On 8/23/22 10:08 AM, 班涛 wrote:
> Samuel Holland <samuel@xxxxxxxxxxxx> 于2022年8月20 日周六 14:57写道：
> On 8/11/22 9:49 AM, Ban Tao wrote:
> > + switch (params_format(params)) {
> > + case SNDRV_PCM_FORMAT_S16_LE:
> > + regmap_update_bits(host->regmap, SUN50I_DMIC_RXFIFO_CTL,
> > + SUN50I_DMIC_RXFIFO_CTL_SAMPLE_MASK,
> > + SUN50I_DMIC_RXFIFO_CTL_SAMPLE_16);
> > + break;
> > + case SNDRV_PCM_FORMAT_S24_LE:
> > + regmap_update_bits(host->regmap, SUN50I_DMIC_RXFIFO_CTL,
> > + SUN50I_DMIC_RXFIFO_CTL_SAMPLE_MASK,
> > + SUN50I_DMIC_RXFIFO_CTL_SAMPLE_24);
> > + break;
> > + default:
> > + dev_err(cpu_dai->dev, "Invalid format!\n");
> > + return -EINVAL;
> > + }
> > + regmap_update_bits(host->regmap, SUN50I_DMIC_RXFIFO_CTL,
> > + SUN50I_DMIC_RXFIFO_CTL_MODE_MASK,
> > + SUN50I_DMIC_RXFIFO_CTL_MODE_MSB);
>
> I checked the manuals again, and I may have given you bad information. There
> appear to be two variants of the DMIC hardware.
>
> A63, H6, V5 V100, and V5x6 manuals list Mode 1 as "reserved" for a 24-bit sample
> resolution. The newer SoCs (A50, A133, D1, H616, and R329) describe Mode 1 as
> extending the 21-bit sample with three zeros at the LSB to make 24 bits, which
> is what we want.
>
> On my D1 board, recording in S24_LE gives me good audio data, with equivalent
> loudness to S16_LE, as I would expect. If this also works on older SoCs like H6,
> then the manual is wrong, and the driver is fine.
>
>
> I checked the H6 manual, DMIC also supports 24bits. The H6 SoC works fine in
> mode 1. I don't know where your manual came from, mine is provided by SUNXI.
I am referencing the manual linked from the linux-sunxi wiki, section 7.4.5.7:
https://linux-sunxi.org/images/4/46/Allwinner_H6_V200_User_Manual_V1.1.pdf
For 24-bit received audio sample:
Mode 0: RXDATA[31:0] = {FIFO_O[23:0], 8'h0}
Mode 1: Reserved
Since the manual is wrong, could you please add a comment? Something like "The
hardware supports FIFO mode 1 for 24-bit samples, even though the H6 manual
describes that combination as reserved."
Regards,
Samuel
