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