Commit | Line | Data |
---|---|---|
35c1682c GI |
1 | /* |
2 | * Backlight driver for Pandora handheld. | |
3 | * Pandora uses TWL4030 PWM0 -> TPS61161 combo for control backlight. | |
4 | * Based on pwm_bl.c | |
5 | * | |
6 | * Copyright 2009,2012 Gražvydas Ignotas <notasas@gmail.com> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | */ | |
12 | ||
13 | #include <linux/module.h> | |
14 | #include <linux/kernel.h> | |
15 | #include <linux/platform_device.h> | |
16 | #include <linux/delay.h> | |
17 | #include <linux/fb.h> | |
18 | #include <linux/backlight.h> | |
19 | #include <linux/i2c/twl.h> | |
20 | #include <linux/err.h> | |
21 | ||
22 | #define TWL_PWM0_ON 0x00 | |
23 | #define TWL_PWM0_OFF 0x01 | |
24 | ||
25 | #define TWL_INTBR_GPBR1 0x0c | |
26 | #define TWL_INTBR_PMBR1 0x0d | |
27 | ||
28 | #define TWL_PMBR1_PWM0_MUXMASK 0x0c | |
29 | #define TWL_PMBR1_PWM0 0x04 | |
30 | #define PWM0_CLK_ENABLE BIT(0) | |
31 | #define PWM0_ENABLE BIT(2) | |
32 | ||
33 | /* range accepted by hardware */ | |
34 | #define MIN_VALUE 9 | |
35 | #define MAX_VALUE 63 | |
36 | #define MAX_USER_VALUE (MAX_VALUE - MIN_VALUE) | |
37 | ||
38 | #define PANDORABL_WAS_OFF BL_CORE_DRIVER1 | |
39 | ||
40 | static int pandora_backlight_update_status(struct backlight_device *bl) | |
41 | { | |
42 | int brightness = bl->props.brightness; | |
43 | u8 r; | |
44 | ||
45 | if (bl->props.power != FB_BLANK_UNBLANK) | |
46 | brightness = 0; | |
47 | if (bl->props.state & BL_CORE_FBBLANK) | |
48 | brightness = 0; | |
49 | if (bl->props.state & BL_CORE_SUSPENDED) | |
50 | brightness = 0; | |
51 | ||
52 | if ((unsigned int)brightness > MAX_USER_VALUE) | |
53 | brightness = MAX_USER_VALUE; | |
54 | ||
55 | if (brightness == 0) { | |
56 | if (bl->props.state & PANDORABL_WAS_OFF) | |
57 | goto done; | |
58 | ||
59 | /* first disable PWM0 output, then clock */ | |
60 | twl_i2c_read_u8(TWL4030_MODULE_INTBR, &r, TWL_INTBR_GPBR1); | |
61 | r &= ~PWM0_ENABLE; | |
62 | twl_i2c_write_u8(TWL4030_MODULE_INTBR, r, TWL_INTBR_GPBR1); | |
63 | r &= ~PWM0_CLK_ENABLE; | |
64 | twl_i2c_write_u8(TWL4030_MODULE_INTBR, r, TWL_INTBR_GPBR1); | |
65 | ||
66 | goto done; | |
67 | } | |
68 | ||
69 | if (bl->props.state & PANDORABL_WAS_OFF) { | |
70 | /* | |
71 | * set PWM duty cycle to max. TPS61161 seems to use this | |
72 | * to calibrate it's PWM sensitivity when it starts. | |
73 | */ | |
b444df2f | 74 | twl_i2c_write_u8(TWL_MODULE_PWM, MAX_VALUE, TWL_PWM0_OFF); |
35c1682c GI |
75 | |
76 | /* first enable clock, then PWM0 out */ | |
77 | twl_i2c_read_u8(TWL4030_MODULE_INTBR, &r, TWL_INTBR_GPBR1); | |
78 | r &= ~PWM0_ENABLE; | |
79 | r |= PWM0_CLK_ENABLE; | |
80 | twl_i2c_write_u8(TWL4030_MODULE_INTBR, r, TWL_INTBR_GPBR1); | |
