RE: [PATCH v14 0/3] Add ASPEED AST2600 I2Cv2 controller driver

[Ryan Chen]

> Subject: Re: [PATCH v14 0/3] Add ASPEED AST2600 I2Cv2 controller driver
> 
> On Wed, Oct 02, 2024 at 03:02:10PM +0800, Ryan Chen wrote:
> > This series add AST2600 i2cv2 new register set driver. The i2cv2
> > driver is new register set that have new clock divider option for more
> > flexiable generation. And also have separate i2c master and slave
> > register set for control, patch #2 is i2c master driver only, patch #3
> > is add i2c slave mode driver.
> >
> > The legacy register layout is mix master/slave register control together.
> > The following is add more detail description about new register layout.
> > And new feature set add for register.
> >
> > -Add new clock divider option for more flexible and accurate clock
> > rate generation -Add tCKHighMin timing to guarantee SCL high pulse width.
> > -Add support dual pool buffer mode, split 32 bytes pool buffer of each
> > device into 2 x 16 bytes for Tx and Rx individually.
> > -Increase DMA buffer size to 4096 bytes and support byte alignment.
> > -Re-define the base address of BUS1 ~ BUS16 and Pool buffer.
> > -Re-define registers for separating master and slave mode control.
> > -Support 4 individual DMA buffers for master Tx and Rx, slave Tx and Rx.
> >
> > And following is new register set for package transfer sequence.
> > -New Master operation mode:
> >  S -> Aw -> P
> >  S -> Aw -> TxD -> P
> >  S -> Ar -> RxD -> P
> >  S -> Aw -> RxD -> Sr -> Ar -> TxD -> P -Bus SDA lock auto-release
> > capability for new master DMA command mode.
> > -Bus auto timeout for new master/slave DMA mode.
> >
> > The following is two versus register layout.
> > Old:
> > {I2CD00}: Function Control Register
> > {I2CD04}: Clock and AC Timing Control Register
> > {I2CD08}: Clock and AC Timing Control Register
> > {I2CD0C}: Interrupt Control Register
> > {I2CD10}: Interrupt Status Register
> > {I2CD14}: Command/Status Register
> > {I2CD18}: Slave Device Address Register
> > {I2CD1C}: Pool Buffer Control Register
> > {I2CD20}: Transmit/Receive Byte Buffer Register
> > {I2CD24}: DMA Mode Buffer Address Register
> > {I2CD28}: DMA Transfer Length Register
> > {I2CD2C}: Original DMA Mode Buffer Address Setting
> > {I2CD30}: Original DMA Transfer Length Setting and Final Status
> >
> > New Register mode
> > {I2CC00}: Master/Slave Function Control Register
> > {I2CC04}: Master/Slave Clock and AC Timing Control Register
> > {I2CC08}: Master/Slave Transmit/Receive Byte Buffer Register
> > {I2CC0C}: Master/Slave Pool Buffer Control Register
> > {I2CM10}: Master Interrupt Control Register
> > {I2CM14}: Master Interrupt Status Register
> > {I2CM18}: Master Command/Status Register
> > {I2CM1C}: Master DMA Buffer Length Register
> > {I2CS20}: Slave~ Interrupt Control Register
> > {I2CS24}: Slave~ Interrupt Status Register
> > {I2CS28}: Slave~ Command/Status Register
> > {I2CS2C}: Slave~ DMA Buffer Length Register
> > {I2CM30}: Master DMA Mode Tx Buffer Base Address
> > {I2CM34}: Master DMA Mode Rx Buffer Base Address
> > {I2CS38}: Slave~ DMA Mode Tx Buffer Base Address
> > {I2CS3C}: Slave~ DMA Mode Rx Buffer Base Address
> > {I2CS40}: Slave Device Address Register
> > {I2CM48}: Master DMA Length Status Register
> > {I2CS4C}: Slave  DMA Length Status Register
> > {I2CC50}: Current DMA Operating Address Status
> > {I2CC54}: Current DMA Operating Length  Status
> >
> > aspeed,global-regs:
> > This global register is needed, global register is setting for new
> > clock divide control, and new register set control.
> >
> > ASPEED SOC chip is server product, i2c bus may have fingerprint
> > connect to another board. And also support hotplug.
> > The following is board-specific design example.
> > Board A                                         Board B
> > -------------------------                       ------------------------
> > |i2c bus#1(master/slave)  <===fingerprint ===> i2c bus#x (master/slave)|
> > |i2c bus#2(master)-> tmp i2c device |          |
> |
> > |i2c bus#3(master)-> adc i2c device |          |
> |
> > -------------------------                       ------------------------
> >
> > i2c-scl-clk-low-timeout-us:
> > For example I2C controller as slave mode, and suddenly disconnected.
> > Slave state machine will keep waiting for master clock in for rx/tx
> > transmit. So it need timeout setting to enable timeout unlock
> > controller state. And in another side. In Master side also need avoid
> > suddenly slave miss(un-plug), Master will timeout and release the SDA/SCL.
> >
> > aspeed,enable-dma:
> > For example The bus#1 have trunk data needed for transfer, it can
> > enable bus dma mode transfer, it can reduce cpu utilized.
> > Others bus bus#2/3 use defautl buffer mode.
> 
> Is it possible to switch to new terminology wherever it's possible?
> I.e. master --> controller, slave --> target. See, for example, f872d28500bd
> ("i2c: uniphier-f: reword according to newest specification").
> 
Just for cover latter? Or I should modify for each patches commit message?
Or entire i2c driver statement need switch to target?
> --
> With Best Regards,
> Andy Shevchenko
>