kernel/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/of.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/slab.h>
  17 #include <linux/fb.h>
  18 #include <linux/i2c.h>
  19 #include <linux/backlight.h>
  20 #include <linux/mfd/88pm860x.h>
  21 #include <linux/module.h>
  22
  23 #define MAX_BRIGHTNESS          (0xFF)
  24 #define MIN_BRIGHTNESS          (0)
  25
  26 #define CURRENT_BITMASK         (0x1F << 1)
  27
  28 struct pm860x_backlight_data {
  29         struct pm860x_chip *chip;
  30         struct i2c_client *i2c;
  31         int     current_brightness;
  32         int     port;
  33         int     pwm;
  34         int     iset;
  35         int     reg_duty_cycle;
  36         int     reg_always_on;
  37         int     reg_current;
  38 };
  39
  40 static int backlight_power_set(struct pm860x_chip *chip, int port,
  41                 int on)
  42 {
  43         int ret = -EINVAL;
  44
  45         switch (port) {
  46         case 0:
  47                 ret = on ? pm8606_osc_enable(chip, WLED1_DUTY) :
  48                         pm8606_osc_disable(chip, WLED1_DUTY);
  49                 break;
  50         case 1:
  51                 ret = on ? pm8606_osc_enable(chip, WLED2_DUTY) :
  52                         pm8606_osc_disable(chip, WLED2_DUTY);
  53                 break;
  54         case 2:
  55                 ret = on ? pm8606_osc_enable(chip, WLED3_DUTY) :
  56                         pm8606_osc_disable(chip, WLED3_DUTY);
  57                 break;
  58         }
  59         return ret;
  60 }
  61
  62 static int pm860x_backlight_set(struct backlight_device *bl, int brightness)
  63 {
  64         struct pm860x_backlight_data *data = bl_get_data(bl);
  65         struct pm860x_chip *chip = data->chip;
  66         unsigned char value;
  67         int ret;
  68
  69         if (brightness > MAX_BRIGHTNESS)
  70                 value = MAX_BRIGHTNESS;
  71         else
  72                 value = brightness;
  73
  74         if (brightness)
  75                 backlight_power_set(chip, data->port, 1);
  76
  77         ret = pm860x_reg_write(data->i2c, data->reg_duty_cycle, value);
  78         if (ret < 0)
  79                 goto out;
  80
  81         if ((data->current_brightness == 0) && brightness) {
  82                 if (data->iset) {
  83                         ret = pm860x_set_bits(data->i2c, data->reg_current,
  84                                               CURRENT_BITMASK, data->iset);
  85                         if (ret < 0)
  86                                 goto out;
  87                 }
  88                 if (data->pwm) {
  89                         ret = pm860x_set_bits(data->i2c, PM8606_PWM,
  90                                               PM8606_PWM_FREQ_MASK, data->pwm);
  91                         if (ret < 0)
  92                                 goto out;
  93                 }
  94                 if (brightness == MAX_BRIGHTNESS) {
  95                         /* set WLED_ON bit as 100% */
  96                         ret = pm860x_set_bits(data->i2c, data->reg_always_on,
  97                                               PM8606_WLED_ON, PM8606_WLED_ON);
  98                 }
  99         } else {
 100                 if (brightness == MAX_BRIGHTNESS) {
 101                         /* set WLED_ON bit as 100% */
 102                         ret = pm860x_set_bits(data->i2c, data->reg_always_on,
 103                                               PM8606_WLED_ON, PM8606_WLED_ON);
 104                 } else {
 105                         /* clear WLED_ON bit since it's not 100% */
 106                         ret = pm860x_set_bits(data->i2c, data->reg_always_on,
 107                                               PM8606_WLED_ON, 0);
 108                 }
 109         }
 110         if (ret < 0)
 111                 goto out;
 112
 113         if (brightness == 0)
 114                 backlight_power_set(chip, data->port, 0);
 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 value: %d\n",
 121                 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, data->reg_duty_cycle);
 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 const 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 #ifdef CONFIG_OF
 164 static int pm860x_backlight_dt_init(struct platform_device *pdev,
 165                                     struct pm860x_backlight_data *data,
 166                                     char *name)
