Re: [alsa-devel] [PATCH 2/6] soundwire: cadence_master: add hw_reset capability in debugfs

From: Pierre-Louis Bossart
Date: Wed Sep 04 2019 - 13:43:53 EST

On 9/4/19 11:49 AM, Vinod Koul wrote:
On 04-09-19, 08:18, Pierre-Louis Bossart wrote:
On 9/4/19 2:13 AM, Vinod Koul wrote:
On 13-08-19, 16:32, Pierre-Louis Bossart wrote:
Provide debugfs capability to kick link and devices into hard-reset
(as defined by MIPI). This capability is really useful when some
devices are no longer responsive and/or to check the software handling
of resynchronization.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
drivers/soundwire/cadence_master.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)

diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c
index 046622e4b264..bd58d80ff636 100644
--- a/drivers/soundwire/cadence_master.c
+++ b/drivers/soundwire/cadence_master.c
@@ -340,6 +340,23 @@ static int cdns_reg_show(struct seq_file *s, void *data)
+static int cdns_hw_reset(void *data, u64 value)
+ struct sdw_cdns *cdns = data;
+ int ret;
+ if (value != 1)
+ return 0;

Should this not be EINVAL to indicate invalid value passed?

Maybe. I must admit I don't know what -EINVAL would do, this is used for
debugfs so it's not clear to me if the user will see a difference?

Well user should see "write error: Invalid argument" when he writes
anything other than valid values :)

ok then, will do.