drivers/video/backlight/88pm860x_bl.c

   1 /*
   2  * Backlight driver for Marvell Semiconductor 88PM8606
   3  *
   4  * Copyright (C) 2009 Marvell International Ltd.
   5  *      Haojian Zhuang <haojian.zhuang@marvell.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/init.h>
  13 #include <linux/kernel.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/slab.h>
  16 #include <linux/fb.h>
  17 #include <linux/i2c.h>
  18 #include <linux/backlight.h>
  19 #include <linux/mfd/88pm860x.h>
  20
  21 #define MAX_BRIGHTNESS          (0xFF)
  22 #define MIN_BRIGHTNESS          (0)
  23
  24 #define CURRENT_BITMASK         (0x1F << 1)
  25
  26 struct pm860x_backlight_data {
  27         struct pm860x_chip *chip;
  28         struct i2c_client *i2c;
  29         int     current_brightness;
  30         int     port;
  31         int     pwm;
  32         int     iset;
  33 };
  34
  35 static inline int wled_a(int port)
  36 {
  37         int ret;
  38
  39         ret = ((port - PM8606_BACKLIGHT1) << 1) + 2;
  40         return ret;
  41 }
  42
  43 static inline int wled_b(int port)
  44 {
  45         int ret;
  46
  47         ret = ((port - PM8606_BACKLIGHT1) << 1) + 3;
  48         return ret;
  49 }
  50
  51 /* WLED2 & WLED3 share the same IDC */
  52 static inline int wled_idc(int port)
  53 {
  54         int ret;
  55
  56         switch (port) {
  57         case PM8606_BACKLIGHT1:
  58         case PM8606_BACKLIGHT2:
  59                 ret = ((port - PM8606_BACKLIGHT1) << 1) + 3;
  60                 break;
  61         case PM8606_BACKLIGHT3:
  62         default:
  63                 ret = ((port - PM8606_BACKLIGHT2) << 1) + 3;
  64                 break;
  65         }
  66         return ret;
  67 }
  68
  69 static int pm860x_backlight_set(struct backlight_device *bl, int brightness)
  70 {
  71         struct pm860x_backlight_data *data = bl_get_data(bl);
  72         struct pm860x_chip *chip = data->chip;
  73         unsigned char value;
  74         int ret;
  75
  76         if (brightness > MAX_BRIGHTNESS)
  77                 value = MAX_BRIGHTNESS;
  78         else
  79                 value = brightness;
  80
  81         ret = pm860x_reg_write(data->i2c, wled_a(data->port), value);
  82         if (ret < 0)
  83                 goto out;
  84
  85         if ((data->current_brightness == 0) && brightness) {
  86                 if (data->iset) {
  87                         ret = pm860x_set_bits(data->i2c, wled_idc(data->port),
  88                                               CURRENT_BITMASK, data->iset);
  89                         if (ret < 0)
  90                                 goto out;
  91                 }
  92                 if (data->pwm) {
  93                         ret = pm860x_set_bits(data->i2c, PM8606_PWM,
  94                                               PM8606_PWM_FREQ_MASK, data->pwm);
  95                         if (ret < 0)
  96                                 goto out;
  97                 }
  98                 if (brightness == MAX_BRIGHTNESS) {
  99                         /* set WLED_ON bit as 100% */
 100                         ret = pm860x_set_bits(data->i2c, wled_b(data->port),
 101                                               PM8606_WLED_ON, PM8606_WLED_ON);
 102                 }
 103         } else {
 104                 if (brightness == MAX_BRIGHTNESS) {
 105                         /* set WLED_ON bit as 100% */
 106                         ret = pm860x_set_bits(data->i2c, wled_b(data->port),
 107                                               PM8606_WLED_ON, PM8606_WLED_ON);
 108                 } else {
 109                         /* clear WLED_ON bit since it's not 100% */
 110                         ret = pm860x_set_bits(data->i2c, wled_b(data->port),
 111                                               PM8606_WLED_ON, 0);
 112                 }
 113         }
 114         if (ret < 0)
 115                 goto out;
 116
 117         dev_dbg(chip->dev, "set brightness %d\n", value);
 118         data->current_brightness = value;
 119         return 0;
 120 out:
 121         dev_dbg(chip->dev, "set brightness %d failure with return "
 122                 "value:%d\n", value, ret);
 123         return ret;
 124 }
 125
 126 static int pm860x_backlight_update_status(struct backlight_device *bl)
 127 {
 128         int brightness = bl->props.brightness;
 129
 130         if (bl->props.power != FB_BLANK_UNBLANK)
 131                 brightness = 0;
 132
 133         if (bl->props.fb_blank != FB_BLANK_UNBLANK)
 134                 brightness = 0;
 135
 136         if (bl->props.state & BL_CORE_SUSPENDED)
 137                 brightness = 0;
 138
 139         return pm860x_backlight_set(bl, brightness);
 140 }
 141
 142 static int pm860x_backlight_get_brightness(struct backlight_device *bl)
 143 {
 144         struct pm860x_backlight_data *data = bl_get_data(bl);
 145         struct pm860x_chip *chip = data->chip;
 146         int ret;
 147
 148         ret = pm860x_reg_read(data->i2c, wled_a(data->port));
 149         if (ret < 0)
 150                 goto out;
 151         data->current_brightness = ret;
