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Greg Kroah-Hartmanb2441312017-11-01 15:07:57 +01001// SPDX-License-Identifier: GPL-2.0
Alexey Brodkine4f23792013-06-24 09:54:27 +04002/*
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>
Caesar Wang1bddd962016-03-14 16:01:54 +080011#include <linux/gpio/consumer.h>
Alexey Brodkine4f23792013-06-24 09:54:27 +040012
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 */
24static 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, R_STATUS);
30
31 status &= MDIO_MASK;
32
33 if (status) {
34 /* Reset "MDIO complete" flag */
35 arc_reg_set(priv, R_STATUS, status);
36 return 0;
37 }
38
39 msleep(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 */
56static 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, R_MDIO,
63 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, 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 */
88static 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, R_MDIO,
Caesar Wang663713e2016-03-14 16:01:55 +080098 0x50020000 | (phy_addr << 23) | (reg_num << 18) | value);
Alexey Brodkine4f23792013-06-24 09:54:27 +040099
100 return arc_mdio_complete_wait(priv);
101}
102
103/**
Caesar Wang1bddd962016-03-14 16:01:54 +0800104 * arc_mdio_reset
105 * @bus: points to the mii_bus structure
106 * Description: reset the MII bus
107 */
Baoyou Xie3f591992016-09-06 16:21:56 +0800108static int arc_mdio_reset(struct mii_bus *bus)
Caesar Wang1bddd962016-03-14 16:01:54 +0800109{
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(data->reset_gpio, 1);
115 msleep(data->msec);
116 gpiod_set_value_cansleep(data->reset_gpio, 0);
117 }
118
119 return 0;
120}
121
122/**
Alexey Brodkine4f23792013-06-24 09:54:27 +0400123 * arc_mdio_probe - MDIO probe function.
Alexey Brodkine4f23792013-06-24 09:54:27 +0400124 * @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 */
Romain Perier93e91b32014-08-26 13:14:50 +0000131int arc_mdio_probe(struct arc_emac_priv *priv)
Alexey Brodkine4f23792013-06-24 09:54:27 +0400132{
Caesar Wang1bddd962016-03-14 16:01:54 +0800133 struct arc_emac_mdio_bus_data *data = &priv->bus_data;
134 struct device_node *np = priv->dev->of_node;
Alexey Brodkine4f23792013-06-24 09:54:27 +0400135 struct mii_bus *bus;
136 int error;
137
138 bus = mdiobus_alloc();
139 if (!bus)
140 return -ENOMEM;
141
142 priv->bus = bus;
143 bus->priv = priv;
144 bus->parent = priv->dev;
Marek Vasut3424d9b2016-05-26 00:40:05 +0200145 bus->name = "Synopsys MII Bus";
Alexey Brodkine4f23792013-06-24 09:54:27 +0400146 bus->read = &arc_mdio_read;
147 bus->write = &arc_mdio_write;
Caesar Wang1bddd962016-03-14 16:01:54 +0800148 bus->reset = &arc_mdio_reset;
149
150 /* optional reset-related properties */
151 data->reset_gpio = devm_gpiod_get_optional(priv->dev, "phy-reset",
152 GPIOD_OUT_LOW);
153 if (IS_ERR(data->reset_gpio)) {
154 error = PTR_ERR(data->reset_gpio);
155 dev_err(priv->dev, "Failed to request gpio: %d\n", error);
156 return error;
157 }
158
159 of_property_read_u32(np, "phy-reset-duration", &data->msec);
160 /* A sane reset duration should not be longer than 1s */
161 if (data->msec > 1000)
162 data->msec = 1;
Alexey Brodkine4f23792013-06-24 09:54:27 +0400163
Romain Perier93e91b32014-08-26 13:14:50 +0000164 snprintf(bus->id, MII_BUS_ID_SIZE, "%s", bus->name);
Alexey Brodkine4f23792013-06-24 09:54:27 +0400165
Romain Perier93e91b32014-08-26 13:14:50 +0000166 error = of_mdiobus_register(bus, priv->dev->of_node);
Alexey Brodkine4f23792013-06-24 09:54:27 +0400167 if (error) {
168 dev_err(priv->dev, "cannot register MDIO bus %s\n", bus->name);
169 mdiobus_free(bus);
170 return error;
171 }
172
173 return 0;
174}
175
176/**
177 * arc_mdio_remove - MDIO remove function.
178 * @priv: Pointer to ARC EMAC private data structure.
179 *
180 * Unregisters the MDIO and frees any associate memory for MII bus.
181 */
182int arc_mdio_remove(struct arc_emac_priv *priv)
183{
184 mdiobus_unregister(priv->bus);
185 mdiobus_free(priv->bus);
186 priv->bus = NULL;
187
188 return 0;
189}