net/phy: micrel: Add clock support for KSZ8021/KSZ8031

The KSZ8021 and KSZ8031 support RMII reference input clocks of 25MHz
and 50MHz. Both PHYs differ in the default frequency they expect
after reset. If this differs from the actual input clock, then
register 0x1f bit 7 must be changed.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 36 insertions, 2 deletions

diff --git a/Documentation/devicetree/bindings/net/micrel.txt b/Documentation/devicetree/bindings/net/micrel.txt
index 98a3e61f9ee8..e1d99b95c4ec 100644
--- a/Documentation/devicetree/bindings/net/micrel.txt
+++ b/Documentation/devicetree/bindings/net/micrel.txt
@@ -16,3 +16,9 @@ Optional properties:
               KSZ8051: register 0x1f, bits 5..4
 
               See the respective PHY datasheet for the mode values.
+
+ - clocks, clock-names: contains clocks according to the common clock bindings.
+
+              supported clocks:
+              - KSZ8021, KSZ8031: "rmii-ref": The RMII refence input clock. Used
+                to determine the XI input clock.
diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
index 011dbda2b2f1..492435fce1d4 100644
--- a/drivers/net/phy/micrel.c
+++ b/drivers/net/phy/micrel.c
@@ -26,6 +26,7 @@
 #include <linux/phy.h>
 #include <linux/micrel_phy.h>
 #include <linux/of.h>
+#include <linux/clk.h>
 
 /* Operation Mode Strap Override */
 #define MII_KSZPHY_OMSO                         0x16
@@ -72,9 +73,12 @@ static int ksz_config_flags(struct phy_device *phydev)
 {
         int regval;
 
-        if (phydev->dev_flags & MICREL_PHY_50MHZ_CLK) {
+        if (phydev->dev_flags & (MICREL_PHY_50MHZ_CLK | MICREL_PHY_25MHZ_CLK)) {
                 regval = phy_read(phydev, MII_KSZPHY_CTRL);
-                regval |= KSZ8051_RMII_50MHZ_CLK;
+                if (phydev->dev_flags & MICREL_PHY_50MHZ_CLK)
+                        regval |= KSZ8051_RMII_50MHZ_CLK;
+                else
+                        regval &= ~KSZ8051_RMII_50MHZ_CLK;
                 return phy_write(phydev, MII_KSZPHY_CTRL, regval);
         }
         return 0;
@@ -440,6 +444,27 @@ ksz9021_wr_mmd_phyreg(struct phy_device *phydev, int ptrad, int devnum,
 {
 }
 
+static int ksz8021_probe(struct phy_device *phydev)
+{
+        struct clk *clk;
+
+        clk = devm_clk_get(&phydev->dev, "rmii-ref");
+        if (!IS_ERR(clk)) {
+                unsigned long rate = clk_get_rate(clk);
+
+                if (rate > 24500000 && rate < 25500000) {
+                        phydev->dev_flags |= MICREL_PHY_25MHZ_CLK;
+                } else if (rate > 49500000 && rate < 50500000) {
+                        phydev->dev_flags |= MICREL_PHY_50MHZ_CLK;
+                } else {
+                        dev_err(&phydev->dev, "Clock rate out of range: %ld\n", rate);
+                        return -EINVAL;
+                }
+        }
+
+        return 0;
+}
+
 static struct phy_driver ksphy_driver[] = {
 {
         .phy_id         = PHY_ID_KS8737,
@@ -462,6 +487,7 @@ static struct phy_driver ksphy_driver[] = {
         .features       = (PHY_BASIC_FEATURES | SUPPORTED_Pause |
                            SUPPORTED_Asym_Pause),
         .flags          = PHY_HAS_MAGICANEG | PHY_HAS_INTERRUPT,
+        .probe          = ksz8021_probe,
         .config_init    = ksz8021_config_init,
         .config_aneg    = genphy_config_aneg,
         .read_status    = genphy_read_status,
@@ -477,6 +503,7 @@ static struct phy_driver ksphy_driver[] = {
         .features       = (PHY_BASIC_FEATURES | SUPPORTED_Pause |
                            SUPPORTED_Asym_Pause),
         .flags          = PHY_HAS_MAGICANEG | PHY_HAS_INTERRUPT,
+        .probe          = ksz8021_probe,
         .config_init    = ksz8021_config_init,
         .config_aneg    = genphy_config_aneg,
         .read_status    = genphy_read_status,
diff --git a/include/linux/micrel_phy.h b/include/linux/micrel_phy.h
index 2e5b194b9b19..53d33dee70e1 100644
--- a/include/linux/micrel_phy.h
+++ b/include/linux/micrel_phy.h
@@ -37,6 +37,7 @@
 
 /* struct phy_device dev_flags definitions */
 #define MICREL_PHY_50MHZ_CLK    0x00000001
+#define MICREL_PHY_25MHZ_CLK    0x00000002
 
 #define MICREL_KSZ9021_EXTREG_CTRL      0xB
 #define MICREL_KSZ9021_EXTREG_DATA_WRITE        0xC