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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
Date: Fri, 13 Sep 2019 11:42:14 +0800	[thread overview]
Message-ID: <20190913034213.GH17142@dragon> (raw)
In-Reply-To: <DB3PR0402MB3916906683B58843B459ABE1F5B60@DB3PR0402MB3916.eurprd04.prod.outlook.com>

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

WARNING: multiple messages have this Message-ID (diff)
From: Shawn Guo <shawnguo@kernel.org>
To: Anson Huang <anson.huang@nxp.com>
Cc: Aisheng Dong <aisheng.dong@nxp.com>, Peng Fan <peng.fan@nxp.com>,
	Dong Aisheng <dongas86@gmail.com>,
	Stephen Boyd <sboyd@kernel.org>,
	"mturquette@baylibre.com" <mturquette@baylibre.com>,
	"linux-clk@vger.kernel.org" <linux-clk@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Abel Vesa <abel.vesa@nxp.com>, dl-linux-imx <linux-imx@nxp.com>,
	"kernel@pengutronix.de" <kernel@pengutronix.de>,
	"festevam@gmail.com" <festevam@gmail.com>,
	"s.hauer@pengutronix.de" <s.hauer@pengutronix.de>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	Jacky Bai <ping.bai@nxp.com>
Subject: Re: [PATCH] clk: imx: lpcg: write twice when writing lpcg regs
Date: Fri, 13 Sep 2019 11:42:14 +0800	[thread overview]
Message-ID: <20190913034213.GH17142@dragon> (raw)
In-Reply-To: <DB3PR0402MB3916906683B58843B459ABE1F5B60@DB3PR0402MB3916.eurprd04.prod.outlook.com>

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

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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply	other threads:[~2019-09-13  3:42 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-27  8:17 [PATCH] clk: imx: lpcg: write twice when writing lpcg regs Peng Fan
2019-08-27  8:17 ` Peng Fan
2019-09-06 17:20 ` Stephen Boyd
2019-09-06 17:20   ` Stephen Boyd
2019-09-09 11:51   ` Dong Aisheng
2019-09-09 11:51     ` Dong Aisheng
2019-09-10  2:47     ` Anson Huang
2019-09-10  2:47       ` Anson Huang
2019-09-10 11:50       ` Daniel Baluta
2019-09-10 11:50         ` Daniel Baluta
2019-09-13  3:42       ` Shawn Guo [this message]
2019-09-13  3:42         ` Shawn Guo
2019-09-09 11:44 ` Dong Aisheng
2019-09-09 11:44   ` Dong Aisheng

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