1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Driver for ISSI IS31FL32xx family of I2C LED controllers
4  *
5  * Copyright 2015 Allworx Corp.
6  *
7  * Datasheets:
8  *   http://www.issi.com/US/product-analog-fxled-driver.shtml
9  *   http://www.si-en.com/product.asp?parentid=890
10  */
11 
12 #include <linux/device.h>
13 #include <linux/i2c.h>
14 #include <linux/kernel.h>
15 #include <linux/leds.h>
16 #include <linux/module.h>
17 #include <linux/of.h>
18 #include <linux/of_device.h>
19 
20 /* Used to indicate a device has no such register */
21 #define IS31FL32XX_REG_NONE 0xFF
22 
23 /* Software Shutdown bit in Shutdown Register */
24 #define IS31FL32XX_SHUTDOWN_SSD_ENABLE  0
25 #define IS31FL32XX_SHUTDOWN_SSD_DISABLE BIT(0)
26 
27 /* IS31FL3216 has a number of unique registers */
28 #define IS31FL3216_CONFIG_REG 0x00
29 #define IS31FL3216_LIGHTING_EFFECT_REG 0x03
30 #define IS31FL3216_CHANNEL_CONFIG_REG 0x04
31 
32 /* Software Shutdown bit in 3216 Config Register */
33 #define IS31FL3216_CONFIG_SSD_ENABLE  BIT(7)
34 #define IS31FL3216_CONFIG_SSD_DISABLE 0
35 
36 struct is31fl32xx_priv;
37 struct is31fl32xx_led_data {
38 	struct led_classdev cdev;
39 	u8 channel; /* 1-based, max priv->cdef->channels */
40 	struct is31fl32xx_priv *priv;
41 };
42 
43 struct is31fl32xx_priv {
44 	const struct is31fl32xx_chipdef *cdef;
45 	struct i2c_client *client;
46 	unsigned int num_leds;
47 	struct is31fl32xx_led_data leds[];
48 };
49 
50 /**
51  * struct is31fl32xx_chipdef - chip-specific attributes
52  * @channels            : Number of LED channels
53  * @shutdown_reg        : address of Shutdown register (optional)
54  * @pwm_update_reg      : address of PWM Update register
55  * @global_control_reg  : address of Global Control register (optional)
56  * @reset_reg           : address of Reset register (optional)
57  * @pwm_register_base   : address of first PWM register
58  * @pwm_registers_reversed: : true if PWM registers count down instead of up
59  * @led_control_register_base : address of first LED control register (optional)
60  * @enable_bits_per_led_control_register: number of LEDs enable bits in each
61  * @reset_func          : pointer to reset function
62  * @sw_shutdown_func    : pointer to software shutdown function
63  *
64  * For all optional register addresses, the sentinel value %IS31FL32XX_REG_NONE
65  * indicates that this chip has no such register.
66  *
67  * If non-NULL, @reset_func will be called during probing to set all
68  * necessary registers to a known initialization state. This is needed
69  * for chips that do not have a @reset_reg.
70  *
71  * @enable_bits_per_led_control_register must be >=1 if
72  * @led_control_register_base != %IS31FL32XX_REG_NONE.
