Messages in this thread | | | From | Min Li <> | Subject | RE: [PATCH misc v2 2/2] misc: Add Renesas Synchronization Management Unit (SMU) support | Date | Thu, 16 Sep 2021 15:33:06 +0000 |
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> -----Original Message----- > From: Greg KH <gregkh@linuxfoundation.org> > Sent: September 16, 2021 1:26 AM > To: Min Li <min.li.xe@renesas.com> > Cc: arnd@arndb.de; derek.kiernan@xilinx.com; dragan.cvetic@xilinx.com; > linux-kernel@vger.kernel.org; lee.jones@linaro.or > Subject: Re: [PATCH misc v2 2/2] misc: Add Renesas Synchronization > Management Unit (SMU) support > > On Wed, Sep 15, 2021 at 02:47:09PM -0400, min.li.xe@renesas.com wrote: > > From: Min Li <min.li.xe@renesas.com> > > > > This driver is developed for the IDT ClockMatrix(TM) and 82P33xxx > > families of timing and synchronization devices.It will be used by > > Renesas PTP Clock Manager for Linux (pcm4l) software to provide > > support to GNSS assisted partial timing support (APTS) and other > networking timing functions. > > Where is that software?
https://www.renesas.com/us/en/software-tool/ptp-clock-manager-linux
> > Why is this new api not a standard one? >
There is no actual standard for the GNSS assisted partial timing support (APTS) In terms of Linux kernel API
> What is the standard here? > > What do other devices do and why is this a new api? >
There is really no standard for APTS and different company has its own hw/sw solutions
> > Current version provides kernel API's to support the following > > functions -set combomode to enable SYNCE clock support -read dpll's > > state to determine if the dpll is locked to the GNSS channel -read > > dpll's ffo (fractional frequency offset) in ppqt > > Why do all of these have to be in the kernel at all? >
Because all these API's need spi/i2c accesses to the RSMU card and spi/i2c accesses have been abstracted to the MFD driver in kernel
> thanks, > > greg k-h
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