1 /* 2 * sky81452-backlight.c SKY81452 backlight driver 3 * 4 * Copyright 2014 Skyworks Solutions Inc. 5 * Author : Gyungoh Yoo <jack.yoo@skyworksinc.com> 6 * 7 * This program is free software; you can redistribute it and/or modify it 8 * under the terms of the GNU General Public License version 2 9 * as published by the Free Software Foundation. 10 * 11 * This program is distributed in the hope that it will be useful, but 12 * WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 * General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License along 17 * with this program; if not, see <http://www.gnu.org/licenses/>. 18 */ 19 20 #include <linux/backlight.h> 21 #include <linux/err.h> 22 #include <linux/gpio.h> 23 #include <linux/init.h> 24 #include <linux/kernel.h> 25 #include <linux/module.h> 26 #include <linux/of.h> 27 #include <linux/of_gpio.h> 28 #include <linux/platform_device.h> 29 #include <linux/regmap.h> 30 #include <linux/platform_data/sky81452-backlight.h> 31 #include <linux/slab.h> 32 33 /* registers */ 34 #define SKY81452_REG0 0x00 35 #define SKY81452_REG1 0x01 36 #define SKY81452_REG2 0x02 37 #define SKY81452_REG4 0x04 38 #define SKY81452_REG5 0x05 39 40 /* bit mask */ 41 #define SKY81452_CS 0xFF 42 #define SKY81452_EN 0x3F 43 #define SKY81452_IGPW 0x20 44 #define SKY81452_PWMMD 0x10 45 #define SKY81452_PHASE 0x08 46 #define SKY81452_ILIM 0x04 47 #define SKY81452_VSHRT 0x03 48 #define SKY81452_OCP 0x80 49 #define SKY81452_OTMP 0x40 50 #define SKY81452_SHRT 0x3F 51 #define SKY81452_OPN 0x3F 52 53 #define SKY81452_DEFAULT_NAME "lcd-backlight" 54 #define SKY81452_MAX_BRIGHTNESS (SKY81452_CS + 1) 55 56 #define CTZ(b) __builtin_ctz(b) 57 58 static int sky81452_bl_update_status(struct backlight_device *bd) 59 { 60 const struct sky81452_bl_platform_data *pdata = 61 dev_get_platdata(bd->dev.parent); 62 const unsigned int brightness = (unsigned int)bd->props.brightness; 63 struct regmap *regmap = bl_get_data(bd); 64 int ret; 65 66 if (brightness > 0) { 67 ret = regmap_write(regmap, SKY81452_REG0, brightness - 1); 68 if (IS_ERR_VALUE(ret)) 69 return ret; 70 71 return regmap_update_bits(regmap, SKY81452_REG1, SKY81452_EN, 72 pdata->enable << CTZ(SKY81452_EN)); 73 } 74 75 return regmap_update_bits(regmap, SKY81452_REG1, SKY81452_EN, 0); 76 } 77 78 static const struct backlight_ops sky81452_bl_ops = { 79 .update_status = sky81452_bl_update_status, 80 }; 81 82 static ssize_t sky81452_bl_store_enable(struct device *dev, 83 struct device_attribute *attr, const char *buf, size_t count) 84 { 85 struct regmap *regmap = bl_get_data(to_backlight_device(dev)); 86 unsigned long value; 87 int ret; 88 89 ret = kstrtoul(buf, 16, &value); 90 if (IS_ERR_VALUE(ret)) 91 return ret; 92 93 ret = regmap_update_bits(regmap, SKY81452_REG1, SKY81452_EN, 94 value << CTZ(SKY81452_EN)); 95 if (IS_ERR_VALUE(ret)) 96 return ret; 97 98 return count; 99 } 100 101 static ssize_t sky81452_bl_show_open_short(struct device *dev, 102 struct device_attribute *attr, char *buf) 103 { 104 struct regmap *regmap = bl_get_data(to_backlight_device(dev)); 105 unsigned int reg, value = 0; 106 char tmp[3]; 107 int i, ret; 108 109 reg = !strcmp(attr->attr.name, "open") ? SKY81452_REG5 : SKY81452_REG4; 110 ret = regmap_read(regmap, reg, &value); 111 if (IS_ERR_VALUE(ret)) 112 return ret; 113 114 if (value & SKY81452_SHRT) { 115 *buf = 0; 116 for (i = 0; i < 6; i++) { 117 if (value & 0x01) { 118 sprintf(tmp, "%d ", i + 1); 119 strcat(buf, tmp); 120 } 121 value >>= 1; 122 } 123 strcat(buf, "\n"); 124 } else { 125 strcpy(buf, "none\n"); 126 } 127 128 return strlen(buf); 129 } 130 131 static ssize_t sky81452_bl_show_fault(struct device *dev, 132 struct device_attribute *attr, char *buf) 133 { 134 struct regmap *regmap = bl_get_data(to_backlight_device(dev)); 135 unsigned int value = 0; 136 int ret; 137 138 ret = regmap_read(regmap, SKY81452_REG4, &value); 139 if (IS_ERR_VALUE(ret)) 140 return ret; 141 142 *buf = 0; 143 144 if (value & SKY81452_OCP) 145 strcat(buf, "over-current "); 146 147 if (value & SKY81452_OTMP) 148 strcat(buf, "over-temperature"); 149 150 strcat(buf, "\n"); 151 return strlen(buf); 152 } 153 154 static DEVICE_ATTR(enable, S_IWGRP | S_IWUSR, NULL, sky81452_bl_store_enable); 