1/*
2 * linux/drivers/video/backlight/aat2870_bl.c
3 *
4 * Copyright (c) 2011, NVIDIA Corporation.
5 * Author: Jin Park <jinyoungp@nvidia.com>
6 *
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.
10 *
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.
15 *
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
19 * 02110-1301 USA
20 */
21
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>
28#include <linux/fb.h>
29#include <linux/backlight.h>
30#include <linux/mfd/aat2870.h>
31
32struct aat2870_bl_driver_data {
33	struct platform_device *pdev;
34	struct backlight_device *bd;
35
36	int channels;
37	int max_current;
38	int brightness; /* current brightness */
39};
40
41static inline int aat2870_brightness(struct aat2870_bl_driver_data *aat2870_bl,
42				     int brightness)
43{
44	struct backlight_device *bd = aat2870_bl->bd;
45	int val;
46
47	val = brightness * (aat2870_bl->max_current - 1);
48	val /= bd->props.max_brightness;
49
50	return val;
51}
52
53static inline int aat2870_bl_enable(struct aat2870_bl_driver_data *aat2870_bl)
54{
55	struct aat2870_data *aat2870
56			= dev_get_drvdata(aat2870_bl->pdev->dev.parent);
57
58	return aat2870->write(aat2870, AAT2870_BL_CH_EN,
59			      (u8)aat2870_bl->channels);
60}
61
62static inline int aat2870_bl_disable(struct aat2870_bl_driver_data *aat2870_bl)
63{
64	struct aat2870_data *aat2870
65			= dev_get_drvdata(aat2870_bl->pdev->dev.parent);
66
67	return aat2870->write(aat2870, AAT2870_BL_CH_EN, 0x0);
68}
69
70static int aat2870_bl_update_status(struct backlight_device *bd)
71{
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;
76	int ret;
77
78	if ((brightness < 0) || (bd->props.max_brightness < brightness)) {
79		dev_err(&bd->dev, "invalid brightness, %d\n", brightness);
80		return -EINVAL;
81	}
82
83	dev_dbg(&bd->dev, "brightness=%d, power=%d, state=%d\n",
84		 bd->props.brightness, bd->props.power, bd->props.state);
85
86	if ((bd->props.power != FB_BLANK_UNBLANK) ||
87			(bd->props.state & BL_CORE_FBBLANK) ||
88			(bd->props.state & BL_CORE_SUSPENDED))
89		brightness = 0;
90
91	ret = aat2870->write(aat2870, AAT2870_BLM,
92			     (u8)aat2870_brightness(aat2870_bl, brightness));
93	if (ret < 0)
94		return ret;
95
96	if (brightness == 0) {
97		ret = aat2870_bl_disable(aat2870_bl);
98		if (ret < 0)
99			return ret;
100	} else if (aat2870_bl->brightness == 0) {
101		ret = aat2870_bl_enable(aat2870_bl);
102		if (ret < 0)
103			return ret;
104	}
105
106	aat2870_bl->brightness = brightness;
107
108	return 0;
109}
110
111static int aat2870_bl_check_fb(struct backlight_device *bd, struct fb_info *fi)
112{
113	return 1;
114}
115
116static 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,
120};
121
122static int aat2870_bl_probe(struct platform_device *pdev)
123{
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;
128	int ret = 0;
129
130	if (!pdata) {
131		dev_err(&pdev->dev, "No platform data\n");
132		ret = -ENXIO;
133		goto out;
134	}
135
136	if (pdev->id != AAT2870_ID_BL) {
137		dev_err(&pdev->dev, "Invalid device ID, %d\n", pdev->id);
138		ret = -EINVAL;
139		goto out;
140	}
141
142	aat2870_bl = devm_kzalloc(&pdev->dev,
143				  sizeof(struct aat2870_bl_driver_data),
144				  GFP_KERNEL);
145	if (!aat2870_bl) {
146		ret = -ENOMEM;
147		goto out;
148	}
149
150	memset(&props, 0, sizeof(struct backlight_properties));
151
152	props.type = BACKLIGHT_RAW;
153	bd = devm_backlight_device_register(&pdev->dev, "aat2870-backlight",
154					&pdev->dev, aat2870_bl, &aat2870_bl_ops,
155					&props);
156	if (IS_ERR(bd)) {
157		dev_err(&pdev->dev,
158			"Failed allocate memory for backlight device\n");
159		ret = PTR_ERR(bd);
160		goto out;
161	}
162
163	aat2870_bl->pdev = pdev;
164	platform_set_drvdata(pdev, aat2870_bl);
165
166	aat2870_bl->bd = bd;
167
168	if (pdata->channels > 0)
169		aat2870_bl->channels = pdata->channels;
170	else
171		aat2870_bl->channels = AAT2870_BL_CH_ALL;
172
173	if (pdata->max_current > 0)
174		aat2870_bl->max_current = pdata->max_current;
175	else
176		aat2870_bl->max_current = AAT2870_CURRENT_27_9;
177
178	if (pdata->max_brightness > 0)
179		bd->props.max_brightness = pdata->max_brightness;
180	else
181		bd->props.max_brightness = 255;
182
183	aat2870_bl->brightness = 0;
184	bd->props.power = FB_BLANK_UNBLANK;
185	bd->props.brightness = bd->props.max_brightness;
186
187	ret = aat2870_bl_update_status(bd);
188	if (ret < 0) {
189		dev_err(&pdev->dev, "Failed to initialize\n");
190		return ret;
191	}
192
193	return 0;
194
195out:
196	return ret;
197}
198
199static int aat2870_bl_remove(struct platform_device *pdev)
200{
201	struct aat2870_bl_driver_data *aat2870_bl = platform_get_drvdata(pdev);
202	struct backlight_device *bd = aat2870_bl->bd;
203
204	bd->props.power = FB_BLANK_POWERDOWN;
205	bd->props.brightness = 0;
206	backlight_update_status(bd);
207
208	return 0;
209}
210
211static struct platform_driver aat2870_bl_driver = {
212	.driver = {
213		.name	= "aat2870-backlight",
214	},
215	.probe		= aat2870_bl_probe,
216	.remove		= aat2870_bl_remove,
217};
218
219static int __init aat2870_bl_init(void)
220{
221	return platform_driver_register(&aat2870_bl_driver);
222}
223subsys_initcall(aat2870_bl_init);
224
225static void __exit aat2870_bl_exit(void)
226{
227	platform_driver_unregister(&aat2870_bl_driver);
228}
229module_exit(aat2870_bl_exit);
230
231MODULE_DESCRIPTION("AnalogicTech AAT2870 Backlight");
232MODULE_LICENSE("GPL");
233MODULE_AUTHOR("Jin Park <jinyoungp@nvidia.com>");
234