 152         dev_dbg(chip->dev, "get brightness %d\n", data->current_brightness);
 153         return data->current_brightness;
 154 out:
 155         return -EINVAL;
 156 }
 157
 158 static const struct backlight_ops pm860x_backlight_ops = {
 159         .options        = BL_CORE_SUSPENDRESUME,
 160         .update_status  = pm860x_backlight_update_status,
 161         .get_brightness = pm860x_backlight_get_brightness,
 162 };
 163
 164 static int pm860x_backlight_probe(struct platform_device *pdev)
 165 {
 166         struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
 167         struct pm860x_backlight_pdata *pdata = NULL;
 168         struct pm860x_backlight_data *data;
 169         struct backlight_device *bl;
 170         struct resource *res;
 171         struct backlight_properties props;
 172         unsigned char value;
 173         char name[MFD_NAME_SIZE];
 174         int ret;
 175
 176         res = platform_get_resource(pdev, IORESOURCE_IO, 0);
 177         if (res == NULL) {
 178                 dev_err(&pdev->dev, "No I/O resource!\n");
 179                 return -EINVAL;
 180         }
 181
 182         pdata = pdev->dev.platform_data;
 183         if (pdata == NULL) {
 184                 dev_err(&pdev->dev, "platform data isn't assigned to "
 185                         "backlight\n");
 186                 return -EINVAL;
 187         }
 188
 189         data = kzalloc(sizeof(struct pm860x_backlight_data), GFP_KERNEL);
 190         if (data == NULL)
 191                 return -ENOMEM;
 192         strncpy(name, res->name, MFD_NAME_SIZE);
 193         data->chip = chip;
 194         data->i2c = (chip->id == CHIP_PM8606) ? chip->client    \
 195                         : chip->companion;
 196         data->current_brightness = MAX_BRIGHTNESS;
 197         data->pwm = pdata->pwm;
 198         data->iset = pdata->iset;
 199         data->port = pdata->flags;
 200         if (data->port < 0) {
 201                 dev_err(&pdev->dev, "wrong platform data is assigned");
 202                 kfree(data);
 203                 return -EINVAL;
 204         }
 205
 206         memset(&props, 0, sizeof(struct backlight_properties));
 207         props.type = BACKLIGHT_RAW;
 208         props.max_brightness = MAX_BRIGHTNESS;
 209         bl = backlight_device_register(name, &pdev->dev, data,
 210                                         &pm860x_backlight_ops, &props);
 211         if (IS_ERR(bl)) {
 212                 dev_err(&pdev->dev, "failed to register backlight\n");
 213                 kfree(data);
 214                 return PTR_ERR(bl);
 215         }
 216         bl->props.brightness = MAX_BRIGHTNESS;
 217
 218         platform_set_drvdata(pdev, bl);
 219
 220         /* Enable reference VSYS */
 221         ret = pm860x_reg_read(data->i2c, PM8606_VSYS);
 222         if (ret < 0)
 223                 goto out;
 224         if ((ret & PM8606_VSYS_EN) == 0) {
 225                 value = ret | PM8606_VSYS_EN;
 226                 ret = pm860x_reg_write(data->i2c, PM8606_VSYS, value);
 227                 if (ret < 0)
 228                         goto out;
 229         }
 230         /* Enable reference OSC */
 231         ret = pm860x_reg_read(data->i2c, PM8606_MISC);
 232         if (ret < 0)
 233                 goto out;
 234         if ((ret & PM8606_MISC_OSC_EN) == 0) {
 235                 value = ret | PM8606_MISC_OSC_EN;
 236                 ret = pm860x_reg_write(data->i2c, PM8606_MISC, value);
 237                 if (ret < 0)
 238                         goto out;
 239         }
 240         /* read current backlight */
 241         ret = pm860x_backlight_get_brightness(bl);
 242         if (ret < 0)
 243                 goto out;
 244
 245         backlight_update_status(bl);
 246         return 0;
 247 out:
 248         backlight_device_unregister(bl);
 249         kfree(data);
 250         return ret;
 251 }
 252
 253 static int pm860x_backlight_remove(struct platform_device *pdev)
 254 {
 255         struct backlight_device *bl = platform_get_drvdata(pdev);
 256         struct pm860x_backlight_data *data = bl_get_data(bl);
 257
 258         backlight_device_unregister(bl);
 259         kfree(data);
 260         return 0;
 261 }
 262
 263 static struct platform_driver pm860x_backlight_driver = {
 264         .driver         = {
 265                 .name   = "88pm860x-backlight",
 266                 .owner  = THIS_MODULE,
 267         },
 268         .probe          = pm860x_backlight_probe,
 269         .remove         = pm860x_backlight_remove,
 270 };
 271
 272 static int __init pm860x_backlight_init(void)
 273 {
 274         return platform_driver_register(&pm860x_backlight_driver);
 275 }
 276 module_init(pm860x_backlight_init);
 277
 278 static void __exit pm860x_backlight_exit(void)
 279 {
 280         platform_driver_unregister(&pm860x_backlight_driver);
 281 }
 282 module_exit(pm860x_backlight_exit);
 283
 284 MODULE_DESCRIPTION("Backlight Driver for Marvell Semiconductor 88PM8606");
 285 MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");
 286 MODULE_LICENSE("GPL");
 287 MODULE_ALIAS("platform:88pm860x-backlight");