net: phy: micrel: Use correct skew values on KSZ9021

Commit ff7bd212cb8a ("net: phy: micrel: fix divisor value for KSZ9031
phy skew") fixed the skew value divisor for the KSZ9031, but left the
code using the same divisor for the KSZ9021, which is incorrect.

The preceding commit c16e69f702b1 ("net: phy: micrel: add documentation
for Micrel KSZ90x1 binding") added the DTS documentation for the
KSZ90x1, changing it from the equivalent file in the Linux kernel to
correctly state that for this part the skew value is set in 120ps steps,
whereas the Linux documentation and driver continue to this day to use
the incorrect value of 200 that came from the original KSZ9021 datasheet
before it was corrected in revision 1.2 (Feb 2014).

This commit sorts out the resulting confusion in a consistent way by
making the following changes:

- Update the documentation to be clear about what the skew values mean,
in the same was as for the KSZ9031.

- Update the Micrel PHY driver to select the appropriate divisor for
both parts.

- Adjust all the device trees that state skew values for KSZ9021 PHYs to
use values based on 120ps steps instead of 200ps steps. This will result
in the same values being programmed into the skew registers as the
equivalent device trees in the Linux kernel do, where it incorrectly
uses 200ps steps (since that's where all these device trees were copied
from).

Signed-off-by: James Byrne <james.byrne@origamienergy.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>

diff --git a/arch/arm/dts/sama5d3xcm.dtsi b/arch/arm/dts/sama5d3xcm.dtsi
index 2cf9c36..d123057 100644 (file)
--- a/arch/arm/dts/sama5d3xcm.dtsi
+++ b/arch/arm/dts/sama5d3xcm.dtsi
@@ -44,28 +44,28 @@
                                        reg = <0x1>;
                                        interrupt-parent = <&pioB>;
                                        interrupts = <25 IRQ_TYPE_EDGE_FALLING>;
-                                       txen-skew-ps = <800>;
-                                       txc-skew-ps = <3000>;
-                                       rxdv-skew-ps = <400>;
-                                       rxc-skew-ps = <3000>;
-                                       rxd0-skew-ps = <400>;
-                                       rxd1-skew-ps = <400>;
-                                       rxd2-skew-ps = <400>;
-                                       rxd3-skew-ps = <400>;
+                                       txen-skew-ps = <480>;
+                                       txc-skew-ps = <1800>;
+                                       rxdv-skew-ps = <240>;
+                                       rxc-skew-ps = <1800>;
+                                       rxd0-skew-ps = <240>;
+                                       rxd1-skew-ps = <240>;
+                                       rxd2-skew-ps = <240>;
+                                       rxd3-skew-ps = <240>;
                                };
 
                                ethernet-phy@7 {
                                        reg = <0x7>;
                                        interrupt-parent = <&pioB>;
                                        interrupts = <25 IRQ_TYPE_EDGE_FALLING>;
-                                       txen-skew-ps = <800>;
-                                       txc-skew-ps = <3000>;
-                                       rxdv-skew-ps = <400>;
-                                       rxc-skew-ps = <3000>;
-                                       rxd0-skew-ps = <400>;
-                                       rxd1-skew-ps = <400>;
-                                       rxd2-skew-ps = <400>;
-                                       rxd3-skew-ps = <400>;
+                                       txen-skew-ps = <480>;
+                                       txc-skew-ps = <1800>;
+                                       rxdv-skew-ps = <240>;
+                                       rxc-skew-ps = <1800>;
+                                       rxd0-skew-ps = <240>;
+                                       rxd1-skew-ps = <240>;
+                                       rxd2-skew-ps = <240>;
+                                       rxd3-skew-ps = <240>;
                                };
                        };
                };

diff --git a/arch/arm/dts/sama5d3xcm_cmp.dtsi b/arch/arm/dts/sama5d3xcm_cmp.dtsi
index 77638c3..332b057 100644 (file)
--- a/arch/arm/dts/sama5d3xcm_cmp.dtsi
+++ b/arch/arm/dts/sama5d3xcm_cmp.dtsi
@@ -43,28 +43,28 @@
                                        reg = <0x1>;
                                        interrupt-parent = <&pioB>;
                                        interrupts = <25 IRQ_TYPE_EDGE_FALLING>;
-                                       txen-skew-ps = <800>;
-                                       txc-skew-ps = <3000>;
-                                       rxdv-skew-ps = <400>;
-                                       rxc-skew-ps = <3000>;
-                                       rxd0-skew-ps = <400>;
-                                       rxd1-skew-ps = <400>;
-                                       rxd2-skew-ps = <400>;
-                                       rxd3-skew-ps = <400>;
+                                       txen-skew-ps = <480>;
+                                       txc-skew-ps = <1800>;
+                                       rxdv-skew-ps = <240>;
+                                       rxc-skew-ps = <1800>;
+                                       rxd0-skew-ps = <240>;
+                                       rxd1-skew-ps = <240>;
+                                       rxd2-skew-ps = <240>;
+                                       rxd3-skew-ps = <240>;
                                };
 
