H Hartley Sweeten | 08b3924 | 2010-05-05 12:13:23 -0500 | [diff] [blame] | 1 | /* |
| 2 | * Driver for the Cirrus EP93xx lcd backlight |
| 3 | * |
| 4 | * Copyright (c) 2010 H Hartley Sweeten <hsweeten@visionengravers.com> |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License version 2 as |
| 8 | * published by the Free Software Foundation. |
| 9 | * |
| 10 | * This driver controls the pulse width modulated brightness control output, |
| 11 | * BRIGHT, on the Cirrus EP9307, EP9312, and EP9315 processors. |
| 12 | */ |
| 13 | |
Axel Lin | 15b1a8f | 2011-08-25 15:59:14 -0700 | [diff] [blame] | 14 | #include <linux/module.h> |
H Hartley Sweeten | 08b3924 | 2010-05-05 12:13:23 -0500 | [diff] [blame] | 15 | #include <linux/platform_device.h> |
| 16 | #include <linux/io.h> |
| 17 | #include <linux/fb.h> |
| 18 | #include <linux/backlight.h> |
| 19 | |
H Hartley Sweeten | 08b3924 | 2010-05-05 12:13:23 -0500 | [diff] [blame] | 20 | #define EP93XX_MAX_COUNT 255 |
| 21 | #define EP93XX_MAX_BRIGHT 255 |
| 22 | #define EP93XX_DEF_BRIGHT 128 |
| 23 | |
| 24 | struct ep93xxbl { |
| 25 | void __iomem *mmio; |
| 26 | int brightness; |
| 27 | }; |
| 28 | |
| 29 | static int ep93xxbl_set(struct backlight_device *bl, int brightness) |
| 30 | { |
| 31 | struct ep93xxbl *ep93xxbl = bl_get_data(bl); |
| 32 | |
Ryan Mallon | 0fd1958 | 2012-01-22 20:31:32 +1100 | [diff] [blame] | 33 | writel((brightness << 8) | EP93XX_MAX_COUNT, ep93xxbl->mmio); |
H Hartley Sweeten | 08b3924 | 2010-05-05 12:13:23 -0500 | [diff] [blame] | 34 | |
| 35 | ep93xxbl->brightness = brightness; |
| 36 | |
| 37 | return 0; |
| 38 | } |
| 39 | |
| 40 | static int ep93xxbl_update_status(struct backlight_device *bl) |
| 41 | { |
| 42 | int brightness = bl->props.brightness; |
| 43 | |
| 44 | if (bl->props.power != FB_BLANK_UNBLANK || |
| 45 | bl->props.fb_blank != FB_BLANK_UNBLANK) |
| 46 | brightness = 0; |
| 47 | |
| 48 | return ep93xxbl_set(bl, brightness); |
| 49 | } |
| 50 | |
| 51 | static int ep93xxbl_get_brightness(struct backlight_device *bl) |
| 52 | { |
| 53 | struct ep93xxbl *ep93xxbl = bl_get_data(bl); |
| 54 | |
| 55 | return ep93xxbl->brightness; |
| 56 | } |
| 57 | |
| 58 | static const struct backlight_ops ep93xxbl_ops = { |
| 59 | .update_status = ep93xxbl_update_status, |
| 60 | .get_brightness = ep93xxbl_get_brightness, |
| 61 | }; |
| 62 | |
Jingoo Han | cb1fbb8 | 2013-04-29 16:17:27 -0700 | [diff] [blame^] | 63 | static int ep93xxbl_probe(struct platform_device *dev) |
H Hartley Sweeten | 08b3924 | 2010-05-05 12:13:23 -0500 | [diff] [blame] | 64 | { |
| 65 | struct ep93xxbl *ep93xxbl; |
| 66 | struct backlight_device *bl; |
| 67 | struct backlight_properties props; |
Ryan Mallon | 0fd1958 | 2012-01-22 20:31:32 +1100 | [diff] [blame] | 68 | struct resource *res; |
H Hartley Sweeten | 08b3924 | 2010-05-05 12:13:23 -0500 | [diff] [blame] | 69 | |
| 70 | ep93xxbl = devm_kzalloc(&dev->dev, sizeof(*ep93xxbl), GFP_KERNEL); |
| 71 | if (!ep93xxbl) |
| 72 | return -ENOMEM; |
| 73 | |
Ryan Mallon | 0fd1958 | 2012-01-22 20:31:32 +1100 | [diff] [blame] | 74 | res = platform_get_resource(dev, IORESOURCE_MEM, 0); |
| 75 | if (!res) |
| 76 | return -ENXIO; |
| 77 | |
H Hartley Sweeten | 08b3924 | 2010-05-05 12:13:23 -0500 | [diff] [blame] | 78 | /* |
