drivers/video/backlight/sky81452-backlight.c

   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 (ret < 0)
  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 (ret < 0)
  91                 return ret;
  92
  93         ret = regmap_update_bits(regmap, SKY81452_REG1, SKY81452_EN,
  94                                         value << CTZ(SKY81452_EN));
  95         if (ret < 0)
  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 (ret < 0)
 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 (ret < 0)
 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 (ret < 0) {
 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 (ret < 0) {
 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 (ret < 0)
 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 (ret < 0)
 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 (ret < 0) {
 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 (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 (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");