Re: [PATCH 3/3] net: phy: realtek: Support SSC for the RTL8211E

From: Heiner Kallweit
Date: Mon Jul 01 2019 - 16:50:02 EST


On 01.07.2019 21:52, Matthias Kaehlcke wrote:
> By default Spread-Spectrum Clocking (SSC) is disabled on the RTL8211E.
> Enable it if the device tree property 'realtek,enable-ssc' exists.
>
> Signed-off-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>
> ---
> drivers/net/phy/realtek.c | 27 ++++++++++++++++++++++++---
> 1 file changed, 24 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/phy/realtek.c b/drivers/net/phy/realtek.c
> index dfc2e20ef335..b617169ccc8c 100644
> --- a/drivers/net/phy/realtek.c
> +++ b/drivers/net/phy/realtek.c
> @@ -9,8 +9,10 @@
> * Copyright (c) 2004 Freescale Semiconductor, Inc.
> */
> #include <linux/bitops.h>
> -#include <linux/phy.h>
> +#include <linux/device.h>
> +#include <linux/of.h>
> #include <linux/module.h>
> +#include <linux/phy.h>
>
> #define RTL821x_PHYSR 0x11
> #define RTL821x_PHYSR_DUPLEX BIT(13)
> @@ -28,6 +30,8 @@
>
> #define RTL8211E_EXT_PAGE 7
> #define RTL8211E_EPAGSR 0x1e
> +#define RTL8211E_SCR 0x1a
> +#define RTL8211E_SCR_DISABLE_RXC_SSC BIT(2)
>
> #define RTL8211F_INSR 0x1d
>
> @@ -87,8 +91,8 @@ static int rtl821e_restore_page(struct phy_device *phydev, int oldpage, int ret)
> return ret;
> }
>
> -static int __maybe_unused rtl8211e_modify_ext_paged(struct phy_device *phydev,
> - int page, u32 regnum, u16 mask, u16 set)
> +static int rtl8211e_modify_ext_paged(struct phy_device *phydev, int page,
> + u32 regnum, u16 mask, u16 set)
> {
> int ret = 0;
> int oldpage;
> @@ -114,6 +118,22 @@ static int __maybe_unused rtl8211e_modify_ext_paged(struct phy_device *phydev,
> return rtl821e_restore_page(phydev, oldpage, ret);
> }
>
> +static int rtl8211e_probe(struct phy_device *phydev)
> +{
> + struct device *dev = &phydev->mdio.dev;
> + int err;
> +
> + if (of_property_read_bool(dev->of_node, "realtek,enable-ssc")) {
> + err = rtl8211e_modify_ext_paged(phydev, 0xa0, RTL8211E_SCR,
> + RTL8211E_SCR_DISABLE_RXC_SSC,
> + 0);
> + if (err)
> + dev_err(dev, "failed to enable SSC on RXC: %d\n", err);
> + }
> +
> + return 0;
> +}
> +
> static int rtl8201_ack_interrupt(struct phy_device *phydev)
> {
> int err;
> @@ -372,6 +392,7 @@ static struct phy_driver realtek_drvs[] = {
> .config_init = &rtl8211e_config_init,
> .ack_interrupt = &rtl821x_ack_interrupt,
> .config_intr = &rtl8211e_config_intr,
> + .probe = rtl8211e_probe,

I'm not sure whether this setting survives soft reset and power-down.
Maybe it should be better applied in the config_init callback.

> .suspend = genphy_suspend,
> .resume = genphy_resume,
> .read_page = rtl821x_read_page,
>