1/* 2 * 3 * Backlight driver for HP Jornada 700 series (710/720/728) 4 * Copyright (C) 2006-2009 Kristoffer Ericson <kristoffer.ericson@gmail.com> 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License version 8 * 2 or any later version as published by the Free Software Foundation. 9 * 10 */ 11 12#include <linux/backlight.h> 13#include <linux/device.h> 14#include <linux/fb.h> 15#include <linux/kernel.h> 16#include <linux/module.h> 17#include <linux/platform_device.h> 18 19#include <mach/jornada720.h> 20#include <mach/hardware.h> 21 22#include <video/s1d13xxxfb.h> 23 24#define BL_MAX_BRIGHT 255 25#define BL_DEF_BRIGHT 25 26 27static int jornada_bl_get_brightness(struct backlight_device *bd) 28{ 29 int ret; 30 31 /* check if backlight is on */ 32 if (!(PPSR & PPC_LDD1)) 33 return 0; 34 35 jornada_ssp_start(); 36 37 /* cmd should return txdummy */ 38 ret = jornada_ssp_byte(GETBRIGHTNESS); 39 40 if (jornada_ssp_byte(GETBRIGHTNESS) != TXDUMMY) { 41 printk(KERN_ERR "bl : get brightness timeout\n"); 42 jornada_ssp_end(); 43 return -ETIMEDOUT; 44 } else /* exchange txdummy for value */ 45 ret = jornada_ssp_byte(TXDUMMY); 46 47 jornada_ssp_end(); 48 49 return (BL_MAX_BRIGHT - ret); 50} 51 52static int jornada_bl_update_status(struct backlight_device *bd) 53{ 54 int ret = 0; 55 56 jornada_ssp_start(); 57 58 /* If backlight is off then really turn it off */ 59 if ((bd->props.power != FB_BLANK_UNBLANK) || (bd->props.fb_blank != FB_BLANK_UNBLANK)) { 60 ret = jornada_ssp_byte(BRIGHTNESSOFF); 61 if (ret != TXDUMMY) { 62 printk(KERN_INFO "bl : brightness off timeout\n"); 63 /* turn off backlight */ 64 PPSR &= ~PPC_LDD1; 65 PPDR |= PPC_LDD1; 66 ret = -ETIMEDOUT; 67 } 68 } else /* turn on backlight */ 69 PPSR |= PPC_LDD1; 70 71 /* send command to our mcu */ 72 if (jornada_ssp_byte(SETBRIGHTNESS) != TXDUMMY) { 73 printk(KERN_INFO "bl : failed to set brightness\n"); 74 ret = -ETIMEDOUT; 75 goto out; 76 } 77 78 /* at this point we expect that the mcu has accepted 79 our command and is waiting for our new value 80 please note that maximum brightness is 255, 81 but due to physical layout it is equal to 0, so we simply 82 invert the value (MAX VALUE - NEW VALUE). */ 83 if (jornada_ssp_byte(BL_MAX_BRIGHT - bd->props.brightness) != TXDUMMY) { 84 printk(KERN_ERR "bl : set brightness failed\n"); 85 ret = -ETIMEDOUT; 86 } 87 88 /* If infact we get an TXDUMMY as output we are happy and dont 89 make any further comments about it */ 90out: 91 jornada_ssp_end(); 92 93 return ret; 94} 95 96static const struct backlight_ops jornada_bl_ops = { 97 .get_brightness = jornada_bl_get_brightness, 98 .update_status = jornada_bl_update_status, 99 .options = BL_CORE_SUSPENDRESUME, 100}; 101 102static int jornada_bl_probe(struct platform_device *pdev) 103{ 104 struct backlight_properties props; 105 int ret; 106 struct backlight_device *bd; 107 108 memset(&props, 0, sizeof(struct backlight_properties)); 109 props.max_brightness = BL_MAX_BRIGHT; 110 bd = backlight_device_register(S1D_DEVICENAME, &pdev->dev, NULL, 111 &jornada_bl_ops, &props); 112 113 if (IS_ERR(bd)) { 114 ret = PTR_ERR(bd); 115 printk(KERN_ERR "bl : failed to register device, err=%x\n", ret); 116 return ret; 117 } 118 119 bd->props.power = FB_BLANK_UNBLANK; 120 bd->props.brightness = BL_DEF_BRIGHT; 121 /* note. make sure max brightness is set otherwise 122 you will get seemingly non-related errors when 123 trying to change brightness */ 124 jornada_bl_update_status(bd); 125 126 platform_set_drvdata(pdev, bd); 127 printk(KERN_INFO "HP Jornada 700 series backlight driver\n"); 128 129 return 0; 130} 131 132static int jornada_bl_remove(struct platform_device *pdev) 133{ 134 struct backlight_device *bd = platform_get_drvdata(pdev); 135 136 backlight_device_unregister(bd); 137 138 return 0; 139} 140 141static struct platform_driver jornada_bl_driver = { 142 .probe = jornada_bl_probe, 143 .remove = jornada_bl_remove, 144 .driver = { 145 .name = "jornada_bl", 146 }, 147}; 148 149int __init jornada_bl_init(void) 150{ 151 return platform_driver_register(&jornada_bl_driver); 152} 153 154void __exit jornada_bl_exit(void) 155{ 156 platform_driver_unregister(&jornada_bl_driver); 157} 158 159MODULE_AUTHOR("Kristoffer Ericson <kristoffer.ericson>"); 160MODULE_DESCRIPTION("HP Jornada 710/720/728 Backlight driver"); 161MODULE_LICENSE("GPL"); 162 163module_init(jornada_bl_init); 164module_exit(jornada_bl_exit); 165