1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * AS3711 PMIC backlight driver, using DCDC Step Up Converters |
4 | * |
5 | * Copyright (C) 2012 Renesas Electronics Corporation |
6 | * Author: Guennadi Liakhovetski, <g.liakhovetski@gmx.de> |
7 | */ |
8 | |
9 | #include <linux/backlight.h> |
10 | #include <linux/delay.h> |
11 | #include <linux/device.h> |
12 | #include <linux/err.h> |
13 | #include <linux/fb.h> |
14 | #include <linux/kernel.h> |
15 | #include <linux/mfd/as3711.h> |
16 | #include <linux/module.h> |
17 | #include <linux/platform_device.h> |
18 | #include <linux/regmap.h> |
19 | #include <linux/slab.h> |
20 | |
21 | enum as3711_bl_type { |
22 | AS3711_BL_SU1, |
23 | AS3711_BL_SU2, |
24 | }; |
25 | |
26 | struct as3711_bl_data { |
27 | bool powered; |
28 | enum as3711_bl_type type; |
29 | int brightness; |
30 | struct backlight_device *bl; |
31 | }; |
32 | |
33 | struct as3711_bl_supply { |
34 | struct as3711_bl_data su1; |
35 | struct as3711_bl_data su2; |
36 | const struct as3711_bl_pdata *pdata; |
37 | struct as3711 *as3711; |
38 | }; |
39 | |
40 | static struct as3711_bl_supply *to_supply(struct as3711_bl_data *su) |
41 | { |
42 | switch (su->type) { |
43 | case AS3711_BL_SU1: |
44 | return container_of(su, struct as3711_bl_supply, su1); |
45 | case AS3711_BL_SU2: |
46 | return container_of(su, struct as3711_bl_supply, su2); |
47 | } |
48 | return NULL; |
49 | } |
50 | |
51 | static int as3711_set_brightness_auto_i(struct as3711_bl_data *data, |
52 | unsigned int brightness) |
53 | { |
54 | struct as3711_bl_supply *supply = to_supply(su: data); |
55 | struct as3711 *as3711 = supply->as3711; |
56 | const struct as3711_bl_pdata *pdata = supply->pdata; |
57 | int ret = 0; |
58 | |
59 | /* Only all equal current values are supported */ |
60 | if (pdata->su2_auto_curr1) |
61 | ret = regmap_write(map: as3711->regmap, AS3711_CURR1_VALUE, |
62 | val: brightness); |
63 | if (!ret && pdata->su2_auto_curr2) |
64 | ret = regmap_write(map: as3711->regmap, AS3711_CURR2_VALUE, |
65 | val: brightness); |
66 | if (!ret && pdata->su2_auto_curr3) |
67 | ret = regmap_write(map: as3711->regmap, AS3711_CURR3_VALUE, |
68 | val: brightness); |
69 | |
70 | return ret; |
71 | } |
72 | |
73 | static int as3711_set_brightness_v(struct as3711 *as3711, |
74 | unsigned int brightness, |
75 | unsigned int reg) |
76 | { |
77 | if (brightness > 31) |
78 | return -EINVAL; |
79 | |
80 | return regmap_update_bits(map: as3711->regmap, reg, mask: 0xf0, |
81 | val: brightness << 4); |
82 | } |
83 | |
84 | static int as3711_bl_su2_reset(struct as3711_bl_supply *supply) |
85 | { |
86 | struct as3711 *as3711 = supply->as3711; |
87 | int ret = regmap_update_bits(map: as3711->regmap, AS3711_STEPUP_CONTROL_5, |
88 | mask: 3, val: supply->pdata->su2_fbprot); |
89 | if (!ret) |
90 | ret = regmap_update_bits(map: as3711->regmap, |
91 | AS3711_STEPUP_CONTROL_2, mask: 1, val: 0); |
92 | if (!ret) |
93 | ret = regmap_update_bits(map: as3711->regmap, |
94 | AS3711_STEPUP_CONTROL_2, mask: 1, val: 1); |
