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23#include <linux/kernel.h>
24#include <linux/module.h>
25#include <linux/device.h>
26#include <linux/interrupt.h>
27#include <linux/workqueue.h>
28#include <linux/i2c.h>
29#include <linux/i2c-smbus.h>
30#include <linux/slab.h>
31
32struct i2c_smbus_alert {
33 unsigned int alert_edge_triggered:1;
34 int irq;
35 struct work_struct alert;
36 struct i2c_client *ara;
37};
38
39struct alert_data {
40 unsigned short addr;
41 u8 flag:1;
42};
43
44
45static int smbus_do_alert(struct device *dev, void *addrp)
46{
47 struct i2c_client *client = i2c_verify_client(dev);
48 struct alert_data *data = addrp;
49 struct i2c_driver *driver;
50
51 if (!client || client->addr != data->addr)
52 return 0;
53 if (client->flags & I2C_CLIENT_TEN)
54 return 0;
55
56
57
58
59
60 device_lock(dev);
61 if (client->dev.driver) {
62 driver = to_i2c_driver(client->dev.driver);
63 if (driver->alert)
64 driver->alert(client, data->flag);
65 else
66 dev_warn(&client->dev, "no driver alert()!\n");
67 } else
68 dev_dbg(&client->dev, "alert with no driver\n");
69 device_unlock(dev);
70
71
72 return -EBUSY;
73}
74
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78
79static void smbus_alert(struct work_struct *work)
80{
81 struct i2c_smbus_alert *alert;
82 struct i2c_client *ara;
83 unsigned short prev_addr = 0;
84
85 alert = container_of(work, struct i2c_smbus_alert, alert);
86 ara = alert->ara;
87
88 for (;;) {
89 s32 status;
90 struct alert_data data;
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100 status = i2c_smbus_read_byte(ara);
101 if (status < 0)
102 break;
103
104 data.flag = status & 1;
105 data.addr = status >> 1;
106
107 if (data.addr == prev_addr) {
108 dev_warn(&ara->dev, "Duplicate SMBALERT# from dev "
109 "0x%02x, skipping\n", data.addr);
110 break;
111 }
112 dev_dbg(&ara->dev, "SMBALERT# from dev 0x%02x, flag %d\n",
113 data.addr, data.flag);
114
115
116 device_for_each_child(&ara->adapter->dev, &data,
117 smbus_do_alert);
118 prev_addr = data.addr;
119 }
120
121
122 if (!alert->alert_edge_triggered)
123 enable_irq(alert->irq);
124}
125
126static irqreturn_t smbalert_irq(int irq, void *d)
127{
128 struct i2c_smbus_alert *alert = d;
129
130
131 if (!alert->alert_edge_triggered)
132 disable_irq_nosync(irq);
133
134 schedule_work(&alert->alert);
135 return IRQ_HANDLED;
136}
137
138
139static int smbalert_probe(struct i2c_client *ara,
140 const struct i2c_device_id *id)
141{
142 struct i2c_smbus_alert_setup *setup = dev_get_platdata(&ara->dev);
143 struct i2c_smbus_alert *alert;
144 struct i2c_adapter *adapter = ara->adapter;
145 int res;
146
147 alert = devm_kzalloc(&ara->dev, sizeof(struct i2c_smbus_alert),
148 GFP_KERNEL);
149 if (!alert)
150 return -ENOMEM;
151
152 alert->alert_edge_triggered = setup->alert_edge_triggered;
153 alert->irq = setup->irq;
154 INIT_WORK(&alert->alert, smbus_alert);
155 alert->ara = ara;
156
157 if (setup->irq > 0) {
158 res = devm_request_irq(&ara->dev, setup->irq, smbalert_irq,
159 0, "smbus_alert", alert);
160 if (res)
161 return res;
162 }
163
164 i2c_set_clientdata(ara, alert);
165 dev_info(&adapter->dev, "supports SMBALERT#, %s trigger\n",
166 setup->alert_edge_triggered ? "edge" : "level");
167
168 return 0;
169}
170
171
172static int smbalert_remove(struct i2c_client *ara)
173{
174 struct i2c_smbus_alert *alert = i2c_get_clientdata(ara);
175
176 cancel_work_sync(&alert->alert);
177 return 0;
178}
179
180static const struct i2c_device_id smbalert_ids[] = {
181 { "smbus_alert", 0 },
182 { }
183};
184MODULE_DEVICE_TABLE(i2c, smbalert_ids);
185
186static struct i2c_driver smbalert_driver = {
187 .driver = {
188 .name = "smbus_alert",
189 },
190 .probe = smbalert_probe,
191 .remove = smbalert_remove,
192 .id_table = smbalert_ids,
193};
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215struct i2c_client *i2c_setup_smbus_alert(struct i2c_adapter *adapter,
216 struct i2c_smbus_alert_setup *setup)
217{
218 struct i2c_board_info ara_board_info = {
219 I2C_BOARD_INFO("smbus_alert", 0x0c),
220 .platform_data = setup,
221 };
222
223 return i2c_new_device(adapter, &ara_board_info);
224}
225EXPORT_SYMBOL_GPL(i2c_setup_smbus_alert);
226
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238
239int i2c_handle_smbus_alert(struct i2c_client *ara)
240{
241 struct i2c_smbus_alert *alert = i2c_get_clientdata(ara);
242
243 return schedule_work(&alert->alert);
244}
245EXPORT_SYMBOL_GPL(i2c_handle_smbus_alert);
246
247module_i2c_driver(smbalert_driver);
248
249MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
250MODULE_DESCRIPTION("SMBus protocol extensions support");
251MODULE_LICENSE("GPL");
252