1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Backlight driver for ArcticSand ARC_X_C_0N_0N Devices
4  *
5  * Copyright 2016 ArcticSand, Inc.
6  * Author : Brian Dodge <bdodge@arcticsand.com>
7  */
8 
9 #include <linux/backlight.h>
10 #include <linux/err.h>
11 #include <linux/i2c.h>
12 #include <linux/module.h>
13 #include <linux/of.h>
14 #include <linux/slab.h>
15 
16 enum arcxcnn_chip_id {
17 	ARC2C0608
18 };
19 
20 /**
21  * struct arcxcnn_platform_data
22  * @name		: Backlight driver name (NULL will use default)
23  * @initial_brightness	: initial value of backlight brightness
24  * @leden		: initial LED string enables, upper bit is global on/off
25  * @led_config_0	: fading speed (period between intensity steps)
26  * @led_config_1	: misc settings, see datasheet
27  * @dim_freq		: pwm dimming frequency if in pwm mode
28  * @comp_config		: misc config, see datasheet
29  * @filter_config	: RC/PWM filter config, see datasheet
30  * @trim_config		: full scale current trim, see datasheet
31  */
32 struct arcxcnn_platform_data {
33 	const char *name;
34 	u16 initial_brightness;
35 	u8	leden;
36 	u8	led_config_0;
37 	u8	led_config_1;
38 	u8	dim_freq;
39 	u8	comp_config;
40 	u8	filter_config;
41 	u8	trim_config;
42 };
43 
44 #define ARCXCNN_CMD		0x00	/* Command Register */
45 #define ARCXCNN_CMD_STDBY	0x80	/*   I2C Standby */
46 #define ARCXCNN_CMD_RESET	0x40	/*   Reset */
47 #define ARCXCNN_CMD_BOOST	0x10	/*   Boost */
48 #define ARCXCNN_CMD_OVP_MASK	0x0C	/*   --- Over Voltage Threshold */
49 #define ARCXCNN_CMD_OVP_XXV	0x0C	/*   <rsvrd> Over Voltage Threshold */
50 #define ARCXCNN_CMD_OVP_20V	0x08	/*   20v Over Voltage Threshold */
51 #define ARCXCNN_CMD_OVP_24V	0x04	/*   24v Over Voltage Threshold */
52 #define ARCXCNN_CMD_OVP_31V	0x00	/*   31.4v Over Voltage Threshold */
53 #define ARCXCNN_CMD_EXT_COMP	0x01	/*   part (0) or full (1) ext. comp */
54 
55 #define ARCXCNN_CONFIG		0x01	/* Configuration */
56 #define ARCXCNN_STATUS1		0x02	/* Status 1 */
57 #define ARCXCNN_STATUS2		0x03	/* Status 2 */
58 #define ARCXCNN_FADECTRL	0x04	/* Fading Control */
59 #define ARCXCNN_ILED_CONFIG	0x05	/* ILED Configuration */
60 #define ARCXCNN_ILED_DIM_PWM	0x00	/*   config dim mode pwm */
61 #define ARCXCNN_ILED_DIM_INT	0x04	/*   config dim mode internal */
62 #define ARCXCNN_LEDEN		0x06	/* LED Enable Register */
63 #define ARCXCNN_LEDEN_ISETEXT	0x80	/*   Full-scale current set extern */
64 #define ARCXCNN_LEDEN_MASK	0x3F	/*   LED string enables mask */
65 #define ARCXCNN_LEDEN_BITS	0x06	/*   Bits of LED string enables */
66 #define ARCXCNN_LEDEN_LED1	0x01
67 #define ARCXCNN_LEDEN_LED2	0x02
68 #define ARCXCNN_LEDEN_LED3	0x04
69 #define ARCXCNN_LEDEN_LED4	0x08
70 #define ARCXCNN_LEDEN_LED5	0x10
71 #define ARCXCNN_LEDEN_LED6	0x20
72 
73 #define ARCXCNN_WLED_ISET_LSB	0x07	/* LED ISET LSB (in upper nibble) */
74 #define ARCXCNN_WLED_ISET_LSB_SHIFT 0x04  /* ISET LSB Left Shift */
75 #define ARCXCNN_WLED_ISET_MSB	0x08	/* LED ISET MSB (8 bits) */
76 
77 #define ARCXCNN_DIMFREQ		0x09
78 #define ARCXCNN_COMP_CONFIG	0x0A
79 #define ARCXCNN_FILT_CONFIG	0x0B
80 #define ARCXCNN_IMAXTUNE	0x0C
81 #define ARCXCNN_ID_MSB		0x1E
82 #define ARCXCNN_ID_LSB		0x1F
83 
84 #define MAX_BRIGHTNESS		4095
