1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * 4 * iPAQ microcontroller backlight support 5 * Author : Linus Walleij <linus.walleij@linaro.org> 6 */ 7 8 #include <linux/backlight.h> 9 #include <linux/err.h> 10 #include <linux/fb.h> 11 #include <linux/init.h> 12 #include <linux/mfd/ipaq-micro.h> 13 #include <linux/module.h> 14 #include <linux/platform_device.h> 15 16 static int micro_bl_update_status(struct backlight_device *bd) 17 { 18 struct ipaq_micro *micro = dev_get_drvdata(&bd->dev); 19 int intensity = bd->props.brightness; 20 struct ipaq_micro_msg msg = { 21 .id = MSG_BACKLIGHT, 22 .tx_len = 3, 23 }; 24 25 if (bd->props.power != FB_BLANK_UNBLANK) 26 intensity = 0; 27 if (bd->props.state & (BL_CORE_FBBLANK | BL_CORE_SUSPENDED)) 28 intensity = 0; 29 30 /* 31 * Message format: 32 * Byte 0: backlight instance (usually 1) 33 * Byte 1: on/off 34 * Byte 2: intensity, 0-255 35 */ 36 msg.tx_data[0] = 0x01; 37 msg.tx_data[1] = intensity > 0 ? 1 : 0; 38 msg.tx_data[2] = intensity; 39 return ipaq_micro_tx_msg_sync(micro, &msg); 40 } 41 42 static const struct backlight_ops micro_bl_ops = { 43 .options = BL_CORE_SUSPENDRESUME, 44 .update_status = micro_bl_update_status, 45 }; 46 47 static const struct backlight_properties micro_bl_props = { 48 .type = BACKLIGHT_RAW, 49 .max_brightness = 255, 50 .power = FB_BLANK_UNBLANK, 51 .brightness = 64, 52 }; 53 54 static int micro_backlight_probe(struct platform_device *pdev) 55 { 56 struct backlight_device *bd; 57 struct ipaq_micro *micro = dev_get_drvdata(pdev->dev.parent); 58 59 bd = devm_backlight_device_register(&pdev->dev, "ipaq-micro-backlight", 60 &pdev->dev, micro, µ_bl_ops, 61 µ_bl_props); 62 if (IS_ERR(bd)) 63 return PTR_ERR(bd); 64 65 platform_set_drvdata(pdev, bd); 66 backlight_update_status(bd); 67 68 return 0; 69 } 70 71 static struct platform_driver micro_backlight_device_driver = { 72 .driver = { 73 .name = "ipaq-micro-backlight", 74 }, 75 .probe = micro_backlight_probe, 76 }; 77 module_platform_driver(micro_backlight_device_driver); 78 79 MODULE_LICENSE("GPL v2"); 80 MODULE_DESCRIPTION("driver for iPAQ Atmel micro backlight"); 81 MODULE_ALIAS("platform:ipaq-micro-backlight"); 82