1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
|
From 69226896ad636b94f6d2e55d75ff21a29c4de83b Mon Sep 17 00:00:00 2001
From: Roger Quadros <rogerq@ti.com>
Date: Fri, 21 Apr 2017 16:15:38 +0300
Subject: [PATCH] mdio_bus: Issue GPIO RESET to PHYs.
Some boards [1] leave the PHYs at an invalid state
during system power-up or reset thus causing unreliability
issues with the PHY which manifests as PHY not being detected
or link not functional. To fix this, these PHYs need to be RESET
via a GPIO connected to the PHY's RESET pin.
Some boards have a single GPIO controlling the PHY RESET pin of all
PHYs on the bus whereas some others have separate GPIOs controlling
individual PHY RESETs.
In both cases, the RESET de-assertion cannot be done in the PHY driver
as the PHY will not probe till its reset is de-asserted.
So do the RESET de-assertion in the MDIO bus driver.
[1] - am572x-idk, am571x-idk, a437x-idk
Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
Documentation/devicetree/bindings/net/mdio.txt | 33 ++++++++++++++++++
drivers/net/phy/mdio_bus.c | 47 ++++++++++++++++++++++++++
drivers/of/of_mdio.c | 7 ++++
include/linux/phy.h | 7 ++++
4 files changed, 94 insertions(+)
create mode 100644 Documentation/devicetree/bindings/net/mdio.txt
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/mdio.txt
@@ -0,0 +1,33 @@
+Common MDIO bus properties.
+
+These are generic properties that can apply to any MDIO bus.
+
+Optional properties:
+- reset-gpios: List of one or more GPIOs that control the RESET lines
+ of the PHYs on that MDIO bus.
+- reset-delay-us: RESET pulse width in microseconds as per PHY datasheet.
+
+A list of child nodes, one per device on the bus is expected. These
+should follow the generic phy.txt, or a device specific binding document.
+
+Example :
+This example shows these optional properties, plus other properties
+required for the TI Davinci MDIO driver.
+
+ davinci_mdio: ethernet@0x5c030000 {
+ compatible = "ti,davinci_mdio";
+ reg = <0x5c030000 0x1000>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ reset-gpios = <&gpio2 5 GPIO_ACTIVE_LOW>;
+ reset-delay-us = <2>; /* PHY datasheet states 1us min */
+
+ ethphy0: ethernet-phy@1 {
+ reg = <1>;
+ };
+
+ ethphy1: ethernet-phy@3 {
+ reg = <3>;
+ };
+ };
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -22,8 +22,11 @@
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/device.h>
+#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
#include <linux/of_device.h>
#include <linux/of_mdio.h>
+#include <linux/of_gpio.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
@@ -304,6 +307,7 @@ int __mdiobus_register(struct mii_bus *b
{
struct mdio_device *mdiodev;
int i, err;
+ struct gpio_desc *gpiod;
if (NULL == bus || NULL == bus->name ||
NULL == bus->read || NULL == bus->write)
@@ -329,6 +333,35 @@ int __mdiobus_register(struct mii_bus *b
if (bus->reset)
bus->reset(bus);
+ /* de-assert bus level PHY GPIO resets */
+ if (bus->num_reset_gpios > 0) {
+ bus->reset_gpiod = devm_kcalloc(&bus->dev,
+ bus->num_reset_gpios,
+ sizeof(struct gpio_desc *),
+ GFP_KERNEL);
+ if (!bus->reset_gpiod)
+ return -ENOMEM;
+ }
+
+ for (i = 0; i < bus->num_reset_gpios; i++) {
+ gpiod = devm_gpiod_get_index(&bus->dev, "reset", i,
+ GPIOD_OUT_LOW);
+ if (IS_ERR(gpiod)) {
+ err = PTR_ERR(gpiod);
+ if (err != -ENOENT) {
+ dev_err(&bus->dev,
+ "mii_bus %s couldn't get reset GPIO\n",
+ bus->id);
+ return err;
+ }
+ } else {
+ bus->reset_gpiod[i] = gpiod;
+ gpiod_set_value_cansleep(gpiod, 1);
+ udelay(bus->reset_delay_us);
+ gpiod_set_value_cansleep(gpiod, 0);
+ }
+ }
+
for (i = 0; i < PHY_MAX_ADDR; i++) {
if ((bus->phy_mask & (1 << i)) == 0) {
struct phy_device *phydev;
@@ -354,6 +387,13 @@ error:
mdiodev->device_remove(mdiodev);
mdiodev->device_free(mdiodev);
}
+
+ /* Put PHYs in RESET to save power */
+ for (i = 0; i < bus->num_reset_gpios; i++) {
+ if (bus->reset_gpiod[i])
+ gpiod_set_value_cansleep(bus->reset_gpiod[i], 1);
+ }
+
device_del(&bus->dev);
return err;
}
@@ -375,6 +415,13 @@ void mdiobus_unregister(struct mii_bus *
mdiodev->device_remove(mdiodev);
mdiodev->device_free(mdiodev);
}
+
+ /* Put PHYs in RESET to save power */
+ for (i = 0; i < bus->num_reset_gpios; i++) {
+ if (bus->reset_gpiod[i])
+ gpiod_set_value_cansleep(bus->reset_gpiod[i], 1);
+ }
+
device_del(&bus->dev);
}
EXPORT_SYMBOL(mdiobus_unregister);
--- a/drivers/of/of_mdio.c
+++ b/drivers/of/of_mdio.c
@@ -22,6 +22,8 @@
#include <linux/of_net.h>
#include <linux/module.h>
+#define DEFAULT_GPIO_RESET_DELAY 10 /* in microseconds */
+
MODULE_AUTHOR("Grant Likely <grant.likely@secretlab.ca>");
MODULE_LICENSE("GPL");
@@ -220,6 +222,11 @@ int of_mdiobus_register(struct mii_bus *
mdio->dev.of_node = np;
+ /* Get bus level PHY reset GPIO details */
+ mdio->reset_delay_us = DEFAULT_GPIO_RESET_DELAY;
+ of_property_read_u32(np, "reset-delay-us", &mdio->reset_delay_us);
+ mdio->num_reset_gpios = of_gpio_named_count(np, "reset-gpios");
+
/* Register the MDIO bus */
rc = mdiobus_register(mdio);
if (rc)
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -193,6 +193,13 @@ struct mii_bus {
* matching its address
*/
int irq[PHY_MAX_ADDR];
+
+ /* GPIO reset pulse width in microseconds */
+ int reset_delay_us;
+ /* Number of reset GPIOs */
+ int num_reset_gpios;
+ /* Array of RESET GPIO descriptors */
+ struct gpio_desc **reset_gpiod;
};
#define to_mii_bus(d) container_of(d, struct mii_bus, dev)
|