95 | return ret; |
96 | } |
97 | |
98 | /* |
99 | * Someone with less fragile or less expensive hardware could try to simplify |
100 | * the brightness adjustment procedure. |
101 | */ |
102 | static int as3711_bl_update_status(struct backlight_device *bl) |
103 | { |
104 | struct as3711_bl_data *data = bl_get_data(bl_dev: bl); |
105 | struct as3711_bl_supply *supply = to_supply(su: data); |
106 | struct as3711 *as3711 = supply->as3711; |
107 | int brightness; |
108 | int ret = 0; |
109 | |
110 | brightness = backlight_get_brightness(bd: bl); |
111 | |
112 | if (data->type == AS3711_BL_SU1) { |
113 | ret = as3711_set_brightness_v(as3711, brightness, |
114 | AS3711_STEPUP_CONTROL_1); |
115 | } else { |
116 | const struct as3711_bl_pdata *pdata = supply->pdata; |
117 | |
118 | switch (pdata->su2_feedback) { |
119 | case AS3711_SU2_VOLTAGE: |
120 | ret = as3711_set_brightness_v(as3711, brightness, |
121 | AS3711_STEPUP_CONTROL_2); |
122 | break; |
123 | case AS3711_SU2_CURR_AUTO: |
124 | ret = as3711_set_brightness_auto_i(data, brightness: brightness / 4); |
125 | if (ret < 0) |
126 | return ret; |
127 | if (brightness) { |
128 | ret = as3711_bl_su2_reset(supply); |
129 | if (ret < 0) |
130 | return ret; |
131 | udelay(500); |
132 | ret = as3711_set_brightness_auto_i(data, brightness); |
133 | } else { |
134 | ret = regmap_update_bits(map: as3711->regmap, |
135 | AS3711_STEPUP_CONTROL_2, mask: 1, val: 0); |
136 | } |
137 | break; |
138 | /* Manual one current feedback pin below */ |
139 | case AS3711_SU2_CURR1: |
140 | ret = regmap_write(map: as3711->regmap, AS3711_CURR1_VALUE, |
141 | val: brightness); |
142 | break; |
143 | case AS3711_SU2_CURR2: |
144 | ret = regmap_write(map: as3711->regmap, AS3711_CURR2_VALUE, |
145 | val: brightness); |
146 | break; |
147 | case AS3711_SU2_CURR3: |
148 | ret = regmap_write(map: as3711->regmap, AS3711_CURR3_VALUE, |
149 | val: brightness); |
150 | break; |
151 | default: |
152 | ret = -EINVAL; |
153 | } |
154 | } |
155 | if (!ret) |
156 | data->brightness = brightness; |
157 | |
158 | return ret; |
159 | } |
160 | |
161 | static int as3711_bl_get_brightness(struct backlight_device *bl) |
162 | { |
163 | struct as3711_bl_data *data = bl_get_data(bl_dev: bl); |
164 | |
165 | return data->brightness; |
166 | } |
167 | |
168 | static const struct backlight_ops as3711_bl_ops = { |
169 | .update_status = as3711_bl_update_status, |
170 | .get_brightness = as3711_bl_get_brightness, |
171 | }; |
172 | |
173 | static int as3711_bl_init_su2(struct as3711_bl_supply *supply) |
174 | { |
175 | struct as3711 *as3711 = supply->as3711; |
176 | const struct as3711_bl_pdata *pdata = supply->pdata; |
177 | u8 ctl = 0; |
178 | int ret; |
179 | |
180 | dev_dbg(as3711->dev, "%s(): use %u\n" , __func__, pdata->su2_feedback); |
181 | |
182 | /* Turn SU2 off */ |
183 | ret = regmap_write(map: as3711->regmap, AS3711_STEPUP_CONTROL_2, val: 0); |
184 | if (ret < 0) |
185 | return ret; |
186 | |
187 | switch (pdata->su2_feedback) { |
188 | case AS3711_SU2_VOLTAGE: |
