348 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * sky81452-backlight.c SKY81452 backlight driver4 *5 * Copyright 2014 Skyworks Solutions Inc.6 * Author : Gyungoh Yoo <jack.yoo@skyworksinc.com>7 */8 9#include <linux/backlight.h>10#include <linux/err.h>11#include <linux/gpio/consumer.h>12#include <linux/init.h>13#include <linux/kernel.h>14#include <linux/module.h>15#include <linux/of.h>16#include <linux/platform_device.h>17#include <linux/regmap.h>18#include <linux/slab.h>19 20/* registers */21#define SKY81452_REG0 0x0022#define SKY81452_REG1 0x0123#define SKY81452_REG2 0x0224#define SKY81452_REG4 0x0425#define SKY81452_REG5 0x0526 27/* bit mask */28#define SKY81452_CS 0xFF29#define SKY81452_EN 0x3F30#define SKY81452_IGPW 0x2031#define SKY81452_PWMMD 0x1032#define SKY81452_PHASE 0x0833#define SKY81452_ILIM 0x0434#define SKY81452_VSHRT 0x0335#define SKY81452_OCP 0x8036#define SKY81452_OTMP 0x4037#define SKY81452_SHRT 0x3F38#define SKY81452_OPN 0x3F39 40#define SKY81452_DEFAULT_NAME "lcd-backlight"41#define SKY81452_MAX_BRIGHTNESS (SKY81452_CS + 1)42 43/**44 * struct sky81452_bl_platform_data - backlight platform data45 * @name: backlight driver name.46 * If it is not defined, default name is lcd-backlight.47 * @gpiod_enable:GPIO descriptor which control EN pin48 * @enable: Enable mask for current sink channel 1, 2, 3, 4, 5 and 6.49 * @ignore_pwm: true if DPWMI should be ignored.50 * @dpwm_mode: true is DPWM dimming mode, otherwise Analog dimming mode.51 * @phase_shift:true is phase shift mode.52 * @short_detection_threshold: It should be one of 4, 5, 6 and 7V.53 * @boost_current_limit: It should be one of 2300, 2750mA.54 */55struct sky81452_bl_platform_data {56 const char *name;57 struct gpio_desc *gpiod_enable;58 unsigned int enable;59 bool ignore_pwm;60 bool dpwm_mode;61 bool phase_shift;62 unsigned int short_detection_threshold;63 unsigned int boost_current_limit;64};65 66#define CTZ(b) __builtin_ctz(b)67 68static int sky81452_bl_update_status(struct backlight_device *bd)69{70 const struct sky81452_bl_platform_data *pdata =71 dev_get_platdata(bd->dev.parent);72 const unsigned int brightness = (unsigned int)bd->props.brightness;73 struct regmap *regmap = bl_get_data(bd);74 int ret;75 76 if (brightness > 0) {77 ret = regmap_write(regmap, SKY81452_REG0, brightness - 1);78 if (ret < 0)79 return ret;80 81 return regmap_update_bits(regmap, SKY81452_REG1, SKY81452_EN,82 pdata->enable << CTZ(SKY81452_EN));83 }84 85 return regmap_update_bits(regmap, SKY81452_REG1, SKY81452_EN, 0);86}87 88static const struct backlight_ops sky81452_bl_ops = {89 .update_status = sky81452_bl_update_status,90};91 92static ssize_t sky81452_bl_store_enable(struct device *dev,93 struct device_attribute *attr, const char *buf, size_t count)94{95 struct regmap *regmap = bl_get_data(to_backlight_device(dev));96 unsigned long value;97 int ret;98 99 ret = kstrtoul(buf, 16, &value);100 if (ret < 0)101 return ret;102 103 ret = regmap_update_bits(regmap, SKY81452_REG1, SKY81452_EN,104 value << CTZ(SKY81452_EN));105 if (ret < 0)106 return ret;107 108 return count;109}110 111static ssize_t sky81452_bl_show_open_short(struct device *dev,112 struct device_attribute *attr, char *buf)113{114 