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 {
32 struct device *fb_dev;
33 enum as3711_bl_type type;
35 struct backlight_device *bl;
38 struct as3711_bl_supply {
39 struct as3711_bl_data su1;
40 struct as3711_bl_data su2;
41 const struct as3711_bl_pdata *pdata;
42 struct as3711 *as3711;
45 static struct as3711_bl_supply *to_supply(struct as3711_bl_data *su)
49 return container_of(su, struct as3711_bl_supply, su1);
51 return container_of(su, struct as3711_bl_supply, su2);
56 static int as3711_set_brightness_auto_i(struct as3711_bl_data *data,
57 unsigned int brightness)
59 struct as3711_bl_supply *supply = to_supply(data);
60 struct as3711 *as3711 = supply->as3711;
61 const struct as3711_bl_pdata *pdata = supply->pdata;
64 /* Only all equal current values are supported */
65 if (pdata->su2_auto_curr1)
66 ret = regmap_write(as3711->regmap, AS3711_CURR1_VALUE,
68 if (!ret && pdata->su2_auto_curr2)
69 ret = regmap_write(as3711->regmap, AS3711_CURR2_VALUE,
71 if (!ret && pdata->su2_auto_curr3)
72 ret = regmap_write(as3711->regmap, AS3711_CURR3_VALUE,
78 static int as3711_set_brightness_v(struct as3711 *as3711,
79 unsigned int brightness,
85 return regmap_update_bits(as3711->regmap, reg, 0xf0,
89 static int as3711_bl_su2_reset(struct as3711_bl_supply *supply)
91 struct as3711 *as3711 = supply->as3711;
92 int ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_5,
93 3, supply->pdata->su2_fbprot);
95 ret = regmap_update_bits(as3711->regmap,
96 AS3711_STEPUP_CONTROL_2, 1, 0);
98 ret = regmap_update_bits(as3711->regmap,
99 AS3711_STEPUP_CONTROL_2, 1, 1);
104 * Someone with less fragile or less expensive hardware could try to simplify
105 * the brightness adjustment procedure.
107 static int as3711_bl_update_status(struct backlight_device *bl)
109 struct as3711_bl_data *data = bl_get_data(bl);
110 struct as3711_bl_supply *supply = to_supply(data);
111 struct as3711 *as3711 = supply->as3711;
112 int brightness = bl->props.brightness;
115 dev_dbg(&bl->dev, "%s(): brightness %u, pwr %x, blank %x, state %x\n",
116 __func__, bl->props.brightness, bl->props.power,
117 bl->props.fb_blank, bl->props.state);
119 if (bl->props.power != FB_BLANK_UNBLANK ||
120 bl->props.fb_blank != FB_BLANK_UNBLANK ||
121 bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
124 if (data->type == AS3711_BL_SU1) {
125 ret = as3711_set_brightness_v(as3711, brightness,
126 AS3711_STEPUP_CONTROL_1);
128 const struct as3711_bl_pdata *pdata = supply->pdata;
130 switch (pdata->su2_feedback) {
131 case AS3711_SU2_VOLTAGE:
132 ret = as3711_set_brightness_v(as3711, brightness,
133 AS3711_STEPUP_CONTROL_2);
135 case AS3711_SU2_CURR_AUTO:
136 ret = as3711_set_brightness_auto_i(data, brightness / 4);
140 ret = as3711_bl_su2_reset(supply);
144 ret = as3711_set_brightness_auto_i(data, brightness);
146 ret = regmap_update_bits(as3711->regmap,
147 AS3711_STEPUP_CONTROL_2, 1, 0);
150 /* Manual one current feedback pin below */
151 case AS3711_SU2_CURR1:
152 ret = regmap_write(as3711->regmap, AS3711_CURR1_VALUE,
155 case AS3711_SU2_CURR2:
156 ret = regmap_write(as3711->regmap, AS3711_CURR2_VALUE,
