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b91c4be7 BW |
1 | /* |
2 | * Driver for a keypad w/16 buttons connected to a PCF8574 I2C I/O expander | |
3 | * | |
4 | * Copyright 2005-2008 Analog Devices Inc. | |
5 | * | |
6 | * Licensed under the GPL-2 or later. | |
7 | */ | |
8 | ||
9 | #include <linux/module.h> | |
10 | #include <linux/init.h> | |
11 | #include <linux/input.h> | |
12 | #include <linux/interrupt.h> | |
13 | #include <linux/i2c.h> | |
14 | #include <linux/slab.h> | |
15 | #include <linux/workqueue.h> | |
16 | ||
17 | #define DRV_NAME "pcf8574_keypad" | |
18 | ||
19 | static const unsigned char pcf8574_kp_btncode[] = { | |
20 | [0] = KEY_RESERVED, | |
21 | [1] = KEY_ENTER, | |
22 | [2] = KEY_BACKSLASH, | |
23 | [3] = KEY_0, | |
24 | [4] = KEY_RIGHTBRACE, | |
25 | [5] = KEY_C, | |
26 | [6] = KEY_9, | |
27 | [7] = KEY_8, | |
28 | [8] = KEY_7, | |
29 | [9] = KEY_B, | |
30 | [10] = KEY_6, | |
31 | [11] = KEY_5, | |
32 | [12] = KEY_4, | |
33 | [13] = KEY_A, | |
34 | [14] = KEY_3, | |
35 | [15] = KEY_2, | |
36 | [16] = KEY_1 | |
37 | }; | |
38 | ||
39 | struct kp_data { | |
40 | unsigned short btncode[ARRAY_SIZE(pcf8574_kp_btncode)]; | |
41 | struct input_dev *idev; | |
42 | struct i2c_client *client; | |
43 | char name[64]; | |
44 | char phys[32]; | |
45 | unsigned char laststate; | |
46 | }; | |
47 | ||
48 | static short read_state(struct kp_data *lp) | |
49 | { | |
50 | unsigned char x, y, a, b; | |
51 | ||
52 | i2c_smbus_write_byte(lp->client, 240); | |
53 | x = 0xF & (~(i2c_smbus_read_byte(lp->client) >> 4)); | |
54 | ||
55 | i2c_smbus_write_byte(lp->client, 15); | |
56 | y = 0xF & (~i2c_smbus_read_byte(lp->client)); | |
57 | ||
58 | for (a = 0; x > 0; a++) | |
59 | x = x >> 1; | |
60 | for (b = 0; y > 0; b++) | |
61 | y = y >> 1; | |
62 | ||
63 | return ((a - 1) * 4) + b; | |
64 | } | |
65 | ||
66 | static irqreturn_t pcf8574_kp_irq_handler(int irq, void *dev_id) | |
67 | { | |
68 | struct kp_data *lp = dev_id; | |
69 | unsigned char nextstate = read_state(lp); | |
70 | ||
71 | if (lp->laststate != nextstate) { | |
0b75f775 | 72 | int key_down = nextstate < ARRAY_SIZE(lp->btncode); |
b91c4be7 BW |
73 | unsigned short keycode = key_down ? |
74 | lp->btncode[nextstate] : lp->btncode[lp->laststate]; | |
75 | ||
76 | input_report_key(lp->idev, keycode, key_down); | |
77 | input_sync(lp->idev); | |
78 | ||
79 | lp->laststate = nextstate; | |
80 | } | |
81 | ||
82 | return IRQ_HANDLED; | |
83 | } | |
84 | ||
85 | static int __devinit pcf8574_kp_probe(struct i2c_client *client, const struct i2c_device_id *id) | |
86 | { | |
87 | int i, ret; | |
88 | struct input_dev *idev; | |
89 | struct kp_data *lp; | |
90 | ||
91 | if (i2c_smbus_write_byte(client, 240) < 0) { | |
92 | dev_err(&client->dev, "probe: write fail\n"); | |
93 | return -ENODEV; | |
94 | } | |
95 | ||
96 | lp = kzalloc(sizeof(*lp), GFP_KERNEL); | |
97 | if (!lp) | |
98 | return -ENOMEM; | |
99 | ||
100 | idev = input_allocate_device(); | |
101 | if (!idev) { | |
102 | dev_err(&client->dev, "Can't allocate input device\n"); | |
103 | ret = -ENOMEM; | |
104 | goto fail_allocate; | |
105 | } | |
106 | ||
107 | lp->idev = idev; | |
108 | lp->client = client; | |
109 | ||
110 | idev->evbit[0] = BIT_MASK(EV_KEY); | |
111 | idev->keycode = lp->btncode; | |
112 | idev->keycodesize = sizeof(lp->btncode[0]); | |
