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Nate Casef46e9202008-07-16 22:49:55 +01001/*
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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090051#include <linux/slab.h>
Nate Casef46e9202008-07-16 22:49:55 +010052
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
59enum pca955x_type {
60 pca9550,
61 pca9551,
62 pca9552,
63 pca9553,
64};
65
66struct 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
72static 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
95static const struct i2c_device_id pca955x_id[] = {
96 { "pca9550", pca9550 },
97 { "pca9551", pca9551 },
98 { "pca9552", pca9552 },
99 { "pca9553", pca9553 },
100 { }
101};
102MODULE_DEVICE_TABLE(i2c, pca955x_id);
103
Alexander Steine7e11d82012-05-29 15:07:30 -0700104struct pca955x {
105 struct mutex lock;
106 struct pca955x_led *leds;
Nate Casef46e9202008-07-16 22:49:55 +0100107 struct pca955x_chipdef *chipdef;
108 struct i2c_client *client;
Alexander Steine7e11d82012-05-29 15:07:30 -0700109};
110
111struct pca955x_led {
112 struct pca955x *pca955x;
Nate Casef46e9202008-07-16 22:49:55 +0100113 struct work_struct work;
Nate Casef46e9202008-07-16 22:49:55 +0100114 enum led_brightness brightness;
115 struct led_classdev led_cdev;
116 int led_num; /* 0 .. 15 potentially */
117 char name[32];
118};
119
120/* 8 bits per input register */
121static inline int pca95xx_num_input_regs(int bits)
122{
123 return (bits + 7) / 8;
124}
125
126/* 4 bits per LED selector register */
127static inline int pca95xx_num_led_regs(int bits)
128{
129 return (bits + 3) / 4;
130}
131
132/*
133 * Return an LED selector register value based on an existing one, with
134 * the appropriate 2-bit state value set for the given LED number (0-3).
135 */
136static inline u8 pca955x_ledsel(u8 oldval, int led_num, int state)
137{
138 return (oldval & (~(0x3 << (led_num << 1)))) |
139 ((state & 0x3) << (led_num << 1));
140}
141
142/*
143 * Write to frequency prescaler register, used to program the
144 * period of the PWM output. period = (PSCx + 1) / 38
145 */
146static void pca955x_write_psc(struct i2c_client *client, int n, u8 val)
147{
Alexander Steine7e11d82012-05-29 15:07:30 -0700148 struct pca955x *pca955x = i2c_get_clientdata(client);
Nate Casef46e9202008-07-16 22:49:55 +0100149
150 i2c_smbus_write_byte_data(client,
151 pca95xx_num_input_regs(pca955x->chipdef->bits) + 2*n,
152 val);
153}
154
155/*
156 * Write to PWM register, which determines the duty cycle of the
157 * output. LED is OFF when the count is less than the value of this
158 * register, and ON when it is greater. If PWMx == 0, LED is always OFF.
159 *
160 * Duty cycle is (256 - PWMx) / 256
161 */
162static void pca955x_write_pwm(struct i2c_client *client, int n, u8 val)
163{
Alexander Steine7e11d82012-05-29 15:07:30 -0700164 struct pca955x *pca955x = i2c_get_clientdata(client);
Nate Casef46e9202008-07-16 22:49:55 +0100165
166 i2c_smbus_write_byte_data(client,
167 pca95xx_num_input_regs(pca955x->chipdef->bits) + 1 + 2*n,
168 val);
169}
170
171/*
172 * Write to LED selector register, which determines the source that
173 * drives the LED output.
174 */
175static void pca955x_write_ls(struct i2c_client *client, int n, u8 val)
176{
Alexander Steine7e11d82012-05-29 15:07:30 -0700177 struct pca955x *pca955x = i2c_get_clientdata(client);
Nate Casef46e9202008-07-16 22:49:55 +0100178
179 i2c_smbus_write_byte_data(client,
180 pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n,
181 val);
182}
183
184/*
185 * Read the LED selector register, which determines the source that
186 * drives the LED output.
