include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit...
[linux-2.6.git] / drivers / leds / leds-pca955x.c
1 /*
2  * Copyright 2007-2008 Extreme Engineering Solutions, Inc.
3  *
4  * Author: Nate Case <ncase@xes-inc.com>
5  *
6  * This file is subject to the terms and conditions of version 2 of
7  * the GNU General Public License.  See the file COPYING in the main
8  * directory of this archive for more details.
9  *
10  * LED driver for various PCA955x I2C LED drivers
11  *
12  * Supported devices:
13  *
14  *      Device          Description             7-bit slave address
15  *      ------          -----------             -------------------
16  *      PCA9550         2-bit driver            0x60 .. 0x61
17  *      PCA9551         8-bit driver            0x60 .. 0x67
18  *      PCA9552         16-bit driver           0x60 .. 0x67
19  *      PCA9553/01      4-bit driver            0x62
20  *      PCA9553/02      4-bit driver            0x63
21  *
22  * Philips PCA955x LED driver chips follow a register map as shown below:
23  *
24  *      Control Register                Description
25  *      ----------------                -----------
26  *      0x0                             Input register 0
27  *                                      ..
28  *      NUM_INPUT_REGS - 1              Last Input register X
29  *
30  *      NUM_INPUT_REGS                  Frequency prescaler 0
31  *      NUM_INPUT_REGS + 1              PWM register 0
32  *      NUM_INPUT_REGS + 2              Frequency prescaler 1
33  *      NUM_INPUT_REGS + 3              PWM register 1
34  *
35  *      NUM_INPUT_REGS + 4              LED selector 0
36  *      NUM_INPUT_REGS + 4
37  *          + NUM_LED_REGS - 1          Last LED selector
38  *
39  *  where NUM_INPUT_REGS and NUM_LED_REGS vary depending on how many
40  *  bits the chip supports.
41  */
42
43 #include <linux/module.h>
44 #include <linux/delay.h>
45 #include <linux/string.h>
46 #include <linux/ctype.h>
47 #include <linux/leds.h>
48 #include <linux/err.h>
49 #include <linux/i2c.h>
50 #include <linux/workqueue.h>
51 #include <linux/slab.h>
52
53 /* LED select registers determine the source that drives LED outputs */
54 #define PCA955X_LS_LED_ON       0x0     /* Output LOW */
55 #define PCA955X_LS_LED_OFF      0x1     /* Output HI-Z */
56 #define PCA955X_LS_BLINK0       0x2     /* Blink at PWM0 rate */
57 #define PCA955X_LS_BLINK1       0x3     /* Blink at PWM1 rate */
58
59 enum pca955x_type {
60         pca9550,
61         pca9551,
62         pca9552,
63         pca9553,
64 };
65
66 struct pca955x_chipdef {
67         int                     bits;
68         u8                      slv_addr;       /* 7-bit slave address mask */
69         int                     slv_addr_shift; /* Number of bits to ignore */
70 };
71
72 static struct pca955x_chipdef pca955x_chipdefs[] = {
73         [pca9550] = {
74                 .bits           = 2,
75                 .slv_addr       = /* 110000x */ 0x60,
76                 .slv_addr_shift = 1,
77         },
78         [pca9551] = {
79                 .bits           = 8,
80                 .slv_addr       = /* 1100xxx */ 0x60,
81                 .slv_addr_shift = 3,
82         },
83         [pca9552] = {
84                 .bits           = 16,
85                 .slv_addr       = /* 1100xxx */ 0x60,
86                 .slv_addr_shift = 3,
87         },
88         [pca9553] = {
89                 .bits           = 4,
90                 .slv_addr       = /* 110001x */ 0x62,
91                 .slv_addr_shift = 1,
92         },
93 };
94
95 static const struct i2c_device_id pca955x_id[] = {
96         { "pca9550", pca9550 },
97         { "pca9551", pca9551 },
98         { "pca9552", pca9552 },
99         { "pca9553", pca9553 },
100         { }
101 };
102 MODULE_DEVICE_TABLE(i2c, pca955x_id);
103
104 struct pca955x_led {
105         struct pca955x_chipdef  *chipdef;
106         struct i2c_client       *client;
107         struct work_struct      work;
108         spinlock_t              lock;
109         enum led_brightness     brightness;
110         struct led_classdev     led_cdev;
111         int                     led_num;        /* 0 .. 15 potentially */
112         char                    name[32];
113 };
114
115 /* 8 bits per input register */
116 static inline int pca95xx_num_input_regs(int bits)
117 {
118         return (bits + 7) / 8;
119 }
120
121 /* 4 bits per LED selector register */
122 static inline int pca95xx_num_led_regs(int bits)
123 {
124         return (bits + 3)  / 4;
125 }
126
127 /*
128  * Return an LED selector register value based on an existing one, with
129  * the appropriate 2-bit state value set for the given LED number (0-3).
