Root/target/linux/ubicom32/files/drivers/video/backlight/ubicom32lcdpower.c

1/*
2 * drivers/video/backlight/ubicom32lcdpowerpower.c
3 * LCD power driver for the Ubicom32 platform
4 *
5 * (C) Copyright 2009, Ubicom, Inc.
6 *
7 * This file is part of the Ubicom32 Linux Kernel Port.
8 *
9 * The Ubicom32 Linux Kernel Port is free software: you can redistribute
10 * it and/or modify it under the terms of the GNU General Public License
11 * as published by the Free Software Foundation, either version 2 of the
12 * License, or (at your option) any later version.
13 *
14 * The Ubicom32 Linux Kernel Port is distributed in the hope that it
15 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
16 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
17 * the GNU General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with the Ubicom32 Linux Kernel Port. If not,
21 * see <http://www.gnu.org/licenses/>.
22 *
23 * Ubicom32 implementation derived from (with many thanks):
24 * arch/m68knommu
25 * arch/blackfin
26 * arch/parisc
27 */
28#include <linux/init.h>
29#include <linux/kernel.h>
30#include <linux/module.h>
31#include <linux/platform_device.h>
32#include <linux/lcd.h>
33#include <linux/fb.h>
34#include <linux/gpio.h>
35
36#include <asm/ubicom32lcdpower.h>
37#include <asm/ip5000.h>
38
39#define DRIVER_NAME "ubicom32lcdpower"
40
41struct ubicom32lcdpower_data {
42    /*
43     * Pointer to the platform data structure. Keep this around since we need values
44     * from it to set the backlight intensity.
45     */
46    const struct ubicom32lcdpower_platform_data *pdata;
47
48    /*
49     * LCD device, we have to save this for use when we remove ourselves.
50     */
51    struct lcd_device *lcddev;
52};
53
54/*
55 * ubicom32lcdpower_set_power
56 */
57static int ubicom32lcdpower_set_power(struct lcd_device *ld, int power)
58{
59    struct ubicom32lcdpower_data *ud = (struct ubicom32lcdpower_data *)lcd_get_data(ld);
60    if (power == FB_BLANK_UNBLANK) {
61        gpio_direction_output(ud->pdata->vgh_gpio, ud->pdata->vgh_polarity);
62        return 0;
63    }
64
65    gpio_direction_output(ud->pdata->vgh_gpio, !ud->pdata->vgh_polarity);
66    return 0;
67}
68
69/*
70 * ubicom32lcdpower_get_power
71 */
72static int ubicom32lcdpower_get_power(struct lcd_device *ld)
73{
74    struct ubicom32lcdpower_data *ud = (struct ubicom32lcdpower_data *)lcd_get_data(ld);
75    int vgh = gpio_get_value(ud->pdata->vgh_gpio);
76    if ((vgh && ud->pdata->vgh_polarity) || (!vgh && !ud->pdata->vgh_polarity)) {
77        return 1;
78    }
79
80    return 0;
81}
82
83static struct lcd_ops ubicom32lcdpower_ops = {
84    .get_power = ubicom32lcdpower_get_power,
85    .set_power = ubicom32lcdpower_set_power,
86};
87
88/*
89 * ubicom32lcdpower_probe
90 */
91static int ubicom32lcdpower_probe(struct platform_device *pdev)
92{
93    const struct ubicom32lcdpower_platform_data *pdata = pdev->dev.platform_data;
94    struct ubicom32lcdpower_data *ud;
95    struct lcd_device *lcddev;
96    int retval;
97
98    /*
99     * Check to see if we have any platform data, if we don't have a LCD to control
100     */
101    if (!pdata) {
102        return -ENODEV;
103    }
104
105    /*
106     * Allocate our private data
107     */
108    ud = kzalloc(sizeof(struct ubicom32lcdpower_data), GFP_KERNEL);
109    if (!ud) {
110        return -ENOMEM;
111    }
112
113    ud->pdata = pdata;
114
115    /*
116     * Request our GPIOs
117     */
118    retval = gpio_request(pdata->vgh_gpio, "vgh");
119    if (retval) {
120        dev_err(&pdev->dev, "Failed to allocate vgh GPIO\n");
121        goto fail_gpio;
122    }
123
124    /*
125     * Register our lcd device
126     */
127    lcddev = lcd_device_register(DRIVER_NAME, &pdev->dev, ud, &ubicom32lcdpower_ops);
128    if (IS_ERR(lcddev)) {
129        retval = PTR_ERR(lcddev);
130        goto fail;
131    }
132
133    ud->lcddev = lcddev;
134    platform_set_drvdata(pdev, ud);
135
136    ubicom32lcdpower_set_power(lcddev, FB_BLANK_UNBLANK);
137
138    printk(KERN_INFO DRIVER_NAME ": LCD driver started\n");
139
140    return 0;
141
142fail:
143    gpio_free(pdata->vgh_gpio);
144
145fail_gpio:
146    platform_set_drvdata(pdev, NULL);
147    kfree(ud);
148    return retval;
149}
150
151/*
152 * ubicom32lcdpower_remove
153 */
154static int __exit ubicom32lcdpower_remove(struct platform_device *pdev)
155{
156    struct ubicom32lcdpower_data *ud = platform_get_drvdata(pdev);
157
158    lcd_device_unregister(ud->lcddev);
159    platform_set_drvdata(pdev, NULL);
160    kfree(ud);
161
162    return 0;
163}
164
165static struct platform_driver ubicom32lcdpower_driver = {
166    .driver = {
167        .name = DRIVER_NAME,
168        .owner = THIS_MODULE,
169    },
170
171    .remove = __exit_p(ubicom32lcdpower_remove),
172};
173
174/*
175 * ubicom32lcdpower_init
176 */
177static int __init ubicom32lcdpower_init(void)
178{
179    return platform_driver_probe(&ubicom32lcdpower_driver, ubicom32lcdpower_probe);
180}
181module_init(ubicom32lcdpower_init);
182
183/*
184 * ubicom32lcdpower_exit
185 */
186static void __exit ubicom32lcdpower_exit(void)
187{
188    platform_driver_unregister(&ubicom32lcdpower_driver);
189}
190module_exit(ubicom32lcdpower_exit);
191
192MODULE_AUTHOR("Patrick Tjin <@ubicom.com>");
193MODULE_DESCRIPTION("Ubicom32 lcd power driver");
194MODULE_LICENSE("GPL");
195

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