Root/drivers/video/backlight/gpm940b0.c

1/*
2 * Copyright (C) 2009, Lars-Peter Clausen <lars@metafoo.de>
3 * JZ4720/JZ4740 SoC LCD framebuffer driver
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License as published by the
7 * Free Software Foundation; either version 2 of the License, or (at your
8 * option) any later version.
9 *
10 * You should have received a copy of the GNU General Public License along
11 * with this program; if not, write to the Free Software Foundation, Inc.,
12 * 675 Mass Ave, Cambridge, MA 02139, USA.
13 *
14 */
15
16#include <linux/module.h>
17#include <linux/spi/spi.h>
18#include <linux/lcd.h>
19#include <linux/backlight.h>
20#include <linux/delay.h>
21
22struct gpm940b0 {
23    struct spi_device *spi;
24    struct lcd_device *lcd;
25    struct backlight_device *bl;
26    unsigned enabled:1;
27};
28
29static int gpm940b0_write_reg(struct spi_device *spi, uint8_t reg,
30                uint8_t data)
31{
32    uint8_t buf[2];
33    buf[0] = ((reg & 0x40) << 1) | (reg & 0x3f);
34    buf[1] = data;
35
36    return spi_write(spi, buf, sizeof(buf));
37}
38
39static void gpm940b0_power_disable(struct gpm940b0 *gpm940b0)
40{
41    int ret = gpm940b0_write_reg(gpm940b0->spi, 0x5, 0xc6) ;
42    if (ret < 0)
43        printk("Failed to disable power: %d\n", ret);
44}
45
46static void gpm940b0_power_enable(struct gpm940b0 *gpm940b0)
47{
48    gpm940b0_write_reg(gpm940b0->spi, 0x5, 0xc7);
49}
50
51
52static int gpm940b0_set_power(struct lcd_device *lcd, int power)
53{
54    struct gpm940b0 *gpm940b0 = lcd_get_data(lcd);
55
56    switch (power) {
57    case FB_BLANK_UNBLANK:
58        mdelay(20);
59        gpm940b0->enabled = 1;
60        gpm940b0_power_enable(gpm940b0);
61        break;
62    default:
63        gpm940b0->enabled = 0;
64        gpm940b0_power_disable(gpm940b0);
65        mdelay(20);
66        break;
67    }
68    return 0;
69}
70
71static int gpm940b0_set_contrast(struct lcd_device *lcd, int contrast)
72{
73    struct gpm940b0 *gpm940b0 = lcd_get_data(lcd);
74    gpm940b0_write_reg(gpm940b0->spi, 0x0d, contrast);
75    return 0;
76}
77
78static int gpm940b0_set_mode(struct lcd_device *lcd, struct fb_videomode *mode)
79{
80    if (mode->xres != 320 && mode->yres != 240)
81        return -EINVAL;
82
83    return 0;
84}
85
86/*
87int gpm940b0_bl_update_status(struct backlight_device *bl)
88{
89    struct gpm940b0 *gpm940b0 = bl_get_data(bl);
90
91    gpm940b0->reg5 &= ~0x38;
92    gpm940b0->reg5 |= ((bl->props.brightness << 3) & 0x38);
93
94    gpm940b0_write_reg(gpm940b0->spi, 0x5, gpm940b0->reg5);
95
96    return 0;
97}*/
98
99static ssize_t reg_write(struct device *dev, struct device_attribute *attr,
100                        const char *buf, size_t count)
101{
102    char *buf2;
103    uint32_t reg = simple_strtoul(buf, &buf2, 10);
104    uint32_t val = simple_strtoul(buf2 + 1, NULL, 10);
105    struct gpm940b0 *gpm940b0 = dev_get_drvdata(dev);
106
107    if (reg < 0 || val < 0)
108        return -EINVAL;
109
110    gpm940b0_write_reg(gpm940b0->spi, reg, val);
111    return count;
112}
113
114static DEVICE_ATTR(reg, 0644, NULL, reg_write);
115
116static struct lcd_ops gpm940b0_lcd_ops = {
117    .set_power = gpm940b0_set_power,
118    .set_contrast = gpm940b0_set_contrast,
119    .set_mode = gpm940b0_set_mode,
120};
121
122#if 0
123static struct backlight_ops gpm940b0_bl_ops = {
124/* .get_brightness = gpm940b0_bl_get_brightness,*/
125    .update_status = gpm940b0_bl_update_status,
126};
127#endif
128
