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 = backlight_get_brightness(bl);
134 int ret;
135
136 ret = arcxcnn_set_brightness(lp, brightness);
137 if (ret)
138 return ret;
139
140 /* set power-on/off/save modes */
141 return arcxcnn_update_field(lp, ARCXCNN_CMD, ARCXCNN_CMD_STDBY,
142 (bl->props.power == 0) ? 0 : ARCXCNN_CMD_STDBY);
143 }
144
145 static const struct backlight_ops arcxcnn_bl_ops = {
146 .options = BL_CORE_SUSPENDRESUME,
147 .update_status = arcxcnn_bl_update_status,
148 };
149
arcxcnn_backlight_register(struct arcxcnn * lp)150 static int arcxcnn_backlight_register(struct arcxcnn *lp)
151 {
152 struct backlight_properties *props;
153 const char *name = lp->pdata->name ? : "arctic_bl";
154
155 props = devm_kzalloc(lp->dev, sizeof(*props), GFP_KERNEL);
156 if (!props)
157 return -ENOMEM;
158
159 props->type = BACKLIGHT_PLATFORM;
160 props->max_brightness = MAX_BRIGHTNESS;
161
162 if (lp->pdata->initial_brightness > props->max_brightness)
163 lp->pdata->initial_brightness = props->max_brightness;
164
165 props->brightness = lp->pdata->initial_brightness;
166
167 lp->bl = devm_backlight_device_register(lp->dev, name, lp->dev, lp,
168 &arcxcnn_bl_ops, props);
169 return PTR_ERR_OR_ZERO(lp->bl);
170 }
171
arcxcnn_parse_dt(struct arcxcnn * lp)172 static void arcxcnn_parse_dt(struct arcxcnn *lp)
173 {
174 struct device *dev = lp->dev;
175 struct device_node *node = dev->of_node;
176 u32 prog_val, num_entry, entry, sources[ARCXCNN_LEDEN_BITS];
177 int ret;
178
179 /* device tree entry isn't required, defaults are OK */
180 if (!node)
181 return;
182
183 ret = of_property_read_string(node, "label", &lp->pdata->name);
184 if (ret < 0)
185 lp->pdata->name = NULL;
186
187 ret = of_property_read_u32(node, "default-brightness", &prog_val);
188 if (ret == 0)
189 lp->pdata->initial_brightness = prog_val;
190
191 ret = of_property_read_u32(node, "arc,led-config-0", &prog_val);
192 if (ret == 0)
193 lp->pdata->led_config_0 = (u8)prog_val;
194
195 ret = of_property_read_u32(node, "arc,led-config-1", &prog_val);
196 if (ret == 0)
197 lp->pdata->led_config_1 = (u8)prog_val;
198
199 ret = of_property_read_u32(node, "arc,dim-freq", &prog_val);
200 if (ret == 0)
201 lp->pdata->dim_freq = (u8)prog_val;
202
203 ret = of_property_read_u32(node, "arc,comp-config", &prog_val);
204 if (ret == 0)
205 lp->pdata->comp_config = (u8)prog_val;
206
207 ret = of_property_read_u32(node, "arc,filter-config", &prog_val);
208 if (ret == 0)
209 lp->pdata->filter_config = (u8)prog_val;
210
211 ret = of_property_read_u32(node, "arc,trim-config", &prog_val);
212 if (ret == 0)
213 lp->pdata->trim_config = (u8)prog_val;
214
215 ret = of_property_count_u32_elems(node, "led-sources");
216 if (ret < 0) {
217 lp->pdata->leden = ARCXCNN_LEDEN_MASK; /* all on is default */
218 } else {
219 num_entry = ret;
220 if (num_entry > ARCXCNN_LEDEN_BITS)
221 num_entry = ARCXCNN_LEDEN_BITS;
222
223 ret = of_property_read_u32_array(node, "led-sources", sources,
224 num_entry);
225 if (ret < 0) {
226 dev_err(dev, "led-sources node is invalid.\n");
227 return;
228 }
229
230 lp->pdata->leden = 0;
231
232 /* for each enable in source, set bit in led enable */
233 for (entry = 0; entry < num_entry; entry++) {
234 u8 onbit = 1 << sources[entry];
235
236 lp->pdata->leden |= onbit;
237 }
238 }
239 }
240
arcxcnn_probe(struct i2c_client * cl)241 static int arcxcnn_probe(struct i2c_client *cl)
242 {
243 struct arcxcnn *lp;
244 int ret;
245
246 if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
247 return -EIO;
248
249 lp = devm_kzalloc(&cl->dev, sizeof(*lp), GFP_KERNEL);
250 if (!lp)
251 return -ENOMEM;
252
253 lp->client = cl;
254 lp->dev = &cl->dev;
255 lp->pdata = dev_get_platdata(&cl->dev);
256
257 /* reset the device */
258 ret = i2c_smbus_write_byte_data(lp->client,
259 ARCXCNN_CMD, ARCXCNN_CMD_RESET);
260 if (ret)
261 goto probe_err;
262
263 if (!lp->pdata) {
