[PATCH net-next] net: phy: vitesse: implement downshift in vsc73xx phys

Pawel Dembicki
2024-08-01T05:09:48Z

This commit implements downshift feature in vsc73xx family phys.

By default downshift was enabled with maximum tries.

Signed-off-by: Pawel Dembicki <paweldembicki@gmail.com>

---
This patch came from net-next patch series[0] which was splitted.
It's simplified as Russell King requested.

[0] https://patchwork.kernel.org/project/netdevbpf/patch/20240729210615.279952-10-paweldembicki@gmail.com/
---
drivers/net/phy/vitesse.c | 90 +++++++++++++++++++++++++++++++++++++++
1 file changed, 90 insertions(+)

diff --git a/drivers/net/phy/vitesse.c b/drivers/net/phy/vitesse.c
index 19b7bf189be5..82b1fc1a3276 100644
--- a/drivers/net/phy/vitesse.c
+++ b/drivers/net/phy/vitesse.c
@@ -10,8 +10,10 @@
#include <linux/mii.h>
#include <linux/ethtool.h>
#include <linux/phy.h>
+#include <linux/bitfield.h>

/* Vitesse Extended Page Magic Register(s) */
+#define MII_VSC73XX_EXT_PAGE_1E 0x01
#define MII_VSC82X4_EXT_PAGE_16E 0x10
#define MII_VSC82X4_EXT_PAGE_17E 0x11
#define MII_VSC82X4_EXT_PAGE_18E 0x12
@@ -60,6 +62,15 @@
/* Vitesse Extended Page Access Register */
#define MII_VSC82X4_EXT_PAGE_ACCESS 0x1f

+/* Vitesse VSC73XX Extended Control Register */
+#define MII_VSC73XX_PHY_CTRL_EXT3 0x14
+
+#define MII_VSC73XX_PHY_CTRL_EXT3_DOWNSHIFT_EN BIT(4)
+#define MII_VSC73XX_PHY_CTRL_EXT3_DOWNSHIFT_CNT GENMASK(3, 2)
+#define MII_VSC73XX_PHY_CTRL_EXT3_DOWNSHIFT_STA BIT(1)
+#define MII_VSC73XX_DOWNSHIFT_MAX 5
+#define MII_VSC73XX_DOWNSHIFT_INVAL 1
+
/* VSC73XX PHY_BYPASS_CTRL register*/
#define MII_VSC73XX_PHY_BYPASS_CTRL MII_DCOUNTER
#define MII_PBC_FORCED_SPEED_AUTO_MDIX_DIS BIT(7)
@@ -133,6 +144,74 @@ static int vsc73xx_write_page(struct phy_device *phydev, int page)
return __phy_write(phydev, VSC73XX_EXT_PAGE_ACCESS, page);
}

+static int vsc73xx_get_downshift(struct phy_device *phydev, u8 *data)
+{
+ int val, enable, cnt;
+
+ val = phy_read_paged(phydev, MII_VSC73XX_EXT_PAGE_1E,
+ MII_VSC73XX_PHY_CTRL_EXT3);
+ if (val < 0)
+ return val;
+
+ enable = FIELD_GET(MII_VSC73XX_PHY_CTRL_EXT3_DOWNSHIFT_EN, val);
+ cnt = FIELD_GET(MII_VSC73XX_PHY_CTRL_EXT3_DOWNSHIFT_CNT, val) + 2;
+
+ *data = enable ? cnt : DOWNSHIFT_DEV_DISABLE;
+
+ return 0;
+}
+
+static int vsc73xx_set_downshift(struct phy_device *phydev, u8 cnt)
+{
+ u16 mask, val;
+ int ret;
+
+ if (cnt > MII_VSC73XX_DOWNSHIFT_MAX)
+ return -E2BIG;
+ else if (cnt == MII_VSC73XX_DOWNSHIFT_INVAL)
+ return -EINVAL;
+
+ mask = MII_VSC73XX_PHY_CTRL_EXT3_DOWNSHIFT_EN;
+
+ if (!cnt) {
+ val = 0;
+ } else {
+ mask |= MII_VSC73XX_PHY_CTRL_EXT3_DOWNSHIFT_CNT;
+ val = MII_VSC73XX_PHY_CTRL_EXT3_DOWNSHIFT_EN |
+ FIELD_PREP(MII_VSC73XX_PHY_CTRL_EXT3_DOWNSHIFT_CNT,
+ cnt - 2);
+ }
+
+ ret = phy_modify_paged(phydev, MII_VSC73XX_EXT_PAGE_1E,
+ MII_VSC73XX_PHY_CTRL_EXT3, mask, val);
+ if (ret < 0)
+ return ret;
+
+ return genphy_soft_reset(phydev);
+}
+
+static int vsc73xx_get_tunable(struct phy_device *phydev,
+ struct ethtool_tunable *tuna, void *data)
+{
+ switch (tuna->id) {
+ case ETHTOOL_PHY_DOWNSHIFT:
+ return vsc73xx_get_downshift(phydev, data);
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static int vsc73xx_set_tunable(struct phy_device *phydev,
+ struct ethtool_tunable *tuna, const void *data)
+{
+ switch (tuna->id) {
+ case ETHTOOL_PHY_DOWNSHIFT:
+ return vsc73xx_set_downshift(phydev, *(const u8 *)data);
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
static void vsc73xx_config_init(struct phy_device *phydev)
{
/* Receiver init */
@@ -142,6 +221,9 @@ static void vsc73xx_config_init(struct phy_device *phydev)

/* Config LEDs 0x61 */
phy_modify(phydev, MII_TPISTATUS, 0xff00, 0x0061);
+
+ /* Enable downshift by default */
+ vsc73xx_set_downshift(phydev, MII_VSC73XX_DOWNSHIFT_MAX);
}

static int vsc738x_config_init(struct phy_device *phydev)
@@ -460,6 +542,8 @@ static struct phy_driver vsc82xx_driver[] = {
.config_aneg = vsc73xx_config_aneg,
.read_page = vsc73xx_read_page,
.write_page = vsc73xx_write_page,
+ .get_tunable = vsc73xx_get_tunable,
+ .set_tunable = vsc73xx_set_tunable,
}, {
.phy_id = PHY_ID_VSC7388,
.name = "Vitesse VSC7388",
@@ -469,6 +553,8 @@ static struct phy_driver vsc82xx_driver[] = {
.config_aneg = vsc73xx_config_aneg,
.read_page = vsc73xx_read_page,
.write_page = vsc73xx_write_page,
+ .get_tunable = vsc73xx_get_tunable,
+ .set_tunable = vsc73xx_set_tunable,
}, {
.phy_id = PHY_ID_VSC7395,
.name = "Vitesse VSC7395",
@@ -478,6 +564,8 @@ static struct phy_driver vsc82xx_driver[] = {
.config_aneg = vsc73xx_config_aneg,
.read_page = vsc73xx_read_page,
.write_page = vsc73xx_write_page,
+ .get_tunable = vsc73xx_get_tunable,
+ .set_tunable = vsc73xx_set_tunable,
}, {
.phy_id = PHY_ID_VSC7398,
.name = "Vitesse VSC7398",
@@ -487,6 +575,8 @@ static struct phy_driver vsc82xx_driver[] = {
.config_aneg = vsc73xx_config_aneg,
.read_page = vsc73xx_read_page,
.write_page = vsc73xx_write_page,
+ .get_tunable = vsc73xx_get_tunable,
+ .set_tunable = vsc73xx_set_tunable,
}, {
.phy_id = PHY_ID_VSC8662,
.name = "Vitesse VSC8662",
--
2.34.1