video/backlight/aat2870_bl.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * linux/drivers/video/backlight/aat2870_bl.c
0004  *
0005  * Copyright (c) 2011, NVIDIA Corporation.
0006  * Author: Jin Park <jinyoungp@nvidia.com>
0007  */
0008
0009 #include <linux/module.h>
0010 #include <linux/kernel.h>
0011 #include <linux/init.h>
0012 #include <linux/platform_device.h>
0013 #include <linux/mutex.h>
0014 #include <linux/delay.h>
0015 #include <linux/fb.h>
0016 #include <linux/backlight.h>
0017 #include <linux/mfd/aat2870.h>
0018
0019 struct aat2870_bl_driver_data {
0020     struct platform_device *pdev;
0021     struct backlight_device *bd;
0022
0023     int channels;
0024     int max_current;
0025     int brightness; /* current brightness */
0026 };
0027
0028 static inline int aat2870_brightness(struct aat2870_bl_driver_data *aat2870_bl,
0029                      int brightness)
0030 {
0031     struct backlight_device *bd = aat2870_bl->bd;
0032     int val;
0033
0034     val = brightness * (aat2870_bl->max_current - 1);
0035     val /= bd->props.max_brightness;
0036
0037     return val;
0038 }
0039
0040 static inline int aat2870_bl_enable(struct aat2870_bl_driver_data *aat2870_bl)
0041 {
0042     struct aat2870_data *aat2870
0043             = dev_get_drvdata(aat2870_bl->pdev->dev.parent);
0044
0045     return aat2870->write(aat2870, AAT2870_BL_CH_EN,
0046                   (u8)aat2870_bl->channels);
0047 }
0048
0049 static inline int aat2870_bl_disable(struct aat2870_bl_driver_data *aat2870_bl)
0050 {
0051     struct aat2870_data *aat2870
0052             = dev_get_drvdata(aat2870_bl->pdev->dev.parent);
0053
0054     return aat2870->write(aat2870, AAT2870_BL_CH_EN, 0x0);
0055 }
0056
0057 static int aat2870_bl_update_status(struct backlight_device *bd)
0058 {
0059     struct aat2870_bl_driver_data *aat2870_bl = bl_get_data(bd);
0060     struct aat2870_data *aat2870 =
0061             dev_get_drvdata(aat2870_bl->pdev->dev.parent);
0062     int brightness = bd->props.brightness;
0063     int ret;
0064
0065     if ((brightness < 0) || (bd->props.max_brightness < brightness)) {
0066         dev_err(&bd->dev, "invalid brightness, %d\n", brightness);
0067         return -EINVAL;
0068     }
0069
0070     dev_dbg(&bd->dev, "brightness=%d, power=%d, state=%d\n",
0071          bd->props.brightness, bd->props.power, bd->props.state);
0072
0073     if ((bd->props.power != FB_BLANK_UNBLANK) ||
0074             (bd->props.state & BL_CORE_FBBLANK) ||
0075             (bd->props.state & BL_CORE_SUSPENDED))
0076         brightness = 0;
0077
0078     ret = aat2870->write(aat2870, AAT2870_BLM,
0079                  (u8)aat2870_brightness(aat2870_bl, brightness));
0080     if (ret < 0)
0081         return ret;
0082
0083     if (brightness == 0) {
0084         ret = aat2870_bl_disable(aat2870_bl);
0085         if (ret < 0)
0086             return ret;
0087     } else if (aat2870_bl->brightness == 0) {
0088         ret = aat2870_bl_enable(aat2870_bl);
0089         if (ret < 0)
0090             return ret;
0091     }
0092
0093     aat2870_bl->brightness = brightness;
0094
0095     return 0;
0096 }
0097
0098 static int aat2870_bl_check_fb(struct backlight_device *bd, struct fb_info *fi)
0099 {
0100     return 1;
0101 }
0102
0103 static const struct backlight_ops aat2870_bl_ops = {
0104     .options = BL_CORE_SUSPENDRESUME,
0105     .update_status = aat2870_bl_update_status,
0106     .check_fb = aat2870_bl_check_fb,
