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