1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * sky81452-backlight.c SKY81452 backlight driver 4 * 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 0x00 22 #define SKY81452_REG1 0x01 23 #define SKY81452_REG2 0x02 24 #define SKY81452_REG4 0x04 25 #define SKY81452_REG5 0x05 26 27 /* bit mask */ 28 #define SKY81452_CS 0xFF 29 #define SKY81452_EN 0x3F 30 #define SKY81452_IGPW 0x20 31 #define SKY81452_PWMMD 0x10 32 #define SKY81452_PHASE 0x08 33 #define SKY81452_ILIM 0x04 34 #define SKY81452_VSHRT 0x03 35 #define SKY81452_OCP 0x80 36 #define SKY81452_OTMP 0x40 37 #define SKY81452_SHRT 0x3F 38 #define SKY81452_OPN 0x3F 39 40 #define SKY81452_DEFAULT_NAME "lcd-backlight" 41 #define SKY81452_MAX_BRIGHTNESS (SKY81452_CS + 1) 42 43 /** 44 * struct sky81452_platform_data 45 * @name: backlight driver name. 46 * If it is not defined, default name is lcd-backlight. 47 * @gpiod_enable:GPIO descriptor which control EN pin 48 * @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 */ 55 struct 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 68 static 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 88 static const struct backlight_ops sky81452_bl_ops = { 89 .update_status = sky81452_bl_update_status, 90 }; 91 92 static 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 } 110 111 static 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 } 140 141 static 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 } 163 164 static DEVICE_ATTR(enable, S_IWGRP | S_IWUSR, NULL, sky81452_bl_store_enable); 165 static DEVICE_ATTR(open, S_IRUGO, sky81452_bl_show_open_short, NULL); 166 static DEVICE_ATTR(short, S_IRUGO, sky81452_bl_show_open_short, NULL); 167 static DEVICE_ATTR(fault, S_IRUGO, sky81452_bl_show_fault, NULL); 168 169 static 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 NULL 175 }; 176 177 static const struct attribute_group sky81452_bl_attr_group = { 178 .attrs = sky81452_bl_attribute, 179 }; 180 181 #ifdef CONFIG_OF 182 static struct sky81452_bl_platform_data *sky81452_bl_parse_dt( 183 struct device *dev) 184 { 185 struct device_node *np = of_node_get(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 of_node_put(np); 199 return ERR_PTR(-ENOMEM); 200 } 201 202 of_property_read_string(np, "name", &pdata->name); 203 pdata->ignore_pwm = of_property_read_bool(np, "skyworks,ignore-pwm"); 204 pdata->dpwm_mode = of_property_read_bool(np, "skyworks,dpwm-mode"); 205 pdata->phase_shift = of_property_read_bool(np, "skyworks,phase-shift"); 206 pdata->gpiod_enable = devm_gpiod_get_optional(dev, NULL, GPIOD_OUT_HIGH); 207 208 ret = of_property_count_u32_elems(np, "led-sources"); 209 if (ret < 0) { 210 pdata->enable = SKY81452_EN >> CTZ(SKY81452_EN); 211 } else { 212 num_entry = ret; 213 if (num_entry > 6) 214 num_entry = 6; 215 216 ret = of_property_read_u32_array(np, "led-sources", sources, 217 num_entry); 218 if (ret < 0) { 219 dev_err(dev, "led-sources node is invalid.