[PATCH v4 3/4] soundwire: debugfs: Switch to sdw_read_no_pm

From: Charles Keepax
Date: Fri Nov 25 2022 - 09:21:00 EST


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@xxxxxxxxxxxxxxx>
Signed-off-by: Charles Keepax <ckeepax@xxxxxxxxxxxxxxxxxxxxx>
---

No change since v3.

drivers/soundwire/debugfs.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/soundwire/debugfs.c b/drivers/soundwire/debugfs.c
index 49900cd207bc7..dea782e0edc4b 100644
--- 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;
--
2.30.2