drivers: eth_smsc91x: Add driver for SMSC91C111 aka LAN91C111 chip

Arm fvp_baser_aemv8r and fvp_base_revc_2xaemv8a boards are using
SMSC91C111 as their ethernet adapters.

Portions of the codes are based on FreeBSD code from its
'src/sys/dev/smc/if_smc.c' and 'src/sys/dev/smc/if_smcreg.h'.

This driver has two parts, one is the ethernet controller driver, which
is MAC layer driver. The other is the MDIO driver, which is the PHY
layer driver. Both of them are in the same source file due to that they
need to share the same reading and writing register functions and
the smsc object.

The mdio driver is needed by the existing 'phy_mii' driver, which is
a driver for the generic MII-compliant PHY.

This driver was developed under the fvp_base_revc_2xaemv8a target and
has been tested on the fvp_baser_aemv8r target.

Signed-off-by: Huifeng Zhang <Huifeng.Zhang@arm.com>

Author: SgrrZhf

drivers/ethernet/CMakeLists.txt

@@ -30,6 +30,7 @@ zephyr_library_sources_ifdef(CONFIG_ETH_W5500		eth_w5500.c)
 zephyr_library_sources_ifdef(CONFIG_ETH_SAM_GMAC	eth_sam_gmac.c)
 zephyr_library_sources_ifdef(CONFIG_ETH_CYCLONEV	eth_cyclonev.c)
 zephyr_library_sources_ifdef(CONFIG_SLIP_TAP		eth_slip_tap.c)
+zephyr_library_sources_ifdef(CONFIG_ETH_SMSC91X		eth_smsc91x.c)
 
 if(CONFIG_ETH_NXP_S32_NETC)
   zephyr_library_sources(eth_nxp_s32_netc.c)

drivers/ethernet/Kconfig

@@ -57,6 +57,7 @@ source "drivers/ethernet/Kconfig.dsa"
 source "drivers/ethernet/Kconfig.xlnx_gem"
 source "drivers/ethernet/Kconfig.cyclonev"
 source "drivers/ethernet/Kconfig.nxp_s32"
+source "drivers/ethernet/Kconfig.smsc91x"
 
 source "drivers/ethernet/phy/Kconfig"
 

drivers/ethernet/Kconfig.smsc91x

@@ -0,0 +1,9 @@
+# Copyright (c) 2023 Arm Limited (or its affiliates). All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+config ETH_SMSC91X
+	bool "SMSC91x Ethernet driver"
+	default y
+	depends on DT_HAS_SMSC_LAN91C111_ENABLED
+	help
+	  Enable driver for SMSC/LAN91x family of chips.