net: phy: meson-gxl: add read and write helpers for banked registers

Add read and write helpers to manipulate banked registers on this PHY
This helps clarify the settings applied to these registers and what the
driver actually does
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/meson-gxl.c

@@ -50,11 +50,13 @@
 #define FR_PLL_DIV0	0x1c
 #define FR_PLL_DIV1	0x1d
 
-static int meson_gxl_config_init(struct phy_device *phydev)
+static int meson_gxl_open_banks(struct phy_device *phydev)
 {
 	int ret;
 
-	/* Enable Analog and DSP register Bank access by */
+	/* Enable Analog and DSP register Bank access by
+	 * toggling TSTCNTL_TEST_MODE bit in the TSTCNTL register
+	 */
 	ret = phy_write(phydev, TSTCNTL, 0);
 	if (ret)
 		return ret;
@@ -64,55 +66,84 @@ static int meson_gxl_config_init(struct phy_device *phydev)
 	ret = phy_write(phydev, TSTCNTL, 0);
 	if (ret)
 		return ret;
-	ret = phy_write(phydev, TSTCNTL, TSTCNTL_TEST_MODE);
-	if (ret)
-		return ret;
+	return phy_write(phydev, TSTCNTL, TSTCNTL_TEST_MODE);
+}
 
-	/* Write CONFIG_A6*/
-	ret = phy_write(phydev, TSTWRITE, 0x8e0d);
+static void meson_gxl_close_banks(struct phy_device *phydev)
+{
+	phy_write(phydev, TSTCNTL, 0);
+}
+
+static int meson_gxl_read_reg(struct phy_device *phydev,
+			      unsigned int bank, unsigned int reg)
+{
+	int ret;
+
+	ret = meson_gxl_open_banks(phydev);
 	if (ret)
-		return ret;
-	ret = phy_write(phydev, TSTCNTL,
-			TSTCNTL_WRITE
-			| FIELD_PREP(TSTCNTL_REG_BANK_SEL, BANK_ANALOG_DSP)
-			| TSTCNTL_TEST_MODE
-			| FIELD_PREP(TSTCNTL_WRITE_ADDRESS, A6_CONFIG_REG));
+		goto out;
+
+	ret = phy_write(phydev, TSTCNTL, TSTCNTL_READ |
+			FIELD_PREP(TSTCNTL_REG_BANK_SEL, bank) |
+			TSTCNTL_TEST_MODE |
+			FIELD_PREP(TSTCNTL_READ_ADDRESS, reg));
 	if (ret)
+		goto out;
+
+	ret = phy_read(phydev, TSTREAD1);
+out:
+	/* Close the bank access on our way out */
+	meson_gxl_close_banks(phydev);
 	return ret;
+}
 
-	/* Enable fractional PLL */
-	ret = phy_write(phydev, TSTWRITE, 0x0005);
+static int meson_gxl_write_reg(struct phy_device *phydev,
+			       unsigned int bank, unsigned int reg,
+			       uint16_t value)
+{
+	int ret;
+
+	ret = meson_gxl_open_banks(phydev);
 	if (ret)
-		return ret;
-	ret = phy_write(phydev, TSTCNTL,
-			TSTCNTL_WRITE
-			| FIELD_PREP(TSTCNTL_REG_BANK_SEL, BANK_BIST)
-			| TSTCNTL_TEST_MODE
-			| FIELD_PREP(TSTCNTL_WRITE_ADDRESS, FR_PLL_CONTROL));
+		goto out;
+
+	ret = phy_write(phydev, TSTWRITE, value);
 	if (ret)
+		goto out;
+
+	ret = phy_write(phydev, TSTCNTL, TSTCNTL_WRITE |
+			FIELD_PREP(TSTCNTL_REG_BANK_SEL, bank) |
+			TSTCNTL_TEST_MODE |
+			FIELD_PREP(TSTCNTL_WRITE_ADDRESS, reg));
+
+out:
+	/* Close the bank access on our way out */
+	meson_gxl_close_banks(phydev);
 	return ret;
+}
 
-	/* Program fraction FR_PLL_DIV1 */
-	ret = phy_write(phydev, TSTWRITE, 0x029a);
+static int meson_gxl_config_init(struct phy_device *phydev)
+{
+	int ret;
+
+	/* Write CONFIG_A6*/
+	ret = meson_gxl_write_reg(phydev, BANK_ANALOG_DSP, A6_CONFIG_REG,
+				  0x8e0d);
 	if (ret)
 		return ret;
-	ret = phy_write(phydev, TSTCNTL,
-			TSTCNTL_WRITE
-			| FIELD_PREP(TSTCNTL_REG_BANK_SEL, BANK_BIST)
-			| TSTCNTL_TEST_MODE
-			| FIELD_PREP(TSTCNTL_WRITE_ADDRESS, FR_PLL_DIV1));
+
+	/* Enable fractional PLL */
+	ret = meson_gxl_write_reg(phydev, BANK_BIST, FR_PLL_CONTROL, 0x5);
 	if (ret)
 		return ret;
 
 	/* Program fraction FR_PLL_DIV1 */
-	ret = phy_write(phydev, TSTWRITE, 0xaaaa);
+	ret = meson_gxl_write_reg(phydev, BANK_BIST, FR_PLL_DIV1, 0x029a);
 	if (ret)
 		return ret;
-	ret = phy_write(phydev, TSTCNTL,
-			TSTCNTL_WRITE
-			| FIELD_PREP(TSTCNTL_REG_BANK_SEL, BANK_BIST)
-			| TSTCNTL_TEST_MODE
-			| FIELD_PREP(TSTCNTL_WRITE_ADDRESS, FR_PLL_DIV0));
+
+	/* Program fraction FR_PLL_DIV1 */
+	ret = meson_gxl_write_reg(phydev, BANK_BIST, FR_PLL_DIV0, 0xaaaa);
 	if (ret)
 		return ret;
 
@@ -146,31 +177,8 @@ static int meson_gxl_read_status(struct phy_device *phydev)
 		else if (!ret)
 			goto read_status_continue;
 
-		/* Need to access WOL bank, make sure the access is open */
-		ret = phy_write(phydev, TSTCNTL, 0);
-		if (ret)
-			return ret;
-		ret = phy_write(phydev, TSTCNTL, TSTCNTL_TEST_MODE);
-		if (ret)
-			return ret;
-		ret = phy_write(phydev, TSTCNTL, 0);
-		if (ret)
-			return ret;
-		ret = phy_write(phydev, TSTCNTL, TSTCNTL_TEST_MODE);
-		if (ret)
-			return ret;
-
-		/* Request LPI_STATUS WOL register */
-		ret = phy_write(phydev, TSTCNTL,
-				TSTCNTL_READ
-				| FIELD_PREP(TSTCNTL_REG_BANK_SEL, BANK_WOL)
-				| TSTCNTL_TEST_MODE
-				| FIELD_PREP(TSTCNTL_READ_ADDRESS, LPI_STATUS));
-		if (ret)
-			return ret;
-
-		/* Read LPI_STATUS value */
-		wol = phy_read(phydev, TSTREAD1);
+		/* Aneg is done, let's check everything is fine */
+		wol = meson_gxl_read_reg(phydev, BANK_WOL, LPI_STATUS);
 		if (wol < 0)
 			return wol;