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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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090050#include <linux/slab.h>
Nate Casef46e9202008-07-16 22:49:55 +010051
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
58enum pca955x_type {
59 pca9550,
60 pca9551,
61 pca9552,
62 pca9553,
63};
64
65struct 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
71static 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
94static const struct i2c_device_id pca955x_id[] = {
95 { "pca9550", pca9550 },
96 { "pca9551", pca9551 },
97 { "pca9552", pca9552 },
98 { "pca9553", pca9553 },
99 { }
100};
101MODULE_DEVICE_TABLE(i2c, pca955x_id);
102
Alexander Steine7e11d82012-05-29 15:07:30 -0700103struct pca955x {
104 struct mutex lock;
105 struct pca955x_led *leds;
Nate Casef46e9202008-07-16 22:49:55 +0100106 struct pca955x_chipdef *chipdef;
107 struct i2c_client *client;
Alexander Steine7e11d82012-05-29 15:07:30 -0700108};
109
110struct pca955x_led {
111 struct pca955x *pca955x;
Nate Casef46e9202008-07-16 22:49:55 +0100112 struct led_classdev led_cdev;
113 int led_num; /* 0 .. 15 potentially */
114 char name[32];
115};
116
117/* 8 bits per input register */
118static inline int pca95xx_num_input_regs(int bits)
119{
120 return (bits + 7) / 8;
121}
122
123/* 4 bits per LED selector register */
124static inline int pca95xx_num_led_regs(int bits)
125{
126 return (bits + 3) / 4;
127}
128
129/*
130 * Return an LED selector register value based on an existing one, with
131 * the appropriate 2-bit state value set for the given LED number (0-3).
132 */
133static inline u8 pca955x_ledsel(u8 oldval, int led_num, int state)
134{
135 return (oldval & (~(0x3 << (led_num << 1)))) |
136 ((state & 0x3) << (led_num << 1));
137}
138
139/*
140 * Write to frequency prescaler register, used to program the
141 * period of the PWM output. period = (PSCx + 1) / 38
142 */
143static void pca955x_write_psc(struct i2c_client *client, int n, u8 val)
144{
Alexander Steine7e11d82012-05-29 15:07:30 -0700145 struct pca955x *pca955x = i2c_get_clientdata(client);
Nate Casef46e9202008-07-16 22:49:55 +0100146
147 i2c_smbus_write_byte_data(client,
148 pca95xx_num_input_regs(pca955x->chipdef->bits) + 2*n,
149 val);
150}
151
152/*
153 * Write to PWM register, which determines the duty cycle of the
154 * output. LED is OFF when the count is less than the value of this
155 * register, and ON when it is greater. If PWMx == 0, LED is always OFF.
156 *
157 * Duty cycle is (256 - PWMx) / 256
158 */
159static void pca955x_write_pwm(struct i2c_client *client, int n, u8 val)
160{
Alexander Steine7e11d82012-05-29 15:07:30 -0700161 struct pca955x *pca955x = i2c_get_clientdata(client);
Nate Casef46e9202008-07-16 22:49:55 +0100162
163 i2c_smbus_write_byte_data(client,
164 pca95xx_num_input_regs(pca955x->chipdef->bits) + 1 + 2*n,
165 val);
166}
167
168/*
169 * Write to LED selector register, which determines the source that
170 * drives the LED output.
171 */
172static void pca955x_write_ls(struct i2c_client *client, int n, u8 val)
173{
Alexander Steine7e11d82012-05-29 15:07:30 -0700174 struct pca955x *pca955x = i2c_get_clientdata(client);
Nate Casef46e9202008-07-16 22:49:55 +0100175
176 i2c_smbus_write_byte_data(client,
177 pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n,
178 val);
179}
180
181/*
182 * Read the LED selector register, which determines the source that
183 * drives the LED output.
