Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6
[linux-2.6] / 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
52 /* LED select registers determine the source that drives LED outputs */
53 #define PCA955X_LS_LED_ON       0x0     /* Output LOW */
54 #define PCA955X_LS_LED_OFF      0x1     /* Output HI-Z */
55 #define PCA955X_LS_BLINK0       0x2     /* Blink at PWM0 rate */
56 #define PCA955X_LS_BLINK1       0x3     /* Blink at PWM1 rate */
57
58 enum pca955x_type {
59         pca9550,
60         pca9551,
61         pca9552,
62         pca9553,
63 };
64
65 struct pca955x_chipdef {
66         int                     bits;
67         u8                      slv_addr;       /* 7-bit slave address mask */
68         int                     slv_addr_shift; /* Number of bits to ignore */
69 };
70
71 static struct pca955x_chipdef pca955x_chipdefs[] = {
72         [pca9550] = {
73                 .bits           = 2,
74                 .slv_addr       = /* 110000x */ 0x60,
75                 .slv_addr_shift = 1,
76         },
77         [pca9551] = {
78                 .bits           = 8,
79                 .slv_addr       = /* 1100xxx */ 0x60,
80                 .slv_addr_shift = 3,
81         },
82         [pca9552] = {
83                 .bits           = 16,
84                 .slv_addr       = /* 1100xxx */ 0x60,
85                 .slv_addr_shift = 3,
86         },
87         [pca9553] = {
88                 .bits           = 4,
89                 .slv_addr       = /* 110001x */ 0x62,
90                 .slv_addr_shift = 1,
91         },
92 };
93
94 static const struct i2c_device_id pca955x_id[] = {
95         { "pca9550", pca9550 },
96         { "pca9551", pca9551 },
97         { "pca9552", pca9552 },
98         { "pca9553", pca9553 },
99         { }
100 };
101 MODULE_DEVICE_TABLE(i2c, pca955x_id);
102
103 struct pca955x_led {
104         struct pca955x_chipdef  *chipdef;
105         struct i2c_client       *client;
106         struct work_struct      work;
107         spinlock_t              lock;
108         enum led_brightness     brightness;
109         struct led_classdev     led_cdev;
110         int                     led_num;        /* 0 .. 15 potentially */
111         char                    name[32];
112 };
113
114 /* 8 bits per input register */
115 static inline int pca95xx_num_input_regs(int bits)
116 {
117         return (bits + 7) / 8;
118 }
119
120 /* 4 bits per LED selector register */
121 static inline int pca95xx_num_led_regs(int bits)
122 {
123         return (bits + 3)  / 4;
124 }
125
126 /*
127  * Return an LED selector register value based on an existing one, with
128  * the appropriate 2-bit state value set for the given LED number (0-3).
129  */
130 static inline u8 pca955x_ledsel(u8 oldval, int led_num, int state)
131 {
132         return (oldval & (~(0x3 << (led_num << 1)))) |
133                 ((state & 0x3) << (led_num << 1));
134 }
135
136 /*
137  * Write to frequency prescaler register, used to program the
138  * period of the PWM output.  period = (PSCx + 1) / 38
139  */
140 static void pca955x_write_psc(struct i2c_client *client, int n, u8 val)
141 {
142         struct pca955x_led *pca955x = i2c_get_clientdata(client);
143
144         i2c_smbus_write_byte_data(client,
145                 pca95xx_num_input_regs(pca955x->chipdef->bits) + 2*n,
146                 val);
147 }
148
149 /*
150  * Write to PWM register, which determines the duty cycle of the
151  * output.  LED is OFF when the count is less than the value of this
152  * register, and ON when it is greater.  If PWMx == 0, LED is always OFF.
153  *
154  * Duty cycle is (256 - PWMx) / 256
155  */
156 static void pca955x_write_pwm(struct i2c_client *client, int n, u8 val)
157 {
158         struct pca955x_led *pca955x = i2c_get_clientdata(client);
159
160         i2c_smbus_write_byte_data(client,
161                 pca95xx_num_input_regs(pca955x->chipdef->bits) + 1 + 2*n,
162                 val);
163 }
164
165 /*
166  * Write to LED selector register, which determines the source that
167  * drives the LED output.
168  */
169 static void pca955x_write_ls(struct i2c_client *client, int n, u8 val)
170 {
171         struct pca955x_led *pca955x = i2c_get_clientdata(client);
172
173         i2c_smbus_write_byte_data(client,
174                 pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n,
175                 val);
176 }
177
178 /*
179  * Read the LED selector register, which determines the source that
180  * drives the LED output.
181  */
182 static u8 pca955x_read_ls(struct i2c_client *client, int n)
183 {
184         struct pca955x_led *pca955x = i2c_get_clientdata(client);
185
186         return (u8) i2c_smbus_read_byte_data(client,
187                 pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n);
188 }
189
190 static void pca955x_led_work(struct work_struct *work)
191 {
192         struct pca955x_led *pca955x;
193         u8 ls;
194         int chip_ls;    /* which LSx to use (0-3 potentially) */
195         int ls_led;     /* which set of bits within LSx to use (0-3) */
196
197         pca955x = container_of(work, struct pca955x_led, work);
198         chip_ls = pca955x->led_num / 4;
199         ls_led = pca955x->led_num % 4;
200
201         ls = pca955x_read_ls(pca955x->client, chip_ls);
202
203         switch (pca955x->brightness) {
204         case LED_FULL:
205                 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_ON);
206                 break;
207         case LED_OFF:
208                 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_OFF);
209                 break;
210         case LED_HALF:
211                 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK0);
212                 break;
213         default:
214                 /*
215                  * Use PWM1 for all other values.  This has the unwanted
216                  * side effect of making all LEDs on the chip share the
217                  * same brightness level if set to a value other than
218                  * OFF, HALF, or FULL.  But, this is probably better than
219                  * just turning off for all other values.
