drivers/video/backlight/max8925_bl.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Backlight driver for Maxim MAX8925
   4  *
   5  * Copyright (C) 2009 Marvell International Ltd.
   6  *      Haojian Zhuang <haojian.zhuang@marvell.com>
   7  */
   8
   9 #include <linux/init.h>
  10 #include <linux/kernel.h>
  11 #include <linux/platform_device.h>
  12 #include <linux/fb.h>
  13 #include <linux/i2c.h>
  14 #include <linux/backlight.h>
  15 #include <linux/mfd/max8925.h>
  16 #include <linux/slab.h>
  17 #include <linux/module.h>
  18
  19 #define MAX_BRIGHTNESS          (0xff)
  20 #define MIN_BRIGHTNESS          (0)
  21
  22 #define LWX_FREQ(x)             (((x - 601) / 100) & 0x7)
  23
  24 struct max8925_backlight_data {
  25         struct max8925_chip     *chip;
  26
  27         int     current_brightness;
  28         int     reg_mode_cntl;
  29         int     reg_cntl;
  30 };
  31
  32 static int max8925_backlight_set(struct backlight_device *bl, int brightness)
  33 {
  34         struct max8925_backlight_data *data = bl_get_data(bl);
  35         struct max8925_chip *chip = data->chip;
  36         unsigned char value;
  37         int ret;
  38
  39         if (brightness > MAX_BRIGHTNESS)
  40                 value = MAX_BRIGHTNESS;
  41         else
  42                 value = brightness;
  43
  44         ret = max8925_reg_write(chip->i2c, data->reg_cntl, value);
  45         if (ret < 0)
  46                 goto out;
  47
  48         if (!data->current_brightness && brightness)
  49                 /* enable WLED output */
  50                 ret = max8925_set_bits(chip->i2c, data->reg_mode_cntl, 1, 1);
  51         else if (!brightness)
  52                 /* disable WLED output */
  53                 ret = max8925_set_bits(chip->i2c, data->reg_mode_cntl, 1, 0);
  54         if (ret < 0)
  55                 goto out;
  56         dev_dbg(chip->dev, "set brightness %d\n", value);
  57         data->current_brightness = value;
  58         return 0;
  59 out:
  60         dev_dbg(chip->dev, "set brightness %d failure with return value:%d\n",
  61                 value, ret);
  62         return ret;
  63 }
  64
  65 static int max8925_backlight_update_status(struct backlight_device *bl)
  66 {
  67         int brightness = bl->props.brightness;
  68
  69         if (bl->props.power != FB_BLANK_UNBLANK)
  70                 brightness = 0;
  71
  72         if (bl->props.fb_blank != FB_BLANK_UNBLANK)
  73                 brightness = 0;
  74
  75         if (bl->props.state & BL_CORE_SUSPENDED)
  76                 brightness = 0;
  77
  78         return max8925_backlight_set(bl, brightness);
  79 }
  80
  81 static int max8925_backlight_get_brightness(struct backlight_device *bl)
  82 {
  83         struct max8925_backlight_data *data = bl_get_data(bl);
  84         struct max8925_chip *chip = data->chip;
  85         int ret;
  86
  87         ret = max8925_reg_read(chip->i2c, data->reg_cntl);
  88         if (ret < 0)
  89                 return -EINVAL;
  90         data->current_brightness = ret;
  91         dev_dbg(chip->dev, "get brightness %d\n", data->current_brightness);
  92         return ret;
  93 }
  94
  95 static const struct backlight_ops max8925_backlight_ops = {
  96         .options        = BL_CORE_SUSPENDRESUME,
  97         .update_status  = max8925_backlight_update_status,
  98         .get_brightness = max8925_backlight_get_brightness,
  99 };
 100
 101 static void max8925_backlight_dt_init(struct platform_device *pdev)
 102 {
 103         struct device_node *nproot = pdev->dev.parent->of_node, *np;
 104         struct max8925_backlight_pdata *pdata;
 105         u32 val;
 106
 107         if (!nproot || !IS_ENABLED(CONFIG_OF))
 108                 return;
 109
