Grazvydas Ignotas | 35c1682 | 2012-03-23 15:02:02 -0700 | [diff] [blame] | 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 | */ |
Peter Ujfalusi | b444df2 | 2012-12-17 16:01:08 -0800 | [diff] [blame] | 74 | twl_i2c_write_u8(TWL_MODULE_PWM, MAX_VALUE, TWL_PWM0_OFF); |
Grazvydas Ignotas | 35c1682 | 2012-03-23 15:02:02 -0700 | [diff] [blame] | 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 | |
Peter Ujfalusi | b444df2 | 2012-12-17 16:01:08 -0800 | [diff] [blame] | 92 | twl_i2c_write_u8(TWL_MODULE_PWM, MIN_VALUE + brightness, TWL_PWM0_OFF); |
Grazvydas Ignotas | 35c1682 | 2012-03-23 15:02:02 -0700 | [diff] [blame] | 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 | |
| 103 | static int pandora_backlight_get_brightness(struct backlight_device *bl) |
| 104 | { |
| 105 | return bl->props.brightness; |
| 106 | } |
| 107 | |
| 108 | static const struct backlight_ops pandora_backlight_ops = { |
| 109 | .options = BL_CORE_SUSPENDRESUME, |
| 110 | .update_status = pandora_backlight_update_status, |
| 111 | .get_brightness = pandora_backlight_get_brightness, |
| 112 | }; |
| 113 | |
| 114 | static int pandora_backlight_probe(struct platform_device *pdev) |
| 115 | { |
| 116 | struct backlight_properties props; |
| 117 | struct backlight_device *bl; |
| 118 | u8 r; |
| 119 | |
| 120 | memset(&props, 0, sizeof(props)); |
| 121 | props.max_brightness = MAX_USER_VALUE; |
| 122 | props.type = BACKLIGHT_RAW; |
| 123 | bl = backlight_device_register(pdev->name, &pdev->dev, |
| 124 | NULL, &pandora_backlight_ops, &props); |
| 125 | if (IS_ERR(bl)) { |
| 126 | dev_err(&pdev->dev, "failed to register backlight\n"); |
| 127 | return PTR_ERR(bl); |
| 128 | } |
| 129 | |
| 130 | platform_set_drvdata(pdev, bl); |
| 131 | |
| 132 | /* 64 cycle period, ON position 0 */ |
Peter Ujfalusi | b444df2 | 2012-12-17 16:01:08 -0800 | [diff] [blame] | 133 | twl_i2c_write_u8(TWL_MODULE_PWM, 0x80, TWL_PWM0_ON); |
Grazvydas Ignotas | 35c1682 | 2012-03-23 15:02:02 -0700 | [diff] [blame] | 134 | |
| 135 | bl->props.state |= PANDORABL_WAS_OFF; |
| 136 | bl->props.brightness = MAX_USER_VALUE; |
| 137 | backlight_update_status(bl); |
| 138 | |
| 139 | /* enable PWM function in pin mux */ |
| 140 | twl_i2c_read_u8(TWL4030_MODULE_INTBR, &r, TWL_INTBR_PMBR1); |
| 141 | r &= ~TWL_PMBR1_PWM0_MUXMASK; |
| 142 | r |= TWL_PMBR1_PWM0; |
| 143 | twl_i2c_write_u8(TWL4030_MODULE_INTBR, r, TWL_INTBR_PMBR1); |
| 144 | |
| 145 | return 0; |
| 146 | } |
| 147 | |
| 148 | static int pandora_backlight_remove(struct platform_device *pdev) |
| 149 | { |
| 150 | struct backlight_device *bl = platform_get_drvdata(pdev); |
| 151 | backlight_device_unregister(bl); |
| 152 | return 0; |
| 153 | } |
| 154 | |
| 155 | static struct platform_driver pandora_backlight_driver = { |
| 156 | .driver = { |
| 157 | .name = "pandora-backlight", |
| 158 | .owner = THIS_MODULE, |
| 159 | }, |
| 160 | .probe = pandora_backlight_probe, |
| 161 | .remove = pandora_backlight_remove, |
| 162 | }; |
| 163 | |
| 164 | module_platform_driver(pandora_backlight_driver); |
| 165 | |
| 166 | MODULE_AUTHOR("Gražvydas Ignotas <notasas@gmail.com>"); |
| 167 | MODULE_DESCRIPTION("Pandora Backlight Driver"); |
| 168 | MODULE_LICENSE("GPL"); |
| 169 | MODULE_ALIAS("platform:pandora-backlight"); |