call slave callback function if there is no slave
+        * attached
+        */
+       if (!is_slave)
+               return 0;
+
        list_for_each_entry(slave, &bus->slaves, node) {
                if (!slave->dev_num)
                        continue;