drivers/video/backlight/wm831x_bl.c

   1 /*
   2  * Backlight driver for Wolfson Microelectronics WM831x PMICs
   3  *
   4  * Copyright 2009 Wolfson Microelectonics plc
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/init.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/fb.h>
  15 #include <linux/backlight.h>
  16 #include <linux/slab.h>
  17
  18 #include <linux/mfd/wm831x/core.h>
  19 #include <linux/mfd/wm831x/pdata.h>
  20 #include <linux/mfd/wm831x/regulator.h>
  21
  22 struct wm831x_backlight_data {
  23         struct wm831x *wm831x;
  24         int isink_reg;
  25         int current_brightness;
  26 };
  27
  28 static int wm831x_backlight_set(struct backlight_device *bl, int brightness)
  29 {
  30         struct wm831x_backlight_data *data = bl_get_data(bl);
  31         struct wm831x *wm831x = data->wm831x;
  32         int power_up = !data->current_brightness && brightness;
  33         int power_down = data->current_brightness && !brightness;
  34         int ret;
  35
  36         if (power_up) {
  37                 /* Enable the ISINK */
  38                 ret = wm831x_set_bits(wm831x, data->isink_reg,
  39                                       WM831X_CS1_ENA, WM831X_CS1_ENA);
  40                 if (ret < 0)
  41                         goto err;
  42
  43                 /* Enable the DC-DC */
  44                 ret = wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE,
  45                                       WM831X_DC4_ENA, WM831X_DC4_ENA);
  46                 if (ret < 0)
  47                         goto err;
  48         }
  49
  50         if (power_down) {
  51                 /* DCDC first */
  52                 ret = wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE,
  53                                       WM831X_DC4_ENA, 0);
  54                 if (ret < 0)
  55                         goto err;
  56
  57                 /* ISINK */
  58                 ret = wm831x_set_bits(wm831x, data->isink_reg,
  59                                       WM831X_CS1_DRIVE | WM831X_CS1_ENA, 0);
  60                 if (ret < 0)
  61                         goto err;
  62         }
  63
  64         /* Set the new brightness */
  65         ret = wm831x_set_bits(wm831x, data->isink_reg,
  66                               WM831X_CS1_ISEL_MASK, brightness);
  67         if (ret < 0)
  68                 goto err;
  69
  70         if (power_up) {
  71                 /* Drive current through the ISINK */
  72                 ret = wm831x_set_bits(wm831x, data->isink_reg,
  73                                       WM831X_CS1_DRIVE, WM831X_CS1_DRIVE);
  74                 if (ret < 0)
  75                         return ret;
  76         }
  77
  78         data->current_brightness = brightness;
  79
  80         return 0;
  81
  82 err:
  83         /* If we were in the middle of a power transition always shut down
  84          * for safety.
  85          */
  86         if (power_up || power_down) {
  87                 wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, WM831X_DC4_ENA, 0);
  88                 wm831x_set_bits(wm831x, data->isink_reg, WM831X_CS1_ENA, 0);
  89         }
  90
  91         return ret;
  92 }
  93
  94 static int wm831x_backlight_update_status(struct backlight_device *bl)
  95 {
  96         int brightness = bl->props.brightness;
  97
  98         if (bl->props.power != FB_BLANK_UNBLANK)
  99                 brightness = 0;
 100
 101         if (bl->props.fb_blank != FB_BLANK_UNBLANK)
 102                 brightness = 0;
 103
 104         if (bl->props.state & BL_CORE_SUSPENDED)
 105                 brightness = 0;
 106
 107         return wm831x_backlight_set(bl, brightness);
 108 }
 109
 110 static int wm831x_backlight_get_brightness(struct backlight_device *bl)
 111 {
 112         struct wm831x_backlight_data *data = bl_get_data(bl);
 113         return data->current_brightness;
 114 }
 115
 116 static const struct backlight_ops wm831x_backlight_ops = {
 117         .options = BL_CORE_SUSPENDRESUME,
 118         .update_status  = wm831x_backlight_update_status,
 119         .get_brightness = wm831x_backlight_get_brightness,
 120 };
 121
 122 static int wm831x_backlight_probe(struct platform_device *pdev)
 123 {
 124         struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
 125         struct wm831x_pdata *wm831x_pdata;
 126         struct wm831x_backlight_pdata *pdata;
 127         struct wm831x_backlight_data *data;
