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From: arnd@arndb•de (Arnd Bergmann)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v8 2/3] net: hisilicon: new hip04 MDIO driver
Date: Tue, 22 Apr 2014 16:30:07 +0200	[thread overview]
Message-ID: <201404221630.07865.arnd@arndb.de> (raw)
In-Reply-To: <535679A6.4020103@linaro.org>

On Tuesday 22 April 2014, zhangfei wrote:
> On 04/22/2014 04:22 PM, Arnd Bergmann wrote:
> 
> >> It's private register of the phy marvell 88e1512.
> >> To make it clearer using define instead.
> >> #define MII_MARVELL_PHY_PAGE    22
> >>
> >> The registers has been grouped into several pages, access register need
> >> choose which page first.
> >
> > You shouldn't touch the PHY private registers in the main driver though,
> > this should be purely handled by drivers/net/phy/marvell.c.
> >
> > I don't see support for 88e1512 there, only 88e1510 and lots of older
> > ones, but I assume it isn't hard to add.
> >
> 
> 88e1512 driver is already supported, same as 88e1510.
> #define MARVELL_PHY_ID_MASK             0xfffffff0
> So it should support 88e151x.
> 
> Reset is required here for get_phy_id, otherwise only 0 can be get.
> phy_device_create will not be called, and can not match any driver.
> 
> However in the experiment, it is found BMCR_RESET is not required in fact.
> Only hip04_mdio_write(bus, i, MII_MARVELL_PHY_PAGE, 0) has to be set.
> 88e151x registers are divided into pages.
> Generic MII registers is in page 0, including MII_PHYSID1 and MII_PHYSID2.
> Unfortunately the default page is not 0, so get_phy_id will fail.
> 
> So bus->reset still required to set the page to 0, prepared for get_phy_id.

But it means that the hip04_mdio driver potentially won't work if connected
to something other than a Marvell PHY.

I noticed that the marvell_of_reg_init() does this at init time:

saved_page = phy_read(phydev, MII_MARVELL_PHY_PAGE);
... /* perform init */
if (page_changed)
	phy_write(phydev, MII_MARVELL_PHY_PAGE, saved_page);

Is this a bug? Maybe it should always set page 0 when leaving
this function.

	Arnd

  reply	other threads:[~2014-04-22 14:30 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-04-19  1:12 [PATCH v8 0/3] add hisilicon hip04 ethernet driver Zhangfei Gao
2014-04-19  1:12 ` [PATCH v8 1/3] Documentation: add Device tree bindings for Hisilicon hip04 ethernet Zhangfei Gao
2014-04-19  1:12 ` [PATCH v8 2/3] net: hisilicon: new hip04 MDIO driver Zhangfei Gao
2014-04-21 17:58   ` Sergei Shtylyov
2014-04-21 18:03     ` Florian Fainelli
2014-04-21 18:21       ` Sergei Shtylyov
2014-04-22  6:03         ` zhangfei
2014-04-22  8:22           ` Arnd Bergmann
2014-04-22 14:16             ` zhangfei
2014-04-22 14:30               ` Arnd Bergmann [this message]
2014-04-22 14:58                 ` zhangfei
2014-04-24 12:28                   ` Arnd Bergmann
2014-04-24 13:00                     ` zhangfei
2014-04-19  1:13 ` [PATCH v8 3/3] net: hisilicon: new hip04 ethernet driver Zhangfei Gao
2014-12-07  0:42   ` Alexander Graf
2014-12-07  3:28     ` Ding Tianhong
2014-12-07  9:49       ` Alexander Graf
2014-12-07 20:09         ` Arnd Bergmann
2014-12-08  1:48           ` Ding Tianhong
2014-12-10  3:51           ` Ding Tianhong
2014-12-10  6:45             ` Ding Tianhong
2014-12-10  9:35               ` Arnd Bergmann
2014-12-10 16:07                 ` David Miller
2014-12-10 16:36                   ` Arnd Bergmann
2014-12-10 17:02                     ` David Miller

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