Re: [PATCH net-next] net: phy: micrel: Adding SQI support for lan8814 phy

Michael Walle
2022-08-26T08:43:33Z

Hi,

> Supports SQI(Signal Quality Index) for lan8814 phy, where
> it has SQI index of 0-7 values and this indicator can be used
> for cable integrity diagnostic and investigating other noise
> sources.
>
> Signed-off-by: Divya Koppera <Divya.Koppera@microchip.com>
> ---
> drivers/net/phy/micrel.c | 35 +++++++++++++++++++++++++++++++++++
> 1 file changed, 35 insertions(+)
>
> diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
> index e78d0bf69bc3..3775da7afc64 100644
> --- a/drivers/net/phy/micrel.c
> +++ b/drivers/net/phy/micrel.c
> @@ -1975,6 +1975,13 @@ static int ksz886x_cable_test_get_status(struct phy_device *phydev,
> #define LAN8814_CLOCK_MANAGEMENT 0xd
> #define LAN8814_LINK_QUALITY 0x8e
>
> +#define LAN8814_DCQ_CTRL 0xe6
> +#define LAN8814_DCQ_CTRL_READ_CAPTURE_ BIT(15)

Why does it end with an underscore?

> +#define LAN8814_DCQ_CTRL_CHANNEL_MASK GENMASK(1, 0)
> +#define LAN8814_DCQ_SQI 0xe4
> +#define LAN8814_DCQ_SQI_MAX 7
> +#define LAN8814_DCQ_SQI_VAL_MASK GENMASK(3, 1)
> +
> static int lanphy_read_page_reg(struct phy_device *phydev, int page, u32 addr)
> {
> int data;
> @@ -2927,6 +2934,32 @@ static int lan8814_probe(struct phy_device *phydev)
> return 0;
> }
>
> +static int lan8814_get_sqi(struct phy_device *phydev)
> +{
> + int rc, val;
> +
> + val = lanphy_read_page_reg(phydev, 1, LAN8814_DCQ_CTRL);
> + if (val < 0)
> + return val;
> +
> + val &= ~LAN8814_DCQ_CTRL_CHANNEL_MASK;

I do have a datasheet for this PHY, but it doesn't mention 0xe6 on EP1.
So I can only guess that this "channel mask" is for the 4 rx/tx pairs
on GbE? And you only seem to evaluate one of them. Is that the correct
thing to do here?

-michael

> + val |= LAN8814_DCQ_CTRL_READ_CAPTURE_;
> + rc = lanphy_write_page_reg(phydev, 1, LAN8814_DCQ_CTRL, val);
> + if (rc < 0)
> + return rc;
> +
> + rc = lanphy_read_page_reg(phydev, 1, LAN8814_DCQ_SQI);
> + if (rc < 0)
> + return rc;
> +
> + return FIELD_GET(LAN8814_DCQ_SQI_VAL_MASK, rc);
> +}