Re: [PATCH v2 2/2] ASoC: fsl_sai: Allow setting the SAI MCLK direction

[Nicolin Chen <nicoleotsuka@gmail.com>]

On Wed, May 04, 2016 at 06:42:52PM -0300, Fabio Estevam wrote:
> From: Fabio Estevam <fabio.estevam@nxp.com>
> 
> On mx6ul the General Purpose Register 1 (GPR1) contains the following
> bits for configuring the direction of the SAI MCLKs:
> SAI1_MCLK_DIR, SAI2_MCLK_DIR, SAI3_MCLK_DIR
> 
> Introduce  the "fsl,sai-mclk-direction-output" optional property to allow
> configuring the SAI_MCLK outputs.
> 
> Tested on a imx6ul-evk board.
> 
> Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
> ---
> Changes since v1:
> - Dropped unneeded gpr node.
> - Change the property name to fsl,sai-mclk-direction-output. (Nicolin)
> - Do a runtime check against fsl,imx6ul-sai. (Nicolin)
> - Use macro instead of switch statement. (Nicolin)
> 
>  .../devicetree/bindings/sound/fsl-sai.txt          |  5 +++++
>  include/linux/mfd/syscon/imx6q-iomuxc-gpr.h        |  6 ++++++
>  sound/soc/fsl/fsl_sai.c                            | 22 ++++++++++++++++++++++
>  3 files changed, 33 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/sound/fsl-sai.txt b/Documentation/devicetree/bindings/sound/fsl-sai.txt
> index 044e5d7..bec3ae0 100644
> --- a/Documentation/devicetree/bindings/sound/fsl-sai.txt
> +++ b/Documentation/devicetree/bindings/sound/fsl-sai.txt
> @@ -48,6 +48,11 @@ Required properties:
>  			  receive data by following their own bit clocks and
>  			  frame sync clocks separately.
>  
> +Optional properties (for mx6ul):
> +
> +  - fsl,sai-mclk-direction-output: This is a boolean property. If present,
> +			 indicates that SAI will output the SAI MCLK clock.
> +
>  Note:
>  - If both fsl,sai-asynchronous and fsl,sai-synchronous-rx are absent, the
>    default synchronous mode (sync Rx with Tx) will be used, which means both
> diff --git a/include/linux/mfd/syscon/imx6q-iomuxc-gpr.h b/include/linux/mfd/syscon/imx6q-iomuxc-gpr.h
> index 238c8db..6835382 100644
> --- a/include/linux/mfd/syscon/imx6q-iomuxc-gpr.h
> +++ b/include/linux/mfd/syscon/imx6q-iomuxc-gpr.h
> @@ -447,5 +447,11 @@
>  #define IMX6UL_GPR1_ENET2_CLK_OUTPUT		(0x1 << 18)
>  #define IMX6UL_GPR1_ENET_CLK_DIR		(0x3 << 17)
>  #define IMX6UL_GPR1_ENET_CLK_OUTPUT		(0x3 << 17)
> +#define IMX6UL_GPR1_SAI1_MCLK_DIR		(0x1 << 19)
> +#define IMX6UL_GPR1_SAI2_MCLK_DIR		(0x1 << 20)
> +#define IMX6UL_GPR1_SAI3_MCLK_DIR		(0x1 << 21)
> +#define IMX6UL_GPR1_SAI_MCLK_MASK		(0x7 << 19)
> +#define MCLK_DIR(x) (x == 1 ? IMX6UL_GPR1_SAI1_MCLK_DIR : x == 2 ? \
> +		     IMX6UL_GPR1_SAI2_MCLK_DIR : IMX6UL_GPR1_SAI3_MCLK_DIR)
>  
>  #endif /* __LINUX_IMX6Q_IOMUXC_GPR_H */
> diff --git a/sound/soc/fsl/fsl_sai.c b/sound/soc/fsl/fsl_sai.c
> index d8b673f..506a5f8 100644
> --- a/sound/soc/fsl/fsl_sai.c
> +++ b/sound/soc/fsl/fsl_sai.c
> @@ -21,6 +21,8 @@
>  #include <sound/core.h>
>  #include <sound/dmaengine_pcm.h>
>  #include <sound/pcm_params.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/mfd/syscon/imx6q-iomuxc-gpr.h>
>  
>  #include "fsl_sai.h"
>  #include "imx-pcm.h"
> @@ -786,10 +788,12 @@ static int fsl_sai_probe(struct platform_device *pdev)
>  {
>  	struct device_node *np = pdev->dev.of_node;
>  	struct fsl_sai *sai;
> +	struct regmap *gpr;
>  	struct resource *res;
>  	void __iomem *base;
>  	char tmp[8];
>  	int irq, ret, i;
> +	u32 index;
>  
>  	sai = devm_kzalloc(&pdev->dev, sizeof(*sai), GFP_KERNEL);
>  	if (!sai)
> @@ -878,6 +882,24 @@ static int fsl_sai_probe(struct platform_device *pdev)
>  		fsl_sai_dai.symmetric_samplebits = 0;
>  	}
>  
> +	if (of_find_property(np, "fsl,sai-mclk-direction-output", NULL) &&
> +	    of_device_is_compatible(pdev->dev.of_node, "fsl,imx6ul-sai")) {
> +		gpr = syscon_regmap_lookup_by_compatible("fsl,imx6ul-iomuxc-gpr");
> +		if (IS_ERR(gpr)) {
> +			dev_err(&pdev->dev, "cannot find iomuxc registers\n");
> +			return PTR_ERR(gpr);
> +		}
> +
> +		ret = of_property_read_u32(np, "sai-index", &index);

Do we need to add this to binding doc as well? Or will it be better
to use alias here? I am not sure though.

Thanks
Nicolin

> +		if (ret) {
> +			dev_err(&pdev->dev, "could not read sai-index\n");
> +			return ret;
> +		}
> +
> +		regmap_update_bits(gpr, IOMUXC_GPR1, MCLK_DIR(index),
> +				   MCLK_DIR(index));
> +	}
> +
>  	sai->dma_params_rx.addr = res->start + FSL_SAI_RDR;
>  	sai->dma_params_tx.addr = res->start + FSL_SAI_TDR;
>  	sai->dma_params_rx.maxburst = FSL_SAI_MAXBURST_RX;
> -- 
> 1.9.1
>