netdev - Re: [PATCH V3] net: phy: tja11xx: Add TJA11xx PHY driver

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Message-ID: <836d9cec-0175-3cd1-b59b-2021195b8461@gmail.com>
Date:   Sat, 22 Dec 2018 18:39:50 +0100
From:   Heiner Kallweit <hkallweit1@...il.com>
To:     Marek Vasut <marex@...x.de>, netdev@...r.kernel.org
Cc:     Andrew Lunn <andrew@...n.ch>,
        Florian Fainelli <f.fainelli@...il.com>
Subject: Re: [PATCH V3] net: phy: tja11xx: Add TJA11xx PHY driver

On 22.12.2018 00:35, Marek Vasut wrote:
> Add driver for the NXP TJA1100 and TJA1101 PHYs. These PHYs are special
> BroadRReach 100BaseT1 PHYs used in automotive.
> 
> Signed-off-by: Marek Vasut <marex@...x.de>
> Cc: Andrew Lunn <andrew@...n.ch>
> Cc: Florian Fainelli <f.fainelli@...il.com>
> Cc: Heiner Kallweit <hkallweit1@...il.com>
> ---
> V2: - Use phy_modify(), phy_{set,clear}_bits()
>     - Drop enable argument of tja11xx_enable_link_control()
>     - Use PHY_BASIC_T1_FEATURES and dont modify supported/advertised
>       features in config_init callback
>     - Use genphy_soft_reset() instead of opencoding the reset sequence.
>     - Drop the aneg parts, since the PHY datasheet claims it does not
>       support aneg
> V3: - Replace clr with mask
>     - Add hwmon support
>     - Check commstat in tja11xx_read_status() only if link is up
>     - Use PHY_ID_MATCH_MODEL()
> ---
>  drivers/net/phy/Kconfig       |   6 +
>  drivers/net/phy/Makefile      |   1 +
>  drivers/net/phy/nxp-tja11xx.c | 424 ++++++++++++++++++++++++++++++++++
>  3 files changed, 431 insertions(+)
>  create mode 100644 drivers/net/phy/nxp-tja11xx.c
> 
[...]
> +
> +struct tja11xx_phy_stats {
> +	const char	*string;
> +	u8		reg;
> +	u8		off;
> +	u16		mask;
> +};
> +
As written in my other mail, you could think of using
FIELD_GET() again. Things like
... n, BIT(n), 
... m, BIT(m), 
are simply redundant.

> +static struct tja11xx_phy_stats tja11xx_hw_stats[] = {
> +	{ "phy_symbol_error_count", 20, 0, 0xffff },
> +	{ "phy_polarity_detect", 25, 6, BIT(6) },
> +	{ "phy_open_detect", 25, 7, BIT(7) },
> +	{ "phy_short_detect", 25, 8, BIT(8) },
> +	{ "phy_rem_rcvr_count", 26, 0, 0xff },
> +	{ "phy_loc_rcvr_count", 26, 8, 0xff },

Shouldn't mask in the last line be 0xff00 ?
In the relevant code you do: val = (reg & mask) >> off

> +static int tja11xx_probe(struct phy_device *phydev)
> +{
> +	struct device *dev = &phydev->mdio.dev;
> +	struct tja11xx_priv *priv;
> +	int i;
> +
> +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	priv->hwmon_name = devm_kstrdup(dev, dev_name(dev), GFP_KERNEL);
> +	if (!priv->hwmon_name)
> +		return -ENODEV;

Do you really need to make a copy of the device name?
Why not simply priv->hwmon_name = dev_name(dev) ?
And if devm_kstrdup fails, then most likely you have an out-of-memory
error, so why not return -ENOMEM as usual?

> +
> +	for (i = 0; priv->hwmon_name[i]; i++)
> +		if (hwmon_is_bad_char(priv->hwmon_name[i]))
> +			priv->hwmon_name[i] = '_';
> +
> +	priv->hwmon_dev =
> +		devm_hwmon_device_register_with_info(dev, priv->hwmon_name,
> +						     phydev,
> +						     &tja11xx_hwmon_chip_info,
> +						     NULL);
> +
Prerequisite for this call is that HWMON is configured in the kernel and
it's reachable. Something like "IS_REACHABLE(CONFIG_HWMON)" would be
needed. You can see driver rtc-ds1307 for an example.