From: Tobias Waldekranz <tobias@waldekranz.com>
To: Andrew Lunn <andrew@lunn.ch>
Cc: davem@davemloft.net, kuba@kernel.org, netdev@vger.kernel.org,
Marcin Wojtas <mw@semihalf.com>,
Calvin Johnson <calvin.johnson@oss.nxp.com>,
Markus Koch <markus@notsyncing.net>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next 4/5] net/fsl: xgmac_mdio: Support setting the MDC frequency
Date: Wed, 26 Jan 2022 14:30:28 +0100 [thread overview]
Message-ID: <87r18ubp57.fsf@waldekranz.com> (raw)
In-Reply-To: <YfFHmkFXtlVus9IW@lunn.ch>
On Wed, Jan 26, 2022 at 14:07, Andrew Lunn <andrew@lunn.ch> wrote:
> Hi Tobias
>
>> struct mdio_fsl_priv {
>> struct tgec_mdio_controller __iomem *mdio_base;
>> + struct clk *enet_clk;
>
> It looks like there is a whitespace issue here?
>
Ahh, sorry about that!
>> + u32 mdc_freq;
>> bool is_little_endian;
>> bool has_a009885;
>> bool has_a011043;
>> @@ -255,6 +258,34 @@ static int xgmac_mdio_read(struct mii_bus *bus, int phy_id, int regnum)
>> return ret;
>> }
>>
>> +static void xgmac_mdio_set_mdc_freq(struct mii_bus *bus)
>> +{
>> + struct mdio_fsl_priv *priv = (struct mdio_fsl_priv *)bus->priv;
>> + struct tgec_mdio_controller __iomem *regs = priv->mdio_base;
>> + struct device *dev = bus->parent;
>> + u32 mdio_stat, div;
>> +
>> + if (device_property_read_u32(dev, "clock-frequency", &priv->mdc_freq))
>> + return;
>> +
>> + priv->enet_clk = devm_clk_get(dev, NULL);
>> + if (IS_ERR(priv->enet_clk)) {
>> + dev_err(dev, "Input clock unknown, not changing MDC frequency");
>
> Is the clock optional or mandatory?
As the code is now, it is mandatory. I could add some default frequency,
but I fear that could do more harm than good?
> If mandatory, then i would prefer -ENODEV and fail the probe.
>
>> + return;
>> + }
>> +
>> + div = ((clk_get_rate(priv->enet_clk) / priv->mdc_freq) - 1) / 2;
>> + if (div < 5 || div > 0x1ff) {
>> + dev_err(dev, "Requested MDC frequecy is out of range, ignoring");
>
> and here return -EINVAL.
>
> I always think it is best to make it obvious something is broken. One
> additional line on the console can be missed for a while. All the
> Ethernet devices missing because the PHYs are missing, because the
> MDIO bus is missing is going to get noticed very quickly.
Darn, the last thing I did was to change this from a hard to a soft
error :)
Ok, no worries about regressions for deployed stuff already out there?
next prev parent reply other threads:[~2022-01-26 13:30 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20220126101432.822818-1-tobias@waldekranz.com>
2022-01-26 10:14 ` [PATCH net-next 1/5] dt-bindings: net: xgmac_mdio: Remove unsupported "bus-frequency" Tobias Waldekranz
2022-01-26 13:31 ` Andrew Lunn
2022-01-26 10:14 ` [PATCH net-next 2/5] net/fsl: xgmac_mdio: Use managed device resources Tobias Waldekranz
2022-01-26 13:08 ` Andrew Lunn
2022-01-26 10:14 ` [PATCH net-next 3/5] net/fsl: xgmac_mdio: Support preamble suppression Tobias Waldekranz
2022-01-26 13:08 ` Andrew Lunn
2022-01-26 10:14 ` [PATCH net-next 4/5] net/fsl: xgmac_mdio: Support setting the MDC frequency Tobias Waldekranz
2022-01-26 13:07 ` Andrew Lunn
2022-01-26 13:30 ` Tobias Waldekranz [this message]
2022-01-26 14:02 ` Andrew Lunn
2022-01-26 10:14 ` [PATCH net-next 5/5] dt-bindings: net: xgmac_mdio: Add "clock-frequency" and "suppress-preamble" Tobias Waldekranz
2022-01-26 13:36 ` Andrew Lunn
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