73  */
74 struct is31fl32xx_chipdef {
75 	u8	channels;
76 	u8	shutdown_reg;
77 	u8	pwm_update_reg;
78 	u8	global_control_reg;
79 	u8	reset_reg;
80 	u8	pwm_register_base;
81 	bool	pwm_registers_reversed;
82 	u8	led_control_register_base;
83 	u8	enable_bits_per_led_control_register;
84 	int (*reset_func)(struct is31fl32xx_priv *priv);
85 	int (*sw_shutdown_func)(struct is31fl32xx_priv *priv, bool enable);
86 };
87 
88 static const struct is31fl32xx_chipdef is31fl3236_cdef = {
89 	.channels				= 36,
90 	.shutdown_reg				= 0x00,
91 	.pwm_update_reg				= 0x25,
92 	.global_control_reg			= 0x4a,
93 	.reset_reg				= 0x4f,
94 	.pwm_register_base			= 0x01,
95 	.led_control_register_base		= 0x26,
96 	.enable_bits_per_led_control_register	= 1,
97 };
98 
99 static const struct is31fl32xx_chipdef is31fl3235_cdef = {
100 	.channels				= 28,
101 	.shutdown_reg				= 0x00,
102 	.pwm_update_reg				= 0x25,
103 	.global_control_reg			= 0x4a,
104 	.reset_reg				= 0x4f,
105 	.pwm_register_base			= 0x05,
106 	.led_control_register_base		= 0x2a,
107 	.enable_bits_per_led_control_register	= 1,
108 };
109 
110 static const struct is31fl32xx_chipdef is31fl3218_cdef = {
111 	.channels				= 18,
112 	.shutdown_reg				= 0x00,
113 	.pwm_update_reg				= 0x16,
114 	.global_control_reg			= IS31FL32XX_REG_NONE,
115 	.reset_reg				= 0x17,
116 	.pwm_register_base			= 0x01,
117 	.led_control_register_base		= 0x13,
118 	.enable_bits_per_led_control_register	= 6,
119 };
120 
121 static int is31fl3216_reset(struct is31fl32xx_priv *priv);
122 static int is31fl3216_software_shutdown(struct is31fl32xx_priv *priv,
123 					bool enable);
124 static const struct is31fl32xx_chipdef is31fl3216_cdef = {
125 	.channels				= 16,
126 	.shutdown_reg				= IS31FL32XX_REG_NONE,
127 	.pwm_update_reg				= 0xB0,
128 	.global_control_reg			= IS31FL32XX_REG_NONE,
129 	.reset_reg				= IS31FL32XX_REG_NONE,
130 	.pwm_register_base			= 0x10,
131 	.pwm_registers_reversed			= true,
132 	.led_control_register_base		= 0x01,
133 	.enable_bits_per_led_control_register	= 8,
134 	.reset_func				= is31fl3216_reset,
135 	.sw_shutdown_func			= is31fl3216_software_shutdown,
136 };
137 
138 static int is31fl32xx_write(struct is31fl32xx_priv *priv, u8 reg, u8 val)
139 {
140 	int ret;
141 
142 	dev_dbg(&priv->client->dev, "writing register 0x%02X=0x%02X", reg, val);
143 
144 	ret =  i2c_smbus_write_byte_data(priv->client, reg, val);
145 	if (ret) {
146 		dev_err(&priv->client->dev,
147 			"register write to 0x%02X failed (error %d)",
148 			reg, ret);
149 	}
150 	return ret;
151 }
152 
153 /*
154  * Custom reset function for IS31FL3216 because it does not have a RESET
155  * register the way that the other IS31FL32xx chips do. We don't bother
156  * writing the GPIO and animation registers, because the registers we
157  * do write ensure those will have no effect.
158  */
159 static int is31fl3216_reset(struct is31fl32xx_priv *priv)
160 {
161 	unsigned int i;
162 	int ret;
163 
164 	ret = is31fl32xx_write(priv, IS31FL3216_CONFIG_REG,
165 			       IS31FL3216_CONFIG_SSD_ENABLE);
166 	if (ret)
167 		return ret;
168 	for (i = 0; i < priv->cdef->channels; i++) {
169 		ret = is31fl32xx_write(priv, priv->cdef->pwm_register_base+i,
170 				       0x00);
171 		if (ret)
172 			return ret;
173 	}
174 	ret = is31fl32xx_write(priv, priv->cdef->pwm_update_reg, 0);
175 	if (ret)
176 		return ret;
177 	ret = is31fl32xx_write(priv, IS31FL3216_LIGHTING_EFFECT_REG, 0x00);
178 	if (ret)
179 		return ret;
180 	ret = is31fl32xx_write(priv, IS31FL3216_CHANNEL_CONFIG_REG, 0x00);
181 	if (ret)
182 		return ret;
183 
184 	return 0;
185 }
186 
187 /*
188  * Custom Software-Shutdown function for IS31FL3216 because it does not have
189  * a SHUTDOWN register the way that the other IS31FL32xx chips do.