187 */
188static u8 pca955x_read_ls(struct i2c_client *client, int n)
189{
Alexander Steine7e11d82012-05-29 15:07:30 -0700190 struct pca955x *pca955x = i2c_get_clientdata(client);
Nate Casef46e9202008-07-16 22:49:55 +0100191
192 return (u8) i2c_smbus_read_byte_data(client,
193 pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n);
194}
195
196static void pca955x_led_work(struct work_struct *work)
197{
Alexander Steine7e11d82012-05-29 15:07:30 -0700198 struct pca955x_led *pca955x_led;
199 struct pca955x *pca955x;
Nate Casef46e9202008-07-16 22:49:55 +0100200 u8 ls;
201 int chip_ls; /* which LSx to use (0-3 potentially) */
202 int ls_led; /* which set of bits within LSx to use (0-3) */
203
Alexander Steine7e11d82012-05-29 15:07:30 -0700204 pca955x_led = container_of(work, struct pca955x_led, work);
205 pca955x = pca955x_led->pca955x;
206
207 chip_ls = pca955x_led->led_num / 4;
208 ls_led = pca955x_led->led_num % 4;
209
210 mutex_lock(&pca955x->lock);
Nate Casef46e9202008-07-16 22:49:55 +0100211
212 ls = pca955x_read_ls(pca955x->client, chip_ls);
213
Alexander Steine7e11d82012-05-29 15:07:30 -0700214 switch (pca955x_led->brightness) {
Nate Casef46e9202008-07-16 22:49:55 +0100215 case LED_FULL:
216 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_ON);
217 break;
218 case LED_OFF:
219 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_OFF);
220 break;
221 case LED_HALF:
222 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK0);
223 break;
224 default:
225 /*
226 * Use PWM1 for all other values. This has the unwanted
227 * side effect of making all LEDs on the chip share the
228 * same brightness level if set to a value other than
229 * OFF, HALF, or FULL. But, this is probably better than
230 * just turning off for all other values.
231 */
Alexander Steine7e11d82012-05-29 15:07:30 -0700232 pca955x_write_pwm(pca955x->client, 1,
233 255 - pca955x_led->brightness);
Nate Casef46e9202008-07-16 22:49:55 +0100234 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK1);
235 break;
236 }
237
238 pca955x_write_ls(pca955x->client, chip_ls, ls);
Alexander Steine7e11d82012-05-29 15:07:30 -0700239
240 mutex_unlock(&pca955x->lock);
Nate Casef46e9202008-07-16 22:49:55 +0100241}
242
Sven Wegener0adaf6e2008-10-20 22:57:56 +0100243static void pca955x_led_set(struct led_classdev *led_cdev, enum led_brightness value)
Nate Casef46e9202008-07-16 22:49:55 +0100244{
245 struct pca955x_led *pca955x;
246
247 pca955x = container_of(led_cdev, struct pca955x_led, led_cdev);
248
Nate Casef46e9202008-07-16 22:49:55 +0100249 pca955x->brightness = value;
250
251 /*
252 * Must use workqueue for the actual I/O since I2C operations
253 * can sleep.
