drivers/video/backlight/sky81452-backlight.c

   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.h>
  12 #include <linux/init.h>
  13 #include <linux/kernel.h>
  14 #include <linux/module.h>
  15 #include <linux/of.h>
  16 #include <linux/of_gpio.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/regmap.h>
  19 #include <linux/platform_data/sky81452-backlight.h>
  20 #include <linux/slab.h>
  21
  22 /* registers */
  23 #define SKY81452_REG0   0x00
  24 #define SKY81452_REG1   0x01
  25 #define SKY81452_REG2   0x02
  26 #define SKY81452_REG4   0x04
  27 #define SKY81452_REG5   0x05
  28
  29 /* bit mask */
  30 #define SKY81452_CS     0xFF
  31 #define SKY81452_EN     0x3F
  32 #define SKY81452_IGPW   0x20
  33 #define SKY81452_PWMMD  0x10
  34 #define SKY81452_PHASE  0x08
  35 #define SKY81452_ILIM   0x04
  36 #define SKY81452_VSHRT  0x03
  37 #define SKY81452_OCP    0x80
  38 #define SKY81452_OTMP   0x40
  39 #define SKY81452_SHRT   0x3F
  40 #define SKY81452_OPN    0x3F
  41
  42 #define SKY81452_DEFAULT_NAME "lcd-backlight"
  43 #define SKY81452_MAX_BRIGHTNESS (SKY81452_CS + 1)
  44
  45 #define CTZ(b) __builtin_ctz(b)
  46
  47 static int sky81452_bl_update_status(struct backlight_device *bd)
  48 {
  49         const struct sky81452_bl_platform_data *pdata =
  50                         dev_get_platdata(bd->dev.parent);
  51         const unsigned int brightness = (unsigned int)bd->props.brightness;
  52         struct regmap *regmap = bl_get_data(bd);
  53         int ret;
  54
  55         if (brightness > 0) {
  56                 ret = regmap_write(regmap, SKY81452_REG0, brightness - 1);
  57                 if (ret < 0)
  58                         return ret;
  59
  60                 return regmap_update_bits(regmap, SKY81452_REG1, SKY81452_EN,
  61                                         pdata->enable << CTZ(SKY81452_EN));
  62         }
  63
  64         return regmap_update_bits(regmap, SKY81452_REG1, SKY81452_EN, 0);
  65 }
  66
  67 static const struct backlight_ops sky81452_bl_ops = {
  68         .update_status = sky81452_bl_update_status,
  69 };
  70
  71 static ssize_t sky81452_bl_store_enable(struct device *dev,
  72                 struct device_attribute *attr, const char *buf, size_t count)
  73 {
  74         struct regmap *regmap = bl_get_data(to_backlight_device(dev));
  75         unsigned long value;
  76         int ret;
  77
  78         ret = kstrtoul(buf, 16, &value);
  79         if (ret < 0)
  80                 return ret;
  81
  82         ret = regmap_update_bits(regmap, SKY81452_REG1, SKY81452_EN,
  83                                         value << CTZ(SKY81452_EN));
  84         if (ret < 0)
  85                 return ret;
  86
  87         return count;
  88 }
  89
  90 static ssize_t sky81452_bl_show_open_short(struct device *dev,
  91                 struct device_attribute *attr, char *buf)
  92 {
  93         struct regmap *regmap = bl_get_data(to_backlight_device(dev));
  94         unsigned int reg, value = 0;
  95         char tmp[3];
  96         int i, ret;
  97
  98         reg = !strcmp(attr->attr.name, "open") ? SKY81452_REG5 : SKY81452_REG4;
  99         ret = regmap_read(regmap, reg, &value);
 100         if (ret < 0)
 101                 return ret;
 102
 103         if (value & SKY81452_SHRT) {
 104                 *buf = 0;
 105                 for (i = 0; i < 6; i++) {
 106                         if (value & 0x01) {
 107                                 sprintf(tmp, "%d ", i + 1);
 108                                 strcat(buf, tmp);
 109                         }
 110                         value >>= 1;
 111                 }
 112                 strcat(buf, "\n");
 113         } else {
 114                 strcpy(buf, "none\n");
 115         }
 116
 117         return strlen(buf);
 118 }
 119
 120 static ssize_t sky81452_bl_show_fault(struct device *dev,
 121                 struct device_attribute *attr, char *buf)
 122 {
 123         struct regmap *regmap = bl_get_data(to_backlight_device(dev));
 124         unsigned int value = 0;
 125         int ret;