184 */
185static u8 pca955x_read_ls(struct i2c_client *client, int n)
186{
Alexander Steine7e11d82012-05-29 15:07:30 -0700187 struct pca955x *pca955x = i2c_get_clientdata(client);
Nate Casef46e9202008-07-16 22:49:55 +0100188
189 return (u8) i2c_smbus_read_byte_data(client,
190 pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n);
191}
192
Andrew Lunnc3482b82015-08-20 12:32:35 +0200193static int pca955x_led_set(struct led_classdev *led_cdev,
194 enum led_brightness value)
Nate Casef46e9202008-07-16 22:49:55 +0100195{
Alexander Steine7e11d82012-05-29 15:07:30 -0700196 struct pca955x_led *pca955x_led;
197 struct pca955x *pca955x;
Nate Casef46e9202008-07-16 22:49:55 +0100198 u8 ls;
199 int chip_ls; /* which LSx to use (0-3 potentially) */
200 int ls_led; /* which set of bits within LSx to use (0-3) */
201
Andrew Lunnc3482b82015-08-20 12:32:35 +0200202 pca955x_led = container_of(led_cdev, struct pca955x_led, led_cdev);
Alexander Steine7e11d82012-05-29 15:07:30 -0700203 pca955x = pca955x_led->pca955x;
204
205 chip_ls = pca955x_led->led_num / 4;
206 ls_led = pca955x_led->led_num % 4;
207
208 mutex_lock(&pca955x->lock);
Nate Casef46e9202008-07-16 22:49:55 +0100209
210 ls = pca955x_read_ls(pca955x->client, chip_ls);
211
Andrew Lunnc3482b82015-08-20 12:32:35 +0200212 switch (value) {
Nate Casef46e9202008-07-16 22:49:55 +0100213 case LED_FULL:
214 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_ON);
215 break;
216 case LED_OFF:
217 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_OFF);
218 break;
219 case LED_HALF:
220 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK0);
221 break;
222 default:
223 /*
224 * Use PWM1 for all other values. This has the unwanted
225 * side effect of making all LEDs on the chip share the
226 * same brightness level if set to a value other than
227 * OFF, HALF, or FULL. But, this is probably better than
228 * just turning off for all other values.
229 */
Alexander Steine7e11d82012-05-29 15:07:30 -0700230 pca955x_write_pwm(pca955x->client, 1,
Andrew Lunnc3482b82015-08-20 12:32:35 +0200231 255 - value);
Nate Casef46e9202008-07-16 22:49:55 +0100232 ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK1);
233 break;
234 }
235
236 pca955x_write_ls(pca955x->client, chip_ls, ls);
Alexander Steine7e11d82012-05-29 15:07:30 -0700237
238 mutex_unlock(&pca955x->lock);
Nate Casef46e9202008-07-16 22:49:55 +0100239
Andrew Lunnc3482b82015-08-20 12:32:35 +0200240 return 0;
Nate Casef46e9202008-07-16 22:49:55 +0100241}
242
Bill Pemberton98ea1ea2012-11-19 13:23:02 -0500243static int pca955x_probe(struct i2c_client *client,
Nate Casef46e9202008-07-16 22:49:55 +0100244 const struct i2c_device_id *id)
245{
Alexander Steine7e11d82012-05-29 15:07:30 -0700246 struct pca955x *pca955x;
247 struct pca955x_led *pca955x_led;
Nate Casef46e9202008-07-16 22:49:55 +0100248 struct pca955x_chipdef *chip;
249 struct i2c_adapter *adapter;
250 struct led_platform_data *pdata;
Sven Wegener95bf14b2008-10-03 15:23:48 -0700251 int i, err;
Nate Casef46e9202008-07-16 22:49:55 +0100252
253 chip = &pca955x_chipdefs[id->driver_data];
254 adapter = to_i2c_adapter(client->dev.parent);
Jingoo Han87aae1e2013-07-30 01:07:35 -0700255 pdata = dev_get_platdata(&client->dev);
Nate Casef46e9202008-07-16 22:49:55 +0100256
257 /* Make sure the slave address / chip type combo given is possible */
258 if ((client->addr & ~((1 << chip->slv_addr_shift) - 1)) !=
259 chip->slv_addr) {
260 dev_err(&client->dev, "invalid slave address %02x\n",
261 client->addr);
262 return -ENODEV;
263 }
264
Sachin Kamatb40b0c12012-11-25 12:21:47 +0530265 dev_info(&client->dev, "leds-pca955x: Using %s %d-bit LED driver at "
Nate Casef46e9202008-07-16 22:49:55 +0100266 "slave address 0x%02x\n",
267 id->name, chip->bits, client->addr);
268
269 if (!i2c_check_functionality(adapter, I2C_FUNC_I2C))
270 return -EIO;
271
272 if (pdata) {
273 if (pdata->num_leds != chip->bits) {
274 dev_err(&client->dev, "board info claims %d LEDs"
275 " on a %d-bit chip\n",