113 | idev->keycodemax = ARRAY_SIZE(lp->btncode); | |
114 | ||
115 | for (i = 0; i < ARRAY_SIZE(pcf8574_kp_btncode); i++) { | |
116 | lp->btncode[i] = pcf8574_kp_btncode[i]; | |
117 | __set_bit(lp->btncode[i] & KEY_MAX, idev->keybit); | |
118 | } | |
119 | ||
120 | sprintf(lp->name, DRV_NAME); | |
121 | sprintf(lp->phys, "kp_data/input0"); | |
122 | ||
123 | idev->name = lp->name; | |
124 | idev->phys = lp->phys; | |
125 | idev->id.bustype = BUS_I2C; | |
126 | idev->id.vendor = 0x0001; | |
127 | idev->id.product = 0x0001; | |
128 | idev->id.version = 0x0100; | |
129 | ||
b91c4be7 BW |
130 | lp->laststate = read_state(lp); |
131 | ||
132 | ret = request_threaded_irq(client->irq, NULL, pcf8574_kp_irq_handler, | |
133 | IRQF_TRIGGER_LOW | IRQF_ONESHOT, | |
134 | DRV_NAME, lp); | |
135 | if (ret) { | |
136 | dev_err(&client->dev, "IRQ %d is not free\n", client->irq); | |
17d01f28 DC |
137 | goto fail_free_device; |
138 | } | |
139 | ||
140 | ret = input_register_device(idev); | |
141 | if (ret) { | |
142 | dev_err(&client->dev, "input_register_device() failed\n"); | |
143 | goto fail_free_irq; | |
b91c4be7 BW |
144 | } |
145 | ||
146 | i2c_set_clientdata(client, lp); | |
147 | return 0; | |
148 | ||
17d01f28 DC |
149 | fail_free_irq: |
150 | free_irq(client->irq, lp); | |
151 | fail_free_device: | |
b91c4be7 BW |
152 | input_free_device(idev); |
153 | fail_allocate: | |
154 | kfree(lp); | |
155 | ||
156 | return ret; | |
157 | } | |
158 | ||
159 | static int __devexit pcf8574_kp_remove(struct i2c_client *client) | |
160 | { | |
161 | struct kp_data *lp = i2c_get_clientdata(client); | |
162 | ||
163 | free_irq(client->irq, lp); | |
164 | ||
165 | input_unregister_device(lp->idev); | |
166 | kfree(lp); | |
167 | ||
b91c4be7 BW |
168 | return 0; |
169 | } | |
170 | ||
171 | #ifdef CONFIG_PM | |
172 | static int pcf8574_kp_resume(struct i2c_client *client) | |
173 | { | |
174 | enable_irq(client->irq); | |
175 | ||
176 | return 0; | |
177 | } | |
178 | ||
179 | static int pcf8574_kp_suspend(struct i2c_client *client, pm_message_t mesg) | |
180 | { | |
181 | disable_irq(client->irq); | |
182 | ||
183 | return 0; | |
184 | } | |
185 | #else | |
186 | # define pcf8574_kp_resume NULL | |
187 | # define pcf8574_kp_suspend NULL | |
188 | #endif | |
189 | ||
190 | static const struct i2c_device_id pcf8574_kp_id[] = { | |
191 | { DRV_NAME, 0 }, | |
192 | { } | |
193 | }; | |
194 | MODULE_DEVICE_TABLE(i2c, pcf8574_kp_id); | |
195 | ||
196 | static struct i2c_driver pcf8574_kp_driver = { | |
197 | .driver = { | |
198 | .name = DRV_NAME, | |
199 | .owner = THIS_MODULE, | |
200 | }, | |
201 | .probe = pcf8574_kp_probe, | |
202 | .remove = __devexit_p(pcf8574_kp_remove), | |
203 | .suspend = pcf8574_kp_suspend, | |
204 | .resume = pcf8574_kp_resume, | |
205 | .id_table = pcf8574_kp_id, | |
206 | }; | |
207 | ||
208 | static int __init pcf8574_kp_init(void) | |
209 | { | |
210 | return i2c_add_driver(&pcf8574_kp_driver); | |
211 | } | |
212 | module_init(pcf8574_kp_init); | |
213 | ||
214 | static void __exit pcf8574_kp_exit(void) | |
215 | { | |
216 | i2c_del_driver(&pcf8574_kp_driver); | |
217 | } | |
218 | module_exit(pcf8574_kp_exit); | |
219 | ||
220 | MODULE_AUTHOR("Michael Hennerich"); | |
221 | MODULE_DESCRIPTION("Keypad input driver for 16 keys connected to PCF8574"); | |
222 | MODULE_LICENSE("GPL"); |