254 */
255 schedule_work(&pca955x->work);
Nate Casef46e9202008-07-16 22:49:55 +0100256}
257
Bill Pemberton98ea1ea2012-11-19 13:23:02 -0500258static int pca955x_probe(struct i2c_client *client,
Nate Casef46e9202008-07-16 22:49:55 +0100259 const struct i2c_device_id *id)
260{
Alexander Steine7e11d82012-05-29 15:07:30 -0700261 struct pca955x *pca955x;
262 struct pca955x_led *pca955x_led;
Nate Casef46e9202008-07-16 22:49:55 +0100263 struct pca955x_chipdef *chip;
264 struct i2c_adapter *adapter;
265 struct led_platform_data *pdata;
Sven Wegener95bf14b2008-10-03 15:23:48 -0700266 int i, err;
Nate Casef46e9202008-07-16 22:49:55 +0100267
268 chip = &pca955x_chipdefs[id->driver_data];
269 adapter = to_i2c_adapter(client->dev.parent);
270 pdata = client->dev.platform_data;
271
272 /* Make sure the slave address / chip type combo given is possible */
273 if ((client->addr & ~((1 << chip->slv_addr_shift) - 1)) !=
274 chip->slv_addr) {
275 dev_err(&client->dev, "invalid slave address %02x\n",
276 client->addr);
277 return -ENODEV;
278 }
279
Sachin Kamatb40b0c12012-11-25 12:21:47 +0530280 dev_info(&client->dev, "leds-pca955x: Using %s %d-bit LED driver at "
Nate Casef46e9202008-07-16 22:49:55 +0100281 "slave address 0x%02x\n",
282 id->name, chip->bits, client->addr);
283
284 if (!i2c_check_functionality(adapter, I2C_FUNC_I2C))
285 return -EIO;
286
287 if (pdata) {
288 if (pdata->num_leds != chip->bits) {
289 dev_err(&client->dev, "board info claims %d LEDs"
290 " on a %d-bit chip\n",
291 pdata->num_leds, chip->bits);
292 return -ENODEV;
293 }
294 }
295
Bryan Wu73759f62012-07-04 12:09:05 +0800296 pca955x = devm_kzalloc(&client->dev, sizeof(*pca955x), GFP_KERNEL);
Sven Wegener95bf14b2008-10-03 15:23:48 -0700297 if (!pca955x)
298 return -ENOMEM;
Nate Casef46e9202008-07-16 22:49:55 +0100299
Bryan Wu73759f62012-07-04 12:09:05 +0800300 pca955x->leds = devm_kzalloc(&client->dev,
301 sizeof(*pca955x_led) * chip->bits, GFP_KERNEL);
302 if (!pca955x->leds)
303 return -ENOMEM;
Alexander Steine7e11d82012-05-29 15:07:30 -0700304
Sven Wegener95bf14b2008-10-03 15:23:48 -0700305 i2c_set_clientdata(client, pca955x);
306
Alexander Steine7e11d82012-05-29 15:07:30 -0700307 mutex_init(&pca955x->lock);
308 pca955x->client = client;
309 pca955x->chipdef = chip;
310
Sven Wegener95bf14b2008-10-03 15:23:48 -0700311 for (i = 0; i < chip->bits; i++) {
Alexander Steine7e11d82012-05-29 15:07:30 -0700312 pca955x_led = &pca955x->leds[i];
313 pca955x_led->led_num = i;
314 pca955x_led->pca955x = pca955x;
Sven Wegener95bf14b2008-10-03 15:23:48 -0700315
Nate Casef46e9202008-07-16 22:49:55 +0100316 /* Platform data can specify LED names and default triggers */
317 if (pdata) {
318 if (pdata->leds[i].name)
Alexander Steine7e11d82012-05-29 15:07:30 -0700319 snprintf(pca955x_led->name,
320 sizeof(pca955x_led->name), "pca955x:%s",
321 pdata->leds[i].name);
Nate Casef46e9202008-07-16 22:49:55 +0100322 if (pdata->leds[i].default_trigger)
Alexander Steine7e11d82012-05-29 15:07:30 -0700323 pca955x_led->led_cdev.default_trigger =
