From: f.fainelli@gmail.com (Florian Fainelli)
To: linux-arm-kernel@lists.infradead.org
Subject: Q about driver code for KSZ8873MML
Date: Thu, 11 Sep 2014 21:29:48 -0700 [thread overview]
Message-ID: <541276BC.7000705@gmail.com> (raw)
In-Reply-To: <20140912040744.GD2522@tarshish>
On 09/11/14 21:07, Baruch Siach wrote:
> Hi Patrick,
>
> On Thu, Sep 11, 2014 at 10:40:29PM -0400, Patrick Boyle wrote:
>> In the linux/include/micrel_phy.h file the PHY ID for the KSZ8873MML
>> is defined as (0x000e7237)
>>
>> #define MICREL_PHY_ID_MASK 0x00fffff0
>>
>> #define PHY_ID_KSZ8873MLL 0x000e7237
>> #define PHY_ID_KSZ9021 0x00221610
>> #define PHY_ID_KSZ8737 0x00221720
>> /* same id: KS8021, KS8031 */
>> #define PHY_ID_KSZ8021 0x00221555
>> #define PHY_ID_KSZ8041 0x00221510
>> #define PHY_ID_KSZ8051 0x00221550
>> /* same id: ks8001 Rev. A/B, and ks8721 Rev 3. */
>> #define PHY_ID_KSZ8001 0x0022161A
>> /* same id: KS8081, KS8091 */
>> #define PHY_ID_KSZ8081 0x00221560
>> #define PHY_ID_KSZ8061 0x00221570
>> #define PHY_ID_KSZ9031 0x00221620
>>
>> /* struct phy_device dev_flags definitions */
>> #define MICREL_PHY_50MHZ_CLK 0x00000001
>>
>> But the datasheet from Micrel for this part (and using mii to probe
>> the part on my board) shows:
>>
>> 0x00221430
>>
>> So where did 0x000e7237 come from?
>
> git has a wonderful tool called 'git blame'. This tool indicates that the
>
> #define PHY_ID_KSZ8873MLL 0x000e7237
>
> line comes from commit 93272e07d8539c
> (http://git.kernel.org/linus/93272e07d8539c) by Jean-Christophe
> PLAGNIOL-VILLARD (added to Cc).
Since that chip is an Ethernet switch, one possible confusion, which is
is easy to get is that the chip will reply with a different value
depending on whether you access one of its port PHY address (e.g: 1
through 3 for the KSZ8873ML) or if you access the switch
pseudo-PHY/global/control address (e.g: 16 for Marvell, 30 for Broadcom).
The correct value indeed seems to be 0x00221430 when accessing PHYAD1 or
PHYAD2. What you can do to prevent the same PHY driver from trying to
bind multiple time to the per-port PHYs is to register a PHY fixup
similar to these ones:
https://dev.openwrt.org/browser/trunk/target/linux/generic/files/drivers/net/phy/mvswitch.c#L389
https://dev.openwrt.org/browser/trunk/target/linux/generic/files/drivers/net/phy/b53/b53_phy_fixup.c
--
Florian
prev parent reply other threads:[~2014-09-12 4:29 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-12 2:40 Q about driver code for KSZ8873MML Patrick Boyle
2014-09-12 4:07 ` Baruch Siach
2014-09-12 4:29 ` Florian Fainelli [this message]
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