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1// SPDX-License-Identifier: GPL-2.02/*3 * AS3711 PMIC backlight driver, using DCDC Step Up Converters4 *5 * Copyright (C) 2012 Renesas Electronics Corporation6 * 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 21enum as3711_bl_type {22 AS3711_BL_SU1,23 AS3711_BL_SU2,24};25 26struct as3711_bl_data {27 bool powered;28 enum as3711_bl_type type;29 int brightness;30 struct backlight_device *bl;31};32 33struct 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 40static 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 51static int as3711_set_brightness_auto_i(struct as3711_bl_data *data,52 unsigned int brightness)53{54 struct as3711_bl_supply *supply = to_supply(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(as3711->regmap, AS3711_CURR1_VALUE,62 brightness);63 if (!ret && pdata->su2_auto_curr2)64 ret = regmap_write(as3711->regmap, AS3711_CURR2_VALUE,65 brightness);66 if (!ret && pdata->su2_auto_curr3)67 ret = regmap_write(as3711->regmap, AS3711_CURR3_VALUE,68 brightness);69 70 return ret;71}72 73static 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(as3711->regmap, reg, 0xf0,81 brightness << 4);82}83 84static int as3711_bl_su2_reset(struct as3711_bl_supply *supply)85{86 struct as3711 *as3711 = supply->as3711;87 int ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_5,88 3, supply->pdata->su2_fbprot);89 if (!ret)90 ret = regmap_update_bits(as3711->regmap,91 AS3711_STEPUP_CONTROL_2, 1, 0);92 if (!ret)93 ret = regmap_update_bits(as3711->regmap,94 AS3711_STEPUP_CONTROL_2, 1, 1);95 return ret;96}97 98/*99 * Someone with less fragile or less expensive hardware could try to simplify100 * the brightness adjustment procedure.101 */102static int as3711_bl_update_status(struct backlight_device *bl)103{104 struct as3711_bl_data *data = bl_get_data(bl);105 struct as3711_bl_supply *supply = to_supply(data);106 struct as3711 *as3711 = supply->as3711;107 int brightness;108 int ret = 0;109 110 brightness = backlight_get_brightness(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 / 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(as3711->regmap,135 AS3711_STEPUP_CONTROL_2, 1, 0);136 }137 break;138 /* Manual one current feedback pin below */139 case AS3711_SU2_CURR1:140 ret = regmap_write(as3711->regmap, AS3711_CURR1_VALUE,141 brightness);142 break;143 case AS3711_SU2_CURR2:144 ret = regmap_write(as3711->regmap, AS3711_CURR2_VALUE,145 brightness);146 break;147 case AS3711_SU2_CURR3:148 ret = regmap_write(as3711->regmap, AS3711_CURR3_VALUE,149 brightness);150 break;151 default:152 ret = -EINVAL;153 }154 }155 if (!ret)156 data->brightness = brightness;157 158 return ret;159}160 161static int as3711_bl_get_brightness(struct backlight_device *bl)162{163 struct as3711_bl_data *data = bl_get_data(bl);164 165 return data->brightness;166}167 168static const struct backlight_ops as3711_bl_ops = {169 .update_status = as3711_bl_update_status,170 .get_brightness = as3711_bl_get_brightness,171};172 173static 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(as3711->regmap, AS3711_STEPUP_CONTROL_2, 0);184 if (ret < 0)185 return ret;186 187 switch (pdata->su2_feedback) {188 case AS3711_SU2_VOLTAGE:189 ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 0);190 break;191 case AS3711_SU2_CURR1:192 ctl = 1;193 ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 1);194 break;195 case AS3711_SU2_CURR2:196 ctl = 4;197 ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 2);198 break;199 case AS3711_SU2_CURR3:200 ctl = 0x10;201 ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 