[PATCH net-next v2 2/5] net: mediatek: sgmii: ensure the SGMII PHY is powered down on configuration

[Alexander Couzens <lynxis@fe80.eu>]

The code expect the PHY to be in power down which is only true after reset.
Allow changes of the SGMII parameters more than once.

Signed-off-by: Alexander Couzens <lynxis@fe80.eu>
---
 drivers/net/ethernet/mediatek/mtk_sgmii.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/net/ethernet/mediatek/mtk_sgmii.c b/drivers/net/ethernet/mediatek/mtk_sgmii.c
index b9b15e1a292c..18de85709e87 100644
--- a/drivers/net/ethernet/mediatek/mtk_sgmii.c
+++ b/drivers/net/ethernet/mediatek/mtk_sgmii.c
@@ -7,6 +7,7 @@
  *
  */
 
+#include <linux/delay.h>
 #include <linux/mfd/syscon.h>
 #include <linux/of.h>
 #include <linux/phylink.h>
@@ -24,6 +25,9 @@ static int mtk_pcs_setup_mode_an(struct mtk_pcs *mpcs)
 {
 	unsigned int val;
 
+	/* PHYA power down */
+	regmap_write(mpcs->regmap, SGMSYS_QPHY_PWR_STATE_CTRL, SGMII_PHYA_PWD);
+
 	/* Setup the link timer and QPHY power up inside SGMIISYS */
 	regmap_write(mpcs->regmap, SGMSYS_PCS_LINK_TIMER,
 		     SGMII_LINK_TIMER_DEFAULT);
@@ -42,8 +46,10 @@ static int mtk_pcs_setup_mode_an(struct mtk_pcs *mpcs)
 	 * prevents SGMII from working. The SGMII still shows link but no traffic
 	 * can flow. Writing 0x0 to the PHYA_PWD register fix the issue. 0x0 was
 	 * taken from a good working state of the SGMII interface.
+	 * Unknown how much the QPHY needs but it is racy without a sleep.
 	 * Tested on mt7622 & mt7986.
 	 */
+	usleep_range(50, 100);
 	regmap_write(mpcs->regmap, SGMSYS_QPHY_PWR_STATE_CTRL, 0);
 
 	return 0;
@@ -58,6 +64,9 @@ static int mtk_pcs_setup_mode_force(struct mtk_pcs *mpcs,
 {
 	unsigned int val;
 
+	/* PHYA power down */
+	regmap_write(mpcs->regmap, SGMSYS_QPHY_PWR_STATE_CTRL, SGMII_PHYA_PWD);
+
 	regmap_read(mpcs->regmap, mpcs->ana_rgc3, &val);
 	val &= ~RG_PHY_SPEED_MASK;
 	if (interface == PHY_INTERFACE_MODE_2500BASEX)
@@ -81,8 +90,10 @@ static int mtk_pcs_setup_mode_force(struct mtk_pcs *mpcs,
 	 * prevents SGMII from working. The SGMII still shows link but no traffic
 	 * can flow. Writing 0x0 to the PHYA_PWD register fix the issue. 0x0 was
 	 * taken from a good working state of the SGMII interface.
+	 * Unknown how much the QPHY needs but it is racy without a sleep.
 	 * Tested on mt7622 & mt7986.
 	 */
+	usleep_range(50, 100);
 	regmap_write(mpcs->regmap, SGMSYS_QPHY_PWR_STATE_CTRL, 0);
 
 	return 0;
-- 
2.37.3