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From:   Cheng-Yi Chiang <cychiang@chromium.org>
To:     linux-kernel@vger.kernel.org
Cc:     Mark Brown <broonie@kernel.org>, Takashi Iwai <tiwai@suse.com>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Jaroslav Kysela <perex@perex.cz>,
        Heiko Stuebner <heiko@sntech.de>, dianders@chromium.org,
        dgreid@chromium.org, tzungbi@chromium.org, mka@chromium.org,
        alsa-devel@alsa-project.org, linux-arm-kernel@lists.infradead.org,
        linux-rockchip@lists.infradead.org,
        Cheng-Yi Chiang <cychiang@chromium.org>
Subject: [PATCH] Revert "ASoC: rockchip: i2s: Support mono capture"
Date:   Fri, 26 Jul 2019 12:42:02 +0800
Message-Id: <20190726044202.26866-1-cychiang@chromium.org>
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Sender: linux-kernel-owner@vger.kernel.org
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This reverts commit db51707b9c9aeedd310ebce60f15d5bb006567e0.

Previous discussion in

https://patchwork.kernel.org/patch/10147153/

explains the issue of the patch.
While device is configured as 1-ch, hardware is still
generating a 2-ch stream.
When user space reads the data and assumes it is a 1-ch stream,
the rate will be slower by 2x.

Revert the change so 1-ch is not supported.
User space can selectively take one channel data out of two channel
if 1-ch is preferred.
Currently, both channels record identical data.

Signed-off-by: Cheng-Yi Chiang <cychiang@chromium.org>
---
 sound/soc/rockchip/rockchip_i2s.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/sound/soc/rockchip/rockchip_i2s.c b/sound/soc/rockchip/rockchip_i2s.c
index 0a34d0eb8dba..88ebaf6e1880 100644
--- a/sound/soc/rockchip/rockchip_i2s.c
+++ b/sound/soc/rockchip/rockchip_i2s.c
@@ -326,7 +326,6 @@ static int rockchip_i2s_hw_params(struct snd_pcm_substream *substream,
 		val |= I2S_CHN_4;
 		break;
 	case 2:
-	case 1:
 		val |= I2S_CHN_2;
 		break;
 	default:
@@ -459,7 +458,7 @@ static struct snd_soc_dai_driver rockchip_i2s_dai = {
 	},
 	.capture = {
 		.stream_name = "Capture",
-		.channels_min = 1,
+		.channels_min = 2,
 		.channels_max = 2,
 		.rates = SNDRV_PCM_RATE_8000_192000,
 		.formats = (SNDRV_PCM_FMTBIT_S8 |
@@ -659,7 +658,7 @@ static int rockchip_i2s_probe(struct platform_device *pdev)
 	}
 
 	if (!of_property_read_u32(node, "rockchip,capture-channels", &val)) {
-		if (val >= 1 && val <= 8)
+		if (val >= 2 && val <= 8)
 			soc_dai->capture.channels_max = val;
 	}
 
-- 
2.22.0.709.g102302147b-goog