struct regmap *regmap = bl_get_data(to_backlight_device(dev));115 unsigned int reg, value = 0;116 char tmp[3];117 int i, ret;118 119 reg = !strcmp(attr->attr.name, "open") ? SKY81452_REG5 : SKY81452_REG4;120 ret = regmap_read(regmap, reg, &value);121 if (ret < 0)122 return ret;123 124 if (value & SKY81452_SHRT) {125 *buf = 0;126 for (i = 0; i < 6; i++) {127 if (value & 0x01) {128 sprintf(tmp, "%d ", i + 1);129 strcat(buf, tmp);130 }131 value >>= 1;132 }133 strcat(buf, "\n");134 } else {135 strcpy(buf, "none\n");136 }137 138 return strlen(buf);139}140 141static ssize_t sky81452_bl_show_fault(struct device *dev,142 struct device_attribute *attr, char *buf)143{144 struct regmap *regmap = bl_get_data(to_backlight_device(dev));145 unsigned int value = 0;146 int ret;147 148 ret = regmap_read(regmap, SKY81452_REG4, &value);149 if (ret < 0)150 return ret;151 152 *buf = 0;153 154 if (value & SKY81452_OCP)155 strcat(buf, "over-current ");156 157 if (value & SKY81452_OTMP)158 strcat(buf, "over-temperature");159 160 strcat(buf, "\n");161 return strlen(buf);162}163 164static DEVICE_ATTR(enable, S_IWGRP | S_IWUSR, NULL, sky81452_bl_store_enable);165static DEVICE_ATTR(open, S_IRUGO, sky81452_bl_show_open_short, NULL);166static DEVICE_ATTR(short, S_IRUGO, sky81452_bl_show_open_short, NULL);167static DEVICE_ATTR(fault, S_IRUGO, sky81452_bl_show_fault, NULL);168 169static struct attribute *sky81452_bl_attribute[] = {170 &dev_attr_enable.attr,171 &dev_attr_open.attr,172 &dev_attr_short.attr,173 &dev_attr_fault.attr,174 NULL175};176 177static const struct attribute_group sky81452_bl_attr_group = {178 .attrs = sky81452_bl_attribute,179};180 181#ifdef CONFIG_OF182static struct sky81452_bl_platform_data *sky81452_bl_parse_dt(183 struct device *dev)184{185 struct device_node *np = dev->of_node;186 struct sky81452_bl_platform_data *pdata;187 int num_entry;188 unsigned int sources[6];189 int ret;190 191 if (!np) {192 dev_err(dev, "backlight node not found.\n");193 return ERR_PTR(-ENODATA);194 }195 196 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);197 if (!pdata)198 return ERR_PTR(-ENOMEM);199 200 of_property_read_string(np, "name", &pdata->name);201 pdata->ignore_pwm = of_property_read_bool(np, "skyworks,ignore-pwm");202 pdata->dpwm_mode = of_property_read_bool(np, "skyworks,dpwm-mode");203 pdata->phase_shift = of_property_read_bool(np, "skyworks,phase-shift");204 pdata->gpiod_enable = devm_gpiod_get_optional(dev, NULL, GPIOD_OUT_HIGH);205 206 ret = of_property_count_u32_elems(np, "led-sources");207 if (ret < 0) {208 pdata->enable = SKY81452_EN >> CTZ(SKY81452_EN);209 } else {210 num_entry = ret;211 if (num_entry > 6)212 num_entry = 6;213 214 ret = of_property_read_u32_array(np, "led-sources", sources,215 num_entry);216 if (ret < 0) {217 dev_err(dev, "led-sources node is invalid.