                                ethernet-phy@7 {
                                        reg = <0x7>;
                                        interrupt-parent = <&pioB>;
                                        interrupts = <25 IRQ_TYPE_EDGE_FALLING>;
-                                       txen-skew-ps = <800>;
-                                       txc-skew-ps = <3000>;
-                                       rxdv-skew-ps = <400>;
-                                       rxc-skew-ps = <3000>;
-                                       rxd0-skew-ps = <400>;
-                                       rxd1-skew-ps = <400>;
-                                       rxd2-skew-ps = <400>;
-                                       rxd3-skew-ps = <400>;
+                                       txen-skew-ps = <480>;
+                                       txc-skew-ps = <1800>;
+                                       rxdv-skew-ps = <240>;
+                                       rxc-skew-ps = <1800>;
+                                       rxd0-skew-ps = <240>;
+                                       rxd1-skew-ps = <240>;
+                                       rxd2-skew-ps = <240>;
+                                       rxd3-skew-ps = <240>;
                                };
                        };
 

diff --git a/arch/arm/dts/socfpga_arria5_socdk.dts b/arch/arm/dts/socfpga_arria5_socdk.dts
index 90e676e..fa972e2 100644 (file)
--- a/arch/arm/dts/socfpga_arria5_socdk.dts
+++ b/arch/arm/dts/socfpga_arria5_socdk.dts
@@ -67,9 +67,9 @@
        rxd2-skew-ps = <0>;
        rxd3-skew-ps = <0>;
        txen-skew-ps = <0>;
-       txc-skew-ps = <2600>;
+       txc-skew-ps = <1560>;
        rxdv-skew-ps = <0>;
-       rxc-skew-ps = <2000>;
+       rxc-skew-ps = <1200>;
 };
 
 &gpio0 {

diff --git a/arch/arm/dts/socfpga_cyclone5_is1.dts b/arch/arm/dts/socfpga_cyclone5_is1.dts
index 2d31412..a769498 100644 (file)
--- a/arch/arm/dts/socfpga_cyclone5_is1.dts
+++ b/arch/arm/dts/socfpga_cyclone5_is1.dts
@@ -43,9 +43,9 @@
        rxd2-skew-ps = <0>;
        rxd3-skew-ps = <0>;
        txen-skew-ps = <0>;
-       txc-skew-ps = <2600>;
+       txc-skew-ps = <1560>;
        rxdv-skew-ps = <0>;
-       rxc-skew-ps = <2000>;
+       rxc-skew-ps = <1200>;
 };
 
 &gpio1 {

diff --git a/arch/arm/dts/socfpga_cyclone5_socdk.dts b/arch/arm/dts/socfpga_cyclone5_socdk.dts
index 6f138b2..95c7619 100644 (file)
--- a/arch/arm/dts/socfpga_cyclone5_socdk.dts
+++ b/arch/arm/dts/socfpga_cyclone5_socdk.dts
@@ -71,9 +71,9 @@
        rxd2-skew-ps = <0>;
        rxd3-skew-ps = <0>;
        txen-skew-ps = <0>;
-       txc-skew-ps = <2600>;
+       txc-skew-ps = <1560>;
        rxdv-skew-ps = <0>;
-       rxc-skew-ps = <2000>;
+       rxc-skew-ps = <1200>;
 };
 
 &gpio0 {

diff --git a/arch/arm/dts/socfpga_cyclone5_sockit.dts b/arch/arm/dts/socfpga_cyclone5_sockit.dts
index c155ff0..90669cd 100644 (file)
--- a/arch/arm/dts/socfpga_cyclone5_sockit.dts
+++ b/arch/arm/dts/socfpga_cyclone5_sockit.dts
@@ -128,9 +128,9 @@
        rxd2-skew-ps = <0>;
        rxd3-skew-ps = <0>;
        txen-skew-ps = <0>;
-       txc-skew-ps = <2600>;
+       txc-skew-ps = <1560>;
        rxdv-skew-ps = <0>;
-       rxc-skew-ps = <2000>;
+       rxc-skew-ps = <1200>;
 };
 
