STRUCT ETHTOOL_PHY_OPS(9)

🎀 NAME 🎀

struct ethtool_phy_ops — the optional PHY device options, bestie. That's it, that's the whole vibe. It's a little bundle of function pointers you can fill in for your PHY, and literally none of them are required (more on that in a sec, it's giving "no pressure" 💅).

This is straight out of the Kernel API Manual, and we're gonna go through the whole thing together, no skipping, no cap ✨

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✨ SYNOPSIS ✨

Okay so here's the struct in all its glory, copied exactly, don't @ me about the line breaks:

struct ethtool_phy_ops {
    int (*get_sset_count)(struct phy_device *dev);
    int (*get_strings)(struct phy_device *dev, u8 *data);
    int (*get_stats)(struct phy_device *dev, struct ethtool_stats
*stats, u64 *data);
    int (*get_plca_cfg)(struct phy_device *dev, struct phy_plca_cfg
*plca_cfg);
    int (*set_plca_cfg)(struct phy_device *dev, const struct
phy_plca_cfg *plca_cfg, struct netlink_ext_ack *extack);
    int (*get_plca_status)(struct phy_device *dev, struct
phy_plca_status *plca_st);
    int (*start_cable_test)(struct phy_device *phydev, struct
netlink_ext_ack *extack);
    int (*start_cable_test_tdr)(struct phy_device *phydev, struct
netlink_ext_ack *extack, const struct phy_tdr_config *config);
 };

Look at all those function pointers 🦋 — every single one of them is a little optional superpower you can bolt onto your PHY. Slay.

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👑 Members 👑

Let's do a lil roll call, one by one, so you know exactly who's who in this friend group 🫶

• get_sset_count — tells you how many strings get_strings is gonna write. Basically the "how many are we expecting" headcount before the party 🎉
• get_strings — hands back a set of strings that describe the objects you asked for. The actual name tags, if you will 🏷️
• get_stats — returns extended statistics about the PHY device. All the numbers, all the receipts 📊
• get_plca_cfg — returns the PLCA configuration. Reading the settings, lowkey iconic.
• set_plca_cfg — sets the PLCA configuration. Now you're writing the settings, main character energy 🔥
• get_plca_status — gets the PLCA configuration. Yep, the doc says "Get PLCA configuration" for this one too — I'm just passing along what it says, fr fr 🙈
• start_cable_test — starts a cable test. Go little cable, go 🧚
• start_cable_test_tdr — starts a Time Domain Reflectometry cable test. The fancy one. The deluxe edition ⭐

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🌸 Description 🌸

Okay here's the part you actually need to remember, bestie, so let me be loud about it:

All operations are optional (i.e. the function pointer may be set to NULL) and callers must take this into account. So like, don't just assume every pointer's been filled in — vibe check your struct first 💀

Also: callers must hold the RTNL lock. That's not a suggestion, that's the rule. Lock first, then call. Periodt 🔒

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🦋 SEE ALSO 🦋

The kernel file lives at ./include/linux/ethtool.h, and honestly the whole extended fam is worth a look 👀:

• enum ethtool_phys_id_state(9)
• struct kernel_ethtool_ringparam(9)
• enum ethtool_supported_ring_param(9)
• ethtool_rxfh_indir_default(9)
• struct ethtool_rxfh_context(9)
• ethtool_link_ksettings_zero_link_mode(9)
• ethtool_link_ksettings_add_link_mode(9)
• ethtool_link_ksettings_del_link_mode(9)
• ethtool_link_ksettings_test_link_mode(9)
• ethtool_intersect_link_masks(9)
• struct ethtool_phy_stats(9)
• struct ethtool_pause_stats(9)
• struct ethtool_fec_hist_range(9)
• struct ethtool_fec_stats(9)
• struct ethtool_rmon_hist_range(9)
• struct ethtool_rmon_stats(9)
• struct ethtool_ts_stats(9)
• struct ethtool_module_eeprom(9)
• struct ethtool_module_power_mode_params(9)
• struct ethtool_mm_state(9)
• struct ethtool_mm_cfg(9)
• struct ethtool_mm_stats(9)
• struct ethtool_mmsv_ops(9)
• struct ethtool_mmsv(9)
• struct ethtool_rxfh_param(9)
• struct ethtool_rxfh_fields(9)
• struct kernel_ethtool_ts_info(9)
• struct ethtool_ops(9)
• struct ethtool_netdev_state(9)
• ethtool_set_ethtool_phy_ops(9)
• ethtool_params_from_link_mode(9)
• ethtool_get_phc_vclocks(9)
• ethtool_mm_frag_size_add_to_min(9)
• ethtool_mm_frag_size_min_to_add(9)
• ethtool_get_ts_info_by_layer(9)
• ethtool_sprintf(9)
• ethtool_puts(9)
• ethtool_cpy(9)

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💖 Friendly reminder before you bounce: set your unset pointers to NULL, check for NULL before you call, and hold the RTNL lock. That's the whole assignment, you've got this 🫶

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And that's the page, bestie! It came from ./include/linux, it's dated October 2026, and the whole thing is filed under struct ethtool_phy_ops(9). Go be iconic with your PHY ops 💅✨🎀