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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> | |
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 | ||
0adaf6e4 | 229 | static void pca955x_led_set(struct led_classdev *led_cdev, enum led_brightness value) |
f46e9203 NC |
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; | |
f46e9203 NC |
251 | struct pca955x_chipdef *chip; |
252 | struct i2c_adapter *adapter; | |
253 | struct led_platform_data *pdata; | |
95bf14bf | 254 | int i, err; |
f46e9203 NC |
255 | |
256 | chip = &pca955x_chipdefs[id->driver_data]; | |
257 | adapter = to_i2c_adapter(client->dev.parent); | |
258 | pdata = client->dev.platform_data; | |
259 | ||
260 | /* Make sure the slave address / chip type combo given is possible */ | |
261 | if ((client->addr & ~((1 << chip->slv_addr_shift) - 1)) != | |
262 | chip->slv_addr) { | |
263 | dev_err(&client->dev, "invalid slave address %02x\n", | |
264 | client->addr); | |
265 | return -ENODEV; | |
266 | } | |
267 | ||
268 | printk(KERN_INFO "leds-pca955x: Using %s %d-bit LED driver at " | |
269 | "slave address 0x%02x\n", | |
270 | id->name, chip->bits, client->addr); | |
271 | ||
272 | if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) | |
273 | return -EIO; | |
274 | ||
275 | if (pdata) { | |
276 | if (pdata->num_leds != chip->bits) { | |
277 | dev_err(&client->dev, "board info claims %d LEDs" | |
278 | " on a %d-bit chip\n", | |
279 | pdata->num_leds, chip->bits); | |
280 | return -ENODEV; | |
281 | } | |
282 | } | |
283 | ||
95bf14bf SW |
284 | pca955x = kzalloc(sizeof(*pca955x) * chip->bits, GFP_KERNEL); |
285 | if (!pca955x) | |
286 | return -ENOMEM; | |
287 | ||
288 | i2c_set_clientdata(client, pca955x); | |
289 | ||
f46e9203 | 290 | for (i = 0; i < chip->bits; i++) { |
95bf14bf SW |
291 | pca955x[i].chipdef = chip; |
292 | pca955x[i].client = client; | |
293 | pca955x[i].led_num = i; | |
f46e9203 | 294 | |
f46e9203 NC |
295 | /* Platform data can specify LED names and default triggers */ |
296 | if (pdata) { | |
297 | if (pdata->leds[i].name) | |
95bf14bf SW |
298 | snprintf(pca955x[i].name, |
299 | sizeof(pca955x[i].name), "pca955x:%s", | |
300 | pdata->leds[i].name); | |
f46e9203 | 301 | if (pdata->leds[i].default_trigger) |
95bf14bf | 302 | pca955x[i].led_cdev.default_trigger = |
f46e9203 NC |
303 | pdata->leds[i].default_trigger; |
304 | } else { | |
95bf14bf SW |
305 | snprintf(pca955x[i].name, sizeof(pca955x[i].name), |
306 | "pca955x:%d", i); | |
f46e9203 | 307 | } |
f46e9203 | 308 | |
95bf14bf | 309 | spin_lock_init(&pca955x[i].lock); |
f46e9203 | 310 | |
95bf14bf SW |
311 | pca955x[i].led_cdev.name = pca955x[i].name; |
312 | pca955x[i].led_cdev.brightness_set = pca955x_led_set; | |
f46e9203 | 313 | |
95bf14bf | 314 | INIT_WORK(&pca955x[i].work, pca955x_led_work); |
f46e9203 | 315 | |
95bf14bf SW |
316 | err = led_classdev_register(&client->dev, &pca955x[i].led_cdev); |
317 | if (err < 0) | |
318 | goto exit; | |
f46e9203 NC |
319 | } |
320 | ||
321 | /* Turn off LEDs */ | |
322 | for (i = 0; i < pca95xx_num_led_regs(chip->bits); i++) | |
323 | pca955x_write_ls(client, i, 0x55); | |
324 | ||
325 | /* PWM0 is used for half brightness or 50% duty cycle */ | |
326 | pca955x_write_pwm(client, 0, 255-LED_HALF); | |
327 | ||
328 | /* PWM1 is used for variable brightness, default to OFF */ | |
329 | pca955x_write_pwm(client, 1, 0); | |
330 | ||
331 | /* Set to fast frequency so we do not see flashing */ | |
332 | pca955x_write_psc(client, 0, 0); | |
333 | pca955x_write_psc(client, 1, 0); | |
334 | ||
335 | return 0; | |
95bf14bf | 336 | |
f46e9203 | 337 | exit: |
95bf14bf SW |
338 | while (i--) { |
339 | led_classdev_unregister(&pca955x[i].led_cdev); | |
340 | cancel_work_sync(&pca955x[i].work); | |
341 | } | |
342 | ||
343 | kfree(pca955x); | |
344 | i2c_set_clientdata(client, NULL); | |
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 SW |
359 | kfree(pca955x); |
360 | i2c_set_clientdata(client, NULL); | |
361 | ||
f46e9203 NC |
362 | return 0; |
363 | } | |
364 | ||
365 | static struct i2c_driver pca955x_driver = { | |
366 | .driver = { | |
367 | .name = "leds-pca955x", | |
368 | .owner = THIS_MODULE, | |
369 | }, | |
370 | .probe = pca955x_probe, | |
371 | .remove = __devexit_p(pca955x_remove), | |
372 | .id_table = pca955x_id, | |
373 | }; | |
374 | ||
375 | static int __init pca955x_leds_init(void) | |
376 | { | |
377 | return i2c_add_driver(&pca955x_driver); | |
378 | } | |
379 | ||
380 | static void __exit pca955x_leds_exit(void) | |
381 | { | |
382 | i2c_del_driver(&pca955x_driver); | |
383 | } | |
384 | ||
385 | module_init(pca955x_leds_init); | |
386 | module_exit(pca955x_leds_exit); | |
387 | ||
388 | MODULE_AUTHOR("Nate Case <ncase@xes-inc.com>"); | |
389 | MODULE_DESCRIPTION("PCA955x LED driver"); | |
390 | MODULE_LICENSE("GPL v2"); |