 167 {
 168         struct device_node *nproot, *np;
 169         int iset = 0;
 170
 171         nproot = of_get_child_by_name(pdev->dev.parent->of_node, "backlights");
 172         if (!nproot) {
 173                 dev_err(&pdev->dev, "failed to find backlights node\n");
 174                 return -ENODEV;
 175         }
 176         for_each_child_of_node(nproot, np) {
 177                 if (!of_node_cmp(np->name, name)) {
 178                         of_property_read_u32(np, "marvell,88pm860x-iset",
 179                                              &iset);
 180                         data->iset = PM8606_WLED_CURRENT(iset);
 181                         of_property_read_u32(np, "marvell,88pm860x-pwm",
 182                                              &data->pwm);
 183                         break;
 184                 }
 185         }
 186         of_node_put(nproot);
 187         return 0;
 188 }
 189 #else
 190 #define pm860x_backlight_dt_init(x, y, z)       (-1)
 191 #endif
 192
 193 static int pm860x_backlight_probe(struct platform_device *pdev)
 194 {
 195         struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
 196         struct pm860x_backlight_pdata *pdata = dev_get_platdata(&pdev->dev);
 197         struct pm860x_backlight_data *data;
 198         struct backlight_device *bl;
 199         struct resource *res;
 200         struct backlight_properties props;
 201         char name[MFD_NAME_SIZE];
 202         int ret = 0;
 203
 204         data = devm_kzalloc(&pdev->dev, sizeof(struct pm860x_backlight_data),
 205                             GFP_KERNEL);
 206         if (data == NULL)
 207                 return -ENOMEM;
 208         res = platform_get_resource_byname(pdev, IORESOURCE_REG, "duty cycle");
 209         if (!res) {
 210                 dev_err(&pdev->dev, "No REG resource for duty cycle\n");
 211                 return -ENXIO;
 212         }
 213         data->reg_duty_cycle = res->start;
 214         res = platform_get_resource_byname(pdev, IORESOURCE_REG, "always on");
 215         if (!res) {
 216                 dev_err(&pdev->dev, "No REG resource for always on\n");
 217                 return -ENXIO;
 218         }
 219         data->reg_always_on = res->start;
 220         res = platform_get_resource_byname(pdev, IORESOURCE_REG, "current");
 221         if (!res) {
 222                 dev_err(&pdev->dev, "No REG resource for current\n");
 223                 return -ENXIO;
 224         }
 225         data->reg_current = res->start;
 226
 227         memset(name, 0, MFD_NAME_SIZE);
 228         sprintf(name, "backlight-%d", pdev->id);
 229         data->port = pdev->id;
 230         data->chip = chip;
 231         data->i2c = (chip->id == CHIP_PM8606) ? chip->client : chip->companion;
 232         data->current_brightness = MAX_BRIGHTNESS;
 233         if (pm860x_backlight_dt_init(pdev, data, name)) {
 234                 if (pdata) {
 235                         data->pwm = pdata->pwm;
 236                         data->iset = pdata->iset;
 237                 }
 238         }
 239
 240         memset(&props, 0, sizeof(struct backlight_properties));
 241         props.type = BACKLIGHT_RAW;
 242         props.max_brightness = MAX_BRIGHTNESS;
 243         bl = devm_backlight_device_register(&pdev->dev, name, &pdev->dev, data,
 244                                         &pm860x_backlight_ops, &props);
 245         if (IS_ERR(bl)) {
 246                 dev_err(&pdev->dev, "failed to register backlight\n");
 247                 return PTR_ERR(bl);
 248         }
 249         bl->props.brightness = MAX_BRIGHTNESS;
 250
 251         platform_set_drvdata(pdev, bl);
 252
 253         /* read current backlight */
 254         ret = pm860x_backlight_get_brightness(bl);
 255         if (ret < 0)
 256                 return ret;
 257
 258         backlight_update_status(bl);
 259         return 0;
 260 }
 261
 262 static struct platform_driver pm860x_backlight_driver = {
 263         .driver         = {
 264                 .name   = "88pm860x-backlight",
 265         },
 266         .probe          = pm860x_backlight_probe,
 267 };
 268
 269 module_platform_driver(pm860x_backlight_driver);
 270
 271 MODULE_DESCRIPTION("Backlight Driver for Marvell Semiconductor 88PM8606");
 272 MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");
 273 MODULE_LICENSE("GPL");
 274 MODULE_ALIAS("platform:88pm860x-backlight");