85 #define INIT_BRIGHT		60
86 
87 struct arcxcnn {
88 	struct i2c_client *client;
89 	struct backlight_device *bl;
90 	struct device *dev;
91 	struct arcxcnn_platform_data *pdata;
92 };
93 
arcxcnn_update_field(struct arcxcnn * lp,u8 reg,u8 mask,u8 data)94 static int arcxcnn_update_field(struct arcxcnn *lp, u8 reg, u8 mask, u8 data)
95 {
96 	int ret;
97 	u8 tmp;
98 
99 	ret = i2c_smbus_read_byte_data(lp->client, reg);
100 	if (ret < 0) {
101 		dev_err(lp->dev, "failed to read 0x%.2x\n", reg);
102 		return ret;
103 	}
104 
105 	tmp = (u8)ret;
106 	tmp &= ~mask;
107 	tmp |= data & mask;
108 
109 	return i2c_smbus_write_byte_data(lp->client, reg, tmp);
110 }
111 
arcxcnn_set_brightness(struct arcxcnn * lp,u32 brightness)112 static int arcxcnn_set_brightness(struct arcxcnn *lp, u32 brightness)
113 {
114 	int ret;
115 	u8 val;
116 
117 	/* lower nibble of brightness goes in upper nibble of LSB register */
118 	val = (brightness & 0xF) << ARCXCNN_WLED_ISET_LSB_SHIFT;
119 	ret = i2c_smbus_write_byte_data(lp->client,
120 		ARCXCNN_WLED_ISET_LSB, val);
121 	if (ret < 0)
122 		return ret;
123 
124 	/* remaining 8 bits of brightness go in MSB register */
125 	val = (brightness >> 4);
126 	return i2c_smbus_write_byte_data(lp->client,
127 		ARCXCNN_WLED_ISET_MSB, val);
128 }
129 
arcxcnn_bl_update_status(struct backlight_device * bl)130 static int arcxcnn_bl_update_status(struct backlight_device *bl)
131 {
132 	struct arcxcnn *lp = bl_get_data(bl);
133 	u32 brightness = bl->props.brightness;
134 	int ret;
135 
136 	if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
137 		brightness = 0;
138 
139 	ret = arcxcnn_set_brightness(lp, brightness);
140 	if (ret)
141 		return ret;
142 
143 	/* set power-on/off/save modes */
144 	return arcxcnn_update_field(lp, ARCXCNN_CMD, ARCXCNN_CMD_STDBY,
145 		(bl->props.power == 0) ? 0 : ARCXCNN_CMD_STDBY);
146 }
147 
148 static const struct backlight_ops arcxcnn_bl_ops = {
149 	.options = BL_CORE_SUSPENDRESUME,
150 	.update_status = arcxcnn_bl_update_status,
151 };
152 
arcxcnn_backlight_register(struct arcxcnn * lp)153 static int arcxcnn_backlight_register(struct arcxcnn *lp)
154 {
155 	struct backlight_properties *props;
156 	const char *name = lp->pdata->name ? : "arctic_bl";
157 
158 	props = devm_kzalloc(lp->dev, sizeof(*props), GFP_KERNEL);
159 	if (!props)
160 		return -ENOMEM;
161 
162 	props->type = BACKLIGHT_PLATFORM;
163 	props->max_brightness = MAX_BRIGHTNESS;
164 
165 	if (lp->pdata->initial_brightness > props->max_brightness)
166 		lp->pdata->initial_brightness = props->max_brightness;
167 
168 	props->brightness = lp->pdata->initial_brightness;
169 
170 	lp->bl = devm_backlight_device_register(lp->dev, name, lp->dev, lp,
171 				       &arcxcnn_bl_ops, props);
172 	return PTR_ERR_OR_ZERO(lp->bl);
173 }
174 
arcxcnn_parse_dt(struct arcxcnn * lp)175 static void arcxcnn_parse_dt(struct arcxcnn *lp)
176 {
177 	struct device *dev = lp->dev;
178 	struct device_node *node = dev->of_node;
179 	u32 prog_val, num_entry, entry, sources[ARCXCNN_LEDEN_BITS];
180 	int ret;
181 
182 	/* device tree entry isn't required, defaults are OK */
183 	if (!node)
184 		return;
185 
186 	ret = of_property_read_string(node, "label", &lp->pdata->name);
187 	if (ret < 0)
