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From: Antoine Tenart <antoine.tenart@bootlin.com>
To: Florian Fainelli <f.fainelli@gmail.com>
Cc: Antoine Tenart <antoine.tenart@bootlin.com>,
	davem@davemloft.net, kishon@ti.com, linux@armlinux.org.uk,
	gregory.clement@bootlin.com, andrew@lunn.ch,
	jason@lakedaemon.net, sebastian.hesselbarth@gmail.com,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	thomas.petazzoni@bootlin.com, maxime.chevallier@bootlin.com,
	miquel.raynal@bootlin.com, nadavh@marvell.com,
	stefanc@marvell.com, ymarkman@marvell.com, mw@semihalf.com,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH net-next v2 01/13] net: phy: sfp: make the i2c-bus property really optional
Date: Fri, 4 May 2018 19:19:27 +0200	[thread overview]
Message-ID: <20180504171927.GB13899@kwain> (raw)
In-Reply-To: <fd91699d-c290-8821-b4a6-0789071cfba1@gmail.com>

Hi Florian,

On Fri, May 04, 2018 at 10:03:16AM -0700, Florian Fainelli wrote:
> On 05/04/2018 06:56 AM, Antoine Tenart wrote:
> >  
> >  static int sfp_read(struct sfp *sfp, bool a2, u8 addr, void *buf, size_t len)
> >  {
> > +	if (!sfp->read)
> > +		return -EOPNOTSUPP;
> 
> -ENODEV would be closer to the intended meaning IMHO, those this could
> be argue that this is yet another color to paint the bikeshed with.

I thought about -ENODEV as well, but ended up choosing -EOPNOTSUPP for
some reason. But I'm really fine with both solutions, it really depends
on if we want to return a callback isn't available from a s/w point of
view (-EOPNOTSUPP) or a h/w point of view (-ENODEV).

> >  	ret = sfp_read(sfp, false, 0, &id, sizeof(id));
> > +	if (ret == -EOPNOTSUPP)
> > +		return ret;
> 
> Can you find a way such that only sfp_sm_mod_probe() needs to check
> whether the sfp read/write operations returned failure and then we just
> make sure the SFP state machine does not make any more progress? Having
> to check the sfp_read()/sfp_write() operations all over the place sounds
> error prone and won't scale in the future.

I tried doing this in this way (only having logic in the probe
function), but that wasn't as simple as this solution and it seemed
quite invasive as these read/write calls can be called from a few
functions but many code paths (as it's a state machine). So I choose the
easiest solution to maintain in the long run, as each future state
machine update could impact this.

Thanks!
Antoine

-- 
Antoine Ténart, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com

  reply	other threads:[~2018-05-04 17:19 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-04 13:56 [PATCH net-next v2 00/13] net: mvpp2: phylink conversion Antoine Tenart
2018-05-04 13:56 ` [PATCH net-next v2 01/13] net: phy: sfp: make the i2c-bus property really optional Antoine Tenart
2018-05-04 17:03   ` Florian Fainelli
2018-05-04 17:19     ` Antoine Tenart [this message]
2018-05-04 13:56 ` [PATCH net-next v2 02/13] net: phy: sfp: handle non-wired SFP connectors Antoine Tenart
2018-05-04 17:04   ` Florian Fainelli
2018-05-04 17:17     ` Andrew Lunn
2018-05-04 17:23     ` Antoine Tenart
2018-05-05 15:39       ` Thomas Petazzoni
2018-05-05 17:48         ` Andrew Lunn
2018-05-08 11:52   ` Russell King - ARM Linux
2018-05-14  9:26     ` Antoine Tenart
2018-05-04 13:56 ` [PATCH net-next v2 03/13] net: phy: sfp: warn the user when no tx_disable pin is available Antoine Tenart
2018-05-04 17:07   ` Florian Fainelli
2018-05-04 17:14     ` Andrew Lunn
2018-05-05 20:38       ` Florian Fainelli
2018-05-05 20:52         ` Andrew Lunn
2018-05-08 12:45           ` Russell King - ARM Linux
2018-05-08 11:53   ` Russell King - ARM Linux
2018-05-04 13:56 ` [PATCH net-next v2 04/13] net: mvpp2: align the ethtool ops definition Antoine Tenart
2018-05-04 13:56 ` [PATCH net-next v2 05/13] net: mvpp2: phylink support Antoine Tenart
2018-05-04 13:56 ` [PATCH net-next v2 06/13] phy: add 2.5G SGMII mode to the phy_mode enum Antoine Tenart
2018-05-08 12:34   ` Russell King - ARM Linux
2018-05-14  8:37     ` Antoine Tenart
2018-05-04 13:56 ` [PATCH net-next v2 07/13] phy: cp110-comphy: 2.5G SGMII mode Antoine Tenart
2018-05-04 13:56 ` [PATCH net-next v2 08/13] net: mvpp2: 1000baseX support Antoine Tenart
2018-05-04 13:56 ` [PATCH net-next v2 09/13] net: mvpp2: 2500baseX support Antoine Tenart
2018-05-04 13:56 ` [PATCH net-next v2 10/13] arm64: dts: marvell: mcbin: add 10G SFP support Antoine Tenart
2018-05-04 13:56 ` [PATCH net-next v2 11/13] arm64: dts: marvell: mcbin: enable the fourth network interface Antoine Tenart
2018-05-04 13:56 ` [PATCH net-next v2 12/13] arm64: dts: marvell: 7040-db: describe the 10G SFP cage Antoine Tenart
2018-05-04 13:56 ` [PATCH net-next v2 13/13] arm64: dts: marvell: 8040-db: describe the 10G SFP cages Antoine Tenart
2018-05-08  3:18 ` [PATCH net-next v2 00/13] net: mvpp2: phylink conversion David Miller

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