159 case AS3711_SU2_CURR3:
160 ret = regmap_write(as3711->regmap, AS3711_CURR3_VALUE,
168 data->brightness = brightness;
173 static int as3711_bl_get_brightness(struct backlight_device *bl)
175 struct as3711_bl_data *data = bl_get_data(bl);
177 return data->brightness;
180 static const struct backlight_ops as3711_bl_ops = {
181 .update_status = as3711_bl_update_status,
182 .get_brightness = as3711_bl_get_brightness,
185 static int as3711_bl_init_su2(struct as3711_bl_supply *supply)
187 struct as3711 *as3711 = supply->as3711;
188 const struct as3711_bl_pdata *pdata = supply->pdata;
192 dev_dbg(as3711->dev, "%s(): use %u\n", __func__, pdata->su2_feedback);
195 ret = regmap_write(as3711->regmap, AS3711_STEPUP_CONTROL_2, 0);
199 switch (pdata->su2_feedback) {
200 case AS3711_SU2_VOLTAGE:
201 ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 0);
203 case AS3711_SU2_CURR1:
205 ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 1);
207 case AS3711_SU2_CURR2:
209 ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 2);
211 case AS3711_SU2_CURR3:
213 ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 3);
215 case AS3711_SU2_CURR_AUTO:
216 if (pdata->su2_auto_curr1)
218 if (pdata->su2_auto_curr2)
220 if (pdata->su2_auto_curr3)
229 ret = regmap_write(as3711->regmap, AS3711_CURR_CONTROL, ctl);
234 static int as3711_bl_register(struct platform_device *pdev,
235 unsigned int max_brightness, struct as3711_bl_data *su)
237 struct backlight_properties props = {.type = BACKLIGHT_RAW,};
238 struct backlight_device *bl;
240 /* max tuning I = 31uA for voltage- and 38250uA for current-feedback */
241 props.max_brightness = max_brightness;
243 bl = devm_backlight_device_register(&pdev->dev,
244 su->type == AS3711_BL_SU1 ?
245 "as3711-su1" : "as3711-su2",
247 &as3711_bl_ops, &props);
249 dev_err(&pdev->dev, "failed to register backlight\n");
253 bl->props.brightness = props.max_brightness;
255 backlight_update_status(bl);
262 static int as3711_backlight_parse_dt(struct device *dev)
264 struct as3711_bl_pdata *pdata = dev_get_platdata(dev);
265 struct device_node *bl =
266 of_find_node_by_name(dev->parent->of_node, "backlight"), *fb;
270 dev_dbg(dev, "backlight node not found\n");
274 fb = of_parse_phandle(bl, "su1-dev", 0);
276 pdata->su1_fb = fb->full_name;
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);
289 pdata->su2_fb = fb->full_name;
291 ret = of_property_read_u32(bl, "su2-max-uA", &pdata->su2_max_uA);
292 if (pdata->su2_max_uA <= 0)
297 if (of_find_property(bl, "su2-feedback-voltage", NULL)) {
298 pdata->su2_feedback = AS3711_SU2_VOLTAGE;
301 if (of_find_property(bl, "su2-feedback-curr1", NULL)) {
302 pdata->su2_feedback = AS3711_SU2_CURR1;
305 if (of_find_property(bl, "su2-feedback-curr2", NULL)) {
306 pdata->su2_feedback = AS3711_SU2_CURR2;
309 if (of_find_property(bl, "su2-feedback-curr3", NULL)) {
310 pdata->su2_feedback = AS3711_SU2_CURR3;
313 if (of_find_property(bl, "su2-feedback-curr-auto", NULL)) {
314 pdata->su2_feedback = AS3711_SU2_CURR_AUTO;
321 if (of_find_property(bl, "su2-fbprot-lx-sd4", NULL)) {
