Hi all,
I am trying to add a D class amplifier using esai0, using the simple-audio-card driver and custom codec tas6424.
Firstly, I implemented the i2c interface for codec driver to i2c0_cm41 which is:
tas6424: tas6424@6a {
compatible = "ti,tas6424";
reg = <0x6a>;
#sound-dai-cells = <0>;
standby-gpios = <&gpio3 5 GPIO_ACTIVE_LOW>;
mute-gpios = <&gpio3 27 GPIO_ACTIVE_LOW>;
};Then, I added simple-card-audio device tree binding as:
sound-ti-d-class {
compatible = "simple-audio-card";
simple-audio-card,name = "TI-D-Class-Amplifier";
simple-audio-card,mclk-fs = <128>;
simple-audio-card,format = "i2s";
simple-audio-card,cpu {
sound-dai = <&esai0>;
};
simple-audio-card,codec {
sound-dai = <&tas6424>;
};
};After doing these, I can see the card by aplay -l as:
card 3: TIDClassAmplifi [TI-D-Class-Amplifier], device 0: 59010000.esai-tas6424-amplifier tas6424-amplifier-0 []
Subdevices: 1/1
Subdevice #0: subdevice #0
and, I can see snd_controls in the alsamixer and able to change these controls.
However, it constantly gives an error:
[ 461.093818] fsl-esai-dai 59010000.esai: failed to derive required HCKT rate
[ 461.100909] asoc-simple-card sound-ti-d-class: ASoC: machine hw_params failed: -22
I examined the fsl_esai.c driver, I concluded that there is a problem with the clock rates. In the amplifier datasheet the clock rates explained as:
The device supports MCLK rates of 128 × fS , 256 × fS , or 512 × fS .
The device supports SCLK rates of 32 × f S , 48 × f S or 64 × f S .
The device supports FSYNC rates of 44.1 kHz, 48 kHz, or 96 kHz.
The maximum clock frequency is 25 MHz. Therefore, for a 96-kHz FSYNC rate, the maximum MCLK rate is
256 × fS .
The MCLK clock must not be in phase to sync to SCLK. Duty cycle of 50% is required for 128x FSYNC, for 256x
and 512x 50% duty is not required.
How can I set the correct clock rates for the esai interface? I think esai documentation is not mature enough to explain these situations clearly. Is there any comment about this subject?
In case you wonder, the BSP is Linux 4.14.98.
&esai0 {
compatible = "fsl,imx8qm-esai";
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_esai0>;
assigned-clocks = <&clk IMX8QM_ACM_ESAI0_MCLK_SEL>,
<&clk IMX8QM_AUD_PLL0_DIV>,
<&clk IMX8QM_AUD_ACM_AUD_PLL_CLK0_DIV>,
<&clk IMX8QM_AUD_ACM_AUD_REC_CLK0_DIV>,
<&clk IMX8QM_AUD_ESAI_0_EXTAL_IPG>;
assigned-clock-parents = <&clk IMX8QM_AUD_ACM_AUD_PLL_CLK0_CLK>;
assigned-clock-rates = <0>, <786432000>, <49152000>, <12288000>, <49152000>;
fsl,txm-rxs;
status = "okay";
};