\n"); 220 of_node_put(np); 221 return ERR_PTR(-EINVAL); 222 } 223 224 pdata->enable = 0; 225 while (--num_entry) 226 pdata->enable |= (1 << sources[num_entry]); 227 } 228 229 ret = of_property_read_u32(np, 230 "skyworks,short-detection-threshold-volt", 231 &pdata->short_detection_threshold); 232 if (ret < 0) 233 pdata->short_detection_threshold = 7; 234 235 ret = of_property_read_u32(np, "skyworks,current-limit-mA", 236 &pdata->boost_current_limit); 237 if (ret < 0) 238 pdata->boost_current_limit = 2750; 239 240 of_node_put(np); 241 return pdata; 242 } 243 #else 244 static struct sky81452_bl_platform_data *sky81452_bl_parse_dt( 245 struct device *dev) 246 { 247 return ERR_PTR(-EINVAL); 248 } 249 #endif 250 251 static int sky81452_bl_init_device(struct regmap *regmap, 252 struct sky81452_bl_platform_data *pdata) 253 { 254 unsigned int value; 255 256 value = pdata->ignore_pwm ? SKY81452_IGPW : 0; 257 value |= pdata->dpwm_mode ? SKY81452_PWMMD : 0; 258 value |= pdata->phase_shift ? 0 : SKY81452_PHASE; 259 260 if (pdata->boost_current_limit == 2300) 261 value |= SKY81452_ILIM; 262 else if (pdata->boost_current_limit != 2750) 263 return -EINVAL; 264 265 if (pdata->short_detection_threshold < 4 || 266 pdata->short_detection_threshold > 7) 267 return -EINVAL; 268 value |= (7 - pdata->short_detection_threshold) << CTZ(SKY81452_VSHRT); 269 270 return regmap_write(regmap, SKY81452_REG2, value); 271 } 272 273 static int sky81452_bl_probe(struct platform_device *pdev) 274 { 275 struct device *dev = &pdev->dev; 276 struct regmap *regmap = dev_get_drvdata(dev->parent); 277 struct sky81452_bl_platform_data *pdata; 278 struct backlight_device *bd; 279 struct backlight_properties props; 280 const char *name; 281 int ret; 282 283 pdata = sky81452_bl_parse_dt(dev); 284 if (IS_ERR(pdata)) 285 return PTR_ERR(pdata); 286 287 ret = sky81452_bl_init_device(regmap, pdata); 288 if (ret < 0) { 289 dev_err(dev, "failed to initialize. err=%d\n", ret); 290 return ret; 291 } 292 293 memset(&props, 0, sizeof(props)); 294 props.max_brightness = SKY81452_MAX_BRIGHTNESS, 295 name = pdata->name ? pdata->name : SKY81452_DEFAULT_NAME; 296 bd = devm_backlight_device_register(dev, name, dev, regmap, 297 &sky81452_bl_ops, &props); 298 if (IS_ERR(bd)) { 299 dev_err(dev, "failed to register. err=%ld\n", PTR_ERR(bd)); 300 return PTR_ERR(bd); 301 } 302 303 platform_set_drvdata(pdev, bd); 304 305 ret = sysfs_create_group(&bd->dev.kobj, &sky81452_bl_attr_group); 306 if (ret < 0) { 307 dev_err(dev, "failed to create attribute. err=%d\n", ret); 308 return ret; 309 } 310 311 return ret; 312 } 313 314 static int sky81452_bl_remove(struct platform_device *pdev) 315 { 316 const struct sky81452_bl_platform_data *pdata = 317 dev_get_platdata(&pdev->dev); 318 struct backlight_device *bd = platform_get_drvdata(pdev); 319 320 sysfs_remove_group(&bd->dev.kobj, &sky81452_bl_attr_group); 321 322 bd->props.power = FB_BLANK_UNBLANK; 323 bd->props.brightness = 0; 324 backlight_update_status(bd); 325 326 if (pdata->gpiod_enable) 327 gpiod_set_value_cansleep(pdata->gpiod_enable, 0); 328 329 return 0; 330 } 331 332 #ifdef CONFIG_OF 333 static const struct of_device_id sky81452_bl_of_match[] = { 334 { .compatible = "skyworks,sky81452-backlight", }, 335 { } 336 }; 337 MODULE_DEVICE_TABLE(of, sky81452_bl_of_match); 338 #endif 339 340 static struct platform_driver sky81452_bl_driver = { 341 .driver = { 342 .name = "sky81452-backlight", 343 .of_match_table = of_match_ptr(sky81452_bl_of_match), 344 }, 345 .probe = sky81452_bl_probe, 346 .remove = sky81452_bl_remove, 347 }; 348 349 module_platform_driver(sky81452_bl_driver); 350 351 MODULE_DESCRIPTION("Skyworks SKY81452 backlight driver"); 352 MODULE_AUTHOR("Gyungoh Yoo <jack.yoo@skyworksinc.com>"); 353 MODULE_LICENSE("GPL v2"); 354