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/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_bl_platform_data - backlight 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 = 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 #else
 240 static struct sky81452_bl_platform_data *sky81452_bl_parse_dt(
 241                                                         struct device *dev)
 242 {
 243         return ERR_PTR(-EINVAL);
 244 }
 245 #endif
 246
 247 static 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
 269 static 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
 310 static 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_OF
 327 static const struct of_device_id sky81452_bl_of_match[] = {
 328         { .compatible = "skyworks,sky81452-backlight", },
 329         { }
 330 };
 331 MODULE_DEVICE_TABLE(of, sky81452_bl_of_match);
 332 #endif
 333
 334 static 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 = sky81452_bl_remove,
 341 };
 342
 343 module_platform_driver(sky81452_bl_driver);
 344
 345 MODULE_DESCRIPTION("Skyworks SKY81452 backlight driver");
 346 MODULE_AUTHOR("Gyungoh Yoo <jack.yoo@skyworksinc.com>");
 347 MODULE_LICENSE("GPL v2");