Re: FAILED: patch "[PATCH] net: dsa: mv88e6xxx: Save power by disabling SerDes" failed to apply to 5.15-stable tree

["Marek Behún" <kabel@kernel.org>]

In fact it was a series of 6 patches, but the 2nd was without fixes tag:

21635d9203e1cf2b73b67e9a86059a62f62a3563
8c3318b4874e2dee867f5ae8f6d38f78e044bf71 (without fixes tag)
7527d66260ac0c603c6baca5146748061fcddbd6 (didnt apply)
93fd8207bed80ce19aaf59932cbe1c03d418a37d
163000dbc772c1eae9bdfe7c8fe30155db1efd74
ede359d8843a2779d232ed30bc36089d4b5962e4

On Sat, 04 Dec 2021 11:28:35 +0100
<gregkh@linuxfoundation.org> wrote:

> The patch below does not apply to the 5.15-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@vger.kernel.org>.
> 
> thanks,
> 
> greg k-h
> 
> ------------------ original commit in Linus's tree ------------------
> 
> From 7527d66260ac0c603c6baca5146748061fcddbd6 Mon Sep 17 00:00:00 2001
> From: =?UTF-8?q?Marek=20Beh=C3=BAn?= <kabel@kernel.org>
> Date: Tue, 30 Nov 2021 18:01:48 +0100
> Subject: [PATCH] net: dsa: mv88e6xxx: Save power by disabling SerDes
>  trasmitter and receiver
> MIME-Version: 1.0
> Content-Type: text/plain; charset=UTF-8
> Content-Transfer-Encoding: 8bit
> 
> Save power on 88E6393X by disabling SerDes receiver and transmitter
> after SerDes is SerDes is disabled.
> 
> Signed-off-by: Marek Behún <kabel@kernel.org>
> Cc: stable@vger.kernel.org # de776d0d316f ("net: dsa: mv88e6xxx: add support for mv88e6393x family")
> Signed-off-by: David S. Miller <davem@davemloft.net>
> 
> diff --git a/drivers/net/dsa/mv88e6xxx/serdes.c b/drivers/net/dsa/mv88e6xxx/serdes.c
> index 3a6244596a67..ceb63d7f1f97 100644
> --- a/drivers/net/dsa/mv88e6xxx/serdes.c
> +++ b/drivers/net/dsa/mv88e6xxx/serdes.c
> @@ -1271,6 +1271,28 @@ void mv88e6390_serdes_get_regs(struct mv88e6xxx_chip *chip, int port, void *_p)
>  	}
>  }
>  
> +static int mv88e6393x_serdes_power_lane(struct mv88e6xxx_chip *chip, int lane,
> +					bool on)
> +{
> +	u16 reg;
> +	int err;
> +
> +	err = mv88e6390_serdes_read(chip, lane, MDIO_MMD_PHYXS,
> +				    MV88E6393X_SERDES_CTRL1, &reg);
> +	if (err)
> +		return err;
> +
> +	if (on)
> +		reg &= ~(MV88E6393X_SERDES_CTRL1_TX_PDOWN |
> +			 MV88E6393X_SERDES_CTRL1_RX_PDOWN);
> +	else
> +		reg |= MV88E6393X_SERDES_CTRL1_TX_PDOWN |
> +		       MV88E6393X_SERDES_CTRL1_RX_PDOWN;
> +
> +	return mv88e6390_serdes_write(chip, lane, MDIO_MMD_PHYXS,
> +				      MV88E6393X_SERDES_CTRL1, reg);
> +}
> +
>  static int mv88e6393x_serdes_erratum_4_6(struct mv88e6xxx_chip *chip, int lane)
>  {
>  	u16 reg;
> @@ -1297,7 +1319,11 @@ static int mv88e6393x_serdes_erratum_4_6(struct mv88e6xxx_chip *chip, int lane)
>  	if (err)
>  		return err;
>  
> -	return mv88e6390_serdes_power_sgmii(chip, lane, false);
> +	err = mv88e6390_serdes_power_sgmii(chip, lane, false);
> +	if (err)
> +		return err;
> +
> +	return mv88e6393x_serdes_power_lane(chip, lane, false);
>  }
>  
>  int mv88e6393x_serdes_setup_errata(struct mv88e6xxx_chip *chip)
> @@ -1362,17 +1388,29 @@ int mv88e6393x_serdes_power(struct mv88e6xxx_chip *chip, int port, int lane,
>  		err = mv88e6393x_serdes_erratum_4_8(chip, lane);
>  		if (err)
>  			return err;
> +
> +		err = mv88e6393x_serdes_power_lane(chip, lane, true);
> +		if (err)
> +			return err;
>  	}
>  
>  	switch (cmode) {
>  	case MV88E6XXX_PORT_STS_CMODE_SGMII:
>  	case MV88E6XXX_PORT_STS_CMODE_1000BASEX:
>  	case MV88E6XXX_PORT_STS_CMODE_2500BASEX:
> -		return mv88e6390_serdes_power_sgmii(chip, lane, on);
> +		err = mv88e6390_serdes_power_sgmii(chip, lane, on);
> +		break;
>  	case MV88E6393X_PORT_STS_CMODE_5GBASER:
>  	case MV88E6393X_PORT_STS_CMODE_10GBASER:
> -		return mv88e6390_serdes_power_10g(chip, lane, on);
> +		err = mv88e6390_serdes_power_10g(chip, lane, on);
> +		break;
>  	}
>  
> -	return 0;
> +	if (err)
> +		return err;
> +
> +	if (!on)
> +		err = mv88e6393x_serdes_power_lane(chip, lane, false);
> +
> +	return err;
>  }
> diff --git a/drivers/net/dsa/mv88e6xxx/serdes.h b/drivers/net/dsa/mv88e6xxx/serdes.h
> index cbb3ba30caea..e9292c8beee4 100644
> --- a/drivers/net/dsa/mv88e6xxx/serdes.h
> +++ b/drivers/net/dsa/mv88e6xxx/serdes.h
> @@ -93,6 +93,9 @@
>  #define MV88E6393X_SERDES_POC_PCS_MASK		0x0007
>  #define MV88E6393X_SERDES_POC_RESET		BIT(15)
>  #define MV88E6393X_SERDES_POC_PDOWN		BIT(5)
> +#define MV88E6393X_SERDES_CTRL1			0xf003
> +#define MV88E6393X_SERDES_CTRL1_TX_PDOWN	BIT(9)
> +#define MV88E6393X_SERDES_CTRL1_RX_PDOWN	BIT(8)
>  
>  #define MV88E6393X_ERRATA_4_8_REG		0xF074
>  #define MV88E6393X_ERRATA_4_8_BIT		BIT(14)
>