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    SubjectRE: [PATCH] ARM: at91: board-dt-sama5: add phy_fixup to override NAND_Tree which improperly strapp-in during the reset period.
    Date
    > -----Original Message-----
    > From: Florian Fainelli [mailto:f.fainelli@gmail.com]
    > Sent: Wednesday, December 17, 2014 3:10 AM
    > To: Ferre, Nicolas; Yang, Wenyou
    > Cc: linux@arm.linux.org.uk; linux-arm-kernel@lists.infradead.org; linux-
    > kernel@vger.kernel.org
    > Subject: Re: [PATCH] ARM: at91: board-dt-sama5: add phy_fixup to override
    > NAND_Tree which improperly strapp-in during the reset period.
    >
    > On 16/12/14 02:20, Nicolas Ferre wrote:
    > > Le 11/12/2014 08:31, Wenyou Yang a écrit :
    > >> Appearance: On some SAMA5D4EK boards, after power up, the Eth1 doesn't
    > work.
    > >>
    > >> Reason: The PIOE2 pin is connected to the NAND_Tree# of KSZ8081, But
    > >> it outputs LOW during the reset period, which cause the NAND_Tree# enabled.
    > >>
    > >> Add phy_fixup() to disable NAND_Tree by overriding the Operation Mode
    > >> Strap Override register(i.e. Register 16h) to clear the NAND_Tree bit.
    > >>
    > >> Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
    > >
    > > It seems correct to me.
    >
    > Just one minor nit, see below
    >
    > >
    > > Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
    > >
    > > Anyway, I add Florian in the loop as he is the one who proposed this
    > > solution. So it would have been good to have his feeling about the
    > > implementation...
    > >
    > > Bye,
    > >
    > >> ---
    > >> arch/arm/mach-at91/board-dt-sama5.c | 18 ++++++++++++++++++
    > >> 1 file changed, 18 insertions(+)
    > >>
    > >> diff --git a/arch/arm/mach-at91/board-dt-sama5.c
    > >> b/arch/arm/mach-at91/board-dt-sama5.c
    > >> index 8fb9ef5..97f7367 100644
    > >> --- a/arch/arm/mach-at91/board-dt-sama5.c
    > >> +++ b/arch/arm/mach-at91/board-dt-sama5.c
    > >> @@ -17,6 +17,7 @@
    > >> #include <linux/of_platform.h>
    > >> #include <linux/phy.h>
    > >> #include <linux/clk-provider.h>
    > >> +#include <linux/phy.h>
    > >>
    > >> #include <asm/setup.h>
    > >> #include <asm/irq.h>
    > >> @@ -26,8 +27,25 @@
    > >>
    > >> #include "generic.h"
    > >>
    > >> +static int ksz8081_phy_fixup(struct phy_device *phy) {
    > >> + int value;
    > >> +
    > >> + value = phy_read(phy, 0x16);
    > >> + value &= ~0x20;
    > >> + phy_write(phy, 0x16, value);
    > >> +
    > >> + return 0;
    > >> +}
    > >> +
    > >> static void __init sama5_dt_device_init(void) {
    > >> + if (of_machine_is_compatible("atmel,sama5d4ek") &&
    > >> + IS_ENABLED(CONFIG_PHYLIB)) {
    > >> + phy_register_fixup_for_id("fc028000.etherne:00",
    > >> + ksz8081_phy_fixup);
    >
    > Matching the bus id certainly works, but I would rather match on your specific PHY
    > device 32-bits OUI to make sure that if you ever change the PHY on a different
    > design, this is not inadvertently writing to a register that is not micrel specific?
    I don't think so.
    Under the board compatible limitation, matching the bus id is enough for this case reason described above.

    Moreover the PHY OUI is default value on the sama5d4ek.
    MII_PHYSID1.15:0: 0x0022
    MII_PHYSID2.15:10: 000101b

    >
    > >> + }
    > >> +
    > >> of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
    > >> }
    > >>
    > >>
    > >
    > >

    Best Regards,
    Wenyou Yang

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