0107 };
0108
0109 static int aat2870_bl_probe(struct platform_device *pdev)
0110 {
0111     struct aat2870_bl_platform_data *pdata = dev_get_platdata(&pdev->dev);
0112     struct aat2870_bl_driver_data *aat2870_bl;
0113     struct backlight_device *bd;
0114     struct backlight_properties props;
0115     int ret = 0;
0116
0117     if (!pdata) {
0118         dev_err(&pdev->dev, "No platform data\n");
0119         ret = -ENXIO;
0120         goto out;
0121     }
0122
0123     if (pdev->id != AAT2870_ID_BL) {
0124         dev_err(&pdev->dev, "Invalid device ID, %d\n", pdev->id);
0125         ret = -EINVAL;
0126         goto out;
0127     }
0128
0129     aat2870_bl = devm_kzalloc(&pdev->dev,
0130                   sizeof(struct aat2870_bl_driver_data),
0131                   GFP_KERNEL);
0132     if (!aat2870_bl) {
0133         ret = -ENOMEM;
0134         goto out;
0135     }
0136
0137     memset(&props, 0, sizeof(struct backlight_properties));
0138
0139     props.type = BACKLIGHT_RAW;
0140     bd = devm_backlight_device_register(&pdev->dev, "aat2870-backlight",
0141                     &pdev->dev, aat2870_bl, &aat2870_bl_ops,
0142                     &props);
0143     if (IS_ERR(bd)) {
0144         dev_err(&pdev->dev,
0145             "Failed allocate memory for backlight device\n");
0146         ret = PTR_ERR(bd);
0147         goto out;
0148     }
0149
0150     aat2870_bl->pdev = pdev;
0151     platform_set_drvdata(pdev, aat2870_bl);
0152
0153     aat2870_bl->bd = bd;
0154
0155     if (pdata->channels > 0)
0156         aat2870_bl->channels = pdata->channels;
0157     else
0158         aat2870_bl->channels = AAT2870_BL_CH_ALL;
0159
0160     if (pdata->max_current > 0)
0161         aat2870_bl->max_current = pdata->max_current;
0162     else
0163         aat2870_bl->max_current = AAT2870_CURRENT_27_9;
0164
0165     if (pdata->max_brightness > 0)
0166         bd->props.max_brightness = pdata->max_brightness;
0167     else
0168         bd->props.max_brightness = 255;
0169
0170     aat2870_bl->brightness = 0;
0171     bd->props.power = FB_BLANK_UNBLANK;
0172     bd->props.brightness = bd->props.max_brightness;
0173
0174     ret = aat2870_bl_update_status(bd);
0175     if (ret < 0) {
0176         dev_err(&pdev->dev, "Failed to initialize\n");
0177         return ret;
0178     }
0179
0180     return 0;
0181
0182 out:
0183     return ret;
0184 }
0185
0186 static int aat2870_bl_remove(struct platform_device *pdev)
0187 {
0188     struct aat2870_bl_driver_data *aat2870_bl = platform_get_drvdata(pdev);
0189     struct backlight_device *bd = aat2870_bl->bd;
0190
0191     bd->props.power = FB_BLANK_POWERDOWN;
0192     bd->props.brightness = 0;
0193     backlight_update_status(bd);
0194
0195     return 0;
0196 }
0197
0198 static struct platform_driver aat2870_bl_driver = {
0199     .driver = {
0200         .name   = "aat2870-backlight",
0201     },
0202     .probe      = aat2870_bl_probe,
0203     .remove     = aat2870_bl_remove,
0204 };
0205
0206 static int __init aat2870_bl_init(void)
0207 {
0208     return platform_driver_register(&aat2870_bl_driver);
0209 }
0210 subsys_initcall(aat2870_bl_init);
0211
0212 static void __exit aat2870_bl_exit(void)
0213 {
0214     platform_driver_unregister(&aat2870_bl_driver);
0215 }
0216 module_exit(aat2870_bl_exit);
0217
0218 MODULE_DESCRIPTION("AnalogicTech AAT2870 Backlight");
0219 MODULE_LICENSE("GPL");
0220 MODULE_AUTHOR("Jin Park <jinyoungp@nvidia.com>");