130  */
131 static inline u8 pca955x_ledsel(u8 oldval, int led_num, int state)
132 {
133         return (oldval & (~(0x3 << (led_num << 1)))) |
134                 ((state & 0x3) << (led_num << 1));
135 }
136
137 /*
138  * Write to frequency prescaler register, used to program the
139  * period of the PWM output.  period = (PSCx + 1) / 38
140  */
141 static void pca955x_write_psc(struct i2c_client *client, int n, u8 val)
142 {
143         struct pca955x_led *pca955x = i2c_get_clientdata(client);
144
145         i2c_smbus_write_byte_data(client,
146                 pca95xx_num_input_regs(pca955x->chipdef->bits) + 2*n,
147                 val);
148 }
149
150 /*
151  * Write to PWM register, which determines the duty cycle of the
152  * output.  LED is OFF when the count is less than the value of this
153  * register, and ON when it is greater.  If PWMx == 0, LED is always OFF.
154  *
155  * Duty cycle is (256 - PWMx) / 256
156  */
157 static void pca955x_write_pwm(struct i2c_client *client, int n, u8 val)
158 {
159         struct pca955x_led *pca955x = i2c_get_clientdata(client);
160
161         i2c_smbus_write_byte_data(client,
162                 pca95xx_num_input_regs(pca955x->chipdef->bits) + 1 + 2*n,
163                 val);
164 }
165
166 /*
167  * Write to LED selector register, which determines the source that
168  * drives the LED output.
169  */
170 static void pca955x_write_ls(struct i2c_client *client, int n, u8 val)
171 {
172         struct pca955x_led *pca955x = i2c_get_clientdata(client);
173
174         i2c_smbus_write_byte_data(client,
175                 pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n,
176                 val);
177 }
178
179 /*
180  * Read the LED selector register, which determines the source that
181  * drives the LED output.
182  */
183 static u8 pca955x_read_ls(struct i2c_client *client, int n)
184 {
185         struct pca955x_led *pca955x = i2c_get_clientdata(client);
186
187         return (u8) i2c_smbus_read_byte_data(client,
188                 pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n);
189 }
190
191 static void pca955x_led_work(struct work_struct *work)
192 {
193         struct pca955x_led *pca955x;
194         u8 ls;
195         int chip_ls;    /* which LSx to use (0-3 potentially) */
196         int ls_led;     /* which set of bits within LSx to use (0-3) */
197
198         pca955x = container_of(work, struct pca955x_led, work);
199         chip_ls = pca955x->led_num / 4;
200         ls_led = pca955x->led_num % 4;
201
202         ls = pca955x_read_ls(pca955x->client, chip_ls);
203
204         switch (pca955x->brightness) {
205         case LED_FULL:
206                 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_ON);
207                 break;
208         case LED_OFF:
209                 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_OFF);
210                 break;
211         case LED_HALF:
212                 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK0);
213                 break;
214         default:
215                 /*
216                  * Use PWM1 for all other values.  This has the unwanted
217                  * side effect of making all LEDs on the chip share the
218                  * same brightness level if set to a value other than
219                  * OFF, HALF, or FULL.  But, this is probably better than
220                  * just turning off for all other values.
221                  */
222                 pca955x_write_pwm(pca955x->client, 1, 255-pca955x->brightness);
223                 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK1);
224                 break;
225         }
226
227         pca955x_write_ls(pca955x->client, chip_ls, ls);
228 }
229
230 static void pca955x_led_set(struct led_classdev *led_cdev, enum led_brightness value)
231 {
232         struct pca955x_led *pca955x;
233
234         pca955x = container_of(led_cdev, struct pca955x_led, led_cdev);
235
236         spin_lock(&pca955x->lock);
237         pca955x->brightness = value;
238
239         /*
240          * Must use workqueue for the actual I/O since I2C operations
241          * can sleep.
