Enable The I2S MCLK

sweckhoff

Hello,

Has anyone figured out how to enable this?

I would like to keep it on all the time.

The bit clock and frame clocks are working as expected. Now I just need to get MCLK for my application.

Thanks!

zhansb

jonsmirl Posted at 10/27/2015 05:07
The I2S section is also missing support for enabling an external I2S clock.

[size=13.63636302948px]try to add the following codec to enable I2s0 clk in rk30_i2s.c :

   i2s->clk_i2s_2ch_out = clk_get(&pdev->dev, "clk_i2s_2ch_out");
  if (IS_ERR(i2s->clk_i2s_2ch_out)) {
    dev_err(&pdev->dev, "Can't retrieve clk_i2s_2ch_out\n");
    ret = PTR_ERR(i2s->clk_i2s_2ch_out);
    goto err;
  }
    clk_prepare_enable(i2s->clk_i2s_2ch_out);

sweckhoff

I am seeing an external MCLK during probe and then it turns off. I would like to have a constant MCLK from probe on. Is this possible with the current drivers?

sweckhoff

It seems like the Rockchip BSP has many errors. Here is what I am seeing in the DT and the I2S driver

Device Tree (NOTE: The pinctrl has been modified because they wouldn't compile when uncommented. This was just another bug.)

473         i2s0: i2s0@10220000 {
474                 compatible = "rockchip-i2s";
475                 reg = <0x10220000 0x1000>;
476                 i2s-id = <0>;
477                 clocks = <&clk_i2s_2ch>, <&clk_i2s_2ch_out>, <&clk_gates7 2>;
478                 clock-names = "i2s_clk", "i2s_mclk", "i2s_hclk";
479                 interrupts = <GIC_SPI 19 IRQ_TYPE_LEVEL_HIGH>;
480                 dmas = <&pdma 0>, <&pdma 1>;
481                 //#dma-cells = <2>;
482                 dma-names = "tx", "rx";
483                 pinctrl-names = "default";
484                 pinctrl-0 = <&i2s0_mclk_mux0 &i2s0_sclk_mux0 &i2s0_lrckrx_mux0 &i2s0_lrcktx_mux0 &i2s0_sdi_mux0 &i2s0_sdo_mux0>;
485                 //pinctrl-0 = <&i2s0_sclk_mux0 &i2s0_lrckrx_mux0 &i2s0_lrcktx_mux0 &i2s0_sdi_mux0 &i2s0_sdo_mux0>;
486                 status = "okay";
487         };              
488                        
489         i2s1: i2s1@10200000 {
490                 compatible = "rockchip-i2s";
491                 reg = <0x10200000 0x1000>;
492                 i2s-id = <1>;
493                 clocks = <&clk_i2s_8ch>, <&clk_gates7 4>;
494                 clock-names = "i2s_clk", "i2s_hclk";
495                 interrupts = <GIC_SPI 68 IRQ_TYPE_LEVEL_HIGH>;
496                 dmas = <&pdma 14>, <&pdma 15>;
497                 //#dma-cells = <2>;
498                 dma-names = "tx", "rx";
499         };

From the I2S Driver

452 struct snd_soc_dai_driver rockchip_i2s_dai[] = {
453         {
454                 .name = "rockchip-i2s.0",
455                 .id = 0,
456                 .playback = {
457                         .channels_min = 2,
458                         .channels_max = 8,
459                         .rates = ROCKCHIP_I2S_STEREO_RATES,
460                         .formats = ROCKCHIP_I2S_FORMATS,
461                 },
462                 .capture = {
463                         .channels_min = 2,
464                         .channels_max = 2,
465                         .rates = ROCKCHIP_I2S_STEREO_RATES,
466                         .formats = ROCKCHIP_I2S_FORMATS,
467                 },
468                 .ops = &rockchip_i2s_dai_ops,
469                 .symmetric_rates = 1,
470         },
471         {
472                 .name = "rockchip-i2s.1",
473                 .id = 1,
474                 .playback = {
475                         .channels_min = 2,
476                         .channels_max = 2,
477                         .rates = ROCKCHIP_I2S_STEREO_RATES,
478                         .formats = ROCKCHIP_I2S_FORMATS,
479                 },
480                 .capture = {
481                         .channels_min = 2,
482                         .channels_max = 2,
483                         .rates = ROCKCHIP_I2S_STEREO_RATES,
484                         .formats = ROCKCHIP_I2S_FORMATS,
485                 },
486                 .ops = &rockchip_i2s_dai_ops,
487                 .symmetric_rates = 1,
488         },
489 };

The number of channels on each I2S interface are swapped! Does anyone know what's what with this?

jonsmirl

The naming is incorrect in the device tree. Look at the reg = <>. The one with the higher address is named I2S0. It just appears to be named wrong. The eight channel I2S is what makes HDMI audio,  8-channel I2S is not accessible on the external pins.

The device tree names can be anything, they are just strings. So this is confusing to a human but the computer doesn't care. The computer does not understand this "i2s1: i2s1@10200000" except as a collection of unique strings. You could name it "blue:rabbit@hat" and the DTC won't care.

jonsmirl

A likely cause for MCLK turning off is that there is default code somewhere turning unused pins into input GPIOs to save power. I have not looked, but you probably need to write a clock driver for the MCLK pin and support it in PINCTRL.  In the DTS IS1 would then depend on this MCLK. Which would trigger the clock driver to turn it on.  Implementing the clock driver marks the pin as in-use and will block the default GPIO behavior.  This is not a lot of code, maybe 30-40 lines.

jonsmirl

The I2S section is also missing support for enabling an external I2S clock.

sweckhoff

jonsmirl Posted at 10/27/2015 05:07
The I2S section is also missing support for enabling an external I2S clock.

Thanks a lot for the help. I will look into this and let you know if it helps.

Overall this is a frustrating platform to work with.

jonsmirl

This is way better than most other Chinese SOCs.

Allwinner only has support because volunteers are doing it, Allwinner pays them nothing.

Zuy

sweckhoff Posted at 10/31/2015 10:36
Thanks a lot for the help. I will look into this and let you know if it helps.

Overall this is ...

Hi, have you finally solved your problem?
Could you please share kernel sources?
I also have to connect external audio codec to RK3128 and having some difficulties.

woody.lee

Hi sweckhoff,
Have you finally solved your problem?
Could you please share kernel sources?
I also have to connect external audio codec(SSM2603) to RK3128 and having "lots" difficulties.