189 | ret = regmap_update_bits(map: as3711->regmap, AS3711_STEPUP_CONTROL_4, mask: 3, val: 0); |
190 | break; |
191 | case AS3711_SU2_CURR1: |
192 | ctl = 1; |
193 | ret = regmap_update_bits(map: as3711->regmap, AS3711_STEPUP_CONTROL_4, mask: 3, val: 1); |
194 | break; |
195 | case AS3711_SU2_CURR2: |
196 | ctl = 4; |
197 | ret = regmap_update_bits(map: as3711->regmap, AS3711_STEPUP_CONTROL_4, mask: 3, val: 2); |
198 | break; |
199 | case AS3711_SU2_CURR3: |
200 | ctl = 0x10; |
201 | ret = regmap_update_bits(map: as3711->regmap, AS3711_STEPUP_CONTROL_4, mask: 3, val: 3); |
202 | break; |
203 | case AS3711_SU2_CURR_AUTO: |
204 | if (pdata->su2_auto_curr1) |
205 | ctl = 2; |
206 | if (pdata->su2_auto_curr2) |
207 | ctl |= 8; |
208 | if (pdata->su2_auto_curr3) |
209 | ctl |= 0x20; |
210 | ret = 0; |
211 | break; |
212 | default: |
213 | return -EINVAL; |
214 | } |
215 | |
216 | if (!ret) |
217 | ret = regmap_write(map: as3711->regmap, AS3711_CURR_CONTROL, val: ctl); |
218 | |
219 | return ret; |
220 | } |
221 | |
222 | static int as3711_bl_register(struct platform_device *pdev, |
223 | unsigned int max_brightness, struct as3711_bl_data *su) |
224 | { |
225 | struct backlight_properties props = {.type = BACKLIGHT_RAW,}; |
226 | struct backlight_device *bl; |
227 | |
228 | /* max tuning I = 31uA for voltage- and 38250uA for current-feedback */ |
229 | props.max_brightness = max_brightness; |
230 | |
231 | bl = devm_backlight_device_register(dev: &pdev->dev, |
232 | name: su->type == AS3711_BL_SU1 ? |
233 | "as3711-su1" : "as3711-su2" , |
234 | parent: &pdev->dev, devdata: su, |
235 | ops: &as3711_bl_ops, props: &props); |
236 | if (IS_ERR(ptr: bl)) { |
237 | dev_err(&pdev->dev, "failed to register backlight\n" ); |
238 | return PTR_ERR(ptr: bl); |
239 | } |
240 | |
241 | bl->props.brightness = props.max_brightness; |
242 | |
243 | backlight_update_status(bd: bl); |
244 | |
245 | su->bl = bl; |
246 | |
247 | return 0; |
248 | } |
249 | |
250 | static int as3711_backlight_parse_dt(struct device *dev) |
251 | { |
252 | struct as3711_bl_pdata *pdata = dev_get_platdata(dev); |
253 | struct device_node *bl, *fb; |
254 | int ret; |
255 | |
256 | bl = of_get_child_by_name(node: dev->parent->of_node, name: "backlight" ); |
257 | if (!bl) { |
258 | dev_dbg(dev, "backlight node not found\n" ); |
259 | return -ENODEV; |
260 | } |
261 | |
262 | fb = of_parse_phandle(np: bl, phandle_name: "su1-dev" , index: 0); |
263 | if (fb) { |
264 | of_node_put(node: fb); |
265 | |
266 | pdata->su1_fb = true; |
267 | |
268 | ret = of_property_read_u32(np: bl, propname: "su1-max-uA" , out_value: &pdata->su1_max_uA); |
269 | if (pdata->su1_max_uA <= 0) |
270 | ret = -EINVAL; |
271 | if (ret < 0) |
272 | goto err_put_bl; |
273 | } |
274 | |
275 | fb = of_parse_phandle(np: bl, phandle_name: "su2-dev" , index: 0); |
276 | if (fb) { |
277 | int count = 0; |
278 | |
279 | of_node_put(node: fb); |
280 | |
281 | pdata->su2_fb = true; |
282 | |
283 | ret = of_property_read_u32(np: bl, propname: "su2-max-uA" , out_value: &pdata->su2_max_uA); |
