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Date:   Fri, 13 Sep 2019 11:42:14 +0800
From:   Shawn Guo <shawnguo@kernel.org>
To:     Anson Huang <anson.huang@nxp.com>
Cc:     Dong Aisheng <dongas86@gmail.com>, Stephen Boyd <sboyd@kernel.org>,
        Peng Fan <peng.fan@nxp.com>,
        "festevam@gmail.com" <festevam@gmail.com>,
        "mturquette@baylibre.com" <mturquette@baylibre.com>,
        "s.hauer@pengutronix.de" <s.hauer@pengutronix.de>,
        Aisheng Dong <aisheng.dong@nxp.com>,
        "kernel@pengutronix.de" <kernel@pengutronix.de>,
        dl-linux-imx <linux-imx@nxp.com>, Jacky Bai <ping.bai@nxp.com>,
        Abel Vesa <abel.vesa@nxp.com>,
        "linux-clk@vger.kernel.org" <linux-clk@vger.kernel.org>,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] clk: imx: lpcg: write twice when writing lpcg regs
Message-ID: <20190913034213.GH17142@dragon>
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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@kernel.org> wrote:
> > >
> > > Quoting Peng Fan (2019-08-27 01:17:50)
> > > > From: Peng Fan <peng.fan@nxp.com>
> > > >
> > > > 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@nxp.com>
> > >
> > > 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