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
max8925_backlight_set(struct backlight_device * bl,int brightness)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
max8925_backlight_update_status(struct backlight_device * bl)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
max8925_backlight_get_brightness(struct backlight_device * bl)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
max8925_backlight_probe(struct platform_device * pdev)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.type = BACKLIGHT_RAW;
140 props.max_brightness = MAX_BRIGHTNESS;
141 bl = backlight_device_register(name, &pdev->dev, data,
142 &max8925_backlight_ops, &props);
143 if (IS_ERR(bl)) {
144 dev_err(&pdev->dev, "failed to register backlight\n");
145 kfree(data);
146 return PTR_ERR(bl);
147 }
148 bl->props.brightness = MAX_BRIGHTNESS;
149
150 platform_set_drvdata(pdev, bl);
151
152 value = 0;
153 if (pdata->lxw_scl)
154 value |= (1 << 7);
155 if (pdata->lxw_freq)
156 value |= (LWX_FREQ(pdata->lxw_freq) << 4);
157 if (pdata->dual_string)
158 value |= (1 << 1);
159 ret = max8925_set_bits(chip->i2c, MAX8925_WLED_MODE_CNTL, 0xfe, value);
160 if (ret < 0)
161 goto out;
162
163 backlight_update_status(bl);
164 return 0;
165 out:
166 backlight_device_unregister(bl);
167 kfree(data);
168 return ret;
169 }
170
max8925_backlight_remove(struct platform_device * pdev)171 static int __devexit max8925_backlight_remove(struct platform_device *pdev)
172 {
173 struct backlight_device *bl = platform_get_drvdata(pdev);
174 struct max8925_backlight_data *data = bl_get_data(bl);
175
176 backlight_device_unregister(bl);
177 kfree(data);
178 return 0;
179 }
180
181 static struct platform_driver max8925_backlight_driver = {
182 .driver = {
183 .name = "max8925-backlight",
184 .owner = THIS_MODULE,
185 },
186 .probe = max8925_backlight_probe,
187 .remove = __devexit_p(max8925_backlight_remove),
188 };
189
max8925_backlight_init(void)190 static int __init max8925_backlight_init(void)
191 {
192 return platform_driver_register(&max8925_backlight_driver);
193 }
194 module_init(max8925_backlight_init);
195
max8925_backlight_exit(void)196 static void __exit max8925_backlight_exit(void)
197 {
198 platform_driver_unregister(&max8925_backlight_driver);
199 };
200 module_exit(max8925_backlight_exit);
201
202 MODULE_DESCRIPTION("Backlight Driver for Maxim MAX8925");
203 MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");
204 MODULE_LICENSE("GPL");
205 MODULE_ALIAS("platform:max8925-backlight");
206