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From: Florian Fainelli <f.fainelli@gmail.com>
To: 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
Cc: 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 10:03:16 -0700	[thread overview]
Message-ID: <fd91699d-c290-8821-b4a6-0789071cfba1@gmail.com> (raw)
In-Reply-To: <20180504135643.23466-2-antoine.tenart@bootlin.com>

On 05/04/2018 06:56 AM, Antoine Tenart wrote:
> The SFF,SFP documentation is clear about making all the DT properties,
> with the exception of the compatible, optional. In practice this is not
> the case and without an i2c-bus property provided the SFP code will
> throw NULL pointer exceptions.
> 
> This patch is an attempt to fix this.
> 
> Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
> ---
>  drivers/net/phy/sfp.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/drivers/net/phy/sfp.c b/drivers/net/phy/sfp.c
> index 4ab6e9a50bbe..4686c443fc22 100644
> --- a/drivers/net/phy/sfp.c
> +++ b/drivers/net/phy/sfp.c
> @@ -298,11 +298,17 @@ static void sfp_set_state(struct sfp *sfp, unsigned int state)
>  
>  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.

> +
>  	return sfp->read(sfp, a2, addr, buf, len);
>  }
>  
>  static int sfp_write(struct sfp *sfp, bool a2, u8 addr, void *buf, size_t len)
>  {
> +	if (!sfp->write)
> +		return -EOPNOTSUPP;
> +
>  	return sfp->write(sfp, a2, addr, buf, len);
>  }
>  
> @@ -533,6 +539,8 @@ static int sfp_sm_mod_hpower(struct sfp *sfp)
>  		return 0;
>  
>  	err = sfp_read(sfp, true, SFP_EXT_STATUS, &val, sizeof(val));
> +	if (err == -EOPNOTSUPP)
> +		goto err;
>  	if (err != sizeof(val)) {
>  		dev_err(sfp->dev, "Failed to read EEPROM: %d\n", err);
>  		err = -EAGAIN;
> @@ -542,6 +550,8 @@ static int sfp_sm_mod_hpower(struct sfp *sfp)
>  	val |= BIT(0);
>  
>  	err = sfp_write(sfp, true, SFP_EXT_STATUS, &val, sizeof(val));
> +	if (err == -EOPNOTSUPP)
> +		goto err;
>  	if (err != sizeof(val)) {
>  		dev_err(sfp->dev, "Failed to write EEPROM: %d\n", err);
>  		err = -EAGAIN;
> @@ -565,6 +575,8 @@ static int sfp_sm_mod_probe(struct sfp *sfp)
>  	int ret;
>  
>  	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.
-- 
Florian

  reply	other threads:[~2018-05-04 17:03 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 [this message]
2018-05-04 17:19     ` Antoine Tenart
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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