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