MCASP as slave with dummy I2S codec as master

Hi, I'm working on an am335x project and I am trying to integrate an audio capture-only codec that acts as I2S master and produces sound in LEFT-J format. This codec has no audio controls over i2c. I've set up a dummy codec module that just accepts any parameter and is fixed to 16KHz, 16-bit LE, stereo audio. I've hooked that up to the davinci-evm module and added this DAI:

static struct snd_soc_dai_link input_dai_dummy_i2s = {            
    .name       = "Dummy I2S Capture",
    .stream_name    = "Capture",
    .codec_dai_name = "dummy-i2s",
    .ops            = &evm_ops,
    .init           = evm_dummy_i2s_init,
    .dai_fmt = SND_SOC_DAIFMT_LEFT_J | SND_SOC_DAIFMT_CBM_CFM | SND_SOC_DAIFMT_NB_NF,
};

And I've updated the device tree IDs for my new codec:

static const struct of_device_id davinci_evm_dt_ids[] = {
    {
        .compatible = "ti,dummy-i2s-evm-audio",
        .data = (void *) &input_dai_dummy_i2s,
    },
    {
        .compatible = "ti,da830-evm-audio",
        .data = (void *) &evm_dai_tlv320aic3x,
    },
    { /* sentinel */ }
}

My evm_dummy_i2s_init is almost the same as the evm_aic3x_init function except I've removed the controls and non-connected pin registration:

static int evm_dummy_i2s_init(struct snd_soc_pcm_runtime *rtd)                
{                                                                         
    struct snd_soc_card *card = rtd->card;                                
    struct snd_soc_codec *codec = rtd->codec;                             
    struct device_node *np = card->dev->of_node;                          
    int ret;                                                              
                                                                          
    if (np) {                                                             
        ret = snd_soc_of_parse_audio_routing(card, "ti,audio-routing");   
        if (ret)                                                          
            return ret;                                                   
    } else {                                                              
        /* Set up davinci-evm specific audio path audio_map */            
        snd_soc_dapm_add_routes(&card->dapm, audio_map,                   
                    ARRAY_SIZE(audio_map));                               
    }
                                                                          
    return 0;                                                             
}                                                                         

Finally, I added some device tree nodes (in this reduced example I'm working on a beaglebone black) and removed all the HDMI connectivity. I also enabled mcasp in mode 3 so I can use P8's pins 33, 35, and 36.

/*
 * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
/dts-v1/;

#include "am33xx.dtsi"
#include "am335x-bone-common.dtsi"

/ {
	model = "TI AM335x BeagleBone Black";
	compatible = "ti,am335x-bone-black", "ti,am335x-bone", "ti,am33xx";
};

&ldo3_reg {
	regulator-min-microvolt = <1800000>;
	regulator-max-microvolt = <1800000>;
	regulator-always-on;
};

&mmc1 {
	vmmc-supply = <&vmmcsd_fixed>;
};

&mmc2 {
	vmmc-supply = <&vmmcsd_fixed>;
	pinctrl-names = "default";
	pinctrl-0 = <&emmc_pins>;
	bus-width = <8>;
	status = "okay";
};

&rtc {
	system-power-controller;
};

&am33xx_pinmux {

	mcasp0_audio_input_pins: mcasp0_audio_input_pins {
		pinctrl-single,pins = <
			0xd0 ( PIN_INPUT | MUX_MODE3 ) /* (V2) lcd_data12.mcasp0_aclkr */
			0xd4 ( PIN_INPUT | MUX_MODE3 ) /* (V3) lcd_data13.mcasp0_fsr */
			0xc8 ( PIN_INPUT | MUX_MODE3 ) /* (U3) lcd_data10.mcasp0_axr0 */
		>;
	};

	mcasp0_audio_input_pins_sleep: mcasp0_audio_input_pins_sleep {
		pinctrl-single,pins = <
			0xd0 ( PIN_INPUT | MUX_MODE3 ) /* (V2) lcd_data12.mcasp0_aclkr */
			0xd4 ( PIN_INPUT | MUX_MODE3 ) /* (V3) lcd_data13.mcasp0_fsr */
			0xc8 ( PIN_INPUT | MUX_MODE3 ) /* (U3) lcd_data10.mcasp0_axr0 */
		>;
	};

};

&mcasp0 {

    pinctrl-names = "default", "sleep";
    pinctrl-0 = <&mcasp0_audio_input_pins>;
    pinctrl-1 = <&mcasp0_audio_input_pins_sleep>;

    status = "okay";
    op-mode = <0>;
    tdm-slots = <2>;
    serial-dir = <
        2 0 0 0
    >;
    rx-num-evt = <1>;
    tx-num-evt = <1>;
};

/ {

	dummy_i2s: dummy_i2s {
		compatible = "linux,dummy-i2s";
		status = "okay";
	};

	sound@0 {
		compatible = "ti,dummy-i2s-evm-audio";
		ti,model = "Dummy I2S";
		ti,audio-codec = <&dummy_i2s>;
		ti,mcasp-controller = <&mcasp0>;
		ti,codec-clock-rate = <1024000>;
		ti,audio-routing = "ANA IN1", "Internal Mic";
	};

};

Anyway, I'm running Linux 4.4.1 and the codec registers correctly after all this. However, when I try to record with arecord, it hangs indefinitely and no audio is produced to the output file. I can verify that the device is producing a 1024000 Hz bit clock and 16000 Hz frame sync clock. I have a 3-wire connection between the codec and my beaglebone with ACLKR, FSR, and AXR0 pins hooked up.

A representative from the codec maker has indicated that the codec does not need a master clock but maybe the mcasp/davinci-evm needs one when operating as slave. Does anyone have any experience in these cases?

Thanks.