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   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/fb.h>
  16 #include <linux/i2c.h>
  17 #include <linux/backlight.h>
  18 #include <linux/mfd/88pm860x.h>
  19
  20 #define MAX_BRIGHTNESS          (0xFF)
  21 #define MIN_BRIGHTNESS          (0)
  22
  23 #define CURRENT_MASK            (0x1F << 1)
  24
  25 struct pm860x_backlight_data {
  26         struct pm860x_chip *chip;
  27         struct i2c_client *i2c;
  28         int     current_brightness;
  29         int     port;
  30         int     pwm;
  31         int     iset;
  32 };
  33
  34 static inline int wled_a(int port)
  35 {
  36         int ret;
  37
  38         ret = ((port - PM8606_BACKLIGHT1) << 1) + 2;
  39         return ret;
  40 }
  41
  42 static inline int wled_b(int port)
  43 {
  44         int ret;
  45
  46         ret = ((port - PM8606_BACKLIGHT1) << 1) + 3;
  47         return ret;
  48 }
  49
  50 /* WLED2 & WLED3 share the same IDC */
  51 static inline int wled_idc(int port)
  52 {
  53         int ret;
  54
  55         switch (port) {
  56         case PM8606_BACKLIGHT1:
  57         case PM8606_BACKLIGHT2:
  58                 ret = ((port - PM8606_BACKLIGHT1) << 1) + 3;
  59                 break;
  60         case PM8606_BACKLIGHT3:
  61         default:
  62                 ret = ((port - PM8606_BACKLIGHT2) << 1) + 3;
  63                 break;
  64         }
  65         return ret;
  66 }
  67
  68 static int pm860x_backlight_set(struct backlight_device *bl, int brightness)
  69 {
  70         struct pm860x_backlight_data *data = bl_get_data(bl);
  71         struct pm860x_chip *chip = data->chip;
  72         unsigned char value;
  73         int ret;
  74
  75         if (brightness > MAX_BRIGHTNESS)
  76                 value = MAX_BRIGHTNESS;
  77         else
  78                 value = brightness;
  79
  80         ret = pm860x_reg_write(data->i2c, wled_a(data->port), value);
  81         if (ret < 0)
  82                 goto out;
  83
  84         if ((data->current_brightness == 0) && brightness) {
  85                 if (data->iset) {
  86                         ret = pm860x_set_bits(data->i2c, wled_idc(data->port),
  87                                               CURRENT_MASK, data->iset);
  88                         if (ret < 0)
  89                                 goto out;
  90                 }
  91                 if (data->pwm) {
  92                         ret = pm860x_set_bits(data->i2c, PM8606_PWM,
  93                                               PM8606_PWM_FREQ_MASK, data->pwm);
  94                         if (ret < 0)
  95                                 goto out;
  96                 }
  97                 if (brightness == MAX_BRIGHTNESS) {
  98                         /* set WLED_ON bit as 100% */
  99                         ret = pm860x_set_bits(data->i2c, wled_b(data->port),
 100                                               PM8606_WLED_ON, PM8606_WLED_ON);
 101                 }
 102         } else {
 103                 if (brightness == MAX_BRIGHTNESS) {
 104                         /* set WLED_ON bit as 100% */
 105                         ret = pm860x_set_bits(data->i2c, wled_b(data->port),
 106                                               PM8606_WLED_ON, PM8606_WLED_ON);
 107                 } else {
 108                         /* clear WLED_ON bit since it's not 100% */
 109                         ret = pm860x_set_bits(data->i2c, wled_b(data->port),
 110                                               PM8606_WLED_ON, 0);
 111                 }
 112         }
 113         if (ret < 0)
 114                 goto out;
 115
 116         dev_dbg(chip->dev, "set brightness %d\n", value);
 117         data->current_brightness = value;
 118         return 0;
 119 out:
 120         dev_dbg(chip->dev, "set brightness %d failure with return "
 121                 "value:%d\n", value, ret);
 122         return ret;
 123 }
 124
 125 static int pm860x_backlight_update_status(struct backlight_device *bl)
 126 {
 127         int brightness = bl->props.brightness;
 128
 129         if (bl->props.power != FB_BLANK_UNBLANK)
 130                 brightness = 0;
 131
 132         if (bl->props.fb_blank != FB_BLANK_UNBLANK)
 133                 brightness = 0;
 134
 135         if (bl->props.state & BL_CORE_SUSPENDED)
 136                 brightness = 0;
 137
 138         return pm860x_backlight_set(bl, brightness);
 139 }
 140
 141 static int pm860x_backlight_get_brightness(struct backlight_device *bl)
 142 {
 143         struct pm860x_backlight_data *data = bl_get_data(bl);
 144         struct pm860x_chip *chip = data->chip;
 145         int ret;
 146
 147         ret = pm860x_reg_read(data->i2c, wled_a(data->port));
 148         if (ret < 0)
 149                 goto out;
 150         data->current_brightness = ret;
 151         dev_dbg(chip->dev, "get brightness %d\n", data->current_brightness);
 152         return data->current_brightness;
 153 out:
 154         return -EINVAL;
 155 }
 156
 157 static struct backlight_ops pm860x_backlight_ops = {
 158         .options        = BL_CORE_SUSPENDRESUME,
 159         .update_status  = pm860x_backlight_update_status,
 160         .get_brightness = pm860x_backlight_get_brightness,
 161 };
 162
