net: phy: microchip_t1s: replace read-modify-write code with phy_modify_mmd

Replace read-modify-write code in the lan867x_config_init function to
avoid handling data type mismatch and to simplify the code.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Parthiban Veerasooran <Parthiban.Veerasooran@microchip.com>
Reviewed-by: Ramón Nordin Rodriguez <ramon.nordin.rodriguez@ferroamp.se>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/drivers/net/phy/microchip_t1s.c b/drivers/net/phy/microchip_t1s.c
index a42a6bb6e3bd556d46bef8e454ec5953dfcb12ee..fd27e94c9ee5d6011de54a75c16660dacfe55a64 100644 (file)
--- a/drivers/net/phy/microchip_t1s.c
+++ b/drivers/net/phy/microchip_t1s.c
@@ -31,19 +31,19 @@
  * W   0x1F 0x0099 0x7F80 ------
  */
 
-static const int lan867x_fixup_registers[12] = {
+static const u32 lan867x_fixup_registers[12] = {
        0x00D0, 0x00D1, 0x0084, 0x0085,
        0x008A, 0x0087, 0x0088, 0x008B,
        0x0080, 0x00F1, 0x0096, 0x0099,
 };
 
-static const int lan867x_fixup_values[12] = {
+static const u16 lan867x_fixup_values[12] = {
        0x0002, 0x0000, 0x3380, 0x0006,
        0xC000, 0x801C, 0x033F, 0x0404,
        0x0600, 0x2400, 0x2000, 0x7F80,
 };
 
-static const int lan867x_fixup_masks[12] = {
+static const u16 lan867x_fixup_masks[12] = {
        0x0E03, 0x0300, 0xFFC0, 0x000F,
        0xF800, 0x801C, 0x1FFF, 0xFFFF,
        0x0600, 0x7F00, 0x2000, 0xFFFF,
@@ -51,35 +51,20 @@ static const int lan867x_fixup_masks[12] = {
 
 static int lan867x_config_init(struct phy_device *phydev)
 {
-       /* HW quirk: Microchip states in the application note (AN1699) for the phy
-        * that a set of read-modify-write (rmw) operations has to be performed
-        * on a set of seemingly magic registers.
-        * The result of these operations is just described as 'optimal performance'
-        * Microchip gives no explanation as to what these mmd regs do,
-        * in fact they are marked as reserved in the datasheet.
-        * It is unclear if phy_modify_mmd would be safe to use or if a write
-        * really has to happen to each register.
-        * In order to exactly conform to what is stated in the AN phy_write_mmd is
-        * used, which might then write the same value back as read + modified.
-        */
-
-       int reg_value;
        int err;
-       int reg;
 
-       /* Read-Modified Write Pseudocode (from AN1699)
-        * current_val = read_register(mmd, addr) // Read current register value
-        * new_val = current_val AND (NOT mask) // Clear bit fields to be written
-        * new_val = new_val OR value // Set bits
-        * write_register(mmd, addr, new_val) // Write back updated register value
+       /* Reference to AN1699
+        * https://ww1.microchip.com/downloads/aemDocuments/documents/AIS/ProductDocuments/SupportingCollateral/AN-LAN8670-1-2-config-60001699.pdf
+        * AN1699 says Read, Modify, Write, but the Write is not required if the
+        * register already has the required value. So it is safe to use
+        * phy_modify_mmd here.
         */
        for (int i = 0; i < ARRAY_SIZE(lan867x_fixup_registers); i++) {
-               reg = lan867x_fixup_registers[i];
-               reg_value = phy_read_mmd(phydev, MDIO_MMD_VEND2, reg);
-               reg_value &= ~lan867x_fixup_masks[i];
-               reg_value |= lan867x_fixup_values[i];
-               err = phy_write_mmd(phydev, MDIO_MMD_VEND2, reg, reg_value);
-               if (err != 0)
+               err = phy_modify_mmd(phydev, MDIO_MMD_VEND2,
+                                    lan867x_fixup_registers[i],
+                                    lan867x_fixup_masks[i],
+                                    lan867x_fixup_values[i]);
+               if (err)
                        return err;
        }