On Wed, 2019-12-11 at 00:48 +0800, Andrew Lunn wrote:

quoted

+static int mt7531_setup(struct dsa_switch *ds)
+{
+	/* Enable PHY power, since phy_device has not yet been created
+	 * provided for phy_[read,write]_mmd_indirect is called, we provide
+	 * our own mt7531_ind_mmd_phy_[read,write] to complete this
+	 * function.
+	 */
+	val = mt7531_ind_mmd_phy_read(priv, 0, PHY_DEV1F,
+				      MT7531_PHY_DEV1F_REG_403);
+	val |= MT7531_PHY_EN_BYPASS_MODE;
+	val &= ~MT7531_PHY_POWER_OFF;
+	mt7531_ind_mmd_phy_write(priv, 0, PHY_DEV1F,
+				 MT7531_PHY_DEV1F_REG_403, val);
+

Is this power to all the PHYs? Or just one?

This is an internal circuit that controls the power to all PHYs before
Generic MII registers are available.

Landen

   Andrew