1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * Copyright (C) 2004-2013 Synopsys, Inc. (www.synopsys.com) |
4 | * |
5 | * MDIO implementation for ARC EMAC |
6 | */ |
7 | |
8 | #include <linux/delay.h> |
9 | #include <linux/of_mdio.h> |
10 | #include <linux/platform_device.h> |
11 | #include <linux/gpio/consumer.h> |
12 | |
13 | #include "emac.h" |
14 | |
15 | /* Number of seconds we wait for "MDIO complete" flag to appear */ |
16 | #define ARC_MDIO_COMPLETE_POLL_COUNT 1 |
17 | |
18 | /** |
19 | * arc_mdio_complete_wait - Waits until MDIO transaction is completed. |
20 | * @priv: Pointer to ARC EMAC private data structure. |
21 | * |
22 | * returns: 0 on success, -ETIMEDOUT on a timeout. |
23 | */ |
24 | static int arc_mdio_complete_wait(struct arc_emac_priv *priv) |
25 | { |
26 | unsigned int i; |
27 | |
28 | for (i = 0; i < ARC_MDIO_COMPLETE_POLL_COUNT * 40; i++) { |
29 | unsigned int status = arc_reg_get(priv, reg: R_STATUS); |
30 | |
31 | status &= MDIO_MASK; |
32 | |
33 | if (status) { |
34 | /* Reset "MDIO complete" flag */ |
35 | arc_reg_set(priv, reg: R_STATUS, value: status); |
36 | return 0; |
37 | } |
38 | |
39 | msleep(msecs: 25); |
40 | } |
41 | |
42 | return -ETIMEDOUT; |
43 | } |
44 | |
45 | /** |
46 | * arc_mdio_read - MDIO interface read function. |
47 | * @bus: Pointer to MII bus structure. |
48 | * @phy_addr: Address of the PHY device. |
49 | * @reg_num: PHY register to read. |
50 | * |
51 | * returns: The register contents on success, -ETIMEDOUT on a timeout. |
52 | * |
53 | * Reads the contents of the requested register from the requested PHY |
54 | * address. |
55 | */ |
56 | static int arc_mdio_read(struct mii_bus *bus, int phy_addr, int reg_num) |
57 | { |
58 | struct arc_emac_priv *priv = bus->priv; |
59 | unsigned int value; |
60 | int error; |
61 | |
62 | arc_reg_set(priv, reg: R_MDIO, |
63 | value: 0x60020000 | (phy_addr << 23) | (reg_num << 18)); |
64 | |
65 | error = arc_mdio_complete_wait(priv); |
66 | if (error < 0) |
67 | return error; |
68 | |
69 | value = arc_reg_get(priv, reg: R_MDIO) & 0xffff; |
70 | |
71 | dev_dbg(priv->dev, "arc_mdio_read(phy_addr=%i, reg_num=%x) = %x\n" , |
72 | phy_addr, reg_num, value); |
73 | |
74 | return value; |
75 | } |
76 | |
77 | /** |
78 | * arc_mdio_write - MDIO interface write function. |
79 | * @bus: Pointer to MII bus structure. |
80 | * @phy_addr: Address of the PHY device. |
81 | * @reg_num: PHY register to write to. |
82 | * @value: Value to be written into the register. |
83 | * |
84 | * returns: 0 on success, -ETIMEDOUT on a timeout. |
85 | * |
86 | * Writes the value to the requested register. |
87 | */ |
88 | static int arc_mdio_write(struct mii_bus *bus, int phy_addr, |
89 | int reg_num, u16 value) |
90 | { |
91 | struct arc_emac_priv *priv = bus->priv; |
92 | |
93 | dev_dbg(priv->dev, |
94 | "arc_mdio_write(phy_addr=%i, reg_num=%x, value=%x)\n" , |
95 | phy_addr, reg_num, value); |
96 | |
97 | arc_reg_set(priv, reg: R_MDIO, |
98 | value: 0x50020000 | (phy_addr << 23) | (reg_num << 18) | value); |