264 lp->pdata = devm_kzalloc(lp->dev,
265 sizeof(*lp->pdata), GFP_KERNEL);
266 if (!lp->pdata)
267 return -ENOMEM;
268
269 /* Setup defaults based on power-on defaults */
270 lp->pdata->name = NULL;
271 lp->pdata->initial_brightness = INIT_BRIGHT;
272 lp->pdata->leden = ARCXCNN_LEDEN_MASK;
273
274 lp->pdata->led_config_0 = i2c_smbus_read_byte_data(
275 lp->client, ARCXCNN_FADECTRL);
276
277 lp->pdata->led_config_1 = i2c_smbus_read_byte_data(
278 lp->client, ARCXCNN_ILED_CONFIG);
279 /* insure dim mode is not default pwm */
280 lp->pdata->led_config_1 |= ARCXCNN_ILED_DIM_INT;
281
282 lp->pdata->dim_freq = i2c_smbus_read_byte_data(
283 lp->client, ARCXCNN_DIMFREQ);
284
285 lp->pdata->comp_config = i2c_smbus_read_byte_data(
286 lp->client, ARCXCNN_COMP_CONFIG);
287
288 lp->pdata->filter_config = i2c_smbus_read_byte_data(
289 lp->client, ARCXCNN_FILT_CONFIG);
290
291 lp->pdata->trim_config = i2c_smbus_read_byte_data(
292 lp->client, ARCXCNN_IMAXTUNE);
293
294 if (IS_ENABLED(CONFIG_OF))
295 arcxcnn_parse_dt(lp);
296 }
297
298 i2c_set_clientdata(cl, lp);
299
300 /* constrain settings to what is possible */
301 if (lp->pdata->initial_brightness > MAX_BRIGHTNESS)
302 lp->pdata->initial_brightness = MAX_BRIGHTNESS;
303
304 /* set initial brightness */
305 ret = arcxcnn_set_brightness(lp, lp->pdata->initial_brightness);
306 if (ret)
307 goto probe_err;
308
309 /* set other register values directly */
310 ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_FADECTRL,
311 lp->pdata->led_config_0);
312 if (ret)
313 goto probe_err;
314
315 ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_ILED_CONFIG,
316 lp->pdata->led_config_1);
317 if (ret)
318 goto probe_err;
319
320 ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_DIMFREQ,
321 lp->pdata->dim_freq);
322 if (ret)
323 goto probe_err;
324
325 ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_COMP_CONFIG,
326 lp->pdata->comp_config);
327 if (ret)
328 goto probe_err;
329
330 ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_FILT_CONFIG,
331 lp->pdata->filter_config);
332 if (ret)
333 goto probe_err;
334
335 ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_IMAXTUNE,
336 lp->pdata->trim_config);
337 if (ret)
338 goto probe_err;
339
340 /* set initial LED Enables */
341 arcxcnn_update_field(lp, ARCXCNN_LEDEN,
342 ARCXCNN_LEDEN_MASK, lp->pdata->leden);
343
344 ret = arcxcnn_backlight_register(lp);
345 if (ret)
346 goto probe_register_err;
347
348 backlight_update_status(lp->bl);
349
350 return 0;
351
352 probe_register_err:
353 dev_err(lp->dev,
354 "failed to register backlight.\n");
355
356 probe_err:
357 dev_err(lp->dev,
358 "failure ret: %d\n", ret);
359 return ret;
360 }
361
arcxcnn_remove(struct i2c_client * cl)362 static void arcxcnn_remove(struct i2c_client *cl)
363 {
364 struct arcxcnn *lp = i2c_get_clientdata(cl);
365
366 /* disable all strings (ignore errors) */
367 i2c_smbus_write_byte_data(lp->client,
368 ARCXCNN_LEDEN, 0x00);
369 /* reset the device (ignore errors) */
370 i2c_smbus_write_byte_data(lp->client,
371 ARCXCNN_CMD, ARCXCNN_CMD_RESET);
372
373 lp->bl->props.brightness = 0;
374
375 backlight_update_status(lp->bl);
376 }
377
378 static const struct of_device_id arcxcnn_dt_ids[] = {
379 { .compatible = "arc,arc2c0608" },
380 { }
381 };
382 MODULE_DEVICE_TABLE(of, arcxcnn_dt_ids);
383
384 static const struct i2c_device_id arcxcnn_ids[] = {
385 {"arc2c0608", ARC2C0608},
386 { }
387 };
388 MODULE_DEVICE_TABLE(i2c, arcxcnn_ids);
389
390 static struct i2c_driver arcxcnn_driver = {
391 .driver = {
392 .name = "arcxcnn_bl",
393 .of_match_table = arcxcnn_dt_ids,
394 },
395 .probe = arcxcnn_probe,
396 .remove = arcxcnn_remove,
397 .id_table = arcxcnn_ids,
398 };
399 module_i2c_driver(arcxcnn_driver);
400
401 MODULE_LICENSE("GPL v2");
402 MODULE_AUTHOR("Brian Dodge <bdodge@arcticsand.com>");
403 MODULE_DESCRIPTION("ARCXCNN Backlight driver");
404