 110         pdata = devm_kzalloc(&pdev->dev,
 111                              sizeof(struct max8925_backlight_pdata),
 112                              GFP_KERNEL);
 113         if (!pdata)
 114                 return;
 115
 116         np = of_get_child_by_name(nproot, "backlight");
 117         if (!np) {
 118                 dev_err(&pdev->dev, "failed to find backlight node\n");
 119                 return;
 120         }
 121
 122         if (!of_property_read_u32(np, "maxim,max8925-dual-string", &val))
 123                 pdata->dual_string = val;
 124
 125         of_node_put(np);
 126
 127         pdev->dev.platform_data = pdata;
 128 }
 129
 130 static int max8925_backlight_probe(struct platform_device *pdev)
 131 {
 132         struct max8925_chip *chip = dev_get_drvdata(pdev->dev.parent);
 133         struct max8925_backlight_pdata *pdata;
 134         struct max8925_backlight_data *data;
 135         struct backlight_device *bl;
 136         struct backlight_properties props;
 137         struct resource *res;
 138         unsigned char value;
 139         int ret = 0;
 140
 141         data = devm_kzalloc(&pdev->dev, sizeof(struct max8925_backlight_data),
 142                             GFP_KERNEL);
 143         if (data == NULL)
 144                 return -ENOMEM;
 145
 146         res = platform_get_resource(pdev, IORESOURCE_REG, 0);
 147         if (!res) {
 148                 dev_err(&pdev->dev, "No REG resource for mode control!\n");
 149                 return -ENXIO;
 150         }
 151         data->reg_mode_cntl = res->start;
 152         res = platform_get_resource(pdev, IORESOURCE_REG, 1);
 153         if (!res) {
 154                 dev_err(&pdev->dev, "No REG resource for control!\n");
 155                 return -ENXIO;
 156         }
 157         data->reg_cntl = res->start;
 158
 159         data->chip = chip;
 160         data->current_brightness = 0;
 161
 162         memset(&props, 0, sizeof(struct backlight_properties));
 163         props.type = BACKLIGHT_RAW;
 164         props.max_brightness = MAX_BRIGHTNESS;
 165         bl = devm_backlight_device_register(&pdev->dev, "max8925-backlight",
 166                                         &pdev->dev, data,
 167                                         &max8925_backlight_ops, &props);
 168         if (IS_ERR(bl)) {
 169                 dev_err(&pdev->dev, "failed to register backlight\n");
 170                 return PTR_ERR(bl);
 171         }
 172         bl->props.brightness = MAX_BRIGHTNESS;
 173
 174         platform_set_drvdata(pdev, bl);
 175
 176         value = 0;
 177         if (!pdev->dev.platform_data)
 178                 max8925_backlight_dt_init(pdev);
 179
 180         pdata = pdev->dev.platform_data;
 181         if (pdata) {
 182                 if (pdata->lxw_scl)
 183                         value |= (1 << 7);
 184                 if (pdata->lxw_freq)
 185                         value |= (LWX_FREQ(pdata->lxw_freq) << 4);
 186                 if (pdata->dual_string)
 187                         value |= (1 << 1);
 188         }
 189         ret = max8925_set_bits(chip->i2c, data->reg_mode_cntl, 0xfe, value);
 190         if (ret < 0)
 191                 return ret;
 192         backlight_update_status(bl);
 193         return 0;
 194 }
 195
 196 static struct platform_driver max8925_backlight_driver = {
 197         .driver         = {
 198                 .name   = "max8925-backlight",
 199         },
 200         .probe          = max8925_backlight_probe,
 201 };
 202
 203 module_platform_driver(max8925_backlight_driver);
 204
 205 MODULE_DESCRIPTION("Backlight Driver for Maxim MAX8925");
 206 MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");
 207 MODULE_LICENSE("GPL");
 208 MODULE_ALIAS("platform:max8925-backlight");