1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Backlight driver for OMAP based boards.
4  *
5  * Copyright (c) 2006 Andrzej Zaborowski  <balrog@zabor.org>
6  */
7 
8 #include <linux/module.h>
9 #include <linux/kernel.h>
10 #include <linux/init.h>
11 #include <linux/platform_device.h>
12 #include <linux/fb.h>
13 #include <linux/backlight.h>
14 #include <linux/slab.h>
15 #include <linux/platform_data/omap1_bl.h>
16 
17 #include <linux/soc/ti/omap1-io.h>
18 #include <linux/soc/ti/omap1-mux.h>
19 
20 #define OMAPBL_MAX_INTENSITY		0xff
21 
22 struct omap_backlight {
23 	int powermode;
24 	int current_intensity;
25 
26 	struct device *dev;
27 	struct omap_backlight_config *pdata;
28 };
29 
omapbl_send_intensity(int intensity)30 static inline void omapbl_send_intensity(int intensity)
31 {
32 	omap_writeb(intensity, OMAP_PWL_ENABLE);
33 }
34 
omapbl_send_enable(int enable)35 static inline void omapbl_send_enable(int enable)
36 {
37 	omap_writeb(enable, OMAP_PWL_CLK_ENABLE);
38 }
39 
omapbl_blank(struct omap_backlight * bl,int mode)40 static void omapbl_blank(struct omap_backlight *bl, int mode)
41 {
42 	if (bl->pdata->set_power)
43 		bl->pdata->set_power(bl->dev, mode);
44 
45 	switch (mode) {
46 	case FB_BLANK_NORMAL:
47 	case FB_BLANK_VSYNC_SUSPEND:
48 	case FB_BLANK_HSYNC_SUSPEND:
49 	case FB_BLANK_POWERDOWN:
50 		omapbl_send_intensity(0);
51 		omapbl_send_enable(0);
52 		break;
53 
54 	case FB_BLANK_UNBLANK:
55 		omapbl_send_intensity(bl->current_intensity);
56 		omapbl_send_enable(1);
57 		break;
58 	}
59 }
60 
61 #ifdef CONFIG_PM_SLEEP
omapbl_suspend(struct device * dev)62 static int omapbl_suspend(struct device *dev)
63 {
64 	struct backlight_device *bl_dev = dev_get_drvdata(dev);
65 	struct omap_backlight *bl = bl_get_data(bl_dev);
66 
67 	omapbl_blank(bl, FB_BLANK_POWERDOWN);
68 	return 0;
69 }
70 
omapbl_resume(struct device * dev)71 static int omapbl_resume(struct device *dev)
72 {
73 	struct backlight_device *bl_dev = dev_get_drvdata(dev);
74 	struct omap_backlight *bl = bl_get_data(bl_dev);
75 
76 	omapbl_blank(bl, bl->powermode);
77 	return 0;
78 }
79 #endif
80 
omapbl_set_power(struct backlight_device * dev,int state)81 static int omapbl_set_power(struct backlight_device *dev, int state)
82 {
83 	struct omap_backlight *bl = bl_get_data(dev);
84 
85 	omapbl_blank(bl, state);
86 	bl->powermode = state;
87 
88 	return 0;
89 }
90 
omapbl_update_status(struct backlight_device * dev)91 static int omapbl_update_status(struct backlight_device *dev)
92 {
93 	struct omap_backlight *bl = bl_get_data(dev);
94 
95 	if (bl->current_intensity != dev->props.brightness) {
96 		if (bl->powermode == FB_BLANK_UNBLANK)
97 			omapbl_send_intensity(dev->props.brightness);
98 		bl->current_intensity = dev->props.brightness;
99 	}
100 
101 	if (dev->props.fb_blank != bl->powermode)
102 		omapbl_set_power(dev, dev->props.fb_blank);
103 
104 	return 0;
105 }
106 
omapbl_get_intensity(struct backlight_device * dev)107 static int omapbl_get_intensity(struct backlight_device *dev)
108 {
109 	struct omap_backlight *bl = bl_get_data(dev);
110 
111 	return bl->current_intensity;
112 }
113 
114 static const struct backlight_ops omapbl_ops = {
115 	.get_brightness = omapbl_get_intensity,
116 	.update_status  = omapbl_update_status,
117 };
118 
omapbl_probe(struct platform_device * pdev)119 static int omapbl_probe(struct platform_device *pdev)
120 {
121 	struct backlight_properties props;
122 	struct backlight_device *dev;
123 	struct omap_backlight *bl;
124 	struct omap_backlight_config *pdata = dev_get_platdata(&pdev->dev);
125 
126 	if (!pdata)
127 		return -ENXIO;
128 
129 	bl = devm_kzalloc(&pdev->dev, sizeof(struct omap_backlight),
130 			  GFP_KERNEL);
131 	if (unlikely(!bl))
132 		return -ENOMEM;
133 
134 	memset(&props, 0, sizeof(struct backlight_properties));
135 	props.type = BACKLIGHT_RAW;
136 	props.max_brightness = OMAPBL_MAX_INTENSITY;
137 	dev = devm_backlight_device_register(&pdev->dev, "omap-bl", &pdev->dev,
138 					bl, &omapbl_ops, &props);
139 	if (IS_ERR(dev))
140 		return PTR_ERR(dev);
141 
142 	bl->powermode = FB_BLANK_POWERDOWN;
143 	bl->current_intensity = 0;
144 
145 	bl->pdata = pdata;
146 	bl->dev = &pdev->dev;
147 
148 	platform_set_drvdata(pdev, dev);
149 
150 	omap_cfg_reg(PWL);	/* Conflicts with UART3 */
151 
152 	dev->props.fb_blank = FB_BLANK_UNBLANK;
153 	dev->props.brightness = pdata->default_intensity;
154 	omapbl_update_status(dev);
155 
156 	dev_info(&pdev->dev, "OMAP LCD backlight initialised\n");
157 
158 	return 0;
159 }
160 
161 static SIMPLE_DEV_PM_OPS(omapbl_pm_ops, omapbl_suspend, omapbl_resume);
162 
163 static struct platform_driver omapbl_driver = {
164 	.probe		= omapbl_probe,
165 	.driver		= {
166 		.name	= "omap-bl",
167 		.pm	= &omapbl_pm_ops,
168 	},
169 };
170 
171 module_platform_driver(omapbl_driver);
172 
173 MODULE_AUTHOR("Andrzej Zaborowski <balrog@zabor.org>");
174 MODULE_DESCRIPTION("OMAP LCD Backlight driver");
175 MODULE_LICENSE("GPL");
176