129static int __devinit gpm940b0_probe(struct spi_device *spi)
130{
131    int ret;
132    struct gpm940b0 *gpm940b0;
133
134    gpm940b0 = kmalloc(sizeof(*gpm940b0), GFP_KERNEL);
135
136    spi->bits_per_word = 8;
137
138    ret = spi_setup(spi);
139    if (ret) {
140        dev_err(&spi->dev, "Failed to setup spi\n");
141        goto err_free_gpm940b0;
142    }
143
144    gpm940b0->spi = spi;
145
146    gpm940b0->lcd = lcd_device_register("gpm940b0-lcd", &spi->dev, gpm940b0,
147                        &gpm940b0_lcd_ops);
148
149    if (IS_ERR(gpm940b0->lcd)) {
150        ret = PTR_ERR(gpm940b0->lcd);
151        dev_err(&spi->dev, "Failed to register lcd device: %d\n", ret);
152        goto err_free_gpm940b0;
153    }
154
155    gpm940b0->lcd->props.max_contrast = 255;
156
157#if 0
158    gpm940b0->bl = backlight_device_register("gpm940b0-bl", &spi->dev, gpm940b0,
159                         &gpm940b0_bl_ops);
160
161    if (IS_ERR(gpm940b0->bl)) {
162        ret = PTR_ERR(gpm940b0->bl);
163        dev_err(&spi->dev, "Failed to register backlight device: %d\n", ret);
164        gpm940b0->bl = NULL;
165    } else {
166        gpm940b0->bl->props.max_brightness = 8;
167        gpm940b0->bl->props.brightness = 0;
168        gpm940b0->bl->props.power = FB_BLANK_UNBLANK;
169    }
170#endif
171
172    ret = device_create_file(&spi->dev, &dev_attr_reg);
173    if (ret)
174        goto err_unregister_lcd;
175
176    gpm940b0->enabled = 1;
177    dev_set_drvdata(&spi->dev, gpm940b0);
178
179    gpm940b0_write_reg(spi, 0x13, 0x01);
180    gpm940b0_write_reg(spi, 0x5, 0xc7);
181    return 0;
182err_unregister_lcd:
183    lcd_device_unregister(gpm940b0->lcd);
184err_free_gpm940b0:
185    kfree(gpm940b0);
186    return ret;
187}
188
189static int __devexit gpm940b0_remove(struct spi_device *spi)
190{
191    struct gpm940b0 *gpm940b0 = spi_get_drvdata(spi);
192#if 0
193    if (gpm940b0->bl)
194        backlight_device_unregister(gpm940b0->bl);
195#endif
196
197    lcd_device_unregister(gpm940b0->lcd);
198
199    spi_set_drvdata(spi, NULL);
200    kfree(gpm940b0);
201    return 0;
202}
203
204#ifdef CONFIG_PM
205
206static int gpm940b0_suspend(struct spi_device *spi, pm_message_t state)
207{
208    struct gpm940b0 *gpm940b0 = spi_get_drvdata(spi);
209    if (gpm940b0->enabled) {
210        gpm940b0_power_disable(gpm940b0);
211        mdelay(10);
212    }
213    return 0;
214}
215
216static int gpm940b0_resume(struct spi_device *spi)
217{
218    struct gpm940b0 *gpm940b0 = spi_get_drvdata(spi);
219    if (gpm940b0->enabled)
220        gpm940b0_power_enable(gpm940b0);
221    return 0;
222}
223
224#else
225#define gpm940b0_suspend NULL
226#define gpm940b0_resume NULL
227#endif
228
229static struct spi_driver gpm940b0_driver = {
230    .driver = {
231        .name = "gpm940b0",
232        .owner = THIS_MODULE,
233    },
234    .probe = gpm940b0_probe,
235    .remove = __devexit_p(gpm940b0_remove),
236    .suspend = gpm940b0_suspend,
237    .resume = gpm940b0_resume,
238};
239
240static int __init gpm940b0_init(void)
241{
242    return spi_register_driver(&gpm940b0_driver);
243}
244module_init(gpm940b0_init);
245
246static void __exit gpm940b0_exit(void)
247{
248    return spi_unregister_driver(&gpm940b0_driver);
249}
250module_exit(gpm940b0_exit)
251
252MODULE_AUTHOR("Lars-Peter Clausen");
253MODULE_LICENSE("GPL v2");
254MODULE_DESCRIPTION("LCD and backlight controll for Giantplus GPM940B0");
255MODULE_ALIAS("spi:gpm940b0");
256

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