\n");218 return ERR_PTR(-EINVAL);219 }220 221 pdata->enable = 0;222 while (--num_entry)223 pdata->enable |= (1 << sources[num_entry]);224 }225 226 ret = of_property_read_u32(np,227 "skyworks,short-detection-threshold-volt",228 &pdata->short_detection_threshold);229 if (ret < 0)230 pdata->short_detection_threshold = 7;231 232 ret = of_property_read_u32(np, "skyworks,current-limit-mA",233 &pdata->boost_current_limit);234 if (ret < 0)235 pdata->boost_current_limit = 2750;236 237 return pdata;238}239#else240static struct sky81452_bl_platform_data *sky81452_bl_parse_dt(241 struct device *dev)242{243 return ERR_PTR(-EINVAL);244}245#endif246 247static int sky81452_bl_init_device(struct regmap *regmap,248 struct sky81452_bl_platform_data *pdata)249{250 unsigned int value;251 252 value = pdata->ignore_pwm ? SKY81452_IGPW : 0;253 value |= pdata->dpwm_mode ? SKY81452_PWMMD : 0;254 value |= pdata->phase_shift ? 0 : SKY81452_PHASE;255 256 if (pdata->boost_current_limit == 2300)257 value |= SKY81452_ILIM;258 else if (pdata->boost_current_limit != 2750)259 return -EINVAL;260 261 if (pdata->short_detection_threshold < 4 ||262 pdata->short_detection_threshold > 7)263 return -EINVAL;264 value |= (7 - pdata->short_detection_threshold) << CTZ(SKY81452_VSHRT);265 266 return regmap_write(regmap, SKY81452_REG2, value);267}268 269static int sky81452_bl_probe(struct platform_device *pdev)270{271 struct device *dev = &pdev->dev;272 struct regmap *regmap = dev_get_drvdata(dev->parent);273 struct sky81452_bl_platform_data *pdata;274 struct backlight_device *bd;275 struct backlight_properties props;276 const char *name;277 int ret;278 279 pdata = sky81452_bl_parse_dt(dev);280 if (IS_ERR(pdata))281 return PTR_ERR(pdata);282 283 ret = sky81452_bl_init_device(regmap, pdata);284 if (ret < 0) {285 dev_err(dev, "failed to initialize. err=%d\n", ret);286 return ret;287 }288 289 memset(&props, 0, sizeof(props));290 props.max_brightness = SKY81452_MAX_BRIGHTNESS;291 name = pdata->name ? pdata->name : SKY81452_DEFAULT_NAME;292 bd = devm_backlight_device_register(dev, name, dev, regmap,293 &sky81452_bl_ops, &props);294 if (IS_ERR(bd)) {295 dev_err(dev, "failed to register. err=%ld\n", PTR_ERR(bd));296 return PTR_ERR(bd);297 }298 299 platform_set_drvdata(pdev, bd);300 301 ret = sysfs_create_group(&bd->dev.kobj, &sky81452_bl_attr_group);302 if (ret < 0) {303 dev_err(dev, "failed to create attribute. err=%d\n", ret);304 return ret;305 }306 307 return ret;308}309 310static void sky81452_bl_remove(struct platform_device *pdev)311{312 const struct sky81452_bl_platform_data *pdata =313 dev_get_platdata(&pdev->dev);314 struct backlight_device *bd = platform_get_drvdata(pdev);315 316 sysfs_remove_group(&bd->dev.kobj, &sky81452_bl_attr_group);317 318 bd->props.power = BACKLIGHT_POWER_ON;319 bd->props.brightness = 0;320 backlight_update_status(bd);321 322 if (pdata->gpiod_enable)323 gpiod_set_value_cansleep(pdata->gpiod_enable, 0);324}325 326#ifdef CONFIG_OF327static const struct of_device_id sky81452_bl_of_match[] = {328 { .compatible = "skyworks,sky81452-backlight", },329 { }330};331MODULE_DEVICE_TABLE(of, sky81452_bl_of_match);332#endif333 334static struct platform_driver sky81452_bl_driver = {335 .driver = {336 .name = "sky81452-backlight",337 .of_match_table = of_match_ptr(sky81452_bl_of_match),338 },339 .probe = sky81452_bl_probe,340 .remove_new = sky81452_bl_remove,341};342 343module_platform_driver(sky81452_bl_driver);344 345MODULE_DESCRIPTION("Skyworks SKY81452 backlight driver");346MODULE_AUTHOR("Gyungoh Yoo <jack.yoo@skyworksinc.com>");347MODULE_LICENSE("GPL v2");348