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f46e9203 NC |
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> | |
5a0e3ad6 | 51 | #include <linux/slab.h> |
f46e9203 NC |
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 | ||
0adaf6e4 | 230 | static void pca955x_led_set(struct led_classdev *led_cdev, enum led_brightness value) |
f46e9203 NC |
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; | |
f46e9203 NC |
252 | struct pca955x_chipdef *chip; |
253 | struct i2c_adapter *adapter; | |
254 | struct led_platform_data *pdata; | |
95bf14bf | 255 | int i, err; |
f46e9203 NC |
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 | ||
95bf14bf SW |
285 | pca955x = kzalloc(sizeof(*pca955x) * chip->bits, GFP_KERNEL); |
286 | if (!pca955x) | |
287 | return -ENOMEM; | |
288 | ||
289 | i2c_set_clientdata(client, pca955x); | |
290 | ||
f46e9203 | 291 | for (i = 0; i < chip->bits; i++) { |
95bf14bf SW |
292 | pca955x[i].chipdef = chip; |
293 | pca955x[i].client = client; | |
294 | pca955x[i].led_num = i; | |
f46e9203 | 295 | |
f46e9203 NC |
296 | /* Platform data can specify LED names and default triggers */ |
297 | if (pdata) { | |
298 | if (pdata->leds[i].name) | |
95bf14bf SW |
299 | snprintf(pca955x[i].name, |
300 | sizeof(pca955x[i].name), "pca955x:%s", | |
301 | pdata->leds[i].name); | |
f46e9203 | 302 | if (pdata->leds[i].default_trigger) |
95bf14bf | 303 | pca955x[i].led_cdev.default_trigger = |
f46e9203 NC |
304 | pdata->leds[i].default_trigger; |
305 | } else { | |
95bf14bf SW |
306 | snprintf(pca955x[i].name, sizeof(pca955x[i].name), |
307 | "pca955x:%d", i); | |
f46e9203 | 308 | } |
f46e9203 | 309 | |
95bf14bf | 310 | spin_lock_init(&pca955x[i].lock); |
f46e9203 | 311 | |
95bf14bf SW |
312 | pca955x[i].led_cdev.name = pca955x[i].name; |
313 | pca955x[i].led_cdev.brightness_set = pca955x_led_set; | |
f46e9203 | 314 | |
95bf14bf | 315 | INIT_WORK(&pca955x[i].work, pca955x_led_work); |
f46e9203 | 316 | |
95bf14bf SW |
317 | err = led_classdev_register(&client->dev, &pca955x[i].led_cdev); |
318 | if (err < 0) | |
319 | goto exit; | |
f46e9203 NC |
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; | |
95bf14bf | 337 | |
f46e9203 | 338 | exit: |
95bf14bf SW |
339 | while (i--) { |
340 | led_classdev_unregister(&pca955x[i].led_cdev); | |
341 | cancel_work_sync(&pca955x[i].work); | |
342 | } | |
343 | ||
344 | kfree(pca955x); | |
95bf14bf | 345 | |
f46e9203 NC |
346 | return err; |
347 | } | |
348 | ||
349 | static int __devexit pca955x_remove(struct i2c_client *client) | |
350 | { | |
351 | struct pca955x_led *pca955x = i2c_get_clientdata(client); | |
f46e9203 NC |
352 | int i; |
353 | ||
95bf14bf SW |
354 | for (i = 0; i < pca955x->chipdef->bits; i++) { |
355 | led_classdev_unregister(&pca955x[i].led_cdev); | |
356 | cancel_work_sync(&pca955x[i].work); | |
f46e9203 NC |
357 | } |
358 | ||
95bf14bf | 359 | kfree(pca955x); |
95bf14bf | 360 | |
f46e9203 NC |
361 | return 0; |
362 | } | |
363 | ||
364 | static struct i2c_driver pca955x_driver = { | |
365 | .driver = { | |
366 | .name = "leds-pca955x", | |
367 | .owner = THIS_MODULE, | |
368 | }, | |
369 | .probe = pca955x_probe, | |
370 | .remove = __devexit_p(pca955x_remove), | |
371 | .id_table = pca955x_id, | |
372 | }; | |
373 | ||
374 | static int __init pca955x_leds_init(void) | |
375 | { | |
376 | return i2c_add_driver(&pca955x_driver); | |
377 | } | |
378 | ||
379 | static void __exit pca955x_leds_exit(void) | |
380 | { | |
381 | i2c_del_driver(&pca955x_driver); | |
382 | } | |
383 | ||
384 | module_init(pca955x_leds_init); | |
385 | module_exit(pca955x_leds_exit); | |
386 | ||
387 | MODULE_AUTHOR("Nate Case <ncase@xes-inc.com>"); | |
388 | MODULE_DESCRIPTION("PCA955x LED driver"); | |
389 | MODULE_LICENSE("GPL v2"); |