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 dev_err(&bd->dev, "get brightness timeout\n"); 42 jornada_ssp_end(); 43 return -ETIMEDOUT; 44 } 45 46 /* exchange txdummy for value */ 47 ret = jornada_ssp_byte(TXDUMMY); 48 49 jornada_ssp_end(); 50 51 return BL_MAX_BRIGHT - ret; 52 } 53 54 static int jornada_bl_update_status(struct backlight_device *bd) 55 { 56 int ret = 0; 57 58 jornada_ssp_start(); 59 60 /* If backlight is off then really turn it off */ 61 if ((bd->props.power != FB_BLANK_UNBLANK) || (bd->props.fb_blank != FB_BLANK_UNBLANK)) { 62 ret = jornada_ssp_byte(BRIGHTNESSOFF); 63 if (ret != TXDUMMY) { 64 dev_info(&bd->dev, "brightness off timeout\n"); 65 /* turn off backlight */ 66 PPSR &= ~PPC_LDD1; 67 PPDR |= PPC_LDD1; 68 ret = -ETIMEDOUT; 69 } 70 } else /* turn on backlight */ 71 PPSR |= PPC_LDD1; 72 73 /* send command to our mcu */ 74 if (jornada_ssp_byte(SETBRIGHTNESS) != TXDUMMY) { 75 dev_info(&bd->dev, "failed to set brightness\n"); 76 ret = -ETIMEDOUT; 77 goto out; 78 } 79 80 /* 81 * at this point we expect that the mcu has accepted 82 * our command and is waiting for our new value 83 * please note that maximum brightness is 255, 84 * but due to physical layout it is equal to 0, so we simply 85 * invert the value (MAX VALUE - NEW VALUE). 86 */ 87 if (jornada_ssp_byte(BL_MAX_BRIGHT - bd->props.brightness) 88 != TXDUMMY) { 89 dev_err(&bd->dev, "set brightness failed\n"); 90 ret = -ETIMEDOUT; 91 } 92 93 /* 94 * If infact we get an TXDUMMY as output we are happy and dont 95 * make any further comments about it 96 */ 97 out: 98 jornada_ssp_end(); 99 100 return ret; 101 } 102 103 static const struct backlight_ops jornada_bl_ops = { 104 .get_brightness = jornada_bl_get_brightness, 105 .update_status = jornada_bl_update_status, 106 .options = BL_CORE_SUSPENDRESUME, 107 }; 108 109 static int jornada_bl_probe(struct platform_device *pdev) 110 { 111 struct backlight_properties props; 112 int ret; 113 struct backlight_device *bd; 114 115 memset(&props, 0, sizeof(struct backlight_properties)); 116 props.type = BACKLIGHT_RAW; 117 props.max_brightness = BL_MAX_BRIGHT; 118 119 bd = devm_backlight_device_register(&pdev->dev, S1D_DEVICENAME, 120 &pdev->dev, NULL, &jornada_bl_ops, 121 &props); 122 if (IS_ERR(bd)) { 123 ret = PTR_ERR(bd); 124 dev_err(&pdev->dev, "failed to register device, err=%x\n", ret); 125 return ret; 126 } 127 128 bd->props.power = FB_BLANK_UNBLANK; 129 bd->props.brightness = BL_DEF_BRIGHT; 130 /* 131 * note. make sure max brightness is set otherwise 132 * you will get seemingly non-related errors when 133 * trying to change brightness 134 */ 135 jornada_bl_update_status(bd); 136 137 platform_set_drvdata(pdev, bd); 138 dev_info(&pdev->dev, "HP Jornada 700 series backlight driver\n"); 139 140 return 0; 141 } 142 143 static struct platform_driver jornada_bl_driver = { 144 .probe = jornada_bl_probe, 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