188 		lp->pdata->name = NULL;
189 
190 	ret = of_property_read_u32(node, "default-brightness", &prog_val);
191 	if (ret == 0)
192 		lp->pdata->initial_brightness = prog_val;
193 
194 	ret = of_property_read_u32(node, "arc,led-config-0", &prog_val);
195 	if (ret == 0)
196 		lp->pdata->led_config_0 = (u8)prog_val;
197 
198 	ret = of_property_read_u32(node, "arc,led-config-1", &prog_val);
199 	if (ret == 0)
200 		lp->pdata->led_config_1 = (u8)prog_val;
201 
202 	ret = of_property_read_u32(node, "arc,dim-freq", &prog_val);
203 	if (ret == 0)
204 		lp->pdata->dim_freq = (u8)prog_val;
205 
206 	ret = of_property_read_u32(node, "arc,comp-config", &prog_val);
207 	if (ret == 0)
208 		lp->pdata->comp_config = (u8)prog_val;
209 
210 	ret = of_property_read_u32(node, "arc,filter-config", &prog_val);
211 	if (ret == 0)
212 		lp->pdata->filter_config = (u8)prog_val;
213 
214 	ret = of_property_read_u32(node, "arc,trim-config", &prog_val);
215 	if (ret == 0)
216 		lp->pdata->trim_config = (u8)prog_val;
217 
218 	ret = of_property_count_u32_elems(node, "led-sources");
219 	if (ret < 0) {
220 		lp->pdata->leden = ARCXCNN_LEDEN_MASK; /* all on is default */
221 	} else {
222 		num_entry = ret;
223 		if (num_entry > ARCXCNN_LEDEN_BITS)
224 			num_entry = ARCXCNN_LEDEN_BITS;
225 
226 		ret = of_property_read_u32_array(node, "led-sources", sources,
227 					num_entry);
228 		if (ret < 0) {
229 			dev_err(dev, "led-sources node is invalid.\n");
230 			return;
231 		}
232 
233 		lp->pdata->leden = 0;
234 
235 		/* for each enable in source, set bit in led enable */
236 		for (entry = 0; entry < num_entry; entry++) {
237 			u8 onbit = 1 << sources[entry];
238 
239 			lp->pdata->leden |= onbit;
240 		}
241 	}
242 }
243 
arcxcnn_probe(struct i2c_client * cl,const struct i2c_device_id * id)244 static int arcxcnn_probe(struct i2c_client *cl, const struct i2c_device_id *id)
245 {
246 	struct arcxcnn *lp;
247 	int ret;
248 
249 	if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
250 		return -EIO;
251 
252 	lp = devm_kzalloc(&cl->dev, sizeof(*lp), GFP_KERNEL);
253 	if (!lp)
254 		return -ENOMEM;
255 
256 	lp->client = cl;
257 	lp->dev = &cl->dev;
258 	lp->pdata = dev_get_platdata(&cl->dev);
259 
260 	/* reset the device */
261 	ret = i2c_smbus_write_byte_data(lp->client,
262 		ARCXCNN_CMD, ARCXCNN_CMD_RESET);
263 	if (ret)
264 		goto probe_err;
265 
266 	if (!lp->pdata) {
267 		lp->pdata = devm_kzalloc(lp->dev,
268 				sizeof(*lp->pdata), GFP_KERNEL);
269 		if (!lp->pdata)
270 			return -ENOMEM;
271 
272 		/* Setup defaults based on power-on defaults */
273 		lp->pdata->name = NULL;
274 		lp->pdata->initial_brightness = INIT_BRIGHT;
275 		lp->pdata->leden = ARCXCNN_LEDEN_MASK;
276 
277 		lp->pdata->led_config_0 = i2c_smbus_read_byte_data(
278 			lp->client, ARCXCNN_FADECTRL);
279 
280 		lp->pdata->led_config_1 = i2c_smbus_read_byte_data(
281 			lp->client, ARCXCNN_ILED_CONFIG);
282 		/* insure dim mode is not default pwm */
283 		lp->pdata->led_config_1 |= ARCXCNN_ILED_DIM_INT;
284 
285 		lp->pdata->dim_freq = i2c_smbus_read_byte_data(
286 			lp->client, ARCXCNN_DIMFREQ);
287 
288 		lp->pdata->comp_config = i2c_smbus_read_byte_data(
289 			lp->client, ARCXCNN_COMP_CONFIG);
290 
291 		lp->pdata->filter_config = i2c_smbus_read_byte_data(
