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
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
|
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Power Management and GPIO expander driver for MPC8349E-mITX-compatible MCU
*
* Copyright (c) 2008 MontaVista Software, Inc.
*
* Author: Anton Vorontsov <avorontsov@ru.mvista.com>
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/mutex.h>
#include <linux/i2c.h>
#include <linux/gpio/driver.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#include <linux/slab.h>
#include <linux/kthread.h>
#include <linux/reboot.h>
#include <asm/prom.h>
#include <asm/machdep.h>
/*
* I don't have specifications for the MCU firmware, I found this register
* and bits positions by the trial&error method.
*/
#define MCU_REG_CTRL 0x20
#define MCU_CTRL_POFF 0x40
#define MCU_CTRL_BTN 0x80
#define MCU_NUM_GPIO 2
struct mcu {
struct mutex lock;
struct i2c_client *client;
struct gpio_chip gc;
u8 reg_ctrl;
};
static struct mcu *glob_mcu;
struct task_struct *shutdown_thread;
static int shutdown_thread_fn(void *data)
{
int ret;
struct mcu *mcu = glob_mcu;
while (!kthread_should_stop()) {
ret = i2c_smbus_read_byte_data(mcu->client, MCU_REG_CTRL);
if (ret < 0)
pr_err("MCU status reg read failed.\n");
mcu->reg_ctrl = ret;
if (mcu->reg_ctrl & MCU_CTRL_BTN) {
i2c_smbus_write_byte_data(mcu->client, MCU_REG_CTRL,
mcu->reg_ctrl & ~MCU_CTRL_BTN);
ctrl_alt_del();
}
set_current_state(TASK_INTERRUPTIBLE);
schedule_timeout(HZ);
}
return 0;
}
static ssize_t show_status(struct device *d,
struct device_attribute *attr, char *buf)
{
int ret;
struct mcu *mcu = glob_mcu;
ret = i2c_smbus_read_byte_data(mcu->client, MCU_REG_CTRL);
if (ret < 0)
return -ENODEV;
mcu->reg_ctrl = ret;
return sprintf(buf, "%02x\n", ret);
}
static DEVICE_ATTR(status, 0444, show_status, NULL);
static void mcu_power_off(void)
{
struct mcu *mcu = glob_mcu;
pr_info("Sending power-off request to the MCU...\n");
mutex_lock(&mcu->lock);
i2c_smbus_write_byte_data(mcu->client, MCU_REG_CTRL,
mcu->reg_ctrl | MCU_CTRL_POFF);
mutex_unlock(&mcu->lock);
}
static void mcu_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
{
struct mcu *mcu = gpiochip_get_data(gc);
u8 bit = 1 << (4 + gpio);
mutex_lock(&mcu->lock);
if (val)
mcu->reg_ctrl &= ~bit;
else
mcu->reg_ctrl |= bit;
i2c_smbus_write_byte_data(mcu->client, MCU_REG_CTRL, mcu->reg_ctrl);
mutex_unlock(&mcu->lock);
}
static int mcu_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
{
mcu_gpio_set(gc, gpio, val);
return 0;
}
static int mcu_gpiochip_add(struct mcu *mcu)
{
struct device_node *np;
struct gpio_chip *gc = &mcu->gc;
np = of_find_compatible_node(NULL, NULL, "fsl,mcu-mpc8349emitx");
if (!np)
return -ENODEV;
gc->owner = THIS_MODULE;
gc->label = kasprintf(GFP_KERNEL, "%pOF", np);
gc->can_sleep = 1;
gc->ngpio = MCU_NUM_GPIO;
gc->base = -1;
gc->set = mcu_gpio_set;
gc->direction_output = mcu_gpio_dir_out;
gc->of_node = np;
return gpiochip_add_data(gc, mcu);
}
static void mcu_gpiochip_remove(struct mcu *mcu)
{
kfree(mcu->gc.label);
gpiochip_remove(&mcu->gc);
}
static int mcu_probe(struct i2c_client *client)
{
struct mcu *mcu;
int ret;
mcu = kzalloc(sizeof(*mcu), GFP_KERNEL);
if (!mcu)
return -ENOMEM;
mutex_init(&mcu->lock);
mcu->client = client;
i2c_set_clientdata(client, mcu);
ret = i2c_smbus_read_byte_data(mcu->client, MCU_REG_CTRL);
if (ret < 0)
goto err;
mcu->reg_ctrl = ret;
ret = mcu_gpiochip_add(mcu);
if (ret)
goto err;
/* XXX: this is potentially racy, but there is no lock for pm_power_off */
if (!pm_power_off) {
glob_mcu = mcu;
pm_power_off = mcu_power_off;
dev_info(&client->dev, "will provide power-off service\n");
}
if (device_create_file(&client->dev, &dev_attr_status))
dev_err(&client->dev,
"couldn't create device file for status\n");
shutdown_thread = kthread_run(shutdown_thread_fn, NULL,
"mcu-i2c-shdn");
return 0;
err:
kfree(mcu);
return ret;
}
static int mcu_remove(struct i2c_client *client)
{
struct mcu *mcu = i2c_get_clientdata(client);
kthread_stop(shutdown_thread);
device_remove_file(&client->dev, &dev_attr_status);
if (glob_mcu == mcu) {
pm_power_off = NULL;
glob_mcu = NULL;
}
mcu_gpiochip_remove(mcu);
kfree(mcu);
return 0;
}
static const struct i2c_device_id mcu_ids[] = {
{ "mcu-mpc8349emitx", },
{},
};
MODULE_DEVICE_TABLE(i2c, mcu_ids);
static const struct of_device_id mcu_of_match_table[] = {
{ .compatible = "fsl,mcu-mpc8349emitx", },
{ },
};
static struct i2c_driver mcu_driver = {
.driver = {
.name = "mcu-mpc8349emitx",
.of_match_table = mcu_of_match_table,
},
.probe_new = mcu_probe,
.remove = mcu_remove,
.id_table = mcu_ids,
};
module_i2c_driver(mcu_driver);
MODULE_DESCRIPTION("Power Management and GPIO expander driver for "
"MPC8349E-mITX-compatible MCU");
MODULE_AUTHOR("Anton Vorontsov <avorontsov@ru.mvista.com>");
MODULE_LICENSE("GPL");
|