284 | if (pdata->su2_max_uA <= 0) |
285 | ret = -EINVAL; |
286 | if (ret < 0) |
287 | goto err_put_bl; |
288 | |
289 | if (of_property_read_bool(np: bl, propname: "su2-feedback-voltage" )) { |
290 | pdata->su2_feedback = AS3711_SU2_VOLTAGE; |
291 | count++; |
292 | } |
293 | if (of_property_read_bool(np: bl, propname: "su2-feedback-curr1" )) { |
294 | pdata->su2_feedback = AS3711_SU2_CURR1; |
295 | count++; |
296 | } |
297 | if (of_property_read_bool(np: bl, propname: "su2-feedback-curr2" )) { |
298 | pdata->su2_feedback = AS3711_SU2_CURR2; |
299 | count++; |
300 | } |
301 | if (of_property_read_bool(np: bl, propname: "su2-feedback-curr3" )) { |
302 | pdata->su2_feedback = AS3711_SU2_CURR3; |
303 | count++; |
304 | } |
305 | if (of_property_read_bool(np: bl, propname: "su2-feedback-curr-auto" )) { |
306 | pdata->su2_feedback = AS3711_SU2_CURR_AUTO; |
307 | count++; |
308 | } |
309 | if (count != 1) { |
310 | ret = -EINVAL; |
311 | goto err_put_bl; |
312 | } |
313 | |
314 | count = 0; |
315 | if (of_property_read_bool(np: bl, propname: "su2-fbprot-lx-sd4" )) { |
316 | pdata->su2_fbprot = AS3711_SU2_LX_SD4; |
317 | count++; |
318 | } |
319 | if (of_property_read_bool(np: bl, propname: "su2-fbprot-gpio2" )) { |
320 | pdata->su2_fbprot = AS3711_SU2_GPIO2; |
321 | count++; |
322 | } |
323 | if (of_property_read_bool(np: bl, propname: "su2-fbprot-gpio3" )) { |
324 | pdata->su2_fbprot = AS3711_SU2_GPIO3; |
325 | count++; |
326 | } |
327 | if (of_property_read_bool(np: bl, propname: "su2-fbprot-gpio4" )) { |
328 | pdata->su2_fbprot = AS3711_SU2_GPIO4; |
329 | count++; |
330 | } |
331 | if (count != 1) { |
332 | ret = -EINVAL; |
333 | goto err_put_bl; |
334 | } |
335 | |
336 | count = 0; |
337 | if (of_property_read_bool(np: bl, propname: "su2-auto-curr1" )) { |
338 | pdata->su2_auto_curr1 = true; |
339 | count++; |
340 | } |
341 | if (of_property_read_bool(np: bl, propname: "su2-auto-curr2" )) { |
342 | pdata->su2_auto_curr2 = true; |
343 | count++; |
344 | } |
345 | if (of_property_read_bool(np: bl, propname: "su2-auto-curr3" )) { |
346 | pdata->su2_auto_curr3 = true; |
347 | count++; |
348 | } |
349 | |
350 | /* |
351 | * At least one su2-auto-curr* must be specified iff |
352 | * AS3711_SU2_CURR_AUTO is used |
353 | */ |
354 | if (!count ^ (pdata->su2_feedback != AS3711_SU2_CURR_AUTO)) { |
355 | ret = -EINVAL; |
356 | goto err_put_bl; |
357 | } |
358 | } |
359 | |
360 | of_node_put(node: bl); |
361 | |
362 | return 0; |
363 | |
364 | err_put_bl: |
365 | of_node_put(node: bl); |
366 | |
367 | return ret; |
368 | } |
369 | |
370 | static int as3711_backlight_probe(struct platform_device *pdev) |
371 | { |
372 | struct as3711_bl_pdata *pdata = dev_get_platdata(dev: &pdev->dev); |
373 | struct as3711 *as3711 = dev_get_drvdata(dev: pdev->dev.parent); |
374 | struct as3711_bl_supply *supply; |
375 | struct as3711_bl_data *su; |
376 | unsigned int max_brightness; |
377 | int ret; |
378 | |
379 | if (!pdata) { |
380 | dev_err(&pdev->dev, "No platform data, exiting...\n" ); |
