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10#include <linux/kernel.h>
11#include <linux/module.h>
12#include <linux/device.h>
13#include <linux/mutex.h>
14#include <linux/i2c.h>
15#include <linux/gpio/driver.h>
16#include <linux/of.h>
17#include <linux/of_gpio.h>
18#include <linux/slab.h>
19#include <linux/kthread.h>
20#include <linux/reboot.h>
21#include <asm/prom.h>
22#include <asm/machdep.h>
23
24
25
26
27
28#define MCU_REG_CTRL 0x20
29#define MCU_CTRL_POFF 0x40
30#define MCU_CTRL_BTN 0x80
31
32#define MCU_NUM_GPIO 2
33
34struct mcu {
35 struct mutex lock;
36 struct i2c_client *client;
37 struct gpio_chip gc;
38 u8 reg_ctrl;
39};
40
41static struct mcu *glob_mcu;
42
43struct task_struct *shutdown_thread;
44static int shutdown_thread_fn(void *data)
45{
46 int ret;
47 struct mcu *mcu = glob_mcu;
48
49 while (!kthread_should_stop()) {
50 ret = i2c_smbus_read_byte_data(mcu->client, MCU_REG_CTRL);
51 if (ret < 0)
52 pr_err("MCU status reg read failed.\n");
53 mcu->reg_ctrl = ret;
54
55
56 if (mcu->reg_ctrl & MCU_CTRL_BTN) {
57 i2c_smbus_write_byte_data(mcu->client, MCU_REG_CTRL,
58 mcu->reg_ctrl & ~MCU_CTRL_BTN);
59
60 ctrl_alt_del();
61 }
62
63 set_current_state(TASK_INTERRUPTIBLE);
64 schedule_timeout(HZ);
65 }
66
67 return 0;
68}
69
70static ssize_t show_status(struct device *d,
71 struct device_attribute *attr, char *buf)
72{
73 int ret;
74 struct mcu *mcu = glob_mcu;
75
76 ret = i2c_smbus_read_byte_data(mcu->client, MCU_REG_CTRL);
77 if (ret < 0)
78 return -ENODEV;
79 mcu->reg_ctrl = ret;
80
81 return sprintf(buf, "%02x\n", ret);
82}
83static DEVICE_ATTR(status, 0444, show_status, NULL);
84
85static void mcu_power_off(void)
86{
87 struct mcu *mcu = glob_mcu;
88
89 pr_info("Sending power-off request to the MCU...\n");
90 mutex_lock(&mcu->lock);
91 i2c_smbus_write_byte_data(mcu->client, MCU_REG_CTRL,
92 mcu->reg_ctrl | MCU_CTRL_POFF);
93 mutex_unlock(&mcu->lock);
94}
95
96static void mcu_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
97{
98 struct mcu *mcu = gpiochip_get_data(gc);
99 u8 bit = 1 << (4 + gpio);
100
101 mutex_lock(&mcu->lock);
102 if (val)
103 mcu->reg_ctrl &= ~bit;
104 else
105 mcu->reg_ctrl |= bit;
106
107 i2c_smbus_write_byte_data(mcu->client, MCU_REG_CTRL, mcu->reg_ctrl);
108 mutex_unlock(&mcu->lock);
109}
110
111static int mcu_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
112{
113 mcu_gpio_set(gc, gpio, val);
114 return 0;
115}
116
117static int mcu_gpiochip_add(struct mcu *mcu)
118{
119 struct device_node *np;
120 struct gpio_chip *gc = &mcu->gc;
121
122 np = of_find_compatible_node(NULL, NULL, "fsl,mcu-mpc8349emitx");
123 if (!np)
124 return -ENODEV;
125
126 gc->owner = THIS_MODULE;
127 gc->label = kasprintf(GFP_KERNEL, "%pOF", np);
128 gc->can_sleep = 1;
129 gc->ngpio = MCU_NUM_GPIO;
130 gc->base = -1;
131 gc->set = mcu_gpio_set;
132 gc->direction_output = mcu_gpio_dir_out;
133 gc->of_node = np;
134
135 return gpiochip_add_data(gc, mcu);
136}
137
138static int mcu_gpiochip_remove(struct mcu *mcu)
139{
140 kfree(mcu->gc.label);
141 gpiochip_remove(&mcu->gc);
142 return 0;
143}
144
145static int mcu_probe(struct i2c_client *client)
146{
147 struct mcu *mcu;
148 int ret;
149
150 mcu = kzalloc(sizeof(*mcu), GFP_KERNEL);
151 if (!mcu)
152 return -ENOMEM;
153
154 mutex_init(&mcu->lock);
155 mcu->client = client;
156 i2c_set_clientdata(client, mcu);
157
158 ret = i2c_smbus_read_byte_data(mcu->client, MCU_REG_CTRL);
159 if (ret < 0)
160 goto err;
161 mcu->reg_ctrl = ret;
162
163 ret = mcu_gpiochip_add(mcu);
164 if (ret)
165 goto err;
166
167
168 if (!pm_power_off) {
169 glob_mcu = mcu;
170 pm_power_off = mcu_power_off;
171 dev_info(&client->dev, "will provide power-off service\n");
172 }
173
174 if (device_create_file(&client->dev, &dev_attr_status))
175 dev_err(&client->dev,
176 "couldn't create device file for status\n");
177
178 shutdown_thread = kthread_run(shutdown_thread_fn, NULL,
179 "mcu-i2c-shdn");
180
181 return 0;
182err:
183 kfree(mcu);
184 return ret;
185}
186
187static int mcu_remove(struct i2c_client *client)
188{
189 struct mcu *mcu = i2c_get_clientdata(client);
190 int ret;
191
192 kthread_stop(shutdown_thread);
193
194 device_remove_file(&client->dev, &dev_attr_status);
195
196 if (glob_mcu == mcu) {
197 pm_power_off = NULL;
198 glob_mcu = NULL;
199 }
200
201 ret = mcu_gpiochip_remove(mcu);
202 if (ret)
203 return ret;
204 kfree(mcu);
205 return 0;
206}
207
208static const struct i2c_device_id mcu_ids[] = {
209 { "mcu-mpc8349emitx", },
210 {},
211};
212MODULE_DEVICE_TABLE(i2c, mcu_ids);
213
214static const struct of_device_id mcu_of_match_table[] = {
215 { .compatible = "fsl,mcu-mpc8349emitx", },
216 { },
217};
218
219static struct i2c_driver mcu_driver = {
220 .driver = {
221 .name = "mcu-mpc8349emitx",
222 .of_match_table = mcu_of_match_table,
223 },
224 .probe_new = mcu_probe,
225 .remove = mcu_remove,
226 .id_table = mcu_ids,
227};
228
229module_i2c_driver(mcu_driver);
230
231MODULE_DESCRIPTION("Power Management and GPIO expander driver for "
232 "MPC8349E-mITX-compatible MCU");
233MODULE_AUTHOR("Anton Vorontsov <avorontsov@ru.mvista.com>");
234MODULE_LICENSE("GPL");
235
