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From: Andrew Lunn <andrew@lunn.ch>
To: Oleksij Rempel <o.rempel@pengutronix.de>
Cc: Shawn Guo <shawnguo@kernel.org>,
	Sascha Hauer <s.hauer@pengutronix.de>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Heiner Kallweit <hkallweit1@gmail.com>,
	kernel@pengutronix.de, netdev@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-imx@nxp.com,
	Fabio Estevam <festevam@gmail.com>,
	David Jander <david@protonic.nl>,
	Russell King <linux@armlinux.org.uk>
Subject: Re: [PATCH v2] ARM: imx: allow to disable board specific PHY fixups
Date: Sun, 29 Mar 2020 17:08:54 +0200	[thread overview]
Message-ID: <20200329150854.GA31812@lunn.ch> (raw)
In-Reply-To: <20200329110457.4113-1-o.rempel@pengutronix.de>

On Sun, Mar 29, 2020 at 01:04:57PM +0200, Oleksij Rempel wrote:

Hi Oleksij

> +config DEPRECATED_PHY_FIXUPS
> +	bool "Enable deprecated PHY fixups"
> +	default y
> +	---help---
> +	  In the early days it was common practice to configure PHYs by adding a
> +	  phy_register_fixup*() in the machine code. This practice turned out to
> +	  be potentially dangerous, because:
> +	  - it affects all PHYs in the system
> +	  - these register changes are usually not preserved during PHY reset
> +	    or suspend/resume cycle.
> +	  - it complicates debugging, since these configuration changes were not
> +	    done by the actual PHY driver.
> +	  This option allows to disable all fixups which are identified as
> +	  potentially harmful and give the developers a chance to implement the
> +	  proper configuration via the device tree (e.g.: phy-mode) and/or the
> +	  related PHY drivers.

This appears to be an IMX only problem. Everybody else seems to of got
this right. There is no need to bother everybody with this new
option. Please put this in arch/arm/mach-mxs/Kconfig and have IMX in
the name.

Having said that, i'm not sure this is the best solution. You cannot
build one kernel which runs on all machines. Did you consider some
sort of DT property to disable these fixup? What other ideas did you
have before deciding on this solution?

     Andrew

WARNING: multiple messages have this Message-ID (diff)
From: Andrew Lunn <andrew@lunn.ch>
To: Oleksij Rempel <o.rempel@pengutronix.de>
Cc: Florian Fainelli <f.fainelli@gmail.com>,
	netdev@vger.kernel.org, Sascha Hauer <s.hauer@pengutronix.de>,
	linux-kernel@vger.kernel.org, Fabio Estevam <festevam@gmail.com>,
	linux-imx@nxp.com, kernel@pengutronix.de,
	David Jander <david@protonic.nl>,
	Russell King <linux@armlinux.org.uk>,
	Shawn Guo <shawnguo@kernel.org>,
	linux-arm-kernel@lists.infradead.org,
	Heiner Kallweit <hkallweit1@gmail.com>
Subject: Re: [PATCH v2] ARM: imx: allow to disable board specific PHY fixups
Date: Sun, 29 Mar 2020 17:08:54 +0200	[thread overview]
Message-ID: <20200329150854.GA31812@lunn.ch> (raw)
In-Reply-To: <20200329110457.4113-1-o.rempel@pengutronix.de>

On Sun, Mar 29, 2020 at 01:04:57PM +0200, Oleksij Rempel wrote:

Hi Oleksij

> +config DEPRECATED_PHY_FIXUPS
> +	bool "Enable deprecated PHY fixups"
> +	default y
> +	---help---
> +	  In the early days it was common practice to configure PHYs by adding a
> +	  phy_register_fixup*() in the machine code. This practice turned out to
> +	  be potentially dangerous, because:
> +	  - it affects all PHYs in the system
> +	  - these register changes are usually not preserved during PHY reset
> +	    or suspend/resume cycle.
> +	  - it complicates debugging, since these configuration changes were not
> +	    done by the actual PHY driver.
> +	  This option allows to disable all fixups which are identified as
> +	  potentially harmful and give the developers a chance to implement the
> +	  proper configuration via the device tree (e.g.: phy-mode) and/or the
> +	  related PHY drivers.

This appears to be an IMX only problem. Everybody else seems to of got
this right. There is no need to bother everybody with this new
option. Please put this in arch/arm/mach-mxs/Kconfig and have IMX in
the name.

Having said that, i'm not sure this is the best solution. You cannot
build one kernel which runs on all machines. Did you consider some
sort of DT property to disable these fixup? What other ideas did you
have before deciding on this solution?

     Andrew

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2020-03-29 15:09 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-29 11:04 [PATCH v2] ARM: imx: allow to disable board specific PHY fixups Oleksij Rempel
2020-03-29 11:04 ` Oleksij Rempel
2020-03-29 15:08 ` Andrew Lunn [this message]
2020-03-29 15:08   ` Andrew Lunn
2020-03-30  5:26   ` Oleksij Rempel
2020-03-30  5:26     ` Oleksij Rempel
2020-03-30 17:33     ` Florian Fainelli
2020-03-30 17:33       ` Florian Fainelli
2020-03-30 17:41       ` Russell King - ARM Linux admin
2020-03-30 17:41         ` Russell King - ARM Linux admin
2020-03-31  7:47         ` Marc Kleine-Budde
2020-03-31  7:47           ` Marc Kleine-Budde
2020-03-31  7:54           ` Russell King - ARM Linux admin
2020-03-31  7:54             ` Russell King - ARM Linux admin
2020-03-31  8:00             ` Marc Kleine-Budde
2020-03-31  8:00               ` Marc Kleine-Budde
2020-03-31  8:19               ` Russell King - ARM Linux admin
2020-03-31  8:19                 ` Russell King - ARM Linux admin
2020-04-01  6:33                 ` Oleksij Rempel
2020-04-01  6:33                   ` Oleksij Rempel
2020-04-01 17:10                   ` Florian Fainelli
2020-04-01 17:10                     ` Florian Fainelli
2020-03-31  8:06         ` Philippe Schenker
2020-03-31  8:06           ` Philippe Schenker
2020-03-31  8:44         ` David Jander
2020-03-31  8:44           ` David Jander
2020-03-31  9:36           ` Russell King - ARM Linux admin
2020-03-31  9:36             ` Russell King - ARM Linux admin
2020-03-31 15:41             ` David Jander
2020-03-31 15:41               ` David Jander
2020-03-31 15:53               ` Russell King - ARM Linux admin
2020-03-31 15:53                 ` Russell King - ARM Linux admin
2020-03-31 12:54           ` Andrew Lunn
2020-03-31 12:54             ` Andrew Lunn
2020-03-31 15:15             ` Russell King - ARM Linux admin
2020-03-31 15:15               ` Russell King - ARM Linux admin
2020-03-31 15:40               ` Vladimir Oltean
2020-03-31 15:40                 ` Vladimir Oltean
2020-03-31 17:03           ` Russell King - ARM Linux admin
2020-03-31 17:03             ` Russell King - ARM Linux admin
2020-03-31 17:16             ` Oleksij Rempel
2020-03-31 17:16               ` Oleksij Rempel
2020-03-31 17:46               ` Russell King - ARM Linux admin
2020-03-31 17:46                 ` Russell King - ARM Linux admin
2020-03-31 13:45         ` Oleksij Rempel
2020-03-31 13:45           ` Oleksij Rempel
2020-03-31 14:08           ` Russell King - ARM Linux admin
2020-03-31 14:08             ` Russell King - ARM Linux admin

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