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    SubjectRe: [PATCH net-next v1 01/14] net: phy: nxp-c45-tja11xx: fix the PTP interrupt enablig/disabling
    On Fri, Jun 16, 2023 at 04:53:10PM +0300, Radu Pirea (NXP OSS) wrote:
    > .config_intr() handles only the link event interrupt and should
    > disable/enable the PTP interrupt also.
    >
    > It's safe to disable/enable the PTP irq even if the egress ts irq
    > is disabled. This interrupt, the PTP one, acts as a global switch for all
    > PTP irqs.
    >
    > Fixes: 514def5dd339 ("phy: nxp-c45-tja11xx: add timestamping support")
    > CC: stable@vger.kernel.org # 5.15+
    > Signed-off-by: Radu Pirea (NXP OSS) <radu-nicolae.pirea@oss.nxp.com>

    Please don't mix fixes and development work in one patchset. Please
    post this to applying to net, not net-next.

    > static int nxp_c45_config_intr(struct phy_device *phydev)
    > {
    > - if (phydev->interrupts == PHY_INTERRUPT_ENABLED)
    > + /* The return value is ignored on purpose. It might be < 0.
    > + * 0x807A register is not present on SJA1110 PHYs.
    > + */
    > + if (phydev->interrupts == PHY_INTERRUPT_ENABLED) {
    > + phy_set_bits_mmd(phydev, MDIO_MMD_VEND1,
    > + VEND1_PORT_FUNC_IRQ_EN, PTP_IRQS);
    > return phy_set_bits_mmd(phydev, MDIO_MMD_VEND1,
    > VEND1_PHY_IRQ_EN, PHY_IRQ_LINK_EVENT);

    phy_set_bits_mmd() will not return an error if the register does not
    exist. There is no such indication for MDIO. This is going to do a
    read/modify/write. That read might get 0xffff, or random junk. And
    then the write back will be successful. The only time
    phy_read()/phy_write return error is when there is a problem within
    the bus master, like its clock gets turned off and the transfer times
    out.

    So it is good to document you are accessing a register which might not
    exist, but there is no need to ignore the return code.

    Andrew

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