190  * We don't bother doing a read/modify/write on the CONFIG register because
191  * we only ever use a value of '0' for the other fields in that register.
192  */
193 static int is31fl3216_software_shutdown(struct is31fl32xx_priv *priv,
194 					bool enable)
195 {
196 	u8 value = enable ? IS31FL3216_CONFIG_SSD_ENABLE :
197 			    IS31FL3216_CONFIG_SSD_DISABLE;
198 
199 	return is31fl32xx_write(priv, IS31FL3216_CONFIG_REG, value);
200 }
201 
202 /*
203  * NOTE: A mutex is not needed in this function because:
204  * - All referenced data is read-only after probe()
205  * - The I2C core has a mutex on to protect the bus
206  * - There are no read/modify/write operations
207  * - Intervening operations between the write of the PWM register
208  *   and the Update register are harmless.
209  *
210  * Example:
211  *	PWM_REG_1 write 16
212  *	UPDATE_REG write 0
213  *	PWM_REG_2 write 128
214  *	UPDATE_REG write 0
215  *   vs:
216  *	PWM_REG_1 write 16
217  *	PWM_REG_2 write 128
218  *	UPDATE_REG write 0
219  *	UPDATE_REG write 0
220  * are equivalent. Poking the Update register merely applies all PWM
221  * register writes up to that point.
222  */
223 static int is31fl32xx_brightness_set(struct led_classdev *led_cdev,
224 				     enum led_brightness brightness)
225 {
226 	const struct is31fl32xx_led_data *led_data =
227 		container_of(led_cdev, struct is31fl32xx_led_data, cdev);
228 	const struct is31fl32xx_chipdef *cdef = led_data->priv->cdef;
229 	u8 pwm_register_offset;
230 	int ret;
231 
232 	dev_dbg(led_cdev->dev, "%s: %d\n", __func__, brightness);
233 
234 	/* NOTE: led_data->channel is 1-based */
235 	if (cdef->pwm_registers_reversed)
236 		pwm_register_offset = cdef->channels - led_data->channel;
237 	else
238 		pwm_register_offset = led_data->channel - 1;
239 
240 	ret = is31fl32xx_write(led_data->priv,
241 			       cdef->pwm_register_base + pwm_register_offset,
242 			       brightness);
243 	if (ret)
244 		return ret;
245 
246 	return is31fl32xx_write(led_data->priv, cdef->pwm_update_reg, 0);
247 }
248 
249 static int is31fl32xx_reset_regs(struct is31fl32xx_priv *priv)
250 {
251 	const struct is31fl32xx_chipdef *cdef = priv->cdef;
252 	int ret;
253 
254 	if (cdef->reset_reg != IS31FL32XX_REG_NONE) {
255 		ret = is31fl32xx_write(priv, cdef->reset_reg, 0);
256 		if (ret)
257 			return ret;
258 	}
259 
260 	if (cdef->reset_func)
261 		return cdef->reset_func(priv);
262 
263 	return 0;
264 }
265 
266 static int is31fl32xx_software_shutdown(struct is31fl32xx_priv *priv,
267 					bool enable)
268 {
269 	const struct is31fl32xx_chipdef *cdef = priv->cdef;
270 	int ret;
271 
272 	if (cdef->shutdown_reg != IS31FL32XX_REG_NONE) {
273 		u8 value = enable ? IS31FL32XX_SHUTDOWN_SSD_ENABLE :
274 				    IS31FL32XX_SHUTDOWN_SSD_DISABLE;
275 		ret = is31fl32xx_write(priv, cdef->shutdown_reg, value);
276 		if (ret)
277 			return ret;
278 	}
279 
280 	if (cdef->sw_shutdown_func)
281 		return cdef->sw_shutdown_func(priv, enable);
282 
283 	return 0;
284 }
285 
286 static int is31fl32xx_init_regs(struct is31fl32xx_priv *priv)
287 {
288 	const struct is31fl32xx_chipdef *cdef = priv->cdef;
289 	int ret;
290 
291 	ret = is31fl32xx_reset_regs(priv);
292 	if (ret)
293 		return ret;
294 
295 	/*
296 	 * Set enable bit for all channels.