155 static DEVICE_ATTR(open, S_IRUGO, sky81452_bl_show_open_short, NULL); 156 static DEVICE_ATTR(short, S_IRUGO, sky81452_bl_show_open_short, NULL); 157 static DEVICE_ATTR(fault, S_IRUGO, sky81452_bl_show_fault, NULL); 158 159 static struct attribute *sky81452_bl_attribute[] = { 160 &dev_attr_enable.attr, 161 &dev_attr_open.attr, 162 &dev_attr_short.attr, 163 &dev_attr_fault.attr, 164 NULL 165 }; 166 167 static const struct attribute_group sky81452_bl_attr_group = { 168 .attrs = sky81452_bl_attribute, 169 }; 170 171 #ifdef CONFIG_OF 172 static struct sky81452_bl_platform_data *sky81452_bl_parse_dt( 173 struct device *dev) 174 { 175 struct device_node *np = of_node_get(dev->of_node); 176 struct sky81452_bl_platform_data *pdata; 177 int num_entry; 178 unsigned int sources[6]; 179 int ret; 180 181 if (!np) { 182 dev_err(dev, "backlight node not found.\n"); 183 return ERR_PTR(-ENODATA); 184 } 185 186 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL); 187 if (!pdata) { 188 of_node_put(np); 189 return ERR_PTR(-ENOMEM); 190 } 191 192 of_property_read_string(np, "name", &pdata->name); 193 pdata->ignore_pwm = of_property_read_bool(np, "skyworks,ignore-pwm"); 194 pdata->dpwm_mode = of_property_read_bool(np, "skyworks,dpwm-mode"); 195 pdata->phase_shift = of_property_read_bool(np, "skyworks,phase-shift"); 196 pdata->gpio_enable = of_get_gpio(np, 0); 197 198 ret = of_property_count_u32_elems(np, "led-sources"); 199 if (IS_ERR_VALUE(ret)) { 200 pdata->enable = SKY81452_EN >> CTZ(SKY81452_EN); 201 } else { 202 num_entry = ret; 203 if (num_entry > 6) 204 num_entry = 6; 205 206 ret = of_property_read_u32_array(np, "led-sources", sources, 207 num_entry); 208 if (IS_ERR_VALUE(ret)) { 209 dev_err(dev, "led-sources node is invalid.\n"); 210 return ERR_PTR(-EINVAL); 211 } 212 213 pdata->enable = 0; 214 while (--num_entry) 215 pdata->enable |= (1 << sources[num_entry]); 216 } 217 218 ret = of_property_read_u32(np, 219 "skyworks,short-detection-threshold-volt", 220 &pdata->short_detection_threshold); 221 if (IS_ERR_VALUE(ret)) 222 pdata->short_detection_threshold = 7; 223 224 ret = of_property_read_u32(np, "skyworks,current-limit-mA", 225 &pdata->boost_current_limit); 226 if (IS_ERR_VALUE(ret)) 227 pdata->boost_current_limit = 2750; 228 229 of_node_put(np); 230 return pdata; 231 } 232 #else 233 static struct sky81452_bl_platform_data *sky81452_bl_parse_dt( 234 struct device *dev) 235 { 236 return ERR_PTR(-EINVAL); 237 } 238 #endif 239 240 static int sky81452_bl_init_device(struct regmap *regmap, 241 struct sky81452_bl_platform_data *pdata) 242 { 243 unsigned int value; 244 245 value = pdata->ignore_pwm ? SKY81452_IGPW : 0; 246 value |= pdata->dpwm_mode ? SKY81452_PWMMD : 0; 247 value |= pdata->phase_shift ? 0 : SKY81452_PHASE; 248 249 if (pdata->boost_current_limit == 2300) 250 value |= SKY81452_ILIM; 251 else if (pdata->boost_current_limit != 2750) 252 return -EINVAL; 253 254 if (pdata->short_detection_threshold < 4 || 255 pdata->short_detection_threshold > 7) 256 return -EINVAL; 257 value |= (7 - pdata->short_detection_threshold) << CTZ(SKY81452_VSHRT); 258 259 return regmap_write(regmap, SKY81452_REG2, value); 260 } 261 262 static int sky81452_bl_probe(struct platform_device *pdev) 263 { 264 struct device *dev = &pdev->dev; 265 struct regmap *regmap = dev_get_drvdata(dev->parent); 266 struct sky81452_bl_platform_data *pdata = dev_get_platdata(dev); 267 struct backlight_device *bd; 268 struct backlight_properties props; 269 const char *name; 270 int ret; 271 272 if (!pdata) { 273 pdata = sky81452_bl_parse_dt(dev); 274 if (IS_ERR(pdata)) 275 return PTR_ERR(pdata); 276 } 277 278 if (gpio_is_valid(pdata->gpio_enable)) { 279 ret = devm_gpio_request_one(dev, pdata->gpio_enable, 280 GPIOF_OUT_INIT_HIGH, "sky81452-en"); 281 if (IS_ERR_VALUE(ret)) { 282 dev_err(dev, "failed to request GPIO. err=%d\n", ret); 283 return ret; 284 } 285 } 286 287 ret = sky81452_bl_init_device(regmap, pdata); 288 if (IS_ERR_VALUE(ret)) { 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 (IS_ERR_VALUE(ret)) { 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 (gpio_is_valid(pdata->gpio_enable)) 327 gpio_set_value_cansleep(pdata->gpio_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