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(as3711->regmap, AS3711_CURR_CONTROL, ctl);218 219 return ret;220}221 222static 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(&pdev->dev,232 su->type == AS3711_BL_SU1 ?233 "as3711-su1" : "as3711-su2",234 &pdev->dev, su,235 &as3711_bl_ops, &props);236 if (IS_ERR(bl)) {237 dev_err(&pdev->dev, "failed to register backlight\n");238 return PTR_ERR(bl);239 }240 241 bl->props.brightness = props.max_brightness;242 243 backlight_update_status(bl);244 245 su->bl = bl;246 247 return 0;248}249 250static 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(dev->parent->of_node, "backlight");257 if (!bl) {258 dev_dbg(dev, "backlight node not found\n");259 return -ENODEV;260 }261 262 fb = of_parse_phandle(bl, "su1-dev", 0);263 if (fb) {264 of_node_put(fb);265 266 pdata->su1_fb = true;267 268 ret = of_property_read_u32(bl, "su1-max-uA", &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(bl, "su2-dev", 0);276 if (fb) {277 int count = 0;278 279 of_node_put(fb);280 281 pdata->su2_fb = true;282 283 ret = of_property_read_u32(bl, "su2-max-uA", &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(bl, "su2-feedback-voltage")) {290 pdata->su2_feedback = AS3711_SU2_VOLTAGE;291 count++;292 }293 if (of_property_read_bool(bl, "su2-feedback-curr1")) {294 pdata->su2_feedback = AS3711_SU2_CURR1;295 count++;296 }297 if (of_property_read_bool(bl, "su2-feedback-curr2")) {298 pdata->su2_feedback = AS3711_SU2_CURR2;299 count++;300 }301 if (of_property_read_bool(bl, "su2-feedback-curr3")) {302 pdata->su2_feedback = AS3711_SU2_CURR3;303 count++;304 }305 if (of_property_read_bool(bl, "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(bl, "su2-fbprot-lx-sd4")) {316 pdata->su2_fbprot = AS3711_SU2_LX_SD4;317 count++;318 }319 if (of_property_read_bool(bl, "su2-fbprot-gpio2")) {320 pdata->su2_fbprot = AS3711_SU2_GPIO2;321 count++;322 }323 if (of_property_read_bool(bl, "su2-fbprot-gpio3")) {324 pdata->su2_fbprot = AS3711_SU2_GPIO3;325 count++;326 }327 if (of_property_read_bool(bl, "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(bl, "su2-auto-curr1")) {338 pdata->su2_auto_curr1 = true;339 count++;340 }341 if (of_property_read_bool(bl, "su2-auto-curr2")) {342 pdata->su2_auto_curr2 = true;343 count++;344 }345 if (of_property_read_bool(bl, "su2-auto-curr3")) {346 pdata->su2_auto_curr3 = true;347 count++;348 }349 350 /*351 * At least one su2-auto-curr* must be specified iff352 * AS3711_SU2_CURR_AUTO is used353 */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(bl);361 362 return 0;363 364err_put_bl:365 of_node_put(bl);366 367 return ret;368}369 370static int as3711_backlight_probe(struct platform_device *pdev)371{372 struct as3711_bl_pdata *pdata = dev_get_platdata(&pdev->dev);373 struct as3711 *as3711 = dev_get_drvdata(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(&pdev->dev);386 if (ret < 0)387 return dev_err_probe(&pdev->dev, ret, "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 modes398 * 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(&pdev->dev, 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, supply);464 465 return 0;466}467 468static struct platform_driver as3711_backlight_driver = {469 .driver = {470 .name = "as3711-backlight",471 },472 .probe = as3711_backlight_probe,473};474 475module_platform_driver(as3711_backlight_driver);476 477MODULE_DESCRIPTION("Backlight Driver for AS3711 PMICs");478MODULE_AUTHOR("Guennadi Liakhovetski <g.liakhovetski@gmx.de");479MODULE_LICENSE("GPL v2");480MODULE_ALIAS("platform:as3711-backlight");481