[Letux-kernel] McBSP clocks on OMAP5?

H. Nikolaus Schaller hns at goldelico.com
Sun Aug 26 08:54:00 CEST 2018


Hi,

> Am 25.08.2018 um 18:29 schrieb H. Nikolaus Schaller <hns at goldelico.com>:
> 
> Hi,
> I am trying to set up a simple sound card on the OMAP5
> using a McBSP like I have it working on OMAP3.
> 
> But I get this messsage:
> 
> [  617.934410] omap_mcbsp_dai_hw_params: not enough bandwidth for desired rate and channels
> [  617.955069] omap-mcbsp 40124000.mcbsp: ASoC: can't set 40124000.mcbsp hw params: -22
> 
> This comes from 
> 
> https://elixir.bootlin.com/linux/v4.18.5/source/sound/soc/omap/omap-mcbsp.c#L368
> 
> Printing the values reveals:
> 
> [  617.946281]   in_freq 0 clk_div 0 div 1
> [  617.950393]   framesize 0 wlen 16 channels 2
> 
> So this means mcbsp->in_freq == 0 which seems to be wrong.
> 
> But how do I set it?
> 
> In omap3.dtsi it appears as if clock is defined:
> 
> 		mcbsp1: mcbsp at 48074000 {
> 			compatible = "ti,omap3-mcbsp";
> 			reg = <0x48074000 0xff>;
> 			reg-names = "mpu";
> 			interrupts = <16>, /* OCP compliant interrupt */
> 				     <59>, /* TX interrupt */
> 				     <60>; /* RX interrupt */
> 			interrupt-names = "common", "tx", "rx";
> 			ti,buffer-size = <128>;
> 			ti,hwmods = "mcbsp1";
> 			dmas = <&sdma 31>,
> 			       <&sdma 32>;
> 			dma-names = "tx", "rx";
> 			clocks = <&mcbsp1_fck>;
> 			clock-names = "fck";
> 			status = "disabled";
> 		};
> 
> while for omap5.dtsi there is no clock:
> 
> 		mcbsp1: mcbsp at 40122000 {
> 			compatible = "ti,omap4-mcbsp";
> 			reg = <0x40122000 0xff>, /* MPU private access */
> 			      <0x49022000 0xff>; /* L3 Interconnect */
> 			reg-names = "mpu", "dma";
> 			interrupts = <GIC_SPI 17 IRQ_TYPE_LEVEL_HIGH>;
> 			interrupt-names = "common";
> 			ti,buffer-size = <128>;
> 			ti,hwmods = "mcbsp1";
> 			dmas = <&sdma 33>,
> 			       <&sdma 34>;
> 			dma-names = "tx", "rx";
> 			status = "disabled";
> 		};
> 
> In both cases I have overwritten status = "okay".
> 
> Any advice?

I have found the issue. I had the wrong dai link definitions for this
mcbsp, assuming a different codec.

There is only one message remaining - after arecord/aplay reports an input/output error:

[   48.492255] omap-mcbsp 40124000.mcbsp: CLKS: could not clk_set_parent() to prcm_fck
[   54.460368] omap-mcbsp 40122000.mcbsp: CLKS: could not clk_set_parent() to prcm_fck

but this may be related to not having activated the pcm master (mcbsp is slave).

BR,
Nikolaus



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