1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2022 Baylibre, SAS.
3 * Author: Jerome Brunet <jbrunet@baylibre.com>
4 */
5
6#include <linux/bitfield.h>
7#include <linux/delay.h>
8#include <linux/clk.h>
9#include <linux/io.h>
10#include <linux/mdio-mux.h>
11#include <linux/module.h>
12#include <linux/platform_device.h>
13
14#define ETH_REG2 0x0
15#define REG2_PHYID GENMASK(21, 0)
16#define EPHY_GXL_ID 0x110181
17#define REG2_LEDACT GENMASK(23, 22)
18#define REG2_LEDLINK GENMASK(25, 24)
19#define REG2_DIV4SEL BIT(27)
20#define REG2_ADCBYPASS BIT(30)
21#define REG2_CLKINSEL BIT(31)
22#define ETH_REG3 0x4
23#define REG3_ENH BIT(3)
24#define REG3_CFGMODE GENMASK(6, 4)
25#define REG3_AUTOMDIX BIT(7)
26#define REG3_PHYADDR GENMASK(12, 8)
27#define REG3_PWRUPRST BIT(21)
28#define REG3_PWRDOWN BIT(22)
29#define REG3_LEDPOL BIT(23)
30#define REG3_PHYMDI BIT(26)
31#define REG3_CLKINEN BIT(29)
32#define REG3_PHYIP BIT(30)
33#define REG3_PHYEN BIT(31)
34#define ETH_REG4 0x8
35#define REG4_PWRUPRSTSIG BIT(0)
36
37#define MESON_GXL_MDIO_EXTERNAL_ID 0
38#define MESON_GXL_MDIO_INTERNAL_ID 1
39
40struct gxl_mdio_mux {
41 void __iomem *regs;
42 void *mux_handle;
43};
44
45static void gxl_enable_internal_mdio(struct gxl_mdio_mux *priv)
46{
47 u32 val;
48
49 /* Setup the internal phy */
50 val = (REG3_ENH |
51 FIELD_PREP(REG3_CFGMODE, 0x7) |
52 REG3_AUTOMDIX |
53 FIELD_PREP(REG3_PHYADDR, 8) |
54 REG3_LEDPOL |
55 REG3_PHYMDI |
56 REG3_CLKINEN |
57 REG3_PHYIP);
58
59 writel(REG4_PWRUPRSTSIG, addr: priv->regs + ETH_REG4);
60 writel(val, addr: priv->regs + ETH_REG3);
61 mdelay(10);
62
63 /* NOTE: The HW kept the phy id configurable at runtime.
64 * The id below is arbitrary. It is the one used in the vendor code.
65 * The only constraint is that it must match the one in
66 * drivers/net/phy/meson-gxl.c to properly match the PHY.
67 */
68 writel(FIELD_PREP(REG2_PHYID, EPHY_GXL_ID),
69 addr: priv->regs + ETH_REG2);
70
71 /* Enable the internal phy */
72 val |= REG3_PHYEN;
73 writel(val, addr: priv->regs + ETH_REG3);
74 writel(val: 0, addr: priv->regs + ETH_REG4);
75
76 /* The phy needs a bit of time to power up */
77 mdelay(10);
78}
79
80static void gxl_enable_external_mdio(struct gxl_mdio_mux *priv)
81{
82 /* Reset the mdio bus mux to the external phy */
83 writel(val: 0, addr: priv->regs + ETH_REG3);
84}
85
86static int gxl_mdio_switch_fn(int current_child, int desired_child,
87 void *data)
88{
89 struct gxl_mdio_mux *priv = dev_get_drvdata(dev: data);
90
91 if (current_child == desired_child)
92 return 0;
93
94 switch (desired_child) {
95 case MESON_GXL_MDIO_EXTERNAL_ID:
96 gxl_enable_external_mdio(priv);
97 break;
98 case MESON_GXL_MDIO_INTERNAL_ID:
99 gxl_enable_internal_mdio(priv);
100 break;
101 default:
102 return -EINVAL;
103 }
104
105 return 0;
106}
107
108static const struct of_device_id gxl_mdio_mux_match[] = {
109 { .compatible = "amlogic,gxl-mdio-mux", },
110 {},
111};
112MODULE_DEVICE_TABLE(of, gxl_mdio_mux_match);
113
114static int gxl_mdio_mux_probe(struct platform_device *pdev)
115{
116 struct device *dev = &pdev->dev;
117 struct gxl_mdio_mux *priv;
118 struct clk *rclk;
119 int ret;
120
121 priv = devm_kzalloc(dev, size: sizeof(*priv), GFP_KERNEL);
122 if (!priv)
123 return -ENOMEM;
124 platform_set_drvdata(pdev, data: priv);
125
126 priv->regs = devm_platform_ioremap_resource(pdev, index: 0);
127 if (IS_ERR(ptr: priv->regs))
128 return PTR_ERR(ptr: priv->regs);
129
130 rclk = devm_clk_get_enabled(dev, id: "ref");
131 if (IS_ERR(ptr: rclk))
132 return dev_err_probe(dev, err: PTR_ERR(ptr: rclk),
133 fmt: "failed to get reference clock\n");
134
135 ret = mdio_mux_init(dev, mux_node: dev->of_node, switch_fn: gxl_mdio_switch_fn,
136 mux_handle: &priv->mux_handle, data: dev, NULL);
137 if (ret)
138 dev_err_probe(dev, err: ret, fmt: "mdio multiplexer init failed\n");
139
140 return ret;
141}
142
143static void gxl_mdio_mux_remove(struct platform_device *pdev)
144{
145 struct gxl_mdio_mux *priv = platform_get_drvdata(pdev);
146
147 mdio_mux_uninit(mux_handle: priv->mux_handle);
148}
149
150static struct platform_driver gxl_mdio_mux_driver = {
151 .probe = gxl_mdio_mux_probe,
152 .remove_new = gxl_mdio_mux_remove,
153 .driver = {
154 .name = "gxl-mdio-mux",
155 .of_match_table = gxl_mdio_mux_match,
156 },
157};
158module_platform_driver(gxl_mdio_mux_driver);
159
160MODULE_DESCRIPTION("Amlogic GXL MDIO multiplexer driver");
161MODULE_AUTHOR("Jerome Brunet <jbrunet@baylibre.com>");
162MODULE_LICENSE("GPL");
163

source code of linux/drivers/net/mdio/mdio-mux-meson-gxl.c