276 pdata->num_leds, chip->bits);
277 return -ENODEV;
278 }
279 }
280
Bryan Wu73759f62012-07-04 12:09:05 +0800281 pca955x = devm_kzalloc(&client->dev, sizeof(*pca955x), GFP_KERNEL);
Sven Wegener95bf14b2008-10-03 15:23:48 -0700282 if (!pca955x)
283 return -ENOMEM;
Nate Casef46e9202008-07-16 22:49:55 +0100284
Bryan Wu73759f62012-07-04 12:09:05 +0800285 pca955x->leds = devm_kzalloc(&client->dev,
286 sizeof(*pca955x_led) * chip->bits, GFP_KERNEL);
287 if (!pca955x->leds)
288 return -ENOMEM;
Alexander Steine7e11d82012-05-29 15:07:30 -0700289
Sven Wegener95bf14b2008-10-03 15:23:48 -0700290 i2c_set_clientdata(client, pca955x);
291
Alexander Steine7e11d82012-05-29 15:07:30 -0700292 mutex_init(&pca955x->lock);
293 pca955x->client = client;
294 pca955x->chipdef = chip;
295
Sven Wegener95bf14b2008-10-03 15:23:48 -0700296 for (i = 0; i < chip->bits; i++) {
Alexander Steine7e11d82012-05-29 15:07:30 -0700297 pca955x_led = &pca955x->leds[i];
298 pca955x_led->led_num = i;
299 pca955x_led->pca955x = pca955x;
Sven Wegener95bf14b2008-10-03 15:23:48 -0700300
Nate Casef46e9202008-07-16 22:49:55 +0100301 /* Platform data can specify LED names and default triggers */
302 if (pdata) {
303 if (pdata->leds[i].name)
Alexander Steine7e11d82012-05-29 15:07:30 -0700304 snprintf(pca955x_led->name,
305 sizeof(pca955x_led->name), "pca955x:%s",
306 pdata->leds[i].name);
Nate Casef46e9202008-07-16 22:49:55 +0100307 if (pdata->leds[i].default_trigger)
Alexander Steine7e11d82012-05-29 15:07:30 -0700308 pca955x_led->led_cdev.default_trigger =
Nate Casef46e9202008-07-16 22:49:55 +0100309 pdata->leds[i].default_trigger;
310 } else {
Alexander Steine7e11d82012-05-29 15:07:30 -0700311 snprintf(pca955x_led->name, sizeof(pca955x_led->name),
Sven Wegener95bf14b2008-10-03 15:23:48 -0700312 "pca955x:%d", i);
Nate Casef46e9202008-07-16 22:49:55 +0100313 }
Nate Casef46e9202008-07-16 22:49:55 +0100314
Alexander Steine7e11d82012-05-29 15:07:30 -0700315 pca955x_led->led_cdev.name = pca955x_led->name;
Andrew Lunnc3482b82015-08-20 12:32:35 +0200316 pca955x_led->led_cdev.brightness_set_blocking = pca955x_led_set;
Nate Casef46e9202008-07-16 22:49:55 +0100317
Alexander Steine7e11d82012-05-29 15:07:30 -0700318 err = led_classdev_register(&client->dev,
319 &pca955x_led->led_cdev);
Sven Wegener95bf14b2008-10-03 15:23:48 -0700320 if (err < 0)
321 goto exit;
Nate Casef46e9202008-07-16 22:49:55 +0100322 }
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;
Sven Wegener95bf14b2008-10-03 15:23:48 -0700339
Nate Casef46e9202008-07-16 22:49:55 +0100340exit:
Andrew Lunnc3482b82015-08-20 12:32:35 +0200341 while (i--)
Alexander Steine7e11d82012-05-29 15:07:30 -0700342 led_classdev_unregister(&pca955x->leds[i].led_cdev);
Sven Wegener95bf14b2008-10-03 15:23:48 -0700343
Nate Casef46e9202008-07-16 22:49:55 +0100344 return err;
345}
346
Bill Pemberton678e8a62012-11-19 13:26:00 -0500347static int pca955x_remove(struct i2c_client *client)
Nate Casef46e9202008-07-16 22:49:55 +0100348{
Alexander Steine7e11d82012-05-29 15:07:30 -0700349 struct pca955x *pca955x = i2c_get_clientdata(client);
Nate Casef46e9202008-07-16 22:49:55 +0100350 int i;
351
Andrew Lunnc3482b82015-08-20 12:32:35 +0200352 for (i = 0; i < pca955x->chipdef->bits; i++)
Alexander Steine7e11d82012-05-29 15:07:30 -0700353 led_classdev_unregister(&pca955x->leds[i].led_cdev);
Nate Casef46e9202008-07-16 22:49:55 +0100354
Nate Casef46e9202008-07-16 22:49:55 +0100355 return 0;
356}
357
358static struct i2c_driver pca955x_driver = {
359 .driver = {
360 .name = "leds-pca955x",
Nate Casef46e9202008-07-16 22:49:55 +0100361 },
362 .probe = pca955x_probe,
Bill Pembertondf07cf82012-11-19 13:20:20 -0500363 .remove = pca955x_remove,
Nate Casef46e9202008-07-16 22:49:55 +0100364 .id_table = pca955x_id,
365};
366
Axel Lin09a0d182012-01-10 15:09:27 -0800367module_i2c_driver(pca955x_driver);
Nate Casef46e9202008-07-16 22:49:55 +0100368
369MODULE_AUTHOR("Nate Case <ncase@xes-inc.com>");
370MODULE_DESCRIPTION("PCA955x LED driver");
371MODULE_LICENSE("GPL v2");