81 | r |= PWM0_ENABLE; | |
82 | twl_i2c_write_u8(TWL4030_MODULE_INTBR, r, TWL_INTBR_GPBR1); | |
83 | ||
84 | /* | |
85 | * TI made it very easy to enable digital control, so easy that | |
86 | * it often triggers unintentionally and disabes PWM control, | |
87 | * so wait until 1 wire mode detection window ends. | |
88 | */ | |
89 | usleep_range(2000, 10000); | |
90 | } | |
91 | ||
b444df2f | 92 | twl_i2c_write_u8(TWL_MODULE_PWM, MIN_VALUE + brightness, TWL_PWM0_OFF); |
35c1682c GI |
93 | |
94 | done: | |
95 | if (brightness != 0) | |
96 | bl->props.state &= ~PANDORABL_WAS_OFF; | |
97 | else | |
98 | bl->props.state |= PANDORABL_WAS_OFF; | |
99 | ||
100 | return 0; | |
101 | } | |
102 | ||
35c1682c GI |
103 | static const struct backlight_ops pandora_backlight_ops = { |
104 | .options = BL_CORE_SUSPENDRESUME, | |
105 | .update_status = pandora_backlight_update_status, | |
35c1682c GI |
106 | }; |
107 | ||
108 | static int pandora_backlight_probe(struct platform_device *pdev) | |
109 | { | |
110 | struct backlight_properties props; | |
111 | struct backlight_device *bl; | |
112 | u8 r; | |
113 | ||
114 | memset(&props, 0, sizeof(props)); | |
115 | props.max_brightness = MAX_USER_VALUE; | |
116 | props.type = BACKLIGHT_RAW; | |
75d4baec JH |
117 | bl = devm_backlight_device_register(&pdev->dev, pdev->name, &pdev->dev, |
118 | NULL, &pandora_backlight_ops, &props); | |
35c1682c GI |
119 | if (IS_ERR(bl)) { |
120 | dev_err(&pdev->dev, "failed to register backlight\n"); | |
121 | return PTR_ERR(bl); | |
122 | } | |
123 | ||
124 | platform_set_drvdata(pdev, bl); | |
125 | ||
126 | /* 64 cycle period, ON position 0 */ | |
b444df2f | 127 | twl_i2c_write_u8(TWL_MODULE_PWM, 0x80, TWL_PWM0_ON); |
35c1682c GI |
128 | |
129 | bl->props.state |= PANDORABL_WAS_OFF; | |
130 | bl->props.brightness = MAX_USER_VALUE; | |
131 | backlight_update_status(bl); | |
132 | ||
133 | /* enable PWM function in pin mux */ | |
134 | twl_i2c_read_u8(TWL4030_MODULE_INTBR, &r, TWL_INTBR_PMBR1); | |
135 | r &= ~TWL_PMBR1_PWM0_MUXMASK; | |
136 | r |= TWL_PMBR1_PWM0; | |
137 | twl_i2c_write_u8(TWL4030_MODULE_INTBR, r, TWL_INTBR_PMBR1); | |
138 | ||
139 | return 0; | |
140 | } | |
141 | ||
35c1682c GI |
142 | static struct platform_driver pandora_backlight_driver = { |
143 | .driver = { | |
144 | .name = "pandora-backlight", | |
35c1682c GI |
145 | }, |
146 | .probe = pandora_backlight_probe, | |
35c1682c GI |
147 | }; |
148 | ||
149 | module_platform_driver(pandora_backlight_driver); | |
150 | ||
151 | MODULE_AUTHOR("Gražvydas Ignotas <notasas@gmail.com>"); | |
152 | MODULE_DESCRIPTION("Pandora Backlight Driver"); | |
153 | MODULE_LICENSE("GPL"); | |
154 | MODULE_ALIAS("platform:pandora-backlight"); |