[PATCH v3 0/4] add support for impedance control for TI dp83867 phy and fix 2nd ethernet on dra72 rev C evm

Add support for configurable impedance control for TI dp83867
phy via devicetree. More documentation in [1].
CPSW second ethernet is not working, fix it by enabling
impedance configuration on the phy.

Verified the patch on DRA72 Rev C evm, logs at [2]. Also pushed
a branch [3] for others to test.

Changes from v2:
* Fixed a typo in dts and driver.

Changes from initial version:
* As per Sekhar's comment, instead of passing impedance values,
  change to max and min impedance from DT
* Adopted phy_read_mmd_indirect() to cunnrent implementation.
* Corrected the phy delay timings to the optimal value.

[1] - http://www.ti.com/lit/ds/symlink/dp83867ir.pdf
[2] - http://pastebin.ubuntu.com/23283056/
[3] - git://git.ti.com/~mugunthanvnm/ti-linux-kernel/linux.git dp83867-v3

Mugunthan V N (4):
  net: phy: dp83867: Add documentation for optional impedance control
  net: phy: dp83867: add support for MAC impedance configuration
  ARM: dts: dra72-evm-revc: add phy impedance settings
  ARM: dts: dra72-evm-revc: fix correct phy delay

 .../devicetree/bindings/net/ti,dp83867.txt         | 12 ++++++++++
 arch/arm/boot/dts/dra72-evm-revc.dts               | 10 ++++----
 drivers/net/phy/dp83867.c                          | 28 ++++++++++++++++++++++
 3 files changed, 46 insertions(+), 4 deletions(-)

-- 
2.10.0.372.g6fe1b14

Add documention of ti,impedance-control which can be used to
correct MAC impedance mismatch using phy extended registers.

Signed-off-by: Mugunthan V N <redacted>
---
 Documentation/devicetree/bindings/net/ti,dp83867.txt | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/Documentation/devicetree/bindings/net/ti,dp83867.txt b/Documentation/devicetree/bindings/net/ti,dp83867.txt
index 5d21141..85bf945 100644
--- a/Documentation/devicetree/bindings/net/ti,dp83867.txt
+++ b/Documentation/devicetree/bindings/net/ti,dp83867.txt

@@ -9,6 +9,18 @@ Required properties:
 	- ti,fifo-depth - Transmitt FIFO depth- see dt-bindings/net/ti-dp83867.h
 		for applicable values
 
+Optional property:
+	- ti,min-output-impedance - MAC Interface Impedance control to set
+				    the programmable output impedance to
+				    minimum value (35 ohms).
+	- ti,max-output-impedance - MAC Interface Impedance control to set
+				    the programmable output impedance to
+				    maximum value (70 ohms).
+
+Note: ti,min-output-impedance and ti,max-output-impedance are mutually
+      exclusive. When both properties are present ti,max-output-impedance
+      takes precedence.
+
 Default child nodes are standard Ethernet PHY device
 nodes as described in Documentation/devicetree/bindings/net/phy.txt
 

-- 
2.10.0.372.g6fe1b14

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Add support for programmable MAC impedance configuration

Signed-off-by: Mugunthan V N <redacted>
---
 drivers/net/phy/dp83867.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/drivers/net/phy/dp83867.c b/drivers/net/phy/dp83867.c
index 91177a4..1b63924 100644
--- a/drivers/net/phy/dp83867.c
+++ b/drivers/net/phy/dp83867.c

@@ -33,6 +33,7 @@
 /* Extended Registers */
 #define DP83867_RGMIICTL	0x0032
 #define DP83867_RGMIIDCTL	0x0086
+#define DP83867_IO_MUX_CFG	0x0170
 
 #define DP83867_SW_RESET	BIT(15)
 #define DP83867_SW_RESTART	BIT(14)

@@ -62,10 +63,17 @@
 /* RGMIIDCTL bits */
 #define DP83867_RGMII_TX_CLK_DELAY_SHIFT	4
 
+/* IO_MUX_CFG bits */
+#define DP83867_IO_MUX_CFG_IO_IMPEDANCE_CTRL	0x1f
+
+#define DP83867_IO_MUX_CFG_IO_IMPEDANCE_MAX	0x0
+#define DP83867_IO_MUX_CFG_IO_IMPEDANCE_MIN	0x1f
+
 struct dp83867_private {
 	int rx_id_delay;
 	int tx_id_delay;
 	int fifo_depth;
+	int io_impedance;
 };
 
 static int dp83867_ack_interrupt(struct phy_device *phydev)

@@ -111,6 +119,14 @@ static int dp83867_of_init(struct phy_device *phydev)
 	if (!of_node)
 		return -ENODEV;
 
+	dp83867->io_impedance = -EINVAL;
+
+	/* Optional configuration */
+	if (of_property_read_bool(of_node, "ti,max-output-impedance"))
+		dp83867->io_impedance = DP83867_IO_MUX_CFG_IO_IMPEDANCE_MAX;
+	else if (of_property_read_bool(of_node, "ti,min-output-impedance"))
+		dp83867->io_impedance = DP83867_IO_MUX_CFG_IO_IMPEDANCE_MIN;
+
 	ret = of_property_read_u32(of_node, "ti,rx-internal-delay",
 				   &dp83867->rx_id_delay);
 	if (ret)

@@ -184,6 +200,18 @@ static int dp83867_config_init(struct phy_device *phydev)
 
 		phy_write_mmd_indirect(phydev, DP83867_RGMIIDCTL,
 				       DP83867_DEVADDR, delay);
+
+		if (dp83867->io_impedance >= 0) {
+			val = phy_read_mmd_indirect(phydev, DP83867_IO_MUX_CFG,
+						    DP83867_DEVADDR);
+
+			val &= ~DP83867_IO_MUX_CFG_IO_IMPEDANCE_CTRL;
+			val |= dp83867->io_impedance &
+			       DP83867_IO_MUX_CFG_IO_IMPEDANCE_CTRL;
+
+			phy_write_mmd_indirect(phydev, DP83867_IO_MUX_CFG,
+					       DP83867_DEVADDR, val);
+		}
 	}
 
 	return 0;

-- 
2.10.0.372.g6fe1b14

The current delay settings of the phy are not the optimal value,
fix it with correct values.

