soundwire: debugfs: Switch to sdw_read_no_pm

It is rather inefficient to be constantly playing with the runtime
PM reference for each individual register, switch to holding a PM
runtime reference across the whole register output.

Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20221125142028.1118618-4-ckeepax@opensource.cirrus.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/soundwire/debugfs.c b/drivers/soundwire/debugfs.c
index 49900cd..dea782e 100644 (file)
--- a/drivers/soundwire/debugfs.c
+++ b/drivers/soundwire/debugfs.c
@@ -4,6 +4,7 @@
 #include <linux/device.h>
 #include <linux/debugfs.h>
 #include <linux/mod_devicetable.h>
+#include <linux/pm_runtime.h>
 #include <linux/slab.h>
 #include <linux/soundwire/sdw.h>
 #include <linux/soundwire/sdw_registers.h>
@@ -35,7 +36,7 @@ static ssize_t sdw_sprintf(struct sdw_slave *slave,
 {
        int value;
 
-       value = sdw_read(slave, reg);
+       value = sdw_read_no_pm(slave, reg);
 
        if (value < 0)
                return scnprintf(buf + pos, RD_BUF - pos, "%3x\tXX\n", reg);
@@ -55,6 +56,12 @@ static int sdw_slave_reg_show(struct seq_file *s_file, void *data)
        if (!buf)
                return -ENOMEM;
 
+       ret = pm_runtime_resume_and_get(&slave->dev);
+       if (ret < 0 && ret != -EACCES) {
+               kfree(buf);
+               return ret;
+       }
+
        ret = scnprintf(buf, RD_BUF, "Register  Value\n");
 
        /* DP0 non-banked registers */
@@ -112,6 +119,10 @@ static int sdw_slave_reg_show(struct seq_file *s_file, void *data)
        }
 
        seq_printf(s_file, "%s", buf);
+
+       pm_runtime_mark_last_busy(&slave->dev);
+       pm_runtime_put(&slave->dev);
+
        kfree(buf);
 
        return 0;