297 	 * We will control state with PWM registers alone.
298 	 */
299 	if (cdef->led_control_register_base != IS31FL32XX_REG_NONE) {
300 		u8 value =
301 		    GENMASK(cdef->enable_bits_per_led_control_register-1, 0);
302 		u8 num_regs = cdef->channels /
303 				cdef->enable_bits_per_led_control_register;
304 		int i;
305 
306 		for (i = 0; i < num_regs; i++) {
307 			ret = is31fl32xx_write(priv,
308 					       cdef->led_control_register_base+i,
309 					       value);
310 			if (ret)
311 				return ret;
312 		}
313 	}
314 
315 	ret = is31fl32xx_software_shutdown(priv, false);
316 	if (ret)
317 		return ret;
318 
319 	if (cdef->global_control_reg != IS31FL32XX_REG_NONE) {
320 		ret = is31fl32xx_write(priv, cdef->global_control_reg, 0x00);
321 		if (ret)
322 			return ret;
323 	}
324 
325 	return 0;
326 }
327 
328 static int is31fl32xx_parse_child_dt(const struct device *dev,
329 				     const struct device_node *child,
330 				     struct is31fl32xx_led_data *led_data)
331 {
332 	struct led_classdev *cdev = &led_data->cdev;
333 	int ret = 0;
334 	u32 reg;
335 
336 	ret = of_property_read_u32(child, "reg", &reg);
337 	if (ret || reg < 1 || reg > led_data->priv->cdef->channels) {
338 		dev_err(dev,
339 			"Child node %pOF does not have a valid reg property\n",
340 			child);
341 		return -EINVAL;
342 	}
343 	led_data->channel = reg;
344 
345 	cdev->brightness_set_blocking = is31fl32xx_brightness_set;
346 
347 	return 0;
348 }
349 
350 static struct is31fl32xx_led_data *is31fl32xx_find_led_data(
351 					struct is31fl32xx_priv *priv,
352 					u8 channel)
353 {
354 	size_t i;
355 
356 	for (i = 0; i < priv->num_leds; i++) {
357 		if (priv->leds[i].channel == channel)
358 			return &priv->leds[i];
359 	}
360 
361 	return NULL;
362 }
363 
364 static int is31fl32xx_parse_dt(struct device *dev,
365 			       struct is31fl32xx_priv *priv)
366 {
367 	struct device_node *child;
368 	int ret = 0;
369 
370 	for_each_available_child_of_node(dev_of_node(dev), child) {
371 		struct led_init_data init_data = {};
372 		struct is31fl32xx_led_data *led_data =
373 			&priv->leds[priv->num_leds];
374 		const struct is31fl32xx_led_data *other_led_data;
375 
376 		led_data->priv = priv;
377 
378 		ret = is31fl32xx_parse_child_dt(dev, child, led_data);
379 		if (ret)
380 			goto err;
381 
382 		/* Detect if channel is already in use by another child */
383 		other_led_data = is31fl32xx_find_led_data(priv,
384 							  led_data->channel);
385 		if (other_led_data) {
386 			dev_err(dev,
387 				"Node %pOF 'reg' conflicts with another LED\n",
388 				child);
389 			ret = -EINVAL;
390 			goto err;
391 		}
392 
393 		init_data.fwnode = of_fwnode_handle(child);
394 
395 		ret = devm_led_classdev_register_ext(dev, &led_data->cdev,
396 						     &init_data);
397 		if (ret) {
