[PATCH v5 07/13] net: phy: adin: make RMII fifo depth configurable

[Alexandru Ardelean]

The FIFO depth can be configured for the RMII mode. This change adds
support for doing this via device-tree (or ACPI).

Reviewed-by: Florian Fainelli <f.faine...@gmail.com>
Reviewed-by: Andrew Lunn <and...@lunn.ch>
Signed-off-by: Alexandru Ardelean <alexandru.ardel...@analog.com>
---
 drivers/net/phy/adin.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/drivers/net/phy/adin.c b/drivers/net/phy/adin.c
index c882fcd9ada5..4ca685780622 100644
--- a/drivers/net/phy/adin.c
+++ b/drivers/net/phy/adin.c
@@ -52,8 +52,19 @@
 #define        ADIN1300_RGMII_2_40_NS                  0x0007
 
 #define ADIN1300_GE_RMII_CFG_REG               0xff24
+#define   ADIN1300_GE_RMII_FIFO_DEPTH_MSK      GENMASK(6, 4)
+#define   ADIN1300_GE_RMII_FIFO_DEPTH_SEL(x)   \
+               FIELD_PREP(ADIN1300_GE_RMII_FIFO_DEPTH_MSK, x)
 #define   ADIN1300_GE_RMII_EN                  BIT(0)
 
+/* RMII fifo depth values */
+#define ADIN1300_RMII_4_BITS                   0x0000
+#define ADIN1300_RMII_8_BITS                   0x0001
+#define ADIN1300_RMII_12_BITS                  0x0002
+#define ADIN1300_RMII_16_BITS                  0x0003
+#define ADIN1300_RMII_20_BITS                  0x0004
+#define ADIN1300_RMII_24_BITS                  0x0005
+
 /**
  * struct adin_cfg_reg_map - map a config value to aregister value
  * @cfg                value in device configuration
@@ -73,6 +84,16 @@ static const struct adin_cfg_reg_map adin_rgmii_delays[] = {
        { },
 };
 
+static const struct adin_cfg_reg_map adin_rmii_fifo_depths[] = {
+       { 4,  ADIN1300_RMII_4_BITS },
+       { 8,  ADIN1300_RMII_8_BITS },
+       { 12, ADIN1300_RMII_12_BITS },
+       { 16, ADIN1300_RMII_16_BITS },
+       { 20, ADIN1300_RMII_20_BITS },
+       { 24, ADIN1300_RMII_24_BITS },
+       { },
+};
+
 static int adin_lookup_reg_value(const struct adin_cfg_reg_map *tbl, int cfg)
 {
        size_t i;
@@ -156,6 +177,7 @@ static int adin_config_rgmii_mode(struct phy_device *phydev)
 
 static int adin_config_rmii_mode(struct phy_device *phydev)
 {
+       u32 val;
        int reg;
 
        if (phydev->interface != PHY_INTERFACE_MODE_RMII)
@@ -169,6 +191,13 @@ static int adin_config_rmii_mode(struct phy_device *phydev)
 
        reg |= ADIN1300_GE_RMII_EN;
 
+       val = adin_get_reg_value(phydev, "adi,fifo-depth-bits",
+                                adin_rmii_fifo_depths,
+                                ADIN1300_RMII_8_BITS);
+
+       reg &= ~ADIN1300_GE_RMII_FIFO_DEPTH_MSK;
+       reg |= ADIN1300_GE_RMII_FIFO_DEPTH_SEL(val);
+
        return phy_write_mmd(phydev, MDIO_MMD_VEND1,
                             ADIN1300_GE_RMII_CFG_REG, reg);
 }
-- 
2.20.1