 126
 127         ret = regmap_read(regmap, SKY81452_REG4, &value);
 128         if (ret < 0)
 129                 return ret;
 130
 131         *buf = 0;
 132
 133         if (value & SKY81452_OCP)
 134                 strcat(buf, "over-current ");
 135
 136         if (value & SKY81452_OTMP)
 137                 strcat(buf, "over-temperature");
 138
 139         strcat(buf, "\n");
 140         return strlen(buf);
 141 }
 142
 143 static DEVICE_ATTR(enable, S_IWGRP | S_IWUSR, NULL, sky81452_bl_store_enable);
 144 static DEVICE_ATTR(open, S_IRUGO, sky81452_bl_show_open_short, NULL);
 145 static DEVICE_ATTR(short, S_IRUGO, sky81452_bl_show_open_short, NULL);
 146 static DEVICE_ATTR(fault, S_IRUGO, sky81452_bl_show_fault, NULL);
 147
 148 static struct attribute *sky81452_bl_attribute[] = {
 149         &dev_attr_enable.attr,
 150         &dev_attr_open.attr,
 151         &dev_attr_short.attr,
 152         &dev_attr_fault.attr,
 153         NULL
 154 };
 155
 156 static const struct attribute_group sky81452_bl_attr_group = {
 157         .attrs = sky81452_bl_attribute,
 158 };
 159
 160 #ifdef CONFIG_OF
 161 static struct sky81452_bl_platform_data *sky81452_bl_parse_dt(
 162                                                         struct device *dev)
 163 {
 164         struct device_node *np = of_node_get(dev->of_node);
 165         struct sky81452_bl_platform_data *pdata;
 166         int num_entry;
 167         unsigned int sources[6];
 168         int ret;
 169
 170         if (!np) {
 171                 dev_err(dev, "backlight node not found.\n");
 172                 return ERR_PTR(-ENODATA);
 173         }
 174
 175         pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
 176         if (!pdata) {
 177                 of_node_put(np);
 178                 return ERR_PTR(-ENOMEM);
 179         }
 180
 181         of_property_read_string(np, "name", &pdata->name);
 182         pdata->ignore_pwm = of_property_read_bool(np, "skyworks,ignore-pwm");
 183         pdata->dpwm_mode = of_property_read_bool(np, "skyworks,dpwm-mode");
 184         pdata->phase_shift = of_property_read_bool(np, "skyworks,phase-shift");
 185         pdata->gpio_enable = of_get_gpio(np, 0);
 186
 187         ret = of_property_count_u32_elems(np, "led-sources");
 188         if (ret < 0) {
 189                 pdata->enable = SKY81452_EN >> CTZ(SKY81452_EN);
 190         } else {
 191                 num_entry = ret;
 192                 if (num_entry > 6)
 193                         num_entry = 6;
 194
 195                 ret = of_property_read_u32_array(np, "led-sources", sources,
 196                                         num_entry);
 197                 if (ret < 0) {
 198                         dev_err(dev, "led-sources node is invalid.\n");
 199                         return ERR_PTR(-EINVAL);
 200                 }
 201
 202                 pdata->enable = 0;
 203                 while (--num_entry)
 204                         pdata->enable |= (1 << sources[num_entry]);
 205         }
 206
 207         ret = of_property_read_u32(np,
 208                         "skyworks,short-detection-threshold-volt",
 209                         &pdata->short_detection_threshold);
 210         if (ret < 0)
 211                 pdata->short_detection_threshold = 7;
 212
 213         ret = of_property_read_u32(np, "skyworks,current-limit-mA",
 214                         &pdata->boost_current_limit);
 215         if (ret < 0)
 216                 pdata->boost_current_limit = 2750;
 217
 218         of_node_put(np);
 219         return pdata;
 220 }
 221 #else
 222 static struct sky81452_bl_platform_data *sky81452_bl_parse_dt(
 223                                                         struct device *dev)
 224 {
 225         return ERR_PTR(-EINVAL);
 226 }
 227 #endif
 228
 229 static int sky81452_bl_init_device(struct regmap *regmap,
 230                 struct sky81452_bl_platform_data *pdata)
 231 {
 232         unsigned int value;
 233
 234         value = pdata->ignore_pwm ? SKY81452_IGPW : 0;
 235         value |= pdata->dpwm_mode ? SKY81452_PWMMD : 0;
