2 * AS3711 PMIC backlight driver, using DCDC Step Up Converters
4 * Copyright (C) 2012 Renesas Electronics Corporation
5 * Author: Guennadi Liakhovetski, <g.liakhovetski@gmx.de>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the version 2 of the GNU General Public License as
9 * published by the Free Software Foundation
12 #include <linux/backlight.h>
13 #include <linux/delay.h>
14 #include <linux/device.h>
15 #include <linux/err.h>
17 #include <linux/kernel.h>
18 #include <linux/mfd/as3711.h>
19 #include <linux/module.h>
20 #include <linux/platform_device.h>
21 #include <linux/regmap.h>
22 #include <linux/slab.h>
29 struct as3711_bl_data {
31 enum as3711_bl_type type;
33 struct backlight_device *bl;
36 struct as3711_bl_supply {
37 struct as3711_bl_data su1;
38 struct as3711_bl_data su2;
39 const struct as3711_bl_pdata *pdata;
40 struct as3711 *as3711;
43 static struct as3711_bl_supply *to_supply(struct as3711_bl_data *su)
47 return container_of(su, struct as3711_bl_supply, su1);
49 return container_of(su, struct as3711_bl_supply, su2);
54 static int as3711_set_brightness_auto_i(struct as3711_bl_data *data,
55 unsigned int brightness)
57 struct as3711_bl_supply *supply = to_supply(data);
58 struct as3711 *as3711 = supply->as3711;
59 const struct as3711_bl_pdata *pdata = supply->pdata;
62 /* Only all equal current values are supported */
63 if (pdata->su2_auto_curr1)
64 ret = regmap_write(as3711->regmap, AS3711_CURR1_VALUE,
66 if (!ret && pdata->su2_auto_curr2)
67 ret = regmap_write(as3711->regmap, AS3711_CURR2_VALUE,
69 if (!ret && pdata->su2_auto_curr3)
70 ret = regmap_write(as3711->regmap, AS3711_CURR3_VALUE,
76 static int as3711_set_brightness_v(struct as3711 *as3711,
77 unsigned int brightness,
83 return regmap_update_bits(as3711->regmap, reg, 0xf0,
87 static int as3711_bl_su2_reset(struct as3711_bl_supply *supply)
89 struct as3711 *as3711 = supply->as3711;
90 int ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_5,
91 3, supply->pdata->su2_fbprot);
93 ret = regmap_update_bits(as3711->regmap,
94 AS3711_STEPUP_CONTROL_2, 1, 0);
96 ret = regmap_update_bits(as3711->regmap,
97 AS3711_STEPUP_CONTROL_2, 1, 1);
102 * Someone with less fragile or less expensive hardware could try to simplify
103 * the brightness adjustment procedure.
105 static int as3711_bl_update_status(struct backlight_device *bl)
107 struct as3711_bl_data *data = bl_get_data(bl);
108 struct as3711_bl_supply *supply = to_supply(data);
109 struct as3711 *as3711 = supply->as3711;
110 int brightness = bl->props.brightness;
113 dev_dbg(&bl->dev, "%s(): brightness %u, pwr %x, blank %x, state %x\n",
114 __func__, bl->props.brightness, bl->props.power,
115 bl->props.fb_blank, bl->props.state);
117 if (bl->props.power != FB_BLANK_UNBLANK ||
118 bl->props.fb_blank != FB_BLANK_UNBLANK ||
119 bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
122 if (data->type == AS3711_BL_SU1) {
123 ret = as3711_set_brightness_v(as3711, brightness,
124 AS3711_STEPUP_CONTROL_1);
126 const struct as3711_bl_pdata *pdata = supply->pdata;
128 switch (pdata->su2_feedback) {
129 case AS3711_SU2_VOLTAGE:
130 ret = as3711_set_brightness_v(as3711, brightness,
131 AS3711_STEPUP_CONTROL_2);
133 case AS3711_SU2_CURR_AUTO:
134 ret = as3711_set_brightness_auto_i(data, brightness / 4);
