Re: [PATCH] clk: imx: lpcg: write twice when writing lpcg regs

From: Shawn Guo
Date: Thu Sep 12 2019 - 23:52:26 EST


On Tue, Sep 10, 2019 at 02:47:59AM +0000, Anson Huang wrote:
>
>
> > On Sat, Sep 7, 2019 at 9:47 PM Stephen Boyd <sboyd@xxxxxxxxxx> wrote:
> > >
> > > Quoting Peng Fan (2019-08-27 01:17:50)
> > > > From: Peng Fan <peng.fan@xxxxxxx>
> > > >
> > > > There is hardware issue that:
> > > > The output clock the LPCG cell will not turn back on as expected,
> > > > even though a read of the IPG registers in the LPCG indicates that
> > > > the clock should be enabled.
> > > >
> > > > The software workaround is to write twice to enable the LPCG clock
> > > > output.
> > > >
> > > > Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
> > >
> > > Does this need a Fixes tag?
> >
> > Not sure as it's not code logic issue but a hardware bug.
> > And 4.19 LTS still have not this driver support.
>
> Looks like there is an errata for this issue, and Ranjani just sent a patch for review internally,

Having errata number in both commit log and code comment is generally
helpful.

Shawn