From: andrew@lunn•ch (Andrew Lunn)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v2 3/5] drivers: net: phy: Add MDIO driver
Date: Thu, 7 Jul 2016 16:03:02 +0200 [thread overview]
Message-ID: <20160707140302.GP19800@lunn.ch> (raw)
In-Reply-To: <CAKh23FnvgWRMo=M35Mj4=a_KeUpvOoHa8stU=bSk9Y3VSRtyzQ@mail.gmail.com>
> Wed, Jul 06, 2016 at 04:44:44PM -0700, Iyappan Subramanian wrote:
> Hi Andrew,
>
> On Tue, Jul 5, 2016 at 6:49 AM, Andrew Lunn <andrew@lunn•ch> wrote:
> > On Mon, Jun 06, 2016 at 10:12:35AM -0700, Iyappan Subramanian wrote:
> >> Hi Andrew,
> >>
> >> Thanks for the review.
> >>
> >> On Tue, May 31, 2016 at 6:11 PM, Andrew Lunn <andrew@lunn•ch> wrote:
> >> > On Tue, May 31, 2016 at 05:10:38PM -0700, Iyappan Subramanian wrote:
> >> >> +static int xgene_mdio_reset(struct xgene_mdio_pdata *pdata)
> >> >> +{
> >> >> + int ret;
> >> >> +
> >> >> + if (pdata->mdio_id == XGENE_MDIO_RGMII) {
> >> >> + if (pdata->dev->of_node) {
> >> >> + clk_prepare_enable(pdata->clk);
> >> >> + clk_disable_unprepare(pdata->clk);
> >> >> + clk_prepare_enable(pdata->clk);
> >> >
> >> > Hi Iyappan
> >> >
> >> > Is that a workaround for a hardware problem? If so, i would suggest
> >> > adding a comment, to stop people submitting a patch simplifying it.
> >>
> >> Hardware expects this clock sequence. I'll add comment as you suggested.
> >
> > What exactly does the hardware require? Is this a workaround for a bug
> > in the clock generator? Or a workaround for a bug in the MDIO device?
>
> Hardware requires a clock pulse. There is no bug.
And how are you guaranteeing a pulse? You enable/disable/enable
without any sleeps, so it could all happen within a single clock
cycle?
Andrew
next prev parent reply other threads:[~2016-07-07 14:03 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-01 0:10 [PATCH v2 0/5] drivers: net: xgene: Fix 1G hot-plug and module support Iyappan Subramanian
2016-06-01 0:10 ` [PATCH v2 1/5] drivers: net: xgene: MAC and PHY configuration changes Iyappan Subramanian
2016-06-01 0:10 ` [PATCH v2 2/5] drivers: net: xgene: Backward compatibility with older firmware Iyappan Subramanian
2016-06-01 0:10 ` [PATCH v2 3/5] drivers: net: phy: Add MDIO driver Iyappan Subramanian
2016-06-01 1:11 ` Andrew Lunn
2016-07-05 4:40 ` Iyappan Subramanian
2016-07-05 13:49 ` Andrew Lunn
2016-07-06 23:44 ` Iyappan Subramanian
2016-07-07 14:03 ` Andrew Lunn [this message]
2016-07-07 14:14 ` Russell King - ARM Linux
2016-07-07 22:58 ` Iyappan Subramanian
2016-07-07 22:57 ` Iyappan Subramanian
2016-06-01 0:10 ` [PATCH v2 4/5] dtb: xgene: Add MDIO node Iyappan Subramanian
2016-06-01 0:10 ` [PATCH v2 5/5] drivers: net: xgene: Fix module load/unload crash Iyappan Subramanian
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