Re: [PATCH 2/2] davinci-mcasp: add option to use AHCLKX pin as clock in

From: Peter Ujfalusi
Date: Fri Feb 06 2015 - 06:49:45 EST


On 02/06/2015 11:22 AM, Urs FÃssler wrote:
> Signed-off-by: Urs FÃssler <urs.fassler@xxxxxxxxxxxxxx>
> ---
> .../bindings/sound/davinci-mcasp-audio.txt | 1 +
> sound/soc/davinci/davinci-mcasp.c | 26
> +++++++++++++++++++---
> 2 files changed, 24 insertions(+), 3 deletions(-)
>
> diff --git
> a/Documentation/devicetree/bindings/sound/davinci-mcasp-audio.txt
> b/Documentation/devicetree/bindings/sound/davinci-mcasp-audio.txt
> index 46bc982..22a91d2 100644
> --- a/Documentation/devicetree/bindings/sound/davinci-mcasp-audio.txt
> +++ b/Documentation/devicetree/bindings/sound/davinci-mcasp-audio.txt
> @@ -39,6 +39,7 @@ Optional properties:
> please refer to pinctrl-bindings.txt
> - fck_parent : Should contain a valid clock name which will be used as
> parent
> for the McASP fck
> +- ahclkx-pin : if set use AHCLKX pin for clock in instead of ACLKX
> Example:
> diff --git a/sound/soc/davinci/davinci-mcasp.c
> b/sound/soc/davinci/davinci-mcasp.c
> index 396cdec..3730288 100644
> --- a/sound/soc/davinci/davinci-mcasp.c
> +++ b/sound/soc/davinci/davinci-mcasp.c
> @@ -85,6 +85,7 @@ struct davinci_mcasp {
> int sysclk_freq;
> bool bclk_master;
> + bool ahclkx_pin;
> /* McASP FIFO related */
> u8 txnumevt;
> @@ -429,7 +430,12 @@ static int davinci_mcasp_set_dai_fmt(struct
> snd_soc_dai *cpu_dai,
> break;
> case SND_SOC_DAIFMT_CBM_CFS:
> /* codec is clock master and frame slave */
> - mcasp_clr_bits(mcasp, DAVINCI_MCASP_ACLKXCTL_REG, ACLKXE);
> + if (mcasp->ahclkx_pin)
> + mcasp_set_bits(mcasp, DAVINCI_MCASP_ACLKXCTL_REG,
> + ACLKXE);
> + else
> + mcasp_clr_bits(mcasp, DAVINCI_MCASP_ACLKXCTL_REG,
> + ACLKXE);

This is not correct. ACLKXE bit of ACLKXCTL register configures the transmit
bit clock source.
With CBM_CFx it has to be set to 0 (codec is providing the bit clock via ACLKX
pin)
and when CBS_CFx it need to be 1 (McASP will provide the bit clock)

> mcasp_set_bits(mcasp, DAVINCI_MCASP_TXFMCTL_REG, AFSXE);
> mcasp_clr_bits(mcasp, DAVINCI_MCASP_ACLKRCTL_REG, ACLKRE);
> @@ -441,7 +447,12 @@ static int davinci_mcasp_set_dai_fmt(struct
> snd_soc_dai *cpu_dai,
> break;
> case SND_SOC_DAIFMT_CBM_CFM:
> /* codec is clock and frame master */
> - mcasp_clr_bits(mcasp, DAVINCI_MCASP_ACLKXCTL_REG, ACLKXE);
> + if (mcasp->ahclkx_pin)
> + mcasp_set_bits(mcasp, DAVINCI_MCASP_ACLKXCTL_REG,
> + ACLKXE);
> + else
> + mcasp_clr_bits(mcasp, DAVINCI_MCASP_ACLKXCTL_REG,
> + ACLKXE);

same here

> mcasp_clr_bits(mcasp, DAVINCI_MCASP_TXFMCTL_REG, AFSXE);
> mcasp_clr_bits(mcasp, DAVINCI_MCASP_ACLKRCTL_REG, ACLKRE);
> @@ -542,7 +553,12 @@ static int davinci_mcasp_set_sysclk(struct
> snd_soc_dai *dai, int clk_id,
> struct davinci_mcasp *mcasp = snd_soc_dai_get_drvdata(dai);
> if (mcasp->bclk_master) {
> - mcasp_set_bits(mcasp, DAVINCI_MCASP_AHCLKXCTL_REG, AHCLKXE);
> + if (mcasp->ahclkx_pin)
> + mcasp_clr_bits(mcasp, DAVINCI_MCASP_AHCLKXCTL_REG,
> + AHCLKXE);
> + else
> + mcasp_set_bits(mcasp, DAVINCI_MCASP_AHCLKXCTL_REG,
> + AHCLKXE);

not sure why you need to do this...

You can just select the sysclk (AHCLKX) from the machine driver:
snd_soc_dai_set_sysclk(cpu_dai, 0, sysclk, SND_SOC_CLOCK_IN);


> mcasp_set_bits(mcasp, DAVINCI_MCASP_AHCLKRCTL_REG, AHCLKRE);
> mcasp_set_bits(mcasp, DAVINCI_MCASP_PDIR_REG, AHCLKX);
> } else {
> @@ -1340,6 +1356,8 @@ static struct davinci_mcasp_pdata
> *davinci_mcasp_set_pdata_from_of(
> if (ret >= 0)
> pdata->sram_size_capture = val;
> + pdata->clk_input_pin = of_property_read_bool(np, "ahclkx-pin");
> +
> return pdata;
> nodata:
> @@ -1412,6 +1430,8 @@ static int davinci_mcasp_probe(struct
> platform_device *pdev)
> goto err;
> }
> + mcasp->ahclkx_pin = pdata->clk_input_pin;
> +
> mcasp->op_mode = pdata->op_mode;
> /* sanity check for tdm slots parameter */
> if (mcasp->op_mode == DAVINCI_MCASP_IIS_MODE) {
>


--
PÃter
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