322 pdata->su2_fbprot = AS3711_SU2_LX_SD4;
325 if (of_find_property(bl, "su2-fbprot-gpio2", NULL)) {
326 pdata->su2_fbprot = AS3711_SU2_GPIO2;
329 if (of_find_property(bl, "su2-fbprot-gpio3", NULL)) {
330 pdata->su2_fbprot = AS3711_SU2_GPIO3;
333 if (of_find_property(bl, "su2-fbprot-gpio4", NULL)) {
334 pdata->su2_fbprot = AS3711_SU2_GPIO4;
341 if (of_find_property(bl, "su2-auto-curr1", NULL)) {
342 pdata->su2_auto_curr1 = true;
345 if (of_find_property(bl, "su2-auto-curr2", NULL)) {
346 pdata->su2_auto_curr2 = true;
349 if (of_find_property(bl, "su2-auto-curr3", NULL)) {
350 pdata->su2_auto_curr3 = true;
355 * At least one su2-auto-curr* must be specified iff
356 * AS3711_SU2_CURR_AUTO is used
358 if (!count ^ (pdata->su2_feedback != AS3711_SU2_CURR_AUTO))
365 static int as3711_backlight_probe(struct platform_device *pdev)
367 struct as3711_bl_pdata *pdata = dev_get_platdata(&pdev->dev);
368 struct as3711 *as3711 = dev_get_drvdata(pdev->dev.parent);
369 struct as3711_bl_supply *supply;
370 struct as3711_bl_data *su;
371 unsigned int max_brightness;
375 dev_err(&pdev->dev, "No platform data, exiting...\n");
379 if (pdev->dev.parent->of_node) {
380 ret = as3711_backlight_parse_dt(&pdev->dev);
382 dev_err(&pdev->dev, "DT parsing failed: %d\n", ret);
387 if (!pdata->su1_fb && !pdata->su2_fb) {
388 dev_err(&pdev->dev, "No framebuffer specified\n");
393 * Due to possible hardware damage I chose to block all modes,
394 * unsupported on my hardware. Anyone, wishing to use any of those modes
395 * will have to first review the code, then activate and test it.
398 pdata->su2_fbprot != AS3711_SU2_GPIO4 ||
399 pdata->su2_feedback != AS3711_SU2_CURR_AUTO) {
401 "Attention! An untested mode has been chosen!\n"
402 "Please, review the code, enable, test, and report success:-)\n");
406 supply = devm_kzalloc(&pdev->dev, sizeof(*supply), GFP_KERNEL);
410 supply->as3711 = as3711;
411 supply->pdata = pdata;
415 su->fb_name = pdata->su1_fb;
416 su->type = AS3711_BL_SU1;
418 max_brightness = min(pdata->su1_max_uA, 31);
419 ret = as3711_bl_register(pdev, max_brightness, su);
426 su->fb_name = pdata->su2_fb;
427 su->type = AS3711_BL_SU2;
429 switch (pdata->su2_fbprot) {
430 case AS3711_SU2_GPIO2:
431 case AS3711_SU2_GPIO3:
432 case AS3711_SU2_GPIO4:
433 case AS3711_SU2_LX_SD4:
439 switch (pdata->su2_feedback) {
440 case AS3711_SU2_VOLTAGE:
441 max_brightness = min(pdata->su2_max_uA, 31);
443 case AS3711_SU2_CURR1:
444 case AS3711_SU2_CURR2:
445 case AS3711_SU2_CURR3:
446 case AS3711_SU2_CURR_AUTO:
447 max_brightness = min(pdata->su2_max_uA / 150, 255);
453 ret = as3711_bl_init_su2(supply);
457 ret = as3711_bl_register(pdev, max_brightness, su);
462 platform_set_drvdata(pdev, supply);
467 static struct platform_driver as3711_backlight_driver = {
469 .name = "as3711-backlight",
471 .probe = as3711_backlight_probe,
474 module_platform_driver(as3711_backlight_driver);
476 MODULE_DESCRIPTION("Backlight Driver for AS3711 PMICs");
477 MODULE_AUTHOR("Guennadi Liakhovetski <g.liakhovetski@gmx.de");
478 MODULE_LICENSE("GPL");
479 MODULE_ALIAS("platform:as3711-backlight");