netdev - Re: [PATCH net-next] net: phy: micrel: Add interrupts support for LAN8804 PHY

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Date:   Tue, 13 Sep 2022 10:18:14 +0200
From:   Michael Walle <michael@...le.cc>
To:     horatiu.vultur@...rochip.com
Cc:     UNGLinuxDriver@...rochip.com, andrew@...n.ch, davem@...emloft.net,
        edumazet@...gle.com, hkallweit1@...il.com, kuba@...nel.org,
        linux-kernel@...r.kernel.org, linux@...linux.org.uk,
        netdev@...r.kernel.org, pabeni@...hat.com,
        Michael Walle <michael@...le.cc>
Subject: Re: [PATCH net-next] net: phy: micrel: Add interrupts support for LAN8804 PHY

> Add support for interrupts for LAN8804 PHY.
> 
> Signed-off-by: Horatiu Vultur <horatiu.vultur@...rochip.com>
> ---
>  drivers/net/phy/micrel.c | 55 ++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 55 insertions(+)
> 
> diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
> index 7b8c5c8d013e..98e9bc101d96 100644
> --- a/drivers/net/phy/micrel.c
> +++ b/drivers/net/phy/micrel.c
> @@ -2676,6 +2676,59 @@ static int lan8804_config_init(struct phy_device *phydev)
>  	return 0;
>  }
>  
> +static irqreturn_t lan8804_handle_interrupt(struct phy_device *phydev)
> +{
> +	int status;
> +
> +	status = phy_read(phydev, LAN8814_INTS);
> +	if (status < 0) {
> +		phy_error(phydev);
> +		return IRQ_NONE;
> +	}
> +
> +	if (status > 0)
> +		phy_trigger_machine(phydev);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +#define LAN8804_OUTPUT_CONTROL			25
> +#define LAN8804_OUTPUT_CONTROL_INTR_BUFFER	BIT(14)
> +#define LAN8804_CONTROL				31
> +#define LAN8804_CONTROL_INTR_POLARITY		BIT(14)
> +
> +static int lan8804_config_intr(struct phy_device *phydev)
> +{
> +	int err;
> +
> +	/* Change interrupt polarity */
> +	phy_write(phydev, LAN8804_CONTROL, LAN8804_CONTROL_INTR_POLARITY);

I assume you change the polarity to high active? Could you add a note?
The LAN966x nor the LAN8804 datasheet describe this bit. You might also add
a note, that this is an internal PHY and you cannot change the polarity on
the GIC. Which begs the question, is this really only an internal PHY or
can you actually buy it as a dedicated one. Then you'd change the polarity
in a really unusual way.


> +
> +	/* Change interrupt buffer type */

To what? Push-pull?

-michael

> +	phy_write(phydev, LAN8804_OUTPUT_CONTROL,
> +		  LAN8804_OUTPUT_CONTROL_INTR_BUFFER);
> +