1 /* 2 * Backlight driver for Maxim MAX8925 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/max8925.h> 19 #include <linux/slab.h> 20 #include <linux/module.h> 21 22 #define MAX_BRIGHTNESS (0xff) 23 #define MIN_BRIGHTNESS (0) 24 25 #define LWX_FREQ(x) (((x - 601) / 100) & 0x7) 26 27 struct max8925_backlight_data { 28 struct max8925_chip *chip; 29 30 int current_brightness; 31 }; 32 33 static int max8925_backlight_set(struct backlight_device *bl, int brightness) 34 { 35 struct max8925_backlight_data *data = bl_get_data(bl); 36 struct max8925_chip *chip = data->chip; 37 unsigned char value; 38 int ret; 39 40 if (brightness > MAX_BRIGHTNESS) 41 value = MAX_BRIGHTNESS; 42 else 43 value = brightness; 44 45 ret = max8925_reg_write(chip->i2c, MAX8925_WLED_CNTL, value); 46 if (ret < 0) 47 goto out; 48 49 if (!data->current_brightness && brightness) 50 /* enable WLED output */ 51 ret = max8925_set_bits(chip->i2c, MAX8925_WLED_MODE_CNTL, 1, 1); 52 else if (!brightness) 53 /* disable WLED output */ 54 ret = max8925_set_bits(chip->i2c, MAX8925_WLED_MODE_CNTL, 1, 0); 55 if (ret < 0) 56 goto out; 57 dev_dbg(chip->dev, "set brightness %d\n", value); 58 data->current_brightness = value; 59 return 0; 60 out: 61 dev_dbg(chip->dev, "set brightness %d failure with return value:%d\n", 62 value, ret); 63 return ret; 64 } 65 66 static int max8925_backlight_update_status(struct backlight_device *bl) 67 { 68 int brightness = bl->props.brightness; 69 70 if (bl->props.power != FB_BLANK_UNBLANK) 71 brightness = 0; 72 73 if (bl->props.fb_blank != FB_BLANK_UNBLANK) 74 brightness = 0; 75 76 if (bl->props.state & BL_CORE_SUSPENDED) 77 brightness = 0; 78 79 return max8925_backlight_set(bl, brightness); 80 } 81 82 static int max8925_backlight_get_brightness(struct backlight_device *bl) 83 { 84 struct max8925_backlight_data *data = bl_get_data(bl); 85 struct max8925_chip *chip = data->chip; 86 int ret; 87 88 ret = max8925_reg_read(chip->i2c, MAX8925_WLED_CNTL); 89 if (ret < 0) 90 return -EINVAL; 91 data->current_brightness = ret; 92 dev_dbg(chip->dev, "get brightness %d\n", data->current_brightness); 93 return ret; 94 } 95 96 static const struct backlight_ops max8925_backlight_ops = { 97 .options = BL_CORE_SUSPENDRESUME, 98 .update_status = max8925_backlight_update_status, 99 .get_brightness = max8925_backlight_get_brightness, 100 }; 101 102 static int __devinit max8925_backlight_probe(struct platform_device *pdev) 103 { 104 struct max8925_chip *chip = dev_get_drvdata(pdev->dev.parent); 105 struct max8925_platform_data *max8925_pdata; 106 struct max8925_backlight_pdata *pdata = NULL; 107 struct max8925_backlight_data *data; 108 struct backlight_device *bl; 109 struct backlight_properties props; 110 struct resource *res; 111 char name[MAX8925_NAME_SIZE]; 112 unsigned char value; 113 int ret; 114 115 res = platform_get_resource(pdev, IORESOURCE_IO, 0); 116 if (res == NULL) { 117 dev_err(&pdev->dev, "No I/O resource!\n"); 118 return -EINVAL; 119 } 120 121 if (pdev->dev.parent->platform_data) { 122 max8925_pdata = pdev->dev.parent->platform_data; 123 pdata = max8925_pdata->backlight; 124 } 125 126 if (!pdata) { 127 dev_err(&pdev->dev, "platform data isn't assigned to " 128 "backlight\n"); 129 return -EINVAL; 130 } 131 132 data = devm_kzalloc(&pdev->dev, sizeof(struct max8925_backlight_data), 133 GFP_KERNEL); 134 if (data == NULL) 135 return -ENOMEM; 136 strncpy(name, res->name, MAX8925_NAME_SIZE); 137 data->chip = chip; 138 data->current_brightness = 0; 139 140 memset(&props, 0, sizeof(struct backlight_properties)); 141 props.type = BACKLIGHT_RAW; 142 props.max_brightness = MAX_BRIGHTNESS; 143 bl = backlight_device_register(name, &pdev->dev, data, 144 &max8925_backlight_ops, &props); 145 if (IS_ERR(bl)) { 146 dev_err(&pdev->dev, "failed to register backlight\n"); 147 return PTR_ERR(bl); 148 } 149 bl->props.brightness = MAX_BRIGHTNESS; 150 151 platform_set_drvdata(pdev, bl); 152 153 value = 0; 154 if (pdata->lxw_scl) 155 value |= (1 << 7); 156 if (pdata->lxw_freq) 157 value |= (LWX_FREQ(pdata->lxw_freq) << 4); 158 if (pdata->dual_string) 159 value |= (1 << 1); 160 ret = max8925_set_bits(chip->i2c, MAX8925_WLED_MODE_CNTL, 0xfe, value); 161 if (ret < 0) 162 goto out; 163 164 backlight_update_status(bl); 165 return 0; 166 out: 167 backlight_device_unregister(bl); 168 return ret; 169 } 170 171 static int __devexit max8925_backlight_remove(struct platform_device *pdev) 172 { 173 struct backlight_device *bl = platform_get_drvdata(pdev); 174 175 backlight_device_unregister(bl); 176 return 0; 177 } 178 179 static struct platform_driver max8925_backlight_driver = { 180 .driver = { 181 .name = "max8925-backlight", 182 .owner = THIS_MODULE, 183 }, 184 .probe = max8925_backlight_probe, 185 .remove = __devexit_p(max8925_backlight_remove), 186 }; 187 188 module_platform_driver(max8925_backlight_driver); 189 190 MODULE_DESCRIPTION("Backlight Driver for Maxim MAX8925"); 191 MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>"); 192 MODULE_LICENSE("GPL"); 193 MODULE_ALIAS("platform:max8925-backlight"); 194