From d20e834e13ce349c9b901b9dd8b7013e255083e8 Mon Sep 17 00:00:00 2001
From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Date: Sat, 5 Sep 2020 02:28:52 +0800
Subject: [PATCH] ASoC: soc-dai: clarify return value for get_sdw_stream()
References: jsc#SLE-16518
Patch-mainline: v5.10-rc1
Git-commit: d20e834e13ce349c9b901b9dd8b7013e255083e8

Previous changes move to use ERR_PTR(-ENOTSUPP), but it's not clear
what implementations can return in case of errors. Explicitly document
that NULL is not a possible return value, only ERR_PTR with a negative
error code is valid.

Fixes: 308811a327c38 ('ASoC: soc-dai: return proper error for get_sdw_stream()')
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Reported-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@linux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20200904182854.3944-2-yung-chuan.liao@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 include/sound/soc-dai.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/sound/soc-dai.h b/include/sound/soc-dai.h
index 776a60529e70..8b693dade9c6 100644
--- a/include/sound/soc-dai.h
+++ b/include/sound/soc-dai.h
@@ -471,7 +471,8 @@ static inline int snd_soc_dai_set_sdw_stream(struct snd_soc_dai *dai,
  * This routine only retrieves that was previously configured
  * with snd_soc_dai_get_sdw_stream()
  *
- * Returns pointer to stream or -ENOTSUPP if callback is not supported;
+ * Returns pointer to stream or an ERR_PTR value, e.g.
+ * ERR_PTR(-ENOTSUPP) if callback is not supported;
  */
 static inline void *snd_soc_dai_get_sdw_stream(struct snd_soc_dai *dai,
 					       int direction)
-- 
2.16.4