381 | return -ENODEV; |
382 | } |
383 | |
384 | if (pdev->dev.parent->of_node) { |
385 | ret = as3711_backlight_parse_dt(dev: &pdev->dev); |
386 | if (ret < 0) |
387 | return dev_err_probe(dev: &pdev->dev, err: ret, fmt: "DT parsing failed\n" ); |
388 | } |
389 | |
390 | if (!pdata->su1_fb && !pdata->su2_fb) { |
391 | dev_err(&pdev->dev, "No framebuffer specified\n" ); |
392 | return -EINVAL; |
393 | } |
394 | |
395 | /* |
396 | * Due to possible hardware damage I chose to block all modes, |
397 | * unsupported on my hardware. Anyone, wishing to use any of those modes |
398 | * will have to first review the code, then activate and test it. |
399 | */ |
400 | if (pdata->su1_fb || |
401 | pdata->su2_fbprot != AS3711_SU2_GPIO4 || |
402 | pdata->su2_feedback != AS3711_SU2_CURR_AUTO) { |
403 | dev_warn(&pdev->dev, |
404 | "Attention! An untested mode has been chosen!\n" |
405 | "Please, review the code, enable, test, and report success:-)\n" ); |
406 | return -EINVAL; |
407 | } |
408 | |
409 | supply = devm_kzalloc(dev: &pdev->dev, size: sizeof(*supply), GFP_KERNEL); |
410 | if (!supply) |
411 | return -ENOMEM; |
412 | |
413 | supply->as3711 = as3711; |
414 | supply->pdata = pdata; |
415 | |
416 | if (pdata->su1_fb) { |
417 | su = &supply->su1; |
418 | su->type = AS3711_BL_SU1; |
419 | |
420 | max_brightness = min(pdata->su1_max_uA, 31); |
421 | ret = as3711_bl_register(pdev, max_brightness, su); |
422 | if (ret < 0) |
423 | return ret; |
424 | } |
425 | |
426 | if (pdata->su2_fb) { |
427 | su = &supply->su2; |
428 | su->type = AS3711_BL_SU2; |
429 | |
430 | switch (pdata->su2_fbprot) { |
431 | case AS3711_SU2_GPIO2: |
432 | case AS3711_SU2_GPIO3: |
433 | case AS3711_SU2_GPIO4: |
434 | case AS3711_SU2_LX_SD4: |
435 | break; |
436 | default: |
437 | return -EINVAL; |
438 | } |
439 | |
440 | switch (pdata->su2_feedback) { |
441 | case AS3711_SU2_VOLTAGE: |
442 | max_brightness = min(pdata->su2_max_uA, 31); |
443 | break; |
444 | case AS3711_SU2_CURR1: |
445 | case AS3711_SU2_CURR2: |
446 | case AS3711_SU2_CURR3: |
447 | case AS3711_SU2_CURR_AUTO: |
448 | max_brightness = min(pdata->su2_max_uA / 150, 255); |
449 | break; |
450 | default: |
451 | return -EINVAL; |
452 | } |
453 | |
454 | ret = as3711_bl_init_su2(supply); |
455 | if (ret < 0) |
456 | return ret; |
457 | |
458 | ret = as3711_bl_register(pdev, max_brightness, su); |
459 | if (ret < 0) |
460 | return ret; |
461 | } |
462 | |
463 | platform_set_drvdata(pdev, data: supply); |
464 | |
465 | return 0; |
466 | } |
467 | |
468 | static struct platform_driver as3711_backlight_driver = { |
469 | .driver = { |
470 | .name = "as3711-backlight" , |
471 | }, |
472 | .probe = as3711_backlight_probe, |
473 | }; |
474 | |
475 | module_platform_driver(as3711_backlight_driver); |
476 | |
477 | MODULE_DESCRIPTION("Backlight Driver for AS3711 PMICs" ); |
478 | MODULE_AUTHOR("Guennadi Liakhovetski <g.liakhovetski@gmx.de" ); |
479 | MODULE_LICENSE("GPL v2" ); |
480 | MODULE_ALIAS("platform:as3711-backlight" ); |
481 | |