 &gpio0 {       /* GPIO 0..29 */

diff --git a/arch/arm/dts/socfpga_cyclone5_vining_fpga.dts b/arch/arm/dts/socfpga_cyclone5_vining_fpga.dts
index 355b3db..ac57f41 100644 (file)
--- a/arch/arm/dts/socfpga_cyclone5_vining_fpga.dts
+++ b/arch/arm/dts/socfpga_cyclone5_vining_fpga.dts
@@ -85,9 +85,9 @@
                        rxd2-skew-ps = <0>;
                        rxd3-skew-ps = <0>;
                        txen-skew-ps = <0>;
-                       txc-skew-ps = <2600>;
+                       txc-skew-ps = <1560>;
                        rxdv-skew-ps = <0>;
-                       rxc-skew-ps = <2000>;
+                       rxc-skew-ps = <1200>;
                };
        };
 };

diff --git a/doc/device-tree-bindings/net/micrel-ksz90x1.txt b/doc/device-tree-bindings/net/micrel-ksz90x1.txt
index 307f53f..a214d35 100644 (file)
--- a/doc/device-tree-bindings/net/micrel-ksz90x1.txt
+++ b/doc/device-tree-bindings/net/micrel-ksz90x1.txt
@@ -14,6 +14,33 @@ KSZ9021:
   value is 0, the maximum value is 1800, and it is incremented by 120ps
   steps.
 
+  The KSZ9021 hardware supports a range of skew values from negative to
+  positive, where the specific range is property dependent. All values
+  specified in the devicetree are offset by the minimum value so they
+  can be represented as positive integers in the devicetree since it's
+  difficult to represent a negative number in the devictree.
+
+  The following 4-bit values table applies to all the skew properties:
+
+  Pad Skew Value       Delay (ps)      Devicetree Value
+  ------------------------------------------------------
+  0000                 -840ps          0
+  0001                 -720ps          120
+  0010                 -600ps          240
+  0011                 -480ps          360
+  0100                 -360ps          480
+  0101                 -240ps          600
+  0110                 -120ps          720
+  0111                 0ps             840
+  1000                 120ps           960
+  1001                 240ps           1080
+  1010                 360ps           1200
+  1011                 480ps           1320
+  1100                 600ps           1440
+  1101                 720ps           1560
+  1110                 840ps           1680
+  1111                 960ps           1800
+
   Optional properties:
 
     - rxc-skew-ps : Skew control of RXC pad

diff --git a/drivers/net/phy/micrel_ksz90x1.c b/drivers/net/phy/micrel_ksz90x1.c
index 63e7b02..1f8d86a 100644 (file)
--- a/drivers/net/phy/micrel_ksz90x1.c
+++ b/drivers/net/phy/micrel_ksz90x1.c
@@ -33,10 +33,14 @@
 #define CTRL1000_CONFIG_MASTER         (1 << 11)
 #define CTRL1000_MANUAL_CONFIG         (1 << 12)
 
+#define KSZ9021_PS_TO_REG              120
+
 /* KSZ9031 PHY Registers */
 #define MII_KSZ9031_MMD_ACCES_CTRL     0x0d
 #define MII_KSZ9031_MMD_REG_DATA       0x0e
 
+#define KSZ9031_PS_TO_REG              60
+
 static int ksz90xx_startup(struct phy_device *phydev)
 {
        unsigned phy_ctl;
@@ -102,11 +106,11 @@ static const struct ksz90x1_reg_field ksz9031_clk_grp[] = {
 };
 
 static int ksz90x1_of_config_group(struct phy_device *phydev,
-                                  struct ksz90x1_ofcfg *ofcfg)
+                                  struct ksz90x1_ofcfg *ofcfg,
+                                  int ps_to_regval)
 {
        struct udevice *dev = phydev->dev;
        struct phy_driver *drv = phydev->drv;
-       const int ps_to_regval = 60;
        int val[4];
        int i, changed = 0, offset, max;
        u16 regval = 0;
@@ -148,7 +152,8 @@ static int ksz9021_of_config(struct phy_device *phydev)
        int i, ret = 0;
 
        for (i = 0; i < ARRAY_SIZE(ofcfg); i++) {
-               ret = ksz90x1_of_config_group(phydev, &(ofcfg[i]));
+               ret = ksz90x1_of_config_group(phydev, &ofcfg[i],
+                                             KSZ9021_PS_TO_REG);
                if (ret)
                        return ret;
        }
@@ -167,7 +172,8 @@ static int ksz9031_of_config(struct phy_device *phydev)
        int i, ret = 0;
 
        for (i = 0; i < ARRAY_SIZE(ofcfg); i++) {
-               ret = ksz90x1_of_config_group(phydev, &(ofcfg[i]));
+               ret = ksz90x1_of_config_group(phydev, &ofcfg[i],
+                                             KSZ9031_PS_TO_REG);
                if (ret)
                        return ret;
        }