292 			lp->client, ARCXCNN_FILT_CONFIG);
293 
294 		lp->pdata->trim_config = i2c_smbus_read_byte_data(
295 			lp->client, ARCXCNN_IMAXTUNE);
296 
297 		if (IS_ENABLED(CONFIG_OF))
298 			arcxcnn_parse_dt(lp);
299 	}
300 
301 	i2c_set_clientdata(cl, lp);
302 
303 	/* constrain settings to what is possible */
304 	if (lp->pdata->initial_brightness > MAX_BRIGHTNESS)
305 		lp->pdata->initial_brightness = MAX_BRIGHTNESS;
306 
307 	/* set initial brightness */
308 	ret = arcxcnn_set_brightness(lp, lp->pdata->initial_brightness);
309 	if (ret)
310 		goto probe_err;
311 
312 	/* set other register values directly */
313 	ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_FADECTRL,
314 		lp->pdata->led_config_0);
315 	if (ret)
316 		goto probe_err;
317 
318 	ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_ILED_CONFIG,
319 		lp->pdata->led_config_1);
320 	if (ret)
321 		goto probe_err;
322 
323 	ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_DIMFREQ,
324 		lp->pdata->dim_freq);
325 	if (ret)
326 		goto probe_err;
327 
328 	ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_COMP_CONFIG,
329 		lp->pdata->comp_config);
330 	if (ret)
331 		goto probe_err;
332 
333 	ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_FILT_CONFIG,
334 		lp->pdata->filter_config);
335 	if (ret)
336 		goto probe_err;
337 
338 	ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_IMAXTUNE,
339 		lp->pdata->trim_config);
340 	if (ret)
341 		goto probe_err;
342 
343 	/* set initial LED Enables */
344 	arcxcnn_update_field(lp, ARCXCNN_LEDEN,
345 		ARCXCNN_LEDEN_MASK, lp->pdata->leden);
346 
347 	ret = arcxcnn_backlight_register(lp);
348 	if (ret)
349 		goto probe_register_err;
350 
351 	backlight_update_status(lp->bl);
352 
353 	return 0;
354 
355 probe_register_err:
356 	dev_err(lp->dev,
357 		"failed to register backlight.\n");
358 
359 probe_err:
360 	dev_err(lp->dev,
361 		"failure ret: %d\n", ret);
362 	return ret;
363 }
364 
arcxcnn_remove(struct i2c_client * cl)365 static int arcxcnn_remove(struct i2c_client *cl)
366 {
367 	struct arcxcnn *lp = i2c_get_clientdata(cl);
368 
369 	/* disable all strings (ignore errors) */
370 	i2c_smbus_write_byte_data(lp->client,
371 		ARCXCNN_LEDEN, 0x00);
372 	/* reset the device (ignore errors) */
373 	i2c_smbus_write_byte_data(lp->client,
374 		ARCXCNN_CMD, ARCXCNN_CMD_RESET);
375 
376 	lp->bl->props.brightness = 0;
377 
378 	backlight_update_status(lp->bl);
379 
380 	return 0;
381 }
382 
383 static const struct of_device_id arcxcnn_dt_ids[] = {
384 	{ .compatible = "arc,arc2c0608" },
385 	{ }
386 };
387 MODULE_DEVICE_TABLE(of, arcxcnn_dt_ids);
388 
389 static const struct i2c_device_id arcxcnn_ids[] = {
390 	{"arc2c0608", ARC2C0608},
391 	{ }
392 };
393 MODULE_DEVICE_TABLE(i2c, arcxcnn_ids);
394 
395 static struct i2c_driver arcxcnn_driver = {
396 	.driver = {
397 		.name = "arcxcnn_bl",
398 		.of_match_table = of_match_ptr(arcxcnn_dt_ids),
399 	},
400 	.probe = arcxcnn_probe,
401 	.remove = arcxcnn_remove,
402 	.id_table = arcxcnn_ids,
403 };
404 module_i2c_driver(arcxcnn_driver);
405 
406 MODULE_LICENSE("GPL v2");
407 MODULE_AUTHOR("Brian Dodge <bdodge@arcticsand.com>");
408 MODULE_DESCRIPTION("ARCXCNN Backlight driver");
409