linux-kernel - Re: [RESEND net-next v5 2/4] net: phy: realtek: Clean up RTL8211E ExtPage access

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Message-ID: <4d26d92e-f083-4a5c-88b5-93c45c6a51a5@lunn.ch>
Date: Tue, 8 Apr 2025 21:21:58 +0200
From: Andrew Lunn <andrew@...n.ch>
To: Michael Klein <michael@...sekall.de>
Cc: Joe Damato <jdamato@...tly.com>, Heiner Kallweit <hkallweit1@...il.com>,
	Russell King <linux@...linux.org.uk>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [RESEND net-next v5 2/4] net: phy: realtek: Clean up RTL8211E
 ExtPage access

On Tue, Apr 08, 2025 at 08:47:20PM +0200, Michael Klein wrote:
> On Mon, Apr 07, 2025 at 07:56:14PM -0700, Joe Damato wrote:
> > > - Factor out RTL8211E extension page access code to
> > >   rtl8211e_modify_ext_page() and clean up rtl8211e_config_init()
> > > 
> > > Signed-off-by: Michael Klein <michael@...sekall.de>
> > > ---
> > >  drivers/net/phy/realtek/realtek_main.c | 38 +++++++++++++++-----------
> > >  1 file changed, 22 insertions(+), 16 deletions(-)
> > > 
> > > diff --git a/drivers/net/phy/realtek/realtek_main.c b/drivers/net/phy/realtek/realtek_main.c
> > > index b27c0f995e56..e60c18551a4e 100644
> > > --- a/drivers/net/phy/realtek/realtek_main.c
> > > +++ b/drivers/net/phy/realtek/realtek_main.c
> > > @@ -37,9 +37,11 @@
> > > 
> > >  #define RTL821x_INSR				0x13
> > > 
> > > -#define RTL821x_EXT_PAGE_SELECT			0x1e
> > >  #define RTL821x_PAGE_SELECT			0x1f
> > > 
> > > +#define RTL8211E_EXT_PAGE_SELECT		0x1e
> > > +#define RTL8211E_SET_EXT_PAGE			0x07
> > > +
> > >  #define RTL8211E_CTRL_DELAY			BIT(13)
> > >  #define RTL8211E_TX_DELAY			BIT(12)
> > >  #define RTL8211E_RX_DELAY			BIT(11)
> > > @@ -135,6 +137,21 @@ static int rtl821x_write_page(struct phy_device *phydev, int page)
> > >  	return __phy_write(phydev, RTL821x_PAGE_SELECT, page);
> > >  }
> > > 
> > > +static int rtl8211e_modify_ext_page(struct phy_device *phydev, u16 ext_page,
> > > +				    u32 regnum, u16 mask, u16 set)
> > > +{
> > > +	int oldpage, ret = 0;
> > > +
> > > +	oldpage = phy_select_page(phydev, RTL8211E_SET_EXT_PAGE);
> > > +	if (oldpage >= 0) {
> > > +		ret = __phy_write(phydev, RTL8211E_EXT_PAGE_SELECT, ext_page);
> > > +		if (ret == 0)
> > > +			ret = __phy_modify(phydev, regnum, mask, set);
> > > +	}
> > > +
> > > +	return phy_restore_page(phydev, oldpage, ret);
> > > +}
> > > +
> > >  static int rtl821x_probe(struct phy_device *phydev)
> > >  {
> > >  	struct device *dev = &phydev->mdio.dev;
> > > @@ -607,7 +624,9 @@ static int rtl8211f_led_hw_control_set(struct phy_device *phydev, u8 index,
> > > 
> > >  static int rtl8211e_config_init(struct phy_device *phydev)
> > >  {
> > > -	int ret = 0, oldpage;
> > > +	const u16 delay_mask = RTL8211E_CTRL_DELAY |
> > > +			       RTL8211E_TX_DELAY |
> > > +			       RTL8211E_RX_DELAY;
> > >  	u16 val;
> > > 
> > >  	/* enable TX/RX delay for rgmii-* modes, and disable them for rgmii. */
> > > @@ -637,20 +656,7 @@ static int rtl8211e_config_init(struct phy_device *phydev)
> > >  	 * 12 = RX Delay, 11 = TX Delay
> > >  	 * 10:0 = Test && debug settings reserved by realtek
> > >  	 */
> > > -	oldpage = phy_select_page(phydev, 0x7);
> > > -	if (oldpage < 0)
> > > -		goto err_restore_page;
> > > -
> > > -	ret = __phy_write(phydev, RTL821x_EXT_PAGE_SELECT, 0xa4);
> > > -	if (ret)
> > > -		goto err_restore_page;
> > > -
> > > -	ret = __phy_modify(phydev, 0x1c, RTL8211E_CTRL_DELAY
> > > -			   | RTL8211E_TX_DELAY | RTL8211E_RX_DELAY,
> > > -			   val);
> > > -
> > > -err_restore_page:
> > > -	return phy_restore_page(phydev, oldpage, ret);
> > > +	return rtl8211e_modify_ext_page(phydev, 0xa4, 0x1c, delay_mask, val);
> > >  }
> > 
> > Seems good to add RTL8211E_SET_EXT_PAGE to remove a constant from
> > the code. Any reason to avoid adding constants for 0xa4 and 0x1c ?
> 
> My copy of the datasheet does not document this register, so I did not
> feel qualified to come up with a meaningful name.

Is the page documented?

As for the register, it appears to contain RGMII delay configuration,
so why not call it RTL8211E_RGMII_DELAY ?

Sometimes you just have to make names up. If somebody has a datasheet
which lists it and wants to rename it, they can.

   Andrew