Re: [PATCH 07/10] ASoC: fsl_sai: Add support for FIFO combine mode

[Lucas Stach <l.stach@pengutronix.de>]

Am Montag, den 22.07.2019, 15:48 +0300 schrieb Daniel Baluta:
> FIFO combining mode allows the separate FIFOs for multiple data
> channels
> to be used as a single FIFO for either software accesses or a single
> data
> channel or both.
> 
> FIFO combined mode is described in chapter 13.10.3.5.4 from i.MX8MQ
> reference manual [1].
> 
> For each direction (RX/TX) fifo combine mode is read from fsl,fcomb-
> mode
> DT property. By default, if no property is specified fifo combine
> mode
> is disabled.
> 
> [1]https://cache.nxp.com/secured/assets/documents/en/reference-manual
> /IMX8MDQLQRM.pdf?__gda__=1563728701_38bea7f0f726472cc675cb141b91bec7&
> fileExt=.pdf
> 
> Signed-off-by: Daniel Baluta <daniel.baluta@nxp.com>
> ---
>  sound/soc/fsl/fsl_sai.c | 37 +++++++++++++++++++++++++++++++++++++
>  sound/soc/fsl/fsl_sai.h |  9 +++++++++
>  2 files changed, 46 insertions(+)
> 
> diff --git a/sound/soc/fsl/fsl_sai.c b/sound/soc/fsl/fsl_sai.c
> index d0fa02188b7c..140014901fce 100644
> --- a/sound/soc/fsl/fsl_sai.c
> +++ b/sound/soc/fsl/fsl_sai.c
> @@ -475,6 +475,35 @@ static int fsl_sai_hw_params(struct
> snd_pcm_substream *substream,
>  		}
>  	}
>  
> +	switch (sai->soc_data->fcomb_mode[tx]) {
> +	case FSL_SAI_FCOMB_NONE:
> +		regmap_update_bits(sai->regmap, FSL_SAI_xCR4(tx),
> +				   FSL_SAI_CR4_FCOMB_SOFT |
> +				   FSL_SAI_CR4_FCOMB_SHIFT, 0);
> +		break;
> +	case FSL_SAI_FCOMB_SHIFT:
> +		regmap_update_bits(sai->regmap, FSL_SAI_xCR4(tx),
> +				   FSL_SAI_CR4_FCOMB_SOFT |
> +				   FSL_SAI_CR4_FCOMB_SHIFT,
> +				   FSL_SAI_CR4_FCOMB_SHIFT);
> +		break;
> +	case FSL_SAI_FCOMB_SOFT:
> +		regmap_update_bits(sai->regmap, FSL_SAI_xCR4(tx),
> +				   FSL_SAI_CR4_FCOMB_SOFT |
> +				   FSL_SAI_CR4_FCOMB_SHIFT,
> +				   FSL_SAI_CR4_FCOMB_SOFT);
> +		break;
> +	case FSL_SAI_FCOMB_BOTH:
> +		regmap_update_bits(sai->regmap, FSL_SAI_xCR4(tx),
> +				   FSL_SAI_CR4_FCOMB_SOFT |
> +				   FSL_SAI_CR4_FCOMB_SHIFT,
> +				   FSL_SAI_CR4_FCOMB_SOFT |
> +				   FSL_SAI_CR4_FCOMB_SHIFT);
> +		break;
> +	default:
> +		break;
> +	}

This would probably look less redundant if you only select the bits to
set in the switch statement and move the regmap_update_bits after the
switch.

Regards,
Lucas

>  	regmap_update_bits(sai->regmap, FSL_SAI_xCR4(tx),
>  			   FSL_SAI_CR4_SYWD_MASK |
> FSL_SAI_CR4_FRSZ_MASK,
>  			   val_cr4);
> @@ -887,6 +916,14 @@ static int fsl_sai_probe(struct platform_device
> *pdev)
>  		}
>  	}
>  
> +	/* FIFO combine mode for TX/RX, defaults to disabled */
> +	sai->fcomb_mode[RX] = FSL_SAI_FCOMB_NONE;
> +	sai->fcomb_mode[TX] = FSL_SAI_FCOMB_NONE;
> +	of_property_read_u32_index(np, "fsl,fcomb-mode", RX,
> +				   &sai->fcomb_mode[RX]);
> +	of_property_read_u32_index(np, "fsl,fcomb-mode", TX,
> +				   &sai->fcomb_mode[TX]);
> +
>  	/* active data lines mask for TX/RX, defaults to 1 (only the
> first
>  	 * data line is enabled
>  	 */
> diff --git a/sound/soc/fsl/fsl_sai.h b/sound/soc/fsl/fsl_sai.h
> index 6d32f0950ec5..abf140951187 100644
> --- a/sound/soc/fsl/fsl_sai.h
> +++ b/sound/soc/fsl/fsl_sai.h
> @@ -115,6 +115,8 @@
>  #define FSL_SAI_CR3_WDFL_MASK	0x1f
>  
>  /* SAI Transmit and Receive Configuration 4 Register */
> +#define FSL_SAI_CR4_FCOMB_SHIFT BIT(26)
> +#define FSL_SAI_CR4_FCOMB_SOFT  BIT(27)
>  #define FSL_SAI_CR4_FRSZ(x)	(((x) - 1) << 16)
>  #define FSL_SAI_CR4_FRSZ_MASK	(0x1f << 16)
>  #define FSL_SAI_CR4_SYWD(x)	(((x) - 1) << 8)
> @@ -155,6 +157,12 @@
>  #define FSL_SAI_MAXBURST_TX 6
>  #define FSL_SAI_MAXBURST_RX 6
>  
> +/* FIFO combine modes */
> +#define FSL_SAI_FCOMB_NONE     0
> +#define FSL_SAI_FCOMB_SHIFT    1
> +#define FSL_SAI_FCOMB_SOFT     2
> +#define FSL_SAI_FCOMB_BOTH     3
> +
>  struct fsl_sai_soc_data {
>  	bool use_imx_pcm;
>  	unsigned int fifo_depth;
> @@ -177,6 +185,7 @@ struct fsl_sai {
>  	unsigned int slot_width;
>  
>  	unsigned int dl_mask[2];
> +	unsigned int fcomb_mode[2];
>  
>  	const struct fsl_sai_soc_data *soc_data;
>  	struct snd_dmaengine_dai_dma_data dma_params_rx;