net: ravb: Avoid unsupported internal delay mode for R-Car E3/D3

According to the R-Car Gen3 Hardware Manual Rev 1.50 of Nov 30, 2018, the
TX clock internal delay mode isn't supported on R-Car E3 (r8a77990) or D3
(r8a77995).

Avoid setting the APSR:TDM bit on these SoCs. Moreover, only set APSR:TDM
when the DT explicitly specifies RGMII ID or TXID mode instead of setting
it unconditionally when the PHY link speed is 1000 Mbit/s.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Cc: Joe Hershberger <joe.hershberger@ni.com>
diff --git a/drivers/net/ravb.c b/drivers/net/ravb.c
index 749562d..11abe5e 100644
--- a/drivers/net/ravb.c
+++ b/drivers/net/ravb.c
@@ -46,6 +46,8 @@
 #define CSR_OPS			0x0000000F
 #define CSR_OPS_CONFIG		BIT(1)
 
+#define APSR_TDM		BIT(14)
+
 #define TCCR_TSRQ0		BIT(0)
 
 #define RFLR_RFL_MIN		0x05EE
@@ -389,9 +391,14 @@
 	/* FIFO size set */
 	writel(0x00222210, eth->iobase + RAVB_REG_TGC);
 
-	/* Delay CLK: 2ns */
-	if (pdata->max_speed == 1000)
-		writel(BIT(14), eth->iobase + RAVB_REG_APSR);
+	/* Delay CLK: 2ns (not applicable on R-Car E3/D3) */
+	if ((rmobile_get_cpu_type() == RMOBILE_CPU_TYPE_R8A77990) ||
+	    (rmobile_get_cpu_type() == RMOBILE_CPU_TYPE_R8A77995))
+		return 0;
+
+	if ((pdata->phy_interface == PHY_INTERFACE_MODE_RGMII_ID) ||
+	    (pdata->phy_interface == PHY_INTERFACE_MODE_RGMII_TXID))
+		writel(APSR_TDM, eth->iobase + RAVB_REG_APSR);
 
 	return 0;
 }