 163 static int __check_device(struct pm860x_backlight_pdata *pdata, char *name)
 164 {
 165         struct pm860x_backlight_pdata *p = pdata;
 166         int ret = -EINVAL;
 167
 168         while (p && p->id) {
 169                 if ((p->id != PM8606_ID_BACKLIGHT) || (p->flags < 0))
 170                         break;
 171
 172                 if (!strncmp(name, pm860x_backlight_name[p->flags],
 173                         MFD_NAME_SIZE)) {
 174                         ret = (int)p->flags;
 175                         break;
 176                 }
 177                 p++;
 178         }
 179         return ret;
 180 }
 181
 182 static int pm860x_backlight_probe(struct platform_device *pdev)
 183 {
 184         struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
 185         struct pm860x_platform_data *pm860x_pdata;
 186         struct pm860x_backlight_pdata *pdata = NULL;
 187         struct pm860x_backlight_data *data;
 188         struct backlight_device *bl;
 189         struct resource *res;
 190         unsigned char value;
 191         char name[MFD_NAME_SIZE];
 192         int ret;
 193
 194         res = platform_get_resource(pdev, IORESOURCE_IO, 0);
 195         if (res == NULL) {
 196                 dev_err(&pdev->dev, "No I/O resource!\n");
 197                 return -EINVAL;
 198         }
 199
 200         if (pdev->dev.parent->platform_data) {
 201                 pm860x_pdata = pdev->dev.parent->platform_data;
 202                 pdata = pm860x_pdata->backlight;
 203         }
 204         if (pdata == NULL) {
 205                 dev_err(&pdev->dev, "platform data isn't assigned to "
 206                         "backlight\n");
 207                 return -EINVAL;
 208         }
 209
 210         data = kzalloc(sizeof(struct pm860x_backlight_data), GFP_KERNEL);
 211         if (data == NULL)
 212                 return -ENOMEM;
 213         strncpy(name, res->name, MFD_NAME_SIZE);
 214         data->chip = chip;
 215         data->i2c = (chip->id == CHIP_PM8606) ? chip->client    \
 216                         : chip->companion;
 217         data->current_brightness = MAX_BRIGHTNESS;
 218         data->pwm = pdata->pwm;
 219         data->iset = pdata->iset;
 220         data->port = __check_device(pdata, name);
 221         if (data->port < 0) {
 222                 dev_err(&pdev->dev, "wrong platform data is assigned");
 223                 return -EINVAL;
 224         }
 225
 226         bl = backlight_device_register(name, &pdev->dev, data,
 227                                         &pm860x_backlight_ops);
 228         if (IS_ERR(bl)) {
 229                 dev_err(&pdev->dev, "failed to register backlight\n");
 230                 kfree(data);
 231                 return PTR_ERR(bl);
 232         }
 233         bl->props.max_brightness = MAX_BRIGHTNESS;
 234         bl->props.brightness = MAX_BRIGHTNESS;
 235
 236         platform_set_drvdata(pdev, bl);
 237
 238         /* Enable reference VSYS */
 239         ret = pm860x_reg_read(data->i2c, PM8606_VSYS);
 240         if (ret < 0)
 241                 goto out;
 242         if ((ret & PM8606_VSYS_EN) == 0) {
 243                 value = ret | PM8606_VSYS_EN;
 244                 ret = pm860x_reg_write(data->i2c, PM8606_VSYS, value);
 245                 if (ret < 0)
 246                         goto out;
 247         }
 248         /* Enable reference OSC */
 249         ret = pm860x_reg_read(data->i2c, PM8606_MISC);
 250         if (ret < 0)
 251                 goto out;
 252         if ((ret & PM8606_MISC_OSC_EN) == 0) {
 253                 value = ret | PM8606_MISC_OSC_EN;
 254                 ret = pm860x_reg_write(data->i2c, PM8606_MISC, value);
 255                 if (ret < 0)
 256                         goto out;
 257         }
 258         /* read current backlight */
 259         ret = pm860x_backlight_get_brightness(bl);
 260         if (ret < 0)
 261                 goto out;
 262
 263         backlight_update_status(bl);
 264         return 0;
 265 out:
 266         kfree(data);
 267         return ret;
 268 }
 269
 270 static int pm860x_backlight_remove(struct platform_device *pdev)
 271 {
 272         struct backlight_device *bl = platform_get_drvdata(pdev);
 273         struct pm860x_backlight_data *data = bl_get_data(bl);
 274
 275         backlight_device_unregister(bl);
 276         kfree(data);
 277         return 0;
 278 }
 279
 280 static struct platform_driver pm860x_backlight_driver = {
 281         .driver         = {
 282                 .name   = "88pm860x-backlight",
 283                 .owner  = THIS_MODULE,
 284         },
 285         .probe          = pm860x_backlight_probe,
 286         .remove         = pm860x_backlight_remove,
 287 };
 288
 289 static int __init pm860x_backlight_init(void)
 290 {
 291         return platform_driver_register(&pm860x_backlight_driver);
 292 }
 293 module_init(pm860x_backlight_init);
 294
 295 static void __exit pm860x_backlight_exit(void)
 296 {
 297         platform_driver_unregister(&pm860x_backlight_driver);
 298 }
 299 module_exit(pm860x_backlight_exit);
 300
 301 MODULE_DESCRIPTION("Backlight Driver for Marvell Semiconductor 88PM8606");
 302 MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");
 303 MODULE_LICENSE("GPL");
 304 MODULE_ALIAS("platform:88pm860x-backlight");