tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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_REVERSED BIT(28)
21#define REG2_ADCBYPASS BIT(30)
22#define REG2_CLKINSEL BIT(31)
23#define ETH_REG3 0x4
24#define REG3_ENH BIT(3)
25#define REG3_CFGMODE GENMASK(6, 4)
26#define REG3_AUTOMDIX BIT(7)
27#define REG3_PHYADDR GENMASK(12, 8)
28#define REG3_PWRUPRST BIT(21)
29#define REG3_PWRDOWN BIT(22)
30#define REG3_LEDPOL BIT(23)
31#define REG3_PHYMDI BIT(26)
32#define REG3_CLKINEN BIT(29)
33#define REG3_PHYIP BIT(30)
34#define REG3_PHYEN BIT(31)
35#define ETH_REG4 0x8
36#define REG4_PWRUPRSTSIG BIT(0)
37
38#define MESON_GXL_MDIO_EXTERNAL_ID 0
39#define MESON_GXL_MDIO_INTERNAL_ID 1
40
41struct gxl_mdio_mux {
42 void __iomem *regs;
43 void *mux_handle;
44};
45
46static void gxl_enable_internal_mdio(struct gxl_mdio_mux *priv)
47{
48 u32 val;
49
50 /* Setup the internal phy */
51 val = (REG3_ENH |
52 FIELD_PREP(REG3_CFGMODE, 0x7) |
53 REG3_AUTOMDIX |
54 FIELD_PREP(REG3_PHYADDR, 8) |
55 REG3_LEDPOL |
56 REG3_PHYMDI |
57 REG3_CLKINEN |
58 REG3_PHYIP);
59
60 writel(REG4_PWRUPRSTSIG, priv->regs + ETH_REG4);
61 writel(val, priv->regs + ETH_REG3);
62 mdelay(10);
63
64 /* NOTE: The HW kept the phy id configurable at runtime.
65 * The id below is arbitrary. It is the one used in the vendor code.
66 * The only constraint is that it must match the one in
67 * drivers/net/phy/meson-gxl.c to properly match the PHY.
68 */
69 writel(REG2_REVERSED | FIELD_PREP(REG2_PHYID, EPHY_GXL_ID),
70 priv->regs + ETH_REG2);
71
72 /* Enable the internal phy */
73 val |= REG3_PHYEN;
74 writel(val, priv->regs + ETH_REG3);
75 writel(0, priv->regs + ETH_REG4);
76
77 /* The phy needs a bit of time to power up */
78 mdelay(10);
79}
80
81static void gxl_enable_external_mdio(struct gxl_mdio_mux *priv)
82{
83 /* Reset the mdio bus mux to the external phy */
84 writel(0, priv->regs + ETH_REG3);
85}
86
87static int gxl_mdio_switch_fn(int current_child, int desired_child,
88 void *data)
89{
90 struct gxl_mdio_mux *priv = dev_get_drvdata(data);
91
92 if (current_child == desired_child)
93 return 0;
94
95 switch (desired_child) {
96 case MESON_GXL_MDIO_EXTERNAL_ID:
97 gxl_enable_external_mdio(priv);
98 break;
99 case MESON_GXL_MDIO_INTERNAL_ID:
100 gxl_enable_internal_mdio(priv);
101 break;
102 default:
103 return -EINVAL;
104 }
105
106 return 0;
107}
108
109static const struct of_device_id gxl_mdio_mux_match[] = {
110 { .compatible = "amlogic,gxl-mdio-mux", },
111 {},
112};
113MODULE_DEVICE_TABLE(of, gxl_mdio_mux_match);
114
115static int gxl_mdio_mux_probe(struct platform_device *pdev)
116{
117 struct device *dev = &pdev->dev;
118 struct gxl_mdio_mux *priv;
119 struct clk *rclk;
120 int ret;
121
122 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
123 if (!priv)
124 return -ENOMEM;
125 platform_set_drvdata(pdev, priv);
126
127 priv->regs = devm_platform_ioremap_resource(pdev, 0);
128 if (IS_ERR(priv->regs))
129 return PTR_ERR(priv->regs);
130
131 rclk = devm_clk_get_enabled(dev, "ref");
132 if (IS_ERR(rclk))
133 return dev_err_probe(dev, PTR_ERR(rclk),
134 "failed to get reference clock\n");
135
136 ret = mdio_mux_init(dev, dev->of_node, gxl_mdio_switch_fn,
137 &priv->mux_handle, dev, NULL);
138 if (ret)
139 dev_err_probe(dev, ret, "mdio multiplexer init failed\n");
140
141 return ret;
142}
143
144static void gxl_mdio_mux_remove(struct platform_device *pdev)
145{
146 struct gxl_mdio_mux *priv = platform_get_drvdata(pdev);
147
148 mdio_mux_uninit(priv->mux_handle);
149}
150
151static struct platform_driver gxl_mdio_mux_driver = {
152 .probe = gxl_mdio_mux_probe,
153 .remove = gxl_mdio_mux_remove,
154 .driver = {
155 .name = "gxl-mdio-mux",
156 .of_match_table = gxl_mdio_mux_match,
157 },
158};
159module_platform_driver(gxl_mdio_mux_driver);
160
161MODULE_DESCRIPTION("Amlogic GXL MDIO multiplexer driver");
162MODULE_AUTHOR("Jerome Brunet <jbrunet@baylibre.com>");
163MODULE_LICENSE("GPL");