242          */
243         schedule_work(&pca955x->work);
244
245         spin_unlock(&pca955x->lock);
246 }
247
248 static int __devinit pca955x_probe(struct i2c_client *client,
249                                         const struct i2c_device_id *id)
250 {
251         struct pca955x_led *pca955x;
252         struct pca955x_chipdef *chip;
253         struct i2c_adapter *adapter;
254         struct led_platform_data *pdata;
255         int i, err;
256
257         chip = &pca955x_chipdefs[id->driver_data];
258         adapter = to_i2c_adapter(client->dev.parent);
259         pdata = client->dev.platform_data;
260
261         /* Make sure the slave address / chip type combo given is possible */
262         if ((client->addr & ~((1 << chip->slv_addr_shift) - 1)) !=
263             chip->slv_addr) {
264                 dev_err(&client->dev, "invalid slave address %02x\n",
265                                 client->addr);
266                 return -ENODEV;
267         }
268
269         printk(KERN_INFO "leds-pca955x: Using %s %d-bit LED driver at "
270                         "slave address 0x%02x\n",
271                         id->name, chip->bits, client->addr);
272
273         if (!i2c_check_functionality(adapter, I2C_FUNC_I2C))
274                 return -EIO;
275
276         if (pdata) {
277                 if (pdata->num_leds != chip->bits) {
278                         dev_err(&client->dev, "board info claims %d LEDs"
279                                         " on a %d-bit chip\n",
280                                         pdata->num_leds, chip->bits);
281                         return -ENODEV;
282                 }
283         }
284
285         pca955x = kzalloc(sizeof(*pca955x) * chip->bits, GFP_KERNEL);
286         if (!pca955x)
287                 return -ENOMEM;
288
289         i2c_set_clientdata(client, pca955x);
290
291         for (i = 0; i < chip->bits; i++) {
292                 pca955x[i].chipdef = chip;
293                 pca955x[i].client = client;
294                 pca955x[i].led_num = i;
295
296                 /* Platform data can specify LED names and default triggers */
297                 if (pdata) {
298                         if (pdata->leds[i].name)
299                                 snprintf(pca955x[i].name,
300                                          sizeof(pca955x[i].name), "pca955x:%s",
301                                          pdata->leds[i].name);
302                         if (pdata->leds[i].default_trigger)
303                                 pca955x[i].led_cdev.default_trigger =
304                                         pdata->leds[i].default_trigger;
305                 } else {
306                         snprintf(pca955x[i].name, sizeof(pca955x[i].name),
307                                  "pca955x:%d", i);
308                 }
309
310                 spin_lock_init(&pca955x[i].lock);
311
312                 pca955x[i].led_cdev.name = pca955x[i].name;
313                 pca955x[i].led_cdev.brightness_set = pca955x_led_set;
314
315                 INIT_WORK(&pca955x[i].work, pca955x_led_work);
316
317                 err = led_classdev_register(&client->dev, &pca955x[i].led_cdev);
318                 if (err < 0)
319                         goto exit;
320         }
321
322         /* Turn off LEDs */
323         for (i = 0; i < pca95xx_num_led_regs(chip->bits); i++)
324                 pca955x_write_ls(client, i, 0x55);
325
326         /* PWM0 is used for half brightness or 50% duty cycle */
327         pca955x_write_pwm(client, 0, 255-LED_HALF);
328
329         /* PWM1 is used for variable brightness, default to OFF */
330         pca955x_write_pwm(client, 1, 0);
331
332         /* Set to fast frequency so we do not see flashing */
333         pca955x_write_psc(client, 0, 0);
334         pca955x_write_psc(client, 1, 0);
335
336         return 0;
337
338 exit:
339         while (i--) {
340                 led_classdev_unregister(&pca955x[i].led_cdev);
341                 cancel_work_sync(&pca955x[i].work);
342         }
343
344         kfree(pca955x);
345         i2c_set_clientdata(client, NULL);
346
347         return err;
348 }
349
350 static int __devexit pca955x_remove(struct i2c_client *client)
351 {
352         struct pca955x_led *pca955x = i2c_get_clientdata(client);
353         int i;
354
355         for (i = 0; i < pca955x->chipdef->bits; i++) {
356                 led_classdev_unregister(&pca955x[i].led_cdev);
357                 cancel_work_sync(&pca955x[i].work);
358         }
359
360         kfree(pca955x);
361         i2c_set_clientdata(client, NULL);
362
363         return 0;
364 }
365
366 static struct i2c_driver pca955x_driver = {
367         .driver = {
368                 .name   = "leds-pca955x",
369                 .owner  = THIS_MODULE,
370         },
371         .probe  = pca955x_probe,
372         .remove = __devexit_p(pca955x_remove),
373         .id_table = pca955x_id,
374 };
375
376 static int __init pca955x_leds_init(void)
377 {
378         return i2c_add_driver(&pca955x_driver);
379 }
380
381 static void __exit pca955x_leds_exit(void)
382 {
383         i2c_del_driver(&pca955x_driver);
384 }
385
386 module_init(pca955x_leds_init);
387 module_exit(pca955x_leds_exit);
388
389 MODULE_AUTHOR("Nate Case <ncase@xes-inc.com>");
390 MODULE_DESCRIPTION("PCA955x LED driver");
391 MODULE_LICENSE("GPL v2");