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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
26struct max8925_backlight_data {
27 struct max8925_chip *chip;
28
29 int current_brightness;
30};
31
32static 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
50 ret = max8925_set_bits(chip->i2c, MAX8925_WLED_MODE_CNTL, 1, 1);
51 else if (!brightness)
52
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;
59out:
60 dev_dbg(chip->dev, "set brightness %d failure with return value:%d\n",
61 value, ret);
62 return ret;
63}
64
65static 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
81static 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
95static 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
101static 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;
164out:
165 backlight_device_unregister(bl);
166 kfree(data);
167 return ret;
168}
169
170static 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
180static 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
189static int __init max8925_backlight_init(void)
190{
191 return platform_driver_register(&max8925_backlight_driver);
192}
193module_init(max8925_backlight_init);
194
195static void __exit max8925_backlight_exit(void)
196{
197 platform_driver_unregister(&max8925_backlight_driver);
198};
199module_exit(max8925_backlight_exit);
200
201MODULE_DESCRIPTION("Backlight Driver for Maxim MAX8925");
202MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");
203MODULE_LICENSE("GPL");
204MODULE_ALIAS("platform:max8925-backlight");
205
