/* * linux/drivers/video/backlight/aat2870_bl.c * * Copyright (c) 2011, NVIDIA Corporation. * Author: Jin Park <jinyoungp@nvidia.com> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * version 2 as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA * 02110-1301 USA */ #include <linux/module.h> #include <linux/kernel.h> #include <linux/init.h> #include <linux/platform_device.h> #include <linux/mutex.h> #include <linux/delay.h> #include <linux/fb.h> #include <linux/backlight.h> #include <linux/mfd/aat2870.h> struct aat2870_bl_driver_data { struct platform_device *pdev; struct backlight_device *bd; int channels; int max_current; int brightness; /* current brightness */ }; static inline int aat2870_brightness(struct aat2870_bl_driver_data *aat2870_bl, int brightness) { struct backlight_device *bd = aat2870_bl->bd; int val; val = brightness * (aat2870_bl->max_current - 1); val /= bd->props.max_brightness; return val; } static inline int aat2870_bl_enable(struct aat2870_bl_driver_data *aat2870_bl) { struct aat2870_data *aat2870 = dev_get_drvdata(aat2870_bl->pdev->dev.parent); return aat2870->write(aat2870, AAT2870_BL_CH_EN, (u8)aat2870_bl->channels); } static inline int aat2870_bl_disable(struct aat2870_bl_driver_data *aat2870_bl) { struct aat2870_data *aat2870 = dev_get_drvdata(aat2870_bl->pdev->dev.parent); return aat2870->write(aat2870, AAT2870_BL_CH_EN, 0x0); } static int aat2870_bl_get_brightness(struct backlight_device *bd) { return bd->props.brightness; } static int aat2870_bl_update_status(struct backlight_device *bd) { struct aat2870_bl_driver_data *aat2870_bl = dev_get_drvdata(&bd->dev); struct aat2870_data *aat2870 = dev_get_drvdata(aat2870_bl->pdev->dev.parent); int brightness = bd->props.brightness; int ret; if ((brightness < 0) || (bd->props.max_brightness < brightness)) { dev_err(&bd->dev, "invalid brightness, %d\n", brightness); return -EINVAL; } dev_dbg(&bd->dev, "brightness=%d, power=%d, state=%d\n", bd->props.brightness, bd->props.power, bd->props.state); if ((bd->props.power != FB_BLANK_UNBLANK) || (bd->props.state & BL_CORE_FBBLANK) || (bd->props.state & BL_CORE_SUSPENDED)) brightness = 0; ret = aat2870->write(aat2870, AAT2870_BLM, (u8)aat2870_brightness(aat2870_bl, brightness)); if (ret < 0) return ret; if (brightness == 0) { ret = aat2870_bl_disable(aat2870_bl); if (ret < 0) return ret; } else if (aat2870_bl->brightness == 0) { ret = aat2870_bl_enable(aat2870_bl); if (ret < 0) return ret; } aat2870_bl->brightness = brightness; return 0; } static int aat2870_bl_check_fb(struct backlight_device *bd, struct fb_info *fi) { return 1; } static const struct backlight_ops aat2870_bl_ops = { .options = BL_CORE_SUSPENDRESUME, .get_brightness = aat2870_bl_get_brightness, .update_status = aat2870_bl_update_status, .check_fb = aat2870_bl_check_fb, }; static int aat2870_bl_probe(struct platform_device *pdev) { struct aat2870_bl_platform_data *pdata = pdev->dev.platform_data; struct aat2870_bl_driver_data *aat2870_bl; struct backlight_device *bd; struct backlight_properties props; int ret = 0; if (!pdata) { dev_err(&pdev->dev, "No platform data\n"); ret = -ENXIO; goto out; } if (pdev->id != AAT2870_ID_BL) { dev_err(&pdev->dev, "Invalid device ID, %d\n", pdev->id); ret = -EINVAL; goto out; } aat2870_bl = devm_kzalloc(&pdev->dev, sizeof(struct aat2870_bl_driver_data), GFP_KERNEL); if (!aat2870_bl) { dev_err(&pdev->dev, "Failed to allocate memory for aat2870 backlight\n"); ret = -ENOMEM; goto out; } memset(&props, 0, sizeof(struct backlight_properties)); props.type = BACKLIGHT_RAW; bd = backlight_device_register("aat2870-backlight", &pdev->dev, aat2870_bl, &aat2870_bl_ops, &props); if (IS_ERR(bd)) { dev_err(&pdev->dev, "Failed allocate memory for backlight device\n"); ret = PTR_ERR(bd); goto out; } aat2870_bl->pdev = pdev; platform_set_drvdata(pdev, aat2870_bl); aat2870_bl->bd = bd; if (pdata->channels > 0) aat2870_bl->channels = pdata->channels; else aat2870_bl->channels = AAT2870_BL_CH_ALL; if (pdata->max_current > 0) aat2870_bl->max_current = pdata->max_current; else aat2870_bl->max_current = AAT2870_CURRENT_27_9; if (pdata->max_brightness > 0) bd->props.max_brightness = pdata->max_brightness; else bd->props.max_brightness = 255; aat2870_bl->brightness = 0; bd->props.power = FB_BLANK_UNBLANK; bd->props.brightness = bd->props.max_brightness; ret = aat2870_bl_update_status(bd); if (ret < 0) { dev_err(&pdev->dev, "Failed to initialize\n"); goto out_bl_dev_unregister; } return 0; out_bl_dev_unregister: backlight_device_unregister(bd); out: return ret; } static int aat2870_bl_remove(struct platform_device *pdev) { struct aat2870_bl_driver_data *aat2870_bl = platform_get_drvdata(pdev); struct backlight_device *bd = aat2870_bl->bd; bd->props.power = FB_BLANK_POWERDOWN; bd->props.brightness = 0; backlight_update_status(bd); backlight_device_unregister(bd); return 0; } static struct platform_driver aat2870_bl_driver = { .driver = { .name = "aat2870-backlight", .owner = THIS_MODULE, }, .probe = aat2870_bl_probe, .remove = aat2870_bl_remove, }; static int __init aat2870_bl_init(void) { return platform_driver_register(&aat2870_bl_driver); } subsys_initcall(aat2870_bl_init); static void __exit aat2870_bl_exit(void) { platform_driver_unregister(&aat2870_bl_driver); } module_exit(aat2870_bl_exit); MODULE_DESCRIPTION("AnalogicTech AAT2870 Backlight"); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Jin Park <jinyoungp@nvidia.com>");