2 * linux/drivers/video/backlight/aat2870_bl.c
4 * Copyright (c) 2011, NVIDIA Corporation.
5 * Author: Jin Park <jinyoungp@nvidia.com>
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * version 2 as published by the Free Software Foundation.
11 * This program is distributed in the hope that it will be useful, but
12 * WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
22 #include <linux/module.h>
23 #include <linux/kernel.h>
24 #include <linux/init.h>
25 #include <linux/platform_device.h>
26 #include <linux/mutex.h>
27 #include <linux/delay.h>
29 #include <linux/backlight.h>
30 #include <linux/mfd/aat2870.h>
32 struct aat2870_bl_driver_data {
33 struct platform_device *pdev;
34 struct backlight_device *bd;
38 int brightness; /* current brightness */
41 static inline int aat2870_brightness(struct aat2870_bl_driver_data *aat2870_bl,
44 struct backlight_device *bd = aat2870_bl->bd;
47 val = brightness * (aat2870_bl->max_current - 1);
48 val /= bd->props.max_brightness;
53 static inline int aat2870_bl_enable(struct aat2870_bl_driver_data *aat2870_bl)
55 struct aat2870_data *aat2870
56 = dev_get_drvdata(aat2870_bl->pdev->dev.parent);
58 return aat2870->write(aat2870, AAT2870_BL_CH_EN,
59 (u8)aat2870_bl->channels);
62 static inline int aat2870_bl_disable(struct aat2870_bl_driver_data *aat2870_bl)
64 struct aat2870_data *aat2870
65 = dev_get_drvdata(aat2870_bl->pdev->dev.parent);
67 return aat2870->write(aat2870, AAT2870_BL_CH_EN, 0x0);
70 static int aat2870_bl_update_status(struct backlight_device *bd)
72 struct aat2870_bl_driver_data *aat2870_bl = bl_get_data(bd);
73 struct aat2870_data *aat2870 =
74 dev_get_drvdata(aat2870_bl->pdev->dev.parent);
75 int brightness = bd->props.brightness;
78 if ((brightness < 0) || (bd->props.max_brightness < brightness)) {
79 dev_err(&bd->dev, "invalid brightness, %d\n", brightness);
83 dev_dbg(&bd->dev, "brightness=%d, power=%d, state=%d\n",
84 bd->props.brightness, bd->props.power, bd->props.state);
86 if ((bd->props.power != FB_BLANK_UNBLANK) ||
87 (bd->props.state & BL_CORE_FBBLANK) ||
88 (bd->props.state & BL_CORE_SUSPENDED))
91 ret = aat2870->write(aat2870, AAT2870_BLM,
92 (u8)aat2870_brightness(aat2870_bl, brightness));
96 if (brightness == 0) {
97 ret = aat2870_bl_disable(aat2870_bl);
100 } else if (aat2870_bl->brightness == 0) {
101 ret = aat2870_bl_enable(aat2870_bl);
106 aat2870_bl->brightness = brightness;
111 static int aat2870_bl_check_fb(struct backlight_device *bd, struct fb_info *fi)
116 static const struct backlight_ops aat2870_bl_ops = {
117 .options = BL_CORE_SUSPENDRESUME,
118 .update_status = aat2870_bl_update_status,
119 .check_fb = aat2870_bl_check_fb,
122 static int aat2870_bl_probe(struct platform_device *pdev)
124 struct aat2870_bl_platform_data *pdata = dev_get_platdata(&pdev->dev);
125 struct aat2870_bl_driver_data *aat2870_bl;
126 struct backlight_device *bd;
127 struct backlight_properties props;
131 dev_err(&pdev->dev, "No platform data\n");
136 if (pdev->id != AAT2870_ID_BL) {
137 dev_err(&pdev->dev, "Invalid device ID, %d\n", pdev->id);
142 aat2870_bl = devm_kzalloc(&pdev->dev,
143 sizeof(struct aat2870_bl_driver_data),
150 memset(&props, 0, sizeof(struct backlight_properties));
152 props.type = BACKLIGHT_RAW;
153 bd = devm_backlight_device_register(&pdev->dev, "aat2870-backlight",
154 &pdev->dev, aat2870_bl, &aat2870_bl_ops,
158 "Failed allocate memory for backlight device\n");
163 aat2870_bl->pdev = pdev;
164 platform_set_drvdata(pdev, aat2870_bl);
168 if (pdata->channels > 0)
169 aat2870_bl->channels = pdata->channels;
171 aat2870_bl->channels = AAT2870_BL_CH_ALL;
173 if (pdata->max_current > 0)
174 aat2870_bl->max_current = pdata->max_current;
176 aat2870_bl->max_current = AAT2870_CURRENT_27_9;
178 if (pdata->max_brightness > 0)
179 bd->props.max_brightness = pdata->max_brightness;
181 bd->props.max_brightness = 255;
183 aat2870_bl->brightness = 0;
184 bd->props.power = FB_BLANK_UNBLANK;
185 bd->props.brightness = bd->props.max_brightness;
187 ret = aat2870_bl_update_status(bd);
189 dev_err(&pdev->dev, "Failed to initialize\n");
199 static int aat2870_bl_remove(struct platform_device *pdev)
201 struct aat2870_bl_driver_data *aat2870_bl = platform_get_drvdata(pdev);
202 struct backlight_device *bd = aat2870_bl->bd;
204 bd->props.power = FB_BLANK_POWERDOWN;
205 bd->props.brightness = 0;
206 backlight_update_status(bd);
211 static struct platform_driver aat2870_bl_driver = {
213 .name = "aat2870-backlight",
214 .owner = THIS_MODULE,
216 .probe = aat2870_bl_probe,
217 .remove = aat2870_bl_remove,
220 static int __init aat2870_bl_init(void)
222 return platform_driver_register(&aat2870_bl_driver);
224 subsys_initcall(aat2870_bl_init);
226 static void __exit aat2870_bl_exit(void)
228 platform_driver_unregister(&aat2870_bl_driver);
230 module_exit(aat2870_bl_exit);
232 MODULE_DESCRIPTION("AnalogicTech AAT2870 Backlight");
233 MODULE_LICENSE("GPL");
234 MODULE_AUTHOR("Jin Park <jinyoungp@nvidia.com>");