Ryan Mallon | 0fd1958 | 2012-01-22 20:31:32 +1100 | [diff] [blame] | 79 | * FIXME - We don't do a request_mem_region here because we are |
| 80 | * sharing the register space with the framebuffer driver (see |
| 81 | * drivers/video/ep93xx-fb.c) and doing so will cause the second |
| 82 | * loaded driver to return -EBUSY. |
H Hartley Sweeten | 08b3924 | 2010-05-05 12:13:23 -0500 | [diff] [blame] | 83 | * |
| 84 | * NOTE: No locking is required; the framebuffer does not touch |
| 85 | * this register. |
| 86 | */ |
Ryan Mallon | 0fd1958 | 2012-01-22 20:31:32 +1100 | [diff] [blame] | 87 | ep93xxbl->mmio = devm_ioremap(&dev->dev, res->start, |
| 88 | resource_size(res)); |
| 89 | if (!ep93xxbl->mmio) |
| 90 | return -ENXIO; |
H Hartley Sweeten | 08b3924 | 2010-05-05 12:13:23 -0500 | [diff] [blame] | 91 | |
| 92 | memset(&props, 0, sizeof(struct backlight_properties)); |
Matthew Garrett | bb7ca74 | 2011-03-22 16:30:21 -0700 | [diff] [blame] | 93 | props.type = BACKLIGHT_RAW; |
H Hartley Sweeten | 08b3924 | 2010-05-05 12:13:23 -0500 | [diff] [blame] | 94 | props.max_brightness = EP93XX_MAX_BRIGHT; |
| 95 | bl = backlight_device_register(dev->name, &dev->dev, ep93xxbl, |
| 96 | &ep93xxbl_ops, &props); |
| 97 | if (IS_ERR(bl)) |
| 98 | return PTR_ERR(bl); |
| 99 | |
| 100 | bl->props.brightness = EP93XX_DEF_BRIGHT; |
| 101 | |
| 102 | platform_set_drvdata(dev, bl); |
| 103 | |
| 104 | ep93xxbl_update_status(bl); |
| 105 | |
| 106 | return 0; |
| 107 | } |
| 108 | |
| 109 | static int ep93xxbl_remove(struct platform_device *dev) |
| 110 | { |
| 111 | struct backlight_device *bl = platform_get_drvdata(dev); |
| 112 | |
| 113 | backlight_device_unregister(bl); |
| 114 | platform_set_drvdata(dev, NULL); |
| 115 | return 0; |
| 116 | } |
| 117 | |
| 118 | #ifdef CONFIG_PM |
| 119 | static int ep93xxbl_suspend(struct platform_device *dev, pm_message_t state) |
| 120 | { |
| 121 | struct backlight_device *bl = platform_get_drvdata(dev); |
| 122 | |
| 123 | return ep93xxbl_set(bl, 0); |
| 124 | } |
| 125 | |
| 126 | static int ep93xxbl_resume(struct platform_device *dev) |
| 127 | { |
| 128 | struct backlight_device *bl = platform_get_drvdata(dev); |
| 129 | |
| 130 | backlight_update_status(bl); |
| 131 | return 0; |
| 132 | } |
| 133 | #else |
| 134 | #define ep93xxbl_suspend NULL |
| 135 | #define ep93xxbl_resume NULL |
| 136 | #endif |
| 137 | |
| 138 | static struct platform_driver ep93xxbl_driver = { |
| 139 | .driver = { |
| 140 | .name = "ep93xx-bl", |
| 141 | .owner = THIS_MODULE, |
| 142 | }, |
| 143 | .probe = ep93xxbl_probe, |
Bill Pemberton | d1723fa | 2012-11-19 13:21:09 -0500 | [diff] [blame] | 144 | .remove = ep93xxbl_remove, |
H Hartley Sweeten | 08b3924 | 2010-05-05 12:13:23 -0500 | [diff] [blame] | 145 | .suspend = ep93xxbl_suspend, |
| 146 | .resume = ep93xxbl_resume, |
| 147 | }; |
| 148 | |
Axel Lin | 81178e0 | 2012-01-10 15:09:11 -0800 | [diff] [blame] | 149 | module_platform_driver(ep93xxbl_driver); |
H Hartley Sweeten | 08b3924 | 2010-05-05 12:13:23 -0500 | [diff] [blame] | 150 | |
| 151 | MODULE_DESCRIPTION("EP93xx Backlight Driver"); |
| 152 | MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>"); |
| 153 | MODULE_LICENSE("GPL"); |
| 154 | MODULE_ALIAS("platform:ep93xx-bl"); |