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