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