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14#include <linux/kernel.h>
15#include <linux/module.h>
16#include <linux/device.h>
17#include <linux/mutex.h>
18#include <linux/i2c.h>
19#include <linux/gpio/driver.h>
20#include <linux/of.h>
21#include <linux/of_gpio.h>
22#include <linux/slab.h>
23#include <linux/kthread.h>
24#include <linux/reboot.h>
25#include <asm/prom.h>
26#include <asm/machdep.h>
27
28
29
30
31
32#define MCU_REG_CTRL 0x20
33#define MCU_CTRL_POFF 0x40
34#define MCU_CTRL_BTN 0x80
35
36#define MCU_NUM_GPIO 2
37
38struct mcu {
39 struct mutex lock;
40 struct i2c_client *client;
41 struct gpio_chip gc;
42 u8 reg_ctrl;
43};
44
45static struct mcu *glob_mcu;
46
47struct task_struct *shutdown_thread;
48static int shutdown_thread_fn(void *data)
49{
50 int ret;
51 struct mcu *mcu = glob_mcu;
52
53 while (!kthread_should_stop()) {
54 ret = i2c_smbus_read_byte_data(mcu->client, MCU_REG_CTRL);
55 if (ret < 0)
56 pr_err("MCU status reg read failed.\n");
57 mcu->reg_ctrl = ret;
58
59
60 if (mcu->reg_ctrl & MCU_CTRL_BTN) {
61 i2c_smbus_write_byte_data(mcu->client, MCU_REG_CTRL,
62 mcu->reg_ctrl & ~MCU_CTRL_BTN);
63
64 ctrl_alt_del();
65 }
66
67 set_current_state(TASK_INTERRUPTIBLE);
68 schedule_timeout(HZ);
69 }
70
71 return 0;
72}
73
74static ssize_t show_status(struct device *d,
75 struct device_attribute *attr, char *buf)
76{
77 int ret;
78 struct mcu *mcu = glob_mcu;
79
80 ret = i2c_smbus_read_byte_data(mcu->client, MCU_REG_CTRL);
81 if (ret < 0)
82 return -ENODEV;
83 mcu->reg_ctrl = ret;
84
85 return sprintf(buf, "%02x\n", ret);
86}
87static DEVICE_ATTR(status, S_IRUGO, show_status, NULL);
88
89static void mcu_power_off(void)
90{
91 struct mcu *mcu = glob_mcu;
92
93 pr_info("Sending power-off request to the MCU...\n");
94 mutex_lock(&mcu->lock);
95 i2c_smbus_write_byte_data(mcu->client, MCU_REG_CTRL,
96 mcu->reg_ctrl | MCU_CTRL_POFF);
97 mutex_unlock(&mcu->lock);
98}
99
100static void mcu_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
101{
102 struct mcu *mcu = gpiochip_get_data(gc);
103 u8 bit = 1 << (4 + gpio);
104
105 mutex_lock(&mcu->lock);
106 if (val)
107 mcu->reg_ctrl &= ~bit;
108 else
109 mcu->reg_ctrl |= bit;
110
111 i2c_smbus_write_byte_data(mcu->client, MCU_REG_CTRL, mcu->reg_ctrl);
112 mutex_unlock(&mcu->lock);
113}
114
115static int mcu_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
116{
117 mcu_gpio_set(gc, gpio, val);
118 return 0;
119}
120
121static int mcu_gpiochip_add(struct mcu *mcu)
122{
123 struct device_node *np;
124 struct gpio_chip *gc = &mcu->gc;
125
126 np = of_find_compatible_node(NULL, NULL, "fsl,mcu-mpc8349emitx");
127 if (!np)
128 return -ENODEV;
129
130 gc->owner = THIS_MODULE;
131 gc->label = np->full_name;
132 gc->can_sleep = 1;
133 gc->ngpio = MCU_NUM_GPIO;
134 gc->base = -1;
135 gc->set = mcu_gpio_set;
136 gc->direction_output = mcu_gpio_dir_out;
137 gc->of_node = np;
138
139 return gpiochip_add_data(gc, mcu);
140}
141
142static int mcu_gpiochip_remove(struct mcu *mcu)
143{
144 gpiochip_remove(&mcu->gc);
145 return 0;
146}
147
148static int mcu_probe(struct i2c_client *client, const struct i2c_device_id *id)
149{
150 struct mcu *mcu;
151 int ret;
152
153 mcu = kzalloc(sizeof(*mcu), GFP_KERNEL);
154 if (!mcu)
155 return -ENOMEM;
156
157 mutex_init(&mcu->lock);
158 mcu->client = client;
159 i2c_set_clientdata(client, mcu);
160
161 ret = i2c_smbus_read_byte_data(mcu->client, MCU_REG_CTRL);
162 if (ret < 0)
163 goto err;
164 mcu->reg_ctrl = ret;
165
166 ret = mcu_gpiochip_add(mcu);
167 if (ret)
168 goto err;
169
170
171 if (!pm_power_off) {
172 glob_mcu = mcu;
173 pm_power_off = mcu_power_off;
174 dev_info(&client->dev, "will provide power-off service\n");
175 }
176
177 if (device_create_file(&client->dev, &dev_attr_status))
178 dev_err(&client->dev,
179 "couldn't create device file for status\n");
180
181 shutdown_thread = kthread_run(shutdown_thread_fn, NULL,
182 "mcu-i2c-shdn");
183
184 return 0;
185err:
186 kfree(mcu);
187 return ret;
188}
189
190static int mcu_remove(struct i2c_client *client)
191{
192 struct mcu *mcu = i2c_get_clientdata(client);
193 int ret;
194
195 kthread_stop(shutdown_thread);
196
197 device_remove_file(&client->dev, &dev_attr_status);
198
199 if (glob_mcu == mcu) {
200 pm_power_off = NULL;
201 glob_mcu = NULL;
202 }
203
204 ret = mcu_gpiochip_remove(mcu);
205 if (ret)
206 return ret;
207 kfree(mcu);
208 return 0;
209}
210
211static const struct i2c_device_id mcu_ids[] = {
212 { "mcu-mpc8349emitx", },
213 {},
214};
215MODULE_DEVICE_TABLE(i2c, mcu_ids);
216
217static const struct of_device_id mcu_of_match_table[] = {
218 { .compatible = "fsl,mcu-mpc8349emitx", },
219 { },
220};
221
222static struct i2c_driver mcu_driver = {
223 .driver = {
224 .name = "mcu-mpc8349emitx",
225 .owner = THIS_MODULE,
226 .of_match_table = mcu_of_match_table,
227 },
228 .probe = mcu_probe,
229 .remove = mcu_remove,
230 .id_table = mcu_ids,
231};
232
233module_i2c_driver(mcu_driver);
234
235MODULE_DESCRIPTION("Power Management and GPIO expander driver for "
236 "MPC8349E-mITX-compatible MCU");
237MODULE_AUTHOR("Anton Vorontsov <avorontsov@ru.mvista.com>");
238MODULE_LICENSE("GPL");
239
