1// SPDX-License-Identifier: GPL-2.0+
 2/* Driver for Asix PHYs
 3 *
 4 * Author: Michael Schmitz <schmitzmic@gmail.com>
 5 */
 6#include <linux/kernel.h>
 7#include <linux/errno.h>
 8#include <linux/init.h>
 9#include <linux/module.h>
10#include <linux/mii.h>
11#include <linux/phy.h>
12
13#define PHY_ID_ASIX_AX88796B		0x003b1841
14
15MODULE_DESCRIPTION("Asix PHY driver");
16MODULE_AUTHOR("Michael Schmitz <schmitzmic@gmail.com>");
17MODULE_LICENSE("GPL");
18
19/**
20 * asix_soft_reset - software reset the PHY via BMCR_RESET bit
21 * @phydev: target phy_device struct
22 *
23 * Description: Perform a software PHY reset using the standard
24 * BMCR_RESET bit and poll for the reset bit to be cleared.
25 * Toggle BMCR_RESET bit off to accommodate broken AX8796B PHY implementation
26 * such as used on the Individual Computers' X-Surf 100 Zorro card.
27 *
28 * Returns: 0 on success, < 0 on failure
29 */
30static int asix_soft_reset(struct phy_device *phydev)
31{
32	int ret;
33
34	/* Asix PHY won't reset unless reset bit toggles */
35	ret = phy_write(phydev, MII_BMCR, 0);
36	if (ret < 0)
37		return ret;
38
39	return genphy_soft_reset(phydev);
40}
41
42static struct phy_driver asix_driver[] = { {
43	.phy_id		= PHY_ID_ASIX_AX88796B,
44	.name		= "Asix Electronics AX88796B",
45	.phy_id_mask	= 0xfffffff0,
46	/* PHY_BASIC_FEATURES */
47	.soft_reset	= asix_soft_reset,
48} };
49
50module_phy_driver(asix_driver);
51
52static struct mdio_device_id __maybe_unused asix_tbl[] = {
53	{ PHY_ID_ASIX_AX88796B, 0xfffffff0 },
54	{ }
55};
56
57MODULE_DEVICE_TABLE(mdio, asix_tbl);