Signed-off-by: Mugunthan V N <redacted>
---
 arch/arm/boot/dts/dra72-evm-revc.dts | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/arm/boot/dts/dra72-evm-revc.dts b/arch/arm/boot/dts/dra72-evm-revc.dts
index aafb594..01e1f39 100644
--- a/arch/arm/boot/dts/dra72-evm-revc.dts
+++ b/arch/arm/boot/dts/dra72-evm-revc.dts

@@ -59,16 +59,16 @@
 &davinci_mdio {
 	dp83867_0: ethernet-phy@2 {
 		reg = <2>;
-		ti,rx-internal-delay = <DP83867_RGMIIDCTL_2_00_NS>;
-		ti,tx-internal-delay = <DP83867_RGMIIDCTL_1_NS>;
+		ti,rx-internal-delay = <DP83867_RGMIIDCTL_2_25_NS>;
+		ti,tx-internal-delay = <DP83867_RGMIIDCTL_250_PS>;
 		ti,fifo-depth = <DP83867_PHYCR_FIFO_DEPTH_8_B_NIB>;
 		ti,min-output-impedance;
 	};
 
 	dp83867_1: ethernet-phy@3 {
 		reg = <3>;
-		ti,rx-internal-delay = <DP83867_RGMIIDCTL_2_00_NS>;
-		ti,tx-internal-delay = <DP83867_RGMIIDCTL_1_NS>;
+		ti,rx-internal-delay = <DP83867_RGMIIDCTL_2_25_NS>;
+		ti,tx-internal-delay = <DP83867_RGMIIDCTL_250_PS>;
 		ti,fifo-depth = <DP83867_PHYCR_FIFO_DEPTH_8_B_NIB>;
 		ti,min-output-imepdance;
 	};

-- 
2.10.0.372.g6fe1b14

The default impedance settings of the phy is not the optimal
value, due to this the second ethernet is not working. Fix it
with correct values which makes the second ethernet port to work.

Signed-off-by: Mugunthan V N <redacted>
---
 arch/arm/boot/dts/dra72-evm-revc.dts | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm/boot/dts/dra72-evm-revc.dts b/arch/arm/boot/dts/dra72-evm-revc.dts
index f9cfd3b..aafb594 100644
--- a/arch/arm/boot/dts/dra72-evm-revc.dts
+++ b/arch/arm/boot/dts/dra72-evm-revc.dts

@@ -62,6 +62,7 @@
 		ti,rx-internal-delay = <DP83867_RGMIIDCTL_2_00_NS>;
 		ti,tx-internal-delay = <DP83867_RGMIIDCTL_1_NS>;
 		ti,fifo-depth = <DP83867_PHYCR_FIFO_DEPTH_8_B_NIB>;
+		ti,min-output-impedance;
 	};
 
 	dp83867_1: ethernet-phy@3 {

@@ -69,5 +70,6 @@
 		ti,rx-internal-delay = <DP83867_RGMIIDCTL_2_00_NS>;
 		ti,tx-internal-delay = <DP83867_RGMIIDCTL_1_NS>;
 		ti,fifo-depth = <DP83867_PHYCR_FIFO_DEPTH_8_B_NIB>;
+		ti,min-output-imepdance;
 	};
 };

-- 
2.10.0.372.g6fe1b14

On Thu, Oct 06, 2016 at 10:43:52AM +0530, Mugunthan V N wrote:

Add documention of ti,impedance-control which can be used to

Needs updating.

Define what are valid range of values for these.

+
+Note: ti,min-output-impedance and ti,max-output-impedance are mutually
+      exclusive. When both properties are present ti,max-output-impedance
+      takes precedence.
+
 Default child nodes are standard Ethernet PHY device
 nodes as described in Documentation/devicetree/bindings/net/phy.txt
 
-- 
2.10.0.372.g6fe1b14

On Monday 10 October 2016 06:48 PM, Rob Herring wrote:

On Thu, Oct 06, 2016 at 10:43:52AM +0530, Mugunthan V N wrote:

quoted

Add documention of ti,impedance-control which can be used to

Needs updating.

Oops, will update this in next version.

quoted

correct MAC impedance mismatch using phy extended registers.

Signed-off-by: Mugunthan V N <redacted>
---
 Documentation/devicetree/bindings/net/ti,dp83867.txt | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/Documentation/devicetree/bindings/net/ti,dp83867.txt b/Documentation/devicetree/bindings/net/ti,dp83867.txt
index 5d21141..85bf945 100644
--- a/Documentation/devicetree/bindings/net/ti,dp83867.txt
+++ b/Documentation/devicetree/bindings/net/ti,dp83867.txt

@@ -9,6 +9,18 @@ Required properties:
 	- ti,fifo-depth - Transmitt FIFO depth- see dt-bindings/net/ti-dp83867.h
 		for applicable values
 
+Optional property:
+	- ti,min-output-impedance - MAC Interface Impedance control to set
+				    the programmable output impedance to
+				    minimum value (35 ohms).
+	- ti,max-output-impedance - MAC Interface Impedance control to set
+				    the programmable output impedance to
+				    maximum value (70 ohms).

Define what are valid range of values for these.

The values are already mentioned in documentation as 35/70 ohms.
Are you mentioning about the register values?

Regards
Mugunthan V N