1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* Driver for MMIO-Mapped MDIO devices. Some IPs expose internal PHYs or PCS
3 * within the MMIO-mapped area
4 *
5 * Copyright (C) 2023 Maxime Chevallier <maxime.chevallier@bootlin.com>
6 */
7 #include <linux/bitfield.h>
8 #include <linux/delay.h>
9 #include <linux/mdio.h>
10 #include <linux/module.h>
11 #include <linux/of.h>
12 #include <linux/of_mdio.h>
13 #include <linux/phy.h>
14 #include <linux/platform_device.h>
15 #include <linux/regmap.h>
16 #include <linux/mdio/mdio-regmap.h>
17
18 #define DRV_NAME "mdio-regmap"
19
20 struct mdio_regmap_priv {
21 struct regmap *regmap;
22 u8 valid_addr;
23 };
24
mdio_regmap_read_c22(struct mii_bus * bus,int addr,int regnum)25 static int mdio_regmap_read_c22(struct mii_bus *bus, int addr, int regnum)
26 {
27 struct mdio_regmap_priv *ctx = bus->priv;
28 unsigned int val;
29 int ret;
30
31 if (ctx->valid_addr != addr)
32 return -ENODEV;
33
34 ret = regmap_read(ctx->regmap, regnum, &val);
35 if (ret < 0)
36 return ret;
37
38 return val;
39 }
40
mdio_regmap_write_c22(struct mii_bus * bus,int addr,int regnum,u16 val)41 static int mdio_regmap_write_c22(struct mii_bus *bus, int addr, int regnum,
42 u16 val)
43 {
44 struct mdio_regmap_priv *ctx = bus->priv;
45
46 if (ctx->valid_addr != addr)
47 return -ENODEV;
48
49 return regmap_write(ctx->regmap, regnum, val);
50 }
51
devm_mdio_regmap_register(struct device * dev,const struct mdio_regmap_config * config)52 struct mii_bus *devm_mdio_regmap_register(struct device *dev,
53 const struct mdio_regmap_config *config)
54 {
55 struct mdio_regmap_priv *mr;
56 struct mii_bus *mii;
57 int rc;
58
59 if (!config->parent)
60 return ERR_PTR(-EINVAL);
61
62 mii = devm_mdiobus_alloc_size(config->parent, sizeof(*mr));
63 if (!mii)
64 return ERR_PTR(-ENOMEM);
65
66 mr = mii->priv;
67 mr->regmap = config->regmap;
68 mr->valid_addr = config->valid_addr;
69
70 mii->name = DRV_NAME;
71 strscpy(mii->id, config->name, MII_BUS_ID_SIZE);
72 mii->parent = config->parent;
73 mii->read = mdio_regmap_read_c22;
74 mii->write = mdio_regmap_write_c22;
75
76 if (config->autoscan)
77 mii->phy_mask = ~BIT(config->valid_addr);
78 else
79 mii->phy_mask = ~0;
80
81 rc = devm_mdiobus_register(dev, mii);
82 if (rc) {
83 dev_err(config->parent, "Cannot register MDIO bus![%s] (%d)\n", mii->id, rc);
84 return ERR_PTR(rc);
85 }
86
87 return mii;
88 }
89 EXPORT_SYMBOL_GPL(devm_mdio_regmap_register);
90
91 MODULE_DESCRIPTION("MDIO API over regmap");
92 MODULE_AUTHOR("Maxime Chevallier <maxime.chevallier@bootlin.com>");
93 MODULE_LICENSE("GPL");
94
