Dell's laptops Inspiron 3500, Inspiron 3501, Inspiron 3505 are using Cirrus Logic
CS8409 HDA bridge with CS42L42 companion codec.

The CS8409 is a multichannel HD audio routing controller.
CS8409 includes support for four channels of digital
microphone data and two bidirectional ASPs for up to 32
channels of TDM data or 4 channels of I2S data. The CS8409 is
intended to be used with a remote companion codec that implements
high performance analog functions in close physical
proximity to the end-equipment audio port or speaker driver.

The CS42L42 is a low-power audio codec with integrated MIPI
SoundWire interface or I2C/I2S/TDM interfaces designed
for portable applications. It provides a high-dynamic range,
stereo DAC for audio playback and a mono high-dynamic-range
ADC for audio capture

CS42L42 is connected to CS8409 HDA bridge via I2C and I2S.

CS8409          CS42L42
-------         --------
ASP1.A TX  -->  ASP_SDIN
ASP1.A RX  <--  ASP_SDOUT
GPIO5      -->  RST#
GPIO4      <--  INT#
GPIO3      <--  WAKE#
GPIO7      <->  I2C SDA
GPIO6      -->  I2C CLK

Tested on DELL Inspiron-3500, DELL Inspiron-3501, DELL Inspiron-3505

This patch will register CS8409 with sound card and create
input/output paths and two input devices, initialise CS42L42
companion codec and configure it for ASP TX/RX TDM mode,
24bit, 48kHz.

cat /proc/asound/pcm
00-00: CS8409 Analog : CS8409 Analog : playback 1 : capture 1
00-03: HDMI 0 : HDMI 0 : playback 1

dmesg
snd_hda_codec_cirrus hdaudioC0D0: autoconfig for CS8409: line_outs=1 (0x2c/0x0/0x0/0x0/0x0) type:speaker
snd_hda_codec_cirrus hdaudioC0D0:    speaker_outs=0 (0x0/0x0/0x0/0x0/0x0)
snd_hda_codec_cirrus hdaudioC0D0:    hp_outs=1 (0x24/0x0/0x0/0x0/0x0)
snd_hda_codec_cirrus hdaudioC0D0:    mono: mono_out=0x0
snd_hda_codec_cirrus hdaudioC0D0:    inputs:
snd_hda_codec_cirrus hdaudioC0D0:      Internal Mic=0x44
snd_hda_codec_cirrus hdaudioC0D0:      Mic=0x34
input: HDA Intel PCH Headphone as /devices/pci0000:00/0000:00:1f.3/sound/card0/input8
input: HDA Intel PCH Headset Mic as /devices/pci0000:00/0000:00:1f.3/sound/card0/input9
Signed-off-by: Vitaly Rodionov <vitalyr@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20210306111934.4832-3-vitalyr@opensource.cirrus.comSigned-off-by: Takashi Iwai <tiwai@suse.de>