138 ret = as3711_bl_su2_reset(supply);
142 ret = as3711_set_brightness_auto_i(data, brightness);
144 ret = regmap_update_bits(as3711->regmap,
145 AS3711_STEPUP_CONTROL_2, 1, 0);
148 /* Manual one current feedback pin below */
149 case AS3711_SU2_CURR1:
150 ret = regmap_write(as3711->regmap, AS3711_CURR1_VALUE,
153 case AS3711_SU2_CURR2:
154 ret = regmap_write(as3711->regmap, AS3711_CURR2_VALUE,
157 case AS3711_SU2_CURR3:
158 ret = regmap_write(as3711->regmap, AS3711_CURR3_VALUE,
166 data->brightness = brightness;
171 static int as3711_bl_get_brightness(struct backlight_device *bl)
173 struct as3711_bl_data *data = bl_get_data(bl);
175 return data->brightness;
178 static const struct backlight_ops as3711_bl_ops = {
179 .update_status = as3711_bl_update_status,
180 .get_brightness = as3711_bl_get_brightness,
183 static int as3711_bl_init_su2(struct as3711_bl_supply *supply)
185 struct as3711 *as3711 = supply->as3711;
186 const struct as3711_bl_pdata *pdata = supply->pdata;
190 dev_dbg(as3711->dev, "%s(): use %u\n", __func__, pdata->su2_feedback);
193 ret = regmap_write(as3711->regmap, AS3711_STEPUP_CONTROL_2, 0);
197 switch (pdata->su2_feedback) {
198 case AS3711_SU2_VOLTAGE:
199 ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 0);
201 case AS3711_SU2_CURR1:
203 ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 1);
205 case AS3711_SU2_CURR2:
207 ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 2);
209 case AS3711_SU2_CURR3:
211 ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 3);
213 case AS3711_SU2_CURR_AUTO:
214 if (pdata->su2_auto_curr1)
216 if (pdata->su2_auto_curr2)
218 if (pdata->su2_auto_curr3)
227 ret = regmap_write(as3711->regmap, AS3711_CURR_CONTROL, ctl);
232 static int as3711_bl_register(struct platform_device *pdev,
233 unsigned int max_brightness, struct as3711_bl_data *su)
235 struct backlight_properties props = {.type = BACKLIGHT_RAW,};
236 struct backlight_device *bl;
238 /* max tuning I = 31uA for voltage- and 38250uA for current-feedback */
239 props.max_brightness = max_brightness;
241 bl = devm_backlight_device_register(&pdev->dev,
242 su->type == AS3711_BL_SU1 ?
243 "as3711-su1" : "as3711-su2",
245 &as3711_bl_ops, &props);
247 dev_err(&pdev->dev, "failed to register backlight\n");
251 bl->props.brightness = props.max_brightness;
253 backlight_update_status(bl);
260 static int as3711_backlight_parse_dt(struct device *dev)
262 struct as3711_bl_pdata *pdata = dev_get_platdata(dev);
263 struct device_node *bl, *fb;
266 bl = of_get_child_by_name(dev->parent->of_node, "backlight");
268 dev_dbg(dev, "backlight node not found\n");
272 fb = of_parse_phandle(bl, "su1-dev", 0);
276 pdata->su1_fb = true;
278 ret = of_property_read_u32(bl, "su1-max-uA", &pdata->su1_max_uA);
279 if (pdata->su1_max_uA <= 0)
285 fb = of_parse_phandle(bl, "su2-dev", 0);
291 pdata->su2_fb = true;
293 ret = of_property_read_u32(bl, "su2-max-uA", &pdata->su2_max_uA);
294 if (pdata->su2_max_uA <= 0)
299 if (of_find_property(bl, "su2-feedback-voltage", NULL)) {
300 pdata->su2_feedback = AS3711_SU2_VOLTAGE;
303 if (of_find_property(bl, "su2-feedback-curr1", NULL)) {
304 pdata->su2_feedback = AS3711_SU2_CURR1;
307 if (of_find_property(bl, "su2-feedback-curr2", NULL)) {
308 pdata->su2_feedback = AS3711_SU2_CURR2;