99 | |
100 | return arc_mdio_complete_wait(priv); |
101 | } |
102 | |
103 | /** |
104 | * arc_mdio_reset |
105 | * @bus: points to the mii_bus structure |
106 | * Description: reset the MII bus |
107 | */ |
108 | static int arc_mdio_reset(struct mii_bus *bus) |
109 | { |
110 | struct arc_emac_priv *priv = bus->priv; |
111 | struct arc_emac_mdio_bus_data *data = &priv->bus_data; |
112 | |
113 | if (data->reset_gpio) { |
114 | gpiod_set_value_cansleep(desc: data->reset_gpio, value: 1); |
115 | msleep(msecs: data->msec); |
116 | gpiod_set_value_cansleep(desc: data->reset_gpio, value: 0); |
117 | } |
118 | |
119 | return 0; |
120 | } |
121 | |
122 | /** |
123 | * arc_mdio_probe - MDIO probe function. |
124 | * @priv: Pointer to ARC EMAC private data structure. |
125 | * |
126 | * returns: 0 on success, -ENOMEM when mdiobus_alloc |
127 | * (to allocate memory for MII bus structure) fails. |
128 | * |
129 | * Sets up and registers the MDIO interface. |
130 | */ |
131 | int arc_mdio_probe(struct arc_emac_priv *priv) |
132 | { |
133 | struct arc_emac_mdio_bus_data *data = &priv->bus_data; |
134 | struct device_node *np = priv->dev->of_node; |
135 | const char *name = "Synopsys MII Bus" ; |
136 | struct mii_bus *bus; |
137 | int error; |
138 | |
139 | bus = mdiobus_alloc(); |
140 | if (!bus) |
141 | return -ENOMEM; |
142 | |
143 | priv->bus = bus; |
144 | bus->priv = priv; |
145 | bus->parent = priv->dev; |
146 | bus->name = name; |
147 | bus->read = &arc_mdio_read; |
148 | bus->write = &arc_mdio_write; |
149 | bus->reset = &arc_mdio_reset; |
150 | |
151 | /* optional reset-related properties */ |
152 | data->reset_gpio = devm_gpiod_get_optional(dev: priv->dev, con_id: "phy-reset" , |
153 | flags: GPIOD_OUT_LOW); |
154 | if (IS_ERR(ptr: data->reset_gpio)) { |
155 | mdiobus_free(bus); |
156 | return dev_err_probe(dev: priv->dev, err: PTR_ERR(ptr: data->reset_gpio), |
157 | fmt: "Failed to request gpio\n" ); |
158 | } |
159 | |
160 | of_property_read_u32(np, propname: "phy-reset-duration" , out_value: &data->msec); |
161 | /* A sane reset duration should not be longer than 1s */ |
162 | if (data->msec > 1000) |
163 | data->msec = 1; |
164 | |
165 | snprintf(buf: bus->id, MII_BUS_ID_SIZE, fmt: "%s" , bus->name); |
166 | |
167 | error = of_mdiobus_register(mdio: bus, np: priv->dev->of_node); |
168 | if (error) { |
169 | mdiobus_free(bus); |
170 | return dev_err_probe(dev: priv->dev, err: error, |
171 | fmt: "cannot register MDIO bus %s\n" , name); |
172 | } |
173 | |
174 | return 0; |
175 | } |
176 | |
177 | /** |
178 | * arc_mdio_remove - MDIO remove function. |
179 | * @priv: Pointer to ARC EMAC private data structure. |
180 | * |
181 | * Unregisters the MDIO and frees any associate memory for MII bus. |
182 | */ |
183 | int arc_mdio_remove(struct arc_emac_priv *priv) |
184 | { |
185 | mdiobus_unregister(bus: priv->bus); |
186 | mdiobus_free(bus: priv->bus); |
187 | priv->bus = NULL; |
188 | |
189 | return 0; |
190 | } |
191 | |