Nate Casef46e9202008-07-16 22:49:55 +0100324 pdata->leds[i].default_trigger;
325 } else {
Alexander Steine7e11d82012-05-29 15:07:30 -0700326 snprintf(pca955x_led->name, sizeof(pca955x_led->name),
Sven Wegener95bf14b2008-10-03 15:23:48 -0700327 "pca955x:%d", i);
Nate Casef46e9202008-07-16 22:49:55 +0100328 }
Nate Casef46e9202008-07-16 22:49:55 +0100329
Alexander Steine7e11d82012-05-29 15:07:30 -0700330 pca955x_led->led_cdev.name = pca955x_led->name;
331 pca955x_led->led_cdev.brightness_set = pca955x_led_set;
Nate Casef46e9202008-07-16 22:49:55 +0100332
Alexander Steine7e11d82012-05-29 15:07:30 -0700333 INIT_WORK(&pca955x_led->work, pca955x_led_work);
Nate Casef46e9202008-07-16 22:49:55 +0100334
Alexander Steine7e11d82012-05-29 15:07:30 -0700335 err = led_classdev_register(&client->dev,
336 &pca955x_led->led_cdev);
Sven Wegener95bf14b2008-10-03 15:23:48 -0700337 if (err < 0)
338 goto exit;
Nate Casef46e9202008-07-16 22:49:55 +0100339 }
340
341 /* Turn off LEDs */
342 for (i = 0; i < pca95xx_num_led_regs(chip->bits); i++)
343 pca955x_write_ls(client, i, 0x55);
344
345 /* PWM0 is used for half brightness or 50% duty cycle */
346 pca955x_write_pwm(client, 0, 255-LED_HALF);
347
348 /* PWM1 is used for variable brightness, default to OFF */
349 pca955x_write_pwm(client, 1, 0);
350
351 /* Set to fast frequency so we do not see flashing */
352 pca955x_write_psc(client, 0, 0);
353 pca955x_write_psc(client, 1, 0);
354
355 return 0;
Sven Wegener95bf14b2008-10-03 15:23:48 -0700356
Nate Casef46e9202008-07-16 22:49:55 +0100357exit:
Sven Wegener95bf14b2008-10-03 15:23:48 -0700358 while (i--) {
Alexander Steine7e11d82012-05-29 15:07:30 -0700359 led_classdev_unregister(&pca955x->leds[i].led_cdev);
360 cancel_work_sync(&pca955x->leds[i].work);
Sven Wegener95bf14b2008-10-03 15:23:48 -0700361 }
362
Nate Casef46e9202008-07-16 22:49:55 +0100363 return err;
364}
365
Bill Pemberton678e8a62012-11-19 13:26:00 -0500366static int pca955x_remove(struct i2c_client *client)
Nate Casef46e9202008-07-16 22:49:55 +0100367{
Alexander Steine7e11d82012-05-29 15:07:30 -0700368 struct pca955x *pca955x = i2c_get_clientdata(client);
Nate Casef46e9202008-07-16 22:49:55 +0100369 int i;
370
Sven Wegener95bf14b2008-10-03 15:23:48 -0700371 for (i = 0; i < pca955x->chipdef->bits; i++) {
Alexander Steine7e11d82012-05-29 15:07:30 -0700372 led_classdev_unregister(&pca955x->leds[i].led_cdev);
373 cancel_work_sync(&pca955x->leds[i].work);
Nate Casef46e9202008-07-16 22:49:55 +0100374 }
375
Nate Casef46e9202008-07-16 22:49:55 +0100376 return 0;
377}
378
379static struct i2c_driver pca955x_driver = {
380 .driver = {
381 .name = "leds-pca955x",
382 .owner = THIS_MODULE,
383 },
384 .probe = pca955x_probe,
Bill Pembertondf07cf82012-11-19 13:20:20 -0500385 .remove = pca955x_remove,
Nate Casef46e9202008-07-16 22:49:55 +0100386 .id_table = pca955x_id,
387};
388
Axel Lin09a0d182012-01-10 15:09:27 -0800389module_i2c_driver(pca955x_driver);
Nate Casef46e9202008-07-16 22:49:55 +0100390
391MODULE_AUTHOR("Nate Case <ncase@xes-inc.com>");
392MODULE_DESCRIPTION("PCA955x LED driver");
393MODULE_LICENSE("GPL v2");