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 = backlight_get_brightness(bd); 20 struct ipaq_micro_msg msg = { 21 .id = MSG_BACKLIGHT, 22 .tx_len = 3, 23 }; 24 25 /* 26 * Message format: 27 * Byte 0: backlight instance (usually 1) 28 * Byte 1: on/off 29 * Byte 2: intensity, 0-255 30 */ 31 msg.tx_data[0] = 0x01; 32 msg.tx_data[1] = intensity > 0 ? 1 : 0; 33 msg.tx_data[2] = intensity; 34 return ipaq_micro_tx_msg_sync(micro, &msg); 35 } 36 37 static const struct backlight_ops micro_bl_ops = { 38 .options = BL_CORE_SUSPENDRESUME, 39 .update_status = micro_bl_update_status, 40 }; 41 42 static const struct backlight_properties micro_bl_props = { 43 .type = BACKLIGHT_RAW, 44 .max_brightness = 255, 45 .power = FB_BLANK_UNBLANK, 46 .brightness = 64, 47 }; 48 49 static int micro_backlight_probe(struct platform_device *pdev) 50 { 51 struct backlight_device *bd; 52 struct ipaq_micro *micro = dev_get_drvdata(pdev->dev.parent); 53 54 bd = devm_backlight_device_register(&pdev->dev, "ipaq-micro-backlight", 55 &pdev->dev, micro, µ_bl_ops, 56 µ_bl_props); 57 if (IS_ERR(bd)) 58 return PTR_ERR(bd); 59 60 platform_set_drvdata(pdev, bd); 61 backlight_update_status(bd); 62 63 return 0; 64 } 65 66 static struct platform_driver micro_backlight_device_driver = { 67 .driver = { 68 .name = "ipaq-micro-backlight", 69 }, 70 .probe = micro_backlight_probe, 71 }; 72 module_platform_driver(micro_backlight_device_driver); 73 74 MODULE_LICENSE("GPL v2"); 75 MODULE_DESCRIPTION("driver for iPAQ Atmel micro backlight"); 76 MODULE_ALIAS("platform:ipaq-micro-backlight"); 77