398 			dev_err(dev, "Failed to register LED for %pOF: %d\n",
399 				child, ret);
400 			goto err;
401 		}
402 
403 		priv->num_leds++;
404 	}
405 
406 	return 0;
407 
408 err:
409 	of_node_put(child);
410 	return ret;
411 }
412 
413 static const struct of_device_id of_is31fl32xx_match[] = {
414 	{ .compatible = "issi,is31fl3236", .data = &is31fl3236_cdef, },
415 	{ .compatible = "issi,is31fl3235", .data = &is31fl3235_cdef, },
416 	{ .compatible = "issi,is31fl3218", .data = &is31fl3218_cdef, },
417 	{ .compatible = "si-en,sn3218",    .data = &is31fl3218_cdef, },
418 	{ .compatible = "issi,is31fl3216", .data = &is31fl3216_cdef, },
419 	{ .compatible = "si-en,sn3216",    .data = &is31fl3216_cdef, },
420 	{},
421 };
422 
423 MODULE_DEVICE_TABLE(of, of_is31fl32xx_match);
424 
425 static int is31fl32xx_probe(struct i2c_client *client,
426 			    const struct i2c_device_id *id)
427 {
428 	const struct is31fl32xx_chipdef *cdef;
429 	struct device *dev = &client->dev;
430 	struct is31fl32xx_priv *priv;
431 	int count;
432 	int ret = 0;
433 
434 	cdef = device_get_match_data(dev);
435 
436 	count = of_get_available_child_count(dev_of_node(dev));
437 	if (!count)
438 		return -EINVAL;
439 
440 	priv = devm_kzalloc(dev, struct_size(priv, leds, count),
441 			    GFP_KERNEL);
442 	if (!priv)
443 		return -ENOMEM;
444 
445 	priv->client = client;
446 	priv->cdef = cdef;
447 	i2c_set_clientdata(client, priv);
448 
449 	ret = is31fl32xx_init_regs(priv);
450 	if (ret)
451 		return ret;
452 
453 	ret = is31fl32xx_parse_dt(dev, priv);
454 	if (ret)
455 		return ret;
456 
457 	return 0;
458 }
459 
460 static void is31fl32xx_remove(struct i2c_client *client)
461 {
462 	struct is31fl32xx_priv *priv = i2c_get_clientdata(client);
463 	int ret;
464 
465 	ret = is31fl32xx_reset_regs(priv);
466 	if (ret)
467 		dev_err(&client->dev, "Failed to reset registers on removal (%pe)\n",
468 			ERR_PTR(ret));
469 }
470 
471 /*
472  * i2c-core (and modalias) requires that id_table be properly filled,
473  * even though it is not used for DeviceTree based instantiation.
474  */
475 static const struct i2c_device_id is31fl32xx_id[] = {
476 	{ "is31fl3236" },
477 	{ "is31fl3235" },
478 	{ "is31fl3218" },
479 	{ "sn3218" },
480 	{ "is31fl3216" },
481 	{ "sn3216" },
482 	{},
483 };
484 
485 MODULE_DEVICE_TABLE(i2c, is31fl32xx_id);
486 
487 static struct i2c_driver is31fl32xx_driver = {
488 	.driver = {
489 		.name	= "is31fl32xx",
490 		.of_match_table = of_is31fl32xx_match,
491 	},
492 	.probe		= is31fl32xx_probe,
493 	.remove		= is31fl32xx_remove,
494 	.id_table	= is31fl32xx_id,
495 };
496 
497 module_i2c_driver(is31fl32xx_driver);
498 
499 MODULE_AUTHOR("David Rivshin <drivshin@allworx.com>");
500 MODULE_DESCRIPTION("ISSI IS31FL32xx LED driver");
501 MODULE_LICENSE("GPL v2");
502