 128         struct backlight_device *bl;
 129         struct backlight_properties props;
 130         int ret, i, max_isel, isink_reg, dcdc_cfg;
 131
 132         /* We need platform data */
 133         if (pdev->dev.parent->platform_data) {
 134                 wm831x_pdata = pdev->dev.parent->platform_data;
 135                 pdata = wm831x_pdata->backlight;
 136         } else {
 137                 pdata = NULL;
 138         }
 139
 140         if (!pdata) {
 141                 dev_err(&pdev->dev, "No platform data supplied\n");
 142                 return -EINVAL;
 143         }
 144
 145         /* Figure out the maximum current we can use */
 146         for (i = 0; i < WM831X_ISINK_MAX_ISEL; i++) {
 147                 if (wm831x_isinkv_values[i] > pdata->max_uA)
 148                         break;
 149         }
 150
 151         if (i == 0) {
 152                 dev_err(&pdev->dev, "Invalid max_uA: %duA\n", pdata->max_uA);
 153                 return -EINVAL;
 154         }
 155         max_isel = i - 1;
 156
 157         if (pdata->max_uA != wm831x_isinkv_values[max_isel])
 158                 dev_warn(&pdev->dev,
 159                          "Maximum current is %duA not %duA as requested\n",
 160                          wm831x_isinkv_values[max_isel], pdata->max_uA);
 161
 162         switch (pdata->isink) {
 163         case 1:
 164                 isink_reg = WM831X_CURRENT_SINK_1;
 165                 dcdc_cfg = 0;
 166                 break;
 167         case 2:
 168                 isink_reg = WM831X_CURRENT_SINK_2;
 169                 dcdc_cfg = WM831X_DC4_FBSRC;
 170                 break;
 171         default:
 172                 dev_err(&pdev->dev, "Invalid ISINK %d\n", pdata->isink);
 173                 return -EINVAL;
 174         }
 175
 176         /* Configure the ISINK to use for feedback */
 177         ret = wm831x_reg_unlock(wm831x);
 178         if (ret < 0)
 179                 return ret;
 180
 181         ret = wm831x_set_bits(wm831x, WM831X_DC4_CONTROL, WM831X_DC4_FBSRC,
 182                               dcdc_cfg);
 183
 184         wm831x_reg_lock(wm831x);
 185         if (ret < 0)
 186                 return ret;
 187
 188         data = kzalloc(sizeof(*data), GFP_KERNEL);
 189         if (data == NULL)
 190                 return -ENOMEM;
 191
 192         data->wm831x = wm831x;
 193         data->current_brightness = 0;
 194         data->isink_reg = isink_reg;
 195
 196         props.type = BACKLIGHT_RAW;
 197         props.max_brightness = max_isel;
 198         bl = backlight_device_register("wm831x", &pdev->dev, data,
 199                                        &wm831x_backlight_ops, &props);
 200         if (IS_ERR(bl)) {
 201                 dev_err(&pdev->dev, "failed to register backlight\n");
 202                 kfree(data);
 203                 return PTR_ERR(bl);
 204         }
 205
 206         bl->props.brightness = max_isel;
 207
 208         platform_set_drvdata(pdev, bl);
 209
 210         /* Disable the DCDC if it was started so we can bootstrap */
 211         wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, WM831X_DC4_ENA, 0);
 212
 213
 214         backlight_update_status(bl);
 215
 216         return 0;
 217 }
 218
 219 static int wm831x_backlight_remove(struct platform_device *pdev)
 220 {
 221         struct backlight_device *bl = platform_get_drvdata(pdev);
 222         struct wm831x_backlight_data *data = bl_get_data(bl);
 223
 224         backlight_device_unregister(bl);
 225         kfree(data);
 226         return 0;
 227 }
 228
 229 static struct platform_driver wm831x_backlight_driver = {
 230         .driver         = {
 231                 .name   = "wm831x-backlight",
 232                 .owner  = THIS_MODULE,
 233         },
 234         .probe          = wm831x_backlight_probe,
 235         .remove         = wm831x_backlight_remove,
 236 };
 237
 238 static int __init wm831x_backlight_init(void)
 239 {
 240         return platform_driver_register(&wm831x_backlight_driver);
 241 }
 242 module_init(wm831x_backlight_init);
 243
 244 static void __exit wm831x_backlight_exit(void)
 245 {
 246         platform_driver_unregister(&wm831x_backlight_driver);
 247 }
 248 module_exit(wm831x_backlight_exit);
 249
 250 MODULE_DESCRIPTION("Backlight Driver for WM831x PMICs");
 251 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com");
 252 MODULE_LICENSE("GPL");
 253 MODULE_ALIAS("platform:wm831x-backlight");