 236         value |= pdata->phase_shift ? 0 : SKY81452_PHASE;
 237
 238         if (pdata->boost_current_limit == 2300)
 239                 value |= SKY81452_ILIM;
 240         else if (pdata->boost_current_limit != 2750)
 241                 return -EINVAL;
 242
 243         if (pdata->short_detection_threshold < 4 ||
 244                                 pdata->short_detection_threshold > 7)
 245                 return -EINVAL;
 246         value |= (7 - pdata->short_detection_threshold) << CTZ(SKY81452_VSHRT);
 247
 248         return regmap_write(regmap, SKY81452_REG2, value);
 249 }
 250
 251 static int sky81452_bl_probe(struct platform_device *pdev)
 252 {
 253         struct device *dev = &pdev->dev;
 254         struct regmap *regmap = dev_get_drvdata(dev->parent);
 255         struct sky81452_bl_platform_data *pdata = dev_get_platdata(dev);
 256         struct backlight_device *bd;
 257         struct backlight_properties props;
 258         const char *name;
 259         int ret;
 260
 261         if (!pdata) {
 262                 pdata = sky81452_bl_parse_dt(dev);
 263                 if (IS_ERR(pdata))
 264                         return PTR_ERR(pdata);
 265         }
 266
 267         if (gpio_is_valid(pdata->gpio_enable)) {
 268                 ret = devm_gpio_request_one(dev, pdata->gpio_enable,
 269                                         GPIOF_OUT_INIT_HIGH, "sky81452-en");
 270                 if (ret < 0) {
 271                         dev_err(dev, "failed to request GPIO. err=%d\n", ret);
 272                         return ret;
 273                 }
 274         }
 275
 276         ret = sky81452_bl_init_device(regmap, pdata);
 277         if (ret < 0) {
 278                 dev_err(dev, "failed to initialize. err=%d\n", ret);
 279                 return ret;
 280         }
 281
 282         memset(&props, 0, sizeof(props));
 283         props.max_brightness = SKY81452_MAX_BRIGHTNESS,
 284         name = pdata->name ? pdata->name : SKY81452_DEFAULT_NAME;
 285         bd = devm_backlight_device_register(dev, name, dev, regmap,
 286                                                 &sky81452_bl_ops, &props);
 287         if (IS_ERR(bd)) {
 288                 dev_err(dev, "failed to register. err=%ld\n", PTR_ERR(bd));
 289                 return PTR_ERR(bd);
 290         }
 291
 292         platform_set_drvdata(pdev, bd);
 293
 294         ret = sysfs_create_group(&bd->dev.kobj, &sky81452_bl_attr_group);
 295         if (ret < 0) {
 296                 dev_err(dev, "failed to create attribute. err=%d\n", ret);
 297                 return ret;
 298         }
 299
 300         return ret;
 301 }
 302
 303 static int sky81452_bl_remove(struct platform_device *pdev)
 304 {
 305         const struct sky81452_bl_platform_data *pdata =
 306                                                 dev_get_platdata(&pdev->dev);
 307         struct backlight_device *bd = platform_get_drvdata(pdev);
 308
 309         sysfs_remove_group(&bd->dev.kobj, &sky81452_bl_attr_group);
 310
 311         bd->props.power = FB_BLANK_UNBLANK;
 312         bd->props.brightness = 0;
 313         backlight_update_status(bd);
 314
 315         if (gpio_is_valid(pdata->gpio_enable))
 316                 gpio_set_value_cansleep(pdata->gpio_enable, 0);
 317
 318         return 0;
 319 }
 320
 321 #ifdef CONFIG_OF
 322 static const struct of_device_id sky81452_bl_of_match[] = {
 323         { .compatible = "skyworks,sky81452-backlight", },
 324         { }
 325 };
 326 MODULE_DEVICE_TABLE(of, sky81452_bl_of_match);
 327 #endif
 328
 329 static struct platform_driver sky81452_bl_driver = {
 330         .driver = {
 331                 .name = "sky81452-backlight",
 332                 .of_match_table = of_match_ptr(sky81452_bl_of_match),
 333         },
 334         .probe = sky81452_bl_probe,
 335         .remove = sky81452_bl_remove,
 336 };
 337
 338 module_platform_driver(sky81452_bl_driver);
 339
 340 MODULE_DESCRIPTION("Skyworks SKY81452 backlight driver");
 341 MODULE_AUTHOR("Gyungoh Yoo <jack.yoo@skyworksinc.com>");
 342 MODULE_LICENSE("GPL v2");