311 if (of_find_property(bl, "su2-feedback-curr3", NULL)) {
312 pdata->su2_feedback = AS3711_SU2_CURR3;
315 if (of_find_property(bl, "su2-feedback-curr-auto", NULL)) {
316 pdata->su2_feedback = AS3711_SU2_CURR_AUTO;
325 if (of_find_property(bl, "su2-fbprot-lx-sd4", NULL)) {
326 pdata->su2_fbprot = AS3711_SU2_LX_SD4;
329 if (of_find_property(bl, "su2-fbprot-gpio2", NULL)) {
330 pdata->su2_fbprot = AS3711_SU2_GPIO2;
333 if (of_find_property(bl, "su2-fbprot-gpio3", NULL)) {
334 pdata->su2_fbprot = AS3711_SU2_GPIO3;
337 if (of_find_property(bl, "su2-fbprot-gpio4", NULL)) {
338 pdata->su2_fbprot = AS3711_SU2_GPIO4;
347 if (of_find_property(bl, "su2-auto-curr1", NULL)) {
348 pdata->su2_auto_curr1 = true;
351 if (of_find_property(bl, "su2-auto-curr2", NULL)) {
352 pdata->su2_auto_curr2 = true;
355 if (of_find_property(bl, "su2-auto-curr3", NULL)) {
356 pdata->su2_auto_curr3 = true;
361 * At least one su2-auto-curr* must be specified iff
362 * AS3711_SU2_CURR_AUTO is used
364 if (!count ^ (pdata->su2_feedback != AS3711_SU2_CURR_AUTO)) {
380 static int as3711_backlight_probe(struct platform_device *pdev)
382 struct as3711_bl_pdata *pdata = dev_get_platdata(&pdev->dev);
383 struct as3711 *as3711 = dev_get_drvdata(pdev->dev.parent);
384 struct as3711_bl_supply *supply;
385 struct as3711_bl_data *su;
386 unsigned int max_brightness;
390 dev_err(&pdev->dev, "No platform data, exiting...\n");
394 if (pdev->dev.parent->of_node) {
395 ret = as3711_backlight_parse_dt(&pdev->dev);
397 dev_err(&pdev->dev, "DT parsing failed: %d\n", ret);
402 if (!pdata->su1_fb && !pdata->su2_fb) {
403 dev_err(&pdev->dev, "No framebuffer specified\n");
408 * Due to possible hardware damage I chose to block all modes,
409 * unsupported on my hardware. Anyone, wishing to use any of those modes
410 * will have to first review the code, then activate and test it.
413 pdata->su2_fbprot != AS3711_SU2_GPIO4 ||
414 pdata->su2_feedback != AS3711_SU2_CURR_AUTO) {
416 "Attention! An untested mode has been chosen!\n"
417 "Please, review the code, enable, test, and report success:-)\n");
421 supply = devm_kzalloc(&pdev->dev, sizeof(*supply), GFP_KERNEL);
425 supply->as3711 = as3711;
426 supply->pdata = pdata;
430 su->type = AS3711_BL_SU1;
432 max_brightness = min(pdata->su1_max_uA, 31);
433 ret = as3711_bl_register(pdev, max_brightness, su);
440 su->type = AS3711_BL_SU2;
442 switch (pdata->su2_fbprot) {
443 case AS3711_SU2_GPIO2:
444 case AS3711_SU2_GPIO3:
445 case AS3711_SU2_GPIO4:
446 case AS3711_SU2_LX_SD4:
452 switch (pdata->su2_feedback) {
453 case AS3711_SU2_VOLTAGE:
454 max_brightness = min(pdata->su2_max_uA, 31);
456 case AS3711_SU2_CURR1:
457 case AS3711_SU2_CURR2:
458 case AS3711_SU2_CURR3:
459 case AS3711_SU2_CURR_AUTO:
460 max_brightness = min(pdata->su2_max_uA / 150, 255);
466 ret = as3711_bl_init_su2(supply);
470 ret = as3711_bl_register(pdev, max_brightness, su);
475 platform_set_drvdata(pdev, supply);
480 static struct platform_driver as3711_backlight_driver = {
482 .name = "as3711-backlight",
484 .probe = as3711_backlight_probe,
487 module_platform_driver(as3711_backlight_driver);
489 MODULE_DESCRIPTION("Backlight Driver for AS3711 PMICs");
490 MODULE_AUTHOR("Guennadi Liakhovetski <g.liakhovetski@gmx.de");
491 MODULE_LICENSE("GPL");
492 MODULE_ALIAS("platform:as3711-backlight");