220                  */
221                 pca955x_write_pwm(pca955x->client, 1, 255-pca955x->brightness);
222                 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK1);
223                 break;
224         }
225
226         pca955x_write_ls(pca955x->client, chip_ls, ls);
227 }
228
229 void pca955x_led_set(struct led_classdev *led_cdev, enum led_brightness value)
230 {
231         struct pca955x_led *pca955x;
232
233         pca955x = container_of(led_cdev, struct pca955x_led, led_cdev);
234
235         spin_lock(&pca955x->lock);
236         pca955x->brightness = value;
237
238         /*
239          * Must use workqueue for the actual I/O since I2C operations
240          * can sleep.
241          */
242         schedule_work(&pca955x->work);
243
244         spin_unlock(&pca955x->lock);
245 }
246
247 static int __devinit pca955x_probe(struct i2c_client *client,
248                                         const struct i2c_device_id *id)
249 {
250         struct pca955x_led *pca955x;
251         int i;
252         int err = -ENODEV;
253         struct pca955x_chipdef *chip;
254         struct i2c_adapter *adapter;
255         struct led_platform_data *pdata;
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         for (i = 0; i < chip->bits; i++) {
286                 pca955x = kzalloc(sizeof(struct pca955x_led), GFP_KERNEL);
287                 if (!pca955x) {
288                         err = -ENOMEM;
289                         goto exit;
290                 }
291
292                 pca955x->chipdef = chip;
293                 pca955x->client = client;
294                 pca955x->led_num = i;
295                 /* Platform data can specify LED names and default triggers */
296                 if (pdata) {
297                         if (pdata->leds[i].name)
298                                 snprintf(pca955x->name, 32, "pca955x:%s",
299                                                         pdata->leds[i].name);
300                         if (pdata->leds[i].default_trigger)
301                                 pca955x->led_cdev.default_trigger =
302                                         pdata->leds[i].default_trigger;
303                 } else {
304                         snprintf(pca955x->name, 32, "pca955x:%d", i);
305                 }
306                 spin_lock_init(&pca955x->lock);
307
308                 pca955x->led_cdev.name = pca955x->name;
309                 pca955x->led_cdev.brightness_set =
310                                 pca955x_led_set;
311
312                 /*
313                  * Client data is a pointer to the _first_ pca955x_led
314                  * struct
315                  */
316                 if (i == 0)
317                         i2c_set_clientdata(client, pca955x);
318
319                 INIT_WORK(&(pca955x->work), pca955x_led_work);
320
321                 led_classdev_register(&client->dev, &(pca955x->led_cdev));
322         }
323
324         /* Turn off LEDs */
325         for (i = 0; i < pca95xx_num_led_regs(chip->bits); i++)
326                 pca955x_write_ls(client, i, 0x55);
327
328         /* PWM0 is used for half brightness or 50% duty cycle */
329         pca955x_write_pwm(client, 0, 255-LED_HALF);
330
331         /* PWM1 is used for variable brightness, default to OFF */
332         pca955x_write_pwm(client, 1, 0);
333
334         /* Set to fast frequency so we do not see flashing */
335         pca955x_write_psc(client, 0, 0);
336         pca955x_write_psc(client, 1, 0);
337
338         return 0;
339 exit:
340         return err;
341 }
342
343 static int __devexit pca955x_remove(struct i2c_client *client)
344 {
345         struct pca955x_led *pca955x = i2c_get_clientdata(client);
346         int leds = pca955x->chipdef->bits;
347         int i;
348
349         for (i = 0; i < leds; i++) {
350                 led_classdev_unregister(&(pca955x->led_cdev));
351                 cancel_work_sync(&(pca955x->work));
352                 kfree(pca955x);
353                 pca955x = pca955x + 1;
354         }
355
356         return 0;
357 }
358
359 static struct i2c_driver pca955x_driver = {
360         .driver = {
361                 .name   = "leds-pca955x",
362                 .owner  = THIS_MODULE,
363         },
364         .probe  = pca955x_probe,
365         .remove = __devexit_p(pca955x_remove),
366         .id_table = pca955x_id,
367 };
368
369 static int __init pca955x_leds_init(void)
370 {
371         return i2c_add_driver(&pca955x_driver);
372 }
373
374 static void __exit pca955x_leds_exit(void)
375 {
376         i2c_del_driver(&pca955x_driver);
377 }
378
379 module_init(pca955x_leds_init);
380 module_exit(pca955x_leds_exit);
381
382 MODULE_AUTHOR("Nate Case <ncase@xes-inc.com>");
383 MODULE_DESCRIPTION("PCA955x LED driver");
384 MODULE_LICENSE("GPL v2");