1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * 4 * Backlight driver for HP Jornada 700 series (710/720/728) 5 * Copyright (C) 2006-2009 Kristoffer Ericson <kristoffer.ericson@gmail.com> 6 */ 7 8 #include <linux/backlight.h> 9 #include <linux/device.h> 10 #include <linux/fb.h> 11 #include <linux/kernel.h> 12 #include <linux/module.h> 13 #include <linux/platform_device.h> 14 15 #include <mach/jornada720.h> 16 #include <mach/hardware.h> 17 18 #include <video/s1d13xxxfb.h> 19 20 #define BL_MAX_BRIGHT 255 21 #define BL_DEF_BRIGHT 25 22 23 static int jornada_bl_get_brightness(struct backlight_device *bd) 24 { 25 int ret; 26 27 /* check if backlight is on */ 28 if (!(PPSR & PPC_LDD1)) 29 return 0; 30 31 jornada_ssp_start(); 32 33 /* cmd should return txdummy */ 34 ret = jornada_ssp_byte(GETBRIGHTNESS); 35 36 if (jornada_ssp_byte(GETBRIGHTNESS) != TXDUMMY) { 37 dev_err(&bd->dev, "get brightness timeout\n"); 38 jornada_ssp_end(); 39 return -ETIMEDOUT; 40 } 41 42 /* exchange txdummy for value */ 43 ret = jornada_ssp_byte(TXDUMMY); 44 45 jornada_ssp_end(); 46 47 return BL_MAX_BRIGHT - ret; 48 } 49 50 static int jornada_bl_update_status(struct backlight_device *bd) 51 { 52 int ret = 0; 53 54 jornada_ssp_start(); 55 56 /* If backlight is off then really turn it off */ 57 if (backlight_is_blank(bd)) { 58 ret = jornada_ssp_byte(BRIGHTNESSOFF); 59 if (ret != TXDUMMY) { 60 dev_info(&bd->dev, "brightness off timeout\n"); 61 /* turn off backlight */ 62 PPSR &= ~PPC_LDD1; 63 PPDR |= PPC_LDD1; 64 ret = -ETIMEDOUT; 65 } 66 } else /* turn on backlight */ 67 PPSR |= PPC_LDD1; 68 69 /* send command to our mcu */ 70 if (jornada_ssp_byte(SETBRIGHTNESS) != TXDUMMY) { 71 dev_info(&bd->dev, "failed to set brightness\n"); 72 ret = -ETIMEDOUT; 73 goto out; 74 } 75 76 /* 77 * at this point we expect that the mcu has accepted 78 * our command and is waiting for our new value 79 * please note that maximum brightness is 255, 80 * but due to physical layout it is equal to 0, so we simply 81 * invert the value (MAX VALUE - NEW VALUE). 82 */ 83 if (jornada_ssp_byte(BL_MAX_BRIGHT - bd->props.brightness) 84 != TXDUMMY) { 85 dev_err(&bd->dev, "set brightness failed\n"); 86 ret = -ETIMEDOUT; 87 } 88 89 /* 90 * If infact we get an TXDUMMY as output we are happy and dont 91 * make any further comments about it 92 */ 93 out: 94 jornada_ssp_end(); 95 96 return ret; 97 } 98 99 static const struct backlight_ops jornada_bl_ops = { 100 .get_brightness = jornada_bl_get_brightness, 101 .update_status = jornada_bl_update_status, 102 .options = BL_CORE_SUSPENDRESUME, 103 }; 104 105 static int jornada_bl_probe(struct platform_device *pdev) 106 { 107 struct backlight_properties props; 108 int ret; 109 struct backlight_device *bd; 110 111 memset(&props, 0, sizeof(struct backlight_properties)); 112 props.type = BACKLIGHT_RAW; 113 props.max_brightness = BL_MAX_BRIGHT; 114 115 bd = devm_backlight_device_register(&pdev->dev, S1D_DEVICENAME, 116 &pdev->dev, NULL, &jornada_bl_ops, 117 &props); 118 if (IS_ERR(bd)) { 119 ret = PTR_ERR(bd); 120 dev_err(&pdev->dev, "failed to register device, err=%x\n", ret); 121 return ret; 122 } 123 124 bd->props.power = FB_BLANK_UNBLANK; 125 bd->props.brightness = BL_DEF_BRIGHT; 126 /* 127 * note. make sure max brightness is set otherwise 128 * you will get seemingly non-related errors when 129 * trying to change brightness 130 */ 131 jornada_bl_update_status(bd); 132 133 platform_set_drvdata(pdev, bd); 134 dev_info(&pdev->dev, "HP Jornada 700 series backlight driver\n"); 135 136 return 0; 137 } 138 139 static struct platform_driver jornada_bl_driver = { 140 .probe = jornada_bl_probe, 141 .driver = { 142 .name = "jornada_bl", 143 }, 144 }; 145 146 module_platform_driver(jornada_bl_driver); 147 148 MODULE_AUTHOR("Kristoffer Ericson <kristoffer.ericson>"); 149 MODULE_DESCRIPTION("HP Jornada 710/720/728 Backlight driver"); 150 MODULE_LICENSE("GPL"); 151