[alsa-devel] CS8409 Macbook Pro 2016 2017

[Takashi Iwai]

On Mon, 19 Nov 2018 18:30:15 +0100,
David Ulricht wrote:
> 
> 
> I have found the schematics of the board its model A1708:
> http://sualaptop365.edu.vn/threads/apple-macbook-pro-13-a1708-820-00875-051-02265-x502-mlb_catz-schematic-boardview.19646/
> page 48 CS8409 audio codec GPIO7 is SDA GPIO6 is SCL.
> page 50:  the four SSM3515B amplifiers connected to CS8409's I2C SDA/SCL
> have found the datasheet of SSM3515 amplifiers as well:
> https://www.analog.com/media/en/technical-documentation/data-sheets/SSM3515.pdf
> Documentation says: If the REG_EN pin is tied to the PVDD the power-up
> sequence is performed internally.
> According to the SSM3515B REG_EN is also called C2.
> According to the 1708 schematics(page 50) REG_EN also called C2, is connected
> to ground. This means if REG_EN is connected to ground, it uses an external
> 1.8V regulator (page 19 of SSM3515 pdf). e.g. the device needs to be
> initialized via i2c commands. This means the 4 amplifiers SSM3515B need to be
> initialized via i2c, because simply apple decided to disable them by default
> for some reason probably save power while booting for example.
> Now I need to figure out how to send the i2c commands i have from windows10.
> page 21: describes the I2C control which should be of help
> 
> The following windows 10 registry about i2c maybe of help, it has the slaves
> addresses, the start/stop the powerup2c commands, everything needed...:
> "I2CSpeedMode"=dword:00000001
> "I2CPolledMode"=dword:00000001
> "I2CQuickMode"=dword:00000001
> "I2CBusClear"=dword:00000006
> "I2CSlave90Config"=dword:01002090
> "InitI2C"=hex:01,90,3a,00,10,10,b0,00,1d,01,00,02,06,00,11,07,01,00,10,09,02,\
>   07,03,00,12,01,00,08,13,05,ff,06,00,07,20,02,0d,00,2a,02,02,03,00,04,00,05,\
>   02,06,00,07,20,08,02,09,00,0a,80,0b,02,0c,00,0d,a0,01,0c,00,29,02,01,03,02,\
>   04,00,05,00,01,01,00,11,01,0a,02,84,00,23,01,00,03,00,02,3f,00,20,01,03,00,\
>   1b,75,b6,73,c2,00,11,29,01,21,f3,03,20,05,00,12,00,13,80,00,1c,03,c0
> "n0AStreamStartI2C"=hex:01,90,02,00,11,01,02
> "n0AStreamStopI2C"=hex:01,90,02,00,11,01,0a
> "I2CSlave28Config"=dword:00004028
> "I2CSlave2AConfig"=dword:0000402a
> "I2CSlave2CConfig"=dword:0000402c
> "I2CSlave2EConfig"=dword:0000402e
> "n02PwrUpI2C"=hex:04,28,2a,2c,2e,07,00,81,01,11,02,32,03,48,04,11,05,10,00,80
> "n03PwrUpI2C"=hex:01,28,01,05,00,01,2a,01,05,02,01,2c,01,05,01,01,2e,01,05,03
> "ExitI2C"=hex:04,28,2a,2c,2e,01,00,83
> "EQ1S1R7"=hex:1e,b2,9a,1a,df,15,c6,f4,11,19,91,ae,c6,f4,11,16,3b,23,16,3b,23,\
>   d3,89,b9,1f,88,d9,c0,78,b8
> "EQ1S2R7"=hex:16,3d,23,16,3d,23,d3,85,bb,1f,8e,8e,c0,73,03,14,62,da,12,94,45,\
>   d9,23,c2,1d,b9,a4,c2,61,3d
> 
> Now comes the problem that I cannot write my own i2c driver to power up the 4
> SSM3515B amps via the I2C on GPIO7/6 on CS8409.
> I have no idea how to get a pointer to the i2c interface knowing the GPIO7/6
> are the i2c interface.
> If someone helps me to get a C pointer to the i2c bus, I might be able to read
> /write to it and test and figure it out.
> I have only experimented with real i2c bus on Raspberry Pi with C code, and it
> is completely different. I have there an /dev/i2c-l device that I can write to
> file handle the bytes.
> Please advise.

You should try to initialize over i2c over HD-audio GPIO pins using a
user-space program at first.  The GPIO pins can be read/written via
hda-verb as I already mentioned, hence you can access to i2c bus from
the user-space directly.

Once when it's confirmed to work from user-space, we can think of the
kernel-side implementation, too.  Instead of setting up the whole
complex i2c subsystem, we may wire up the existing stuff in
sound/i2c/*, too.


Takashi


> 
> On Fri, Nov 16, 2018 at 7:31 PM Takashi Iwai <tiwai at suse.de> wrote:
> 
>     On Fri, 16 Nov 2018 17:50:24 +0100,
>     David Ulricht wrote:
>     >
>     >     The stuff in sound/i2c/* are mostly for the i2c bus on a PCI sound
>     >     cards, an implementation independent from the standard i2c stuff.
>     >   
>     >     And, in your case, it's hard to know how the i2c bus is connected.
>     >     If it's controlled over HD-audio GPIO pin (one for clk and one for
>     >     data), then some stuff in sound/i2c can be re-used.  Or, if it's on
>     >     another i2c bus, the story will be completely different...
>     >
>     > I have the schematics of the CS8409. the i2c is connected to the GPIO of
>     the
>     > HDA.
>     >
>     > MAX98374 has a Reset Low pin which is connected to GPIO 5 on the HDA
>     > controller CS8409.  This must
>     > be driven high, then wait for 1.5 ms.  Only then will the amps be out of
>     > device shutdown.
>     > GPIO6 is  8409_I2C_SCL
>     > GPIO7 is  8409_I2C_SDA
>     >
>     > GPIO5 is AUD_SPKRAMP_RESET_L
>     >
>     > Knowing GPIO6 is the clock and GPIO7 is the data, how can I use them?
>     > Can I use hda-verb /dev/snd/hwC0D0 0x01 XXX YYY ? what XXX YYY would be
>     ?
>    
>     You need to set GPIO mask, direction then data.
>       0x01 SET_GPIO_MASK 0xXX
>       0x01 SET_GPIO_DIR 0xXX
>       0x01 SET_GPIO_DATA 0xXX
>    
>     The value to be pass is the bits.  GPIO0=0x01, GPIO1=0x02, GPIO3=0x04,
>     ...
>    
>     You can read the data after setting mask and dir by 0x01
>     GET_GPIO_DATA.  Pass 0 for the value, and you'll get a byte value as a
>     read result.
> 
>     Takashi
> 
>