Hi Leif > -----Original Message----- > From: Leif Lindholm [mailto:leif.lindh...@linaro.org] > Sent: Monday, April 23, 2018 2:08 PM > To: Meenakshi Aggarwal <meenakshi.aggar...@nxp.com> > Cc: ard.biesheu...@linaro.org; edk2-devel@lists.01.org; Udit Kumar > <udit.ku...@nxp.com>; Varun Sethi <v.se...@nxp.com> > Subject: Re: [PATCH edk2-platforms 05/39] Silicon/NXP: Add support for I2c > driver > > On Mon, Apr 23, 2018 at 08:21:22AM +0000, Meenakshi Aggarwal wrote: > > > > +/** > > > > + Function to read data using i2c bus > > > > + > > > > + @param I2cBus I2c Controller number > > > > + @param Chip Address of slave device from where data to > > > > be > read > > > > + @param Offset Offset of slave memory > > > > + @param Alen Address length of slave > > > > + @param Buffer A pointer to the destination buffer for the > > > > data > > > > + @param Len Length of data to be read > > > > + > > > > + @retval EFI_NOT_READY Arbitration lost > > > > + @retval EFI_TIMEOUT Failed to initialize data transfer in > predefined > > > time > > > > + @retval EFI_NOT_FOUND ACK was not recieved > > > > + @retval EFI_SUCCESS Read was successful > > > > + > > > > +**/ > > > > +STATIC > > > > +EFI_STATUS > > > > +I2cDataRead ( > > > > + IN UINT32 I2cBus, > > > > + IN UINT8 Chip, > > > > + IN UINT32 Offset, > > > > + IN UINT32 Alen, > > > > + IN UINT8 *Buffer, > > > > + IN UINT32 Len > > > > + ) > > > > +{ > > > > + EFI_STATUS Status; > > > > + UINT32 Temp; > > > > + INT32 I; > > > > + I2C_REGS *I2cRegs; > > > > + > > > > + I2cRegs = (I2C_REGS *)(FixedPcdGet64 (PcdI2c0BaseAddr + > > > > + (I2cBus * FixedPcdGet32 (PcdI2cSize)))); > > > > > > Please get rid of this hardcoded base address and use NonDiscoverable > > > Have a look at Silicon/Socionext/SynQuacer/Drivers/PlatformDxe/ and > > > Silicon/Socionext/SynQuacer/Drivers/SynQuacerI2cDxe/ > > > for example. > > > > > I have checked SynQuacer code and i dont see its adding much advantage. > > What it gives is the ability to cover more than one controller by this > driver, regardless of whether you need it for this particular platform > port or not. > Current board needs one controller. In case of multiple controller, we can use a loop to install multiple protocols and If needed then our preference would be to use I2c enumeration protocol. This will allow to use correct controller for connected devices.
With sample implementation of SynQuacer code, Please advise, how a right controller is being connected to driver e.g. we are registering two controllers mI2c0Desc and mI2c1Desc and both are exporting same protocols. Its user, RTC lib just checking gEfiI2cMasterProtocolGuid. There is possibility to connect with any of the controller. I dont see in code where it is assuring connection with right controller. And how we can assure we are connecting to the correct controller. > > There also base address is hard coded SYNQUACER_I2C1_BASE in > > PlatformDxe driver. > > Yes, the PlatformDxe driver statically instantiates dynamic drivers > for non-discoverable buses. But there is no longer any hard-coded > addresses in the device driver itself. > > / > Leif _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
