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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 13 14 #include <linux/backlight.h> 15 #include <linux/device.h> 16 #include <linux/fb.h> 17 #include <linux/kernel.h> 18 #include <linux/module.h> 19 #include <linux/platform_device.h> 20 21 #include <mach/jornada720.h> 22 #include <mach/hardware.h> 23 24 #include <video/s1d13xxxfb.h> 25 26 #define BL_MAX_BRIGHT 255 27 #define BL_DEF_BRIGHT 25 28 29 static int jornada_bl_get_brightness(struct backlight_device *bd) 30 { 31 int ret; 32 33 /* check if backlight is on */ 34 if (!(PPSR & PPC_LDD1)) 35 return 0; 36 37 jornada_ssp_start(); 38 39 /* cmd should return txdummy */ 40 ret = jornada_ssp_byte(GETBRIGHTNESS); 41 42 if (jornada_ssp_byte(GETBRIGHTNESS) != TXDUMMY) { 43 pr_err("get brightness timeout\n"); 44 jornada_ssp_end(); 45 return -ETIMEDOUT; 46 } else /* 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 pr_info("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 pr_info("failed to set brightness\n"); 76 ret = -ETIMEDOUT; 77 goto out; 78 } 79 80 /* at this point we expect that the mcu has accepted 81 our command and is waiting for our new value 82 please note that maximum brightness is 255, 83 but due to physical layout it is equal to 0, so we simply 84 invert the value (MAX VALUE - NEW VALUE). */ 85 if (jornada_ssp_byte(BL_MAX_BRIGHT - bd->props.brightness) != TXDUMMY) { 86 pr_err("set brightness failed\n"); 87 ret = -ETIMEDOUT; 88 } 89 90 /* If infact we get an TXDUMMY as output we are happy and dont 91 make any further comments about it */ 92 out: 93 jornada_ssp_end(); 94 95 return ret; 96 } 97 98 static const struct backlight_ops jornada_bl_ops = { 99 .get_brightness = jornada_bl_get_brightness, 100 .update_status = jornada_bl_update_status, 101 .options = BL_CORE_SUSPENDRESUME, 102 }; 103 104 static int jornada_bl_probe(struct platform_device *pdev) 105 { 106 struct backlight_properties props; 107 int ret; 108 struct backlight_device *bd; 109 110 memset(&props, 0, sizeof(struct backlight_properties)); 111 props.type = BACKLIGHT_RAW; 112 props.max_brightness = BL_MAX_BRIGHT; 113 bd = backlight_device_register(S1D_DEVICENAME, &pdev->dev, NULL, 114 &jornada_bl_ops, &props); 115 116 if (IS_ERR(bd)) { 117 ret = PTR_ERR(bd); 118 pr_err("failed to register device, err=%x\n", ret); 119 return ret; 120 } 121 122 bd->props.power = FB_BLANK_UNBLANK; 123 bd->props.brightness = BL_DEF_BRIGHT; 124 /* note. make sure max brightness is set otherwise 125 you will get seemingly non-related errors when 126 trying to change brightness */ 127 jornada_bl_update_status(bd); 128 129 platform_set_drvdata(pdev, bd); 130 pr_info("HP Jornada 700 series backlight driver\n"); 131 132 return 0; 133 } 134 135 static int jornada_bl_remove(struct platform_device *pdev) 136 { 137 struct backlight_device *bd = platform_get_drvdata(pdev); 138 139 backlight_device_unregister(bd); 140 141 return 0; 142 } 143 144 static struct platform_driver jornada_bl_driver = { 145 .probe = jornada_bl_probe, 146 .remove = jornada_bl_remove, 147 .driver = { 148 .name = "jornada_bl", 149 }, 150 }; 151 152 module_platform_driver(jornada_bl_driver); 153 154 MODULE_AUTHOR("Kristoffer Ericson <kristoffer.ericson>"); 155 MODULE_DESCRIPTION("HP Jornada 710/720/728 Backlight driver"); 156 MODULE_LICENSE("GPL"); 157