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 21 #define MAX_BRIGHTNESS (0xff) 22 #define MIN_BRIGHTNESS (0) 23 24 #define LWX_FREQ(x) (((x - 601) / 100) & 0x7) 25 26 struct max8925_backlight_data { 27 struct max8925_chip *chip; 28 29 int current_brightness; 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, MAX8925_WLED_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, MAX8925_WLED_MODE_CNTL, 1, 1); 51 else if (!brightness) 52 /* disable WLED output */ 53 ret = max8925_set_bits(chip->i2c, MAX8925_WLED_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, MAX8925_WLED_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 int __devinit max8925_backlight_probe(struct platform_device *pdev) 102 { 103 struct max8925_chip *chip = dev_get_drvdata(pdev->dev.parent); 104 struct max8925_platform_data *max8925_pdata; 105 struct max8925_backlight_pdata *pdata = NULL; 106 struct max8925_backlight_data *data; 107 struct backlight_device *bl; 108 struct backlight_properties props; 109 struct resource *res; 110 char name[MAX8925_NAME_SIZE]; 111 unsigned char value; 112 int ret; 113 114 res = platform_get_resource(pdev, IORESOURCE_IO, 0); 115 if (res == NULL) { 116 dev_err(&pdev->dev, "No I/O resource!\n"); 117 return -EINVAL; 118 } 119 120 if (pdev->dev.parent->platform_data) { 121 max8925_pdata = pdev->dev.parent->platform_data; 122 pdata = max8925_pdata->backlight; 123 } 124 125 if (!pdata) { 126 dev_err(&pdev->dev, "platform data isn't assigned to " 127 "backlight\n"); 128 return -EINVAL; 129 } 130 131 data = kzalloc(sizeof(struct max8925_backlight_data), GFP_KERNEL); 132 if (data == NULL) 133 return -ENOMEM; 134 strncpy(name, res->name, MAX8925_NAME_SIZE); 135 data->chip = chip; 136 data->current_brightness = 0; 137 138 memset(&props, 0, sizeof(struct backlight_properties)); 139 props.max_brightness = MAX_BRIGHTNESS; 140 bl = backlight_device_register(name, &pdev->dev, data, 141 &max8925_backlight_ops, &props); 142 if (IS_ERR(bl)) { 143 dev_err(&pdev->dev, "failed to register backlight\n"); 144 kfree(data); 145 return PTR_ERR(bl); 146 } 147 bl->props.brightness = MAX_BRIGHTNESS; 148 149 platform_set_drvdata(pdev, bl); 150 151 value = 0; 152 if (pdata->lxw_scl) 153 value |= (1 << 7); 154 if (pdata->lxw_freq) 155 value |= (LWX_FREQ(pdata->lxw_freq) << 4); 156 if (pdata->dual_string) 157 value |= (1 << 1); 158 ret = max8925_set_bits(chip->i2c, MAX8925_WLED_MODE_CNTL, 0xfe, value); 159 if (ret < 0) 160 goto out; 161 162 backlight_update_status(bl); 163 return 0; 164 out: 165 backlight_device_unregister(bl); 166 kfree(data); 167 return ret; 168 } 169 170 static int __devexit max8925_backlight_remove(struct platform_device *pdev) 171 { 172 struct backlight_device *bl = platform_get_drvdata(pdev); 173 struct max8925_backlight_data *data = bl_get_data(bl); 174 175 backlight_device_unregister(bl); 176 kfree(data); 177 return 0; 178 } 179 180 static struct platform_driver max8925_backlight_driver = { 181 .driver = { 182 .name = "max8925-backlight", 183 .owner = THIS_MODULE, 184 }, 185 .probe = max8925_backlight_probe, 186 .remove = __devexit_p(max8925_backlight_remove), 187 }; 188 189 static int __init max8925_backlight_init(void) 190 { 191 return platform_driver_register(&max8925_backlight_driver); 192 } 193 module_init(max8925_backlight_init); 194 195 static void __exit max8925_backlight_exit(void) 196 { 197 platform_driver_unregister(&max8925_backlight_driver); 198 }; 199 module_exit(max8925_backlight_exit); 200 201 MODULE_DESCRIPTION("Backlight Driver for Maxim MAX8925"); 202 MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>"); 203 MODULE_LICENSE("GPL"); 204 MODULE_ALIAS("platform:max8925-backlight"); 205