dma_request_chan() returns error pointer in case of failures, but the rz_ssi_dma_request() checked for NULL pointer instead.

This patch fixes the issue by checking for ERR_PTR() instead of NULL and sets the DMA pointers to NULL in error case so that ssi can fallback to PIO mode.

Fixes: 26ac471c5354 ("ASoC: sh: rz-ssi: Add SSI DMAC support") Signed-off-by: Biju Das biju.das.jz@bp.renesas.com Reviewed-by: Lad Prabhakar prabhakar.mahadev-lad.rj@bp.renesas.com --- v2->v3: * Added Fixes tag * For SSI with with full-duplex transmission and reception, Add support for fallback to PIO mode, if both channels are not available.

v1->v2: * Replaced IS_ERR_OR_NULL with IS_ERR for error pointer check, as the dma_request_chan function never returns NULL pointer for error case. --- sound/soc/sh/rz-ssi.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/sound/soc/sh/rz-ssi.c b/sound/soc/sh/rz-ssi.c index f097c773d413..fa0cc08f70ec 100644 --- a/sound/soc/sh/rz-ssi.c +++ b/sound/soc/sh/rz-ssi.c @@ -185,7 +185,7 @@ rz_ssi_stream_get(struct rz_ssi_priv *ssi, struct snd_pcm_substream *substream)

static inline bool rz_ssi_is_dma_enabled(struct rz_ssi_priv *ssi) { - return (ssi->playback.dma_ch || ssi->capture.dma_ch); + return (ssi->playback.dma_ch && (ssi->dma_rt || ssi->capture.dma_ch)); }

static int rz_ssi_stream_is_valid(struct rz_ssi_priv *ssi, @@ -676,15 +676,26 @@ static void rz_ssi_release_dma_channels(struct rz_ssi_priv *ssi) static int rz_ssi_dma_request(struct rz_ssi_priv *ssi, struct device *dev) { ssi->playback.dma_ch = dma_request_chan(dev, "tx"); + if (IS_ERR(ssi->playback.dma_ch)) + ssi->playback.dma_ch = NULL; + ssi->capture.dma_ch = dma_request_chan(dev, "rx"); + if (IS_ERR(ssi->capture.dma_ch)) + ssi->capture.dma_ch = NULL; + if (!ssi->playback.dma_ch && !ssi->capture.dma_ch) { ssi->playback.dma_ch = dma_request_chan(dev, "rt"); - if (!ssi->playback.dma_ch) + if (IS_ERR(ssi->playback.dma_ch)) { + ssi->playback.dma_ch = NULL; goto no_dma; + }

ssi->dma_rt = true; }

+ if (!rz_ssi_is_dma_enabled(ssi)) + goto no_dma; + if (ssi->playback.dma_ch && (rz_ssi_dma_slave_config(ssi, ssi->playback.dma_ch, true) < 0)) goto no_dma;