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 27 static 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 52 static 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 */ 90 out: 91 jornada_ssp_end(); 92 93 return ret; 94 } 95 96 static 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 }; 101 102 static int jornada_bl_probe(struct platform_device *pdev) 103 { 104 int ret; 105 struct backlight_device *bd; 106 107 bd = backlight_device_register(S1D_DEVICENAME, &pdev->dev, NULL, &jornada_bl_ops); 108 109 if (IS_ERR(bd)) { 110 ret = PTR_ERR(bd); 111 printk(KERN_ERR "bl : failed to register device, err=%x\n", ret); 112 return ret; 113 } 114 115 bd->props.power = FB_BLANK_UNBLANK; 116 bd->props.brightness = BL_DEF_BRIGHT; 117 /* note. make sure max brightness is set otherwise 118 you will get seemingly non-related errors when 119 trying to change brightness */ 120 bd->props.max_brightness = BL_MAX_BRIGHT; 121 jornada_bl_update_status(bd); 122 123 platform_set_drvdata(pdev, bd); 124 printk(KERN_INFO "HP Jornada 700 series backlight driver\n"); 125 126 return 0; 127 } 128 129 static int jornada_bl_remove(struct platform_device *pdev) 130 { 131 struct backlight_device *bd = platform_get_drvdata(pdev); 132 133 backlight_device_unregister(bd); 134 135 return 0; 136 } 137 138 static struct platform_driver jornada_bl_driver = { 139 .probe = jornada_bl_probe, 140 .remove = jornada_bl_remove, 141 .driver = { 142 .name = "jornada_bl", 143 }, 144 }; 145 146 int __init jornada_bl_init(void) 147 { 148 return platform_driver_register(&jornada_bl_driver); 149 } 150 151 void __exit jornada_bl_exit(void) 152 { 153 platform_driver_unregister(&jornada_bl_driver); 154 } 155 156 MODULE_AUTHOR("Kristoffer Ericson <kristoffer.ericson>"); 157 MODULE_DESCRIPTION("HP Jornada 710/720/728 Backlight driver"); 158 MODULE_LICENSE("GPL"); 159 160 module_init(jornada_bl_init); 161 module_exit(jornada_bl_exit); 162