fbdev/nvidia/nv_backlight.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Backlight code for nVidia based graphic cards
0004  *
0005  * Copyright 2004 Antonino Daplas <adaplas@pol.net>
0006  * Copyright (c) 2006 Michael Hanselmann <linux-kernel@hansmi.ch>
0007  */
0008
0009 #include <linux/backlight.h>
0010 #include <linux/fb.h>
0011 #include <linux/pci.h>
0012
0013 #ifdef CONFIG_PMAC_BACKLIGHT
0014 #include <asm/backlight.h>
0015 #endif
0016
0017 #include "nv_local.h"
0018 #include "nv_type.h"
0019 #include "nv_proto.h"
0020
0021 /* We do not have any information about which values are allowed, thus
0022  * we used safe values.
0023  */
0024 #define MIN_LEVEL 0x158
0025 #define MAX_LEVEL 0x534
0026 #define LEVEL_STEP ((MAX_LEVEL - MIN_LEVEL) / FB_BACKLIGHT_MAX)
0027
0028 static int nvidia_bl_get_level_brightness(struct nvidia_par *par,
0029         int level)
0030 {
0031     struct fb_info *info = pci_get_drvdata(par->pci_dev);
0032     int nlevel;
0033
0034     /* Get and convert the value */
0035     /* No locking of bl_curve since we read a single value */
0036     nlevel = MIN_LEVEL + info->bl_curve[level] * LEVEL_STEP;
0037
0038     if (nlevel < 0)
0039         nlevel = 0;
0040     else if (nlevel < MIN_LEVEL)
0041         nlevel = MIN_LEVEL;
0042     else if (nlevel > MAX_LEVEL)
0043         nlevel = MAX_LEVEL;
0044
0045     return nlevel;
0046 }
0047
0048 static int nvidia_bl_update_status(struct backlight_device *bd)
0049 {
0050     struct nvidia_par *par = bl_get_data(bd);
0051     u32 tmp_pcrt, tmp_pmc, fpcontrol;
0052     int level;
0053
0054     if (!par->FlatPanel)
0055         return 0;
0056
0057     if (bd->props.power != FB_BLANK_UNBLANK ||
0058         bd->props.fb_blank != FB_BLANK_UNBLANK)
0059         level = 0;
0060     else
0061         level = bd->props.brightness;
0062
0063     tmp_pmc = NV_RD32(par->PMC, 0x10F0) & 0x0000FFFF;
0064     tmp_pcrt = NV_RD32(par->PCRTC0, 0x081C) & 0xFFFFFFFC;
0065     fpcontrol = NV_RD32(par->PRAMDAC, 0x0848) & 0xCFFFFFCC;
0066
0067     if (level > 0) {
0068         tmp_pcrt |= 0x1;
0069         tmp_pmc |= (1 << 31); /* backlight bit */
0070         tmp_pmc |= nvidia_bl_get_level_brightness(par, level) << 16;
0071         fpcontrol |= par->fpSyncs;
0072     } else
0073         fpcontrol |= 0x20000022;
0074
0075     NV_WR32(par->PCRTC0, 0x081C, tmp_pcrt);
0076     NV_WR32(par->PMC, 0x10F0, tmp_pmc);
0077     NV_WR32(par->PRAMDAC, 0x848, fpcontrol);
0078
0079     return 0;
0080 }
0081
0082 static const struct backlight_ops nvidia_bl_ops = {
0083     .update_status  = nvidia_bl_update_status,
0084 };
0085
0086 void nvidia_bl_init(struct nvidia_par *par)
0087 {
0088     struct backlight_properties props;
0089     struct fb_info *info = pci_get_drvdata(par->pci_dev);
0090     struct backlight_device *bd;
0091     char name[12];
0092
0093     if (!par->FlatPanel)
0094         return;
0095
0096 #ifdef CONFIG_PMAC_BACKLIGHT
0097     if (!machine_is(powermac) ||
0098         !pmac_has_backlight_type("mnca"))
0099         return;
0100 #endif
0101
0102     snprintf(name, sizeof(name), "nvidiabl%d", info->node);
0103
0104     memset(&props, 0, sizeof(struct backlight_properties));
0105     props.type = BACKLIGHT_RAW;
0106     props.max_brightness = FB_BACKLIGHT_LEVELS - 1;
0107     bd = backlight_device_register(name, info->dev, par, &nvidia_bl_ops,
0108                        &props);
0109     if (IS_ERR(bd)) {
0110         info->bl_dev = NULL;
0111         printk(KERN_WARNING "nvidia: Backlight registration failed\n");
0112         goto error;
0113     }
0114
0115     info->bl_dev = bd;
0116     fb_bl_default_curve(info, 0,
0117         0x158 * FB_BACKLIGHT_MAX / MAX_LEVEL,
0118         0x534 * FB_BACKLIGHT_MAX / MAX_LEVEL);
0119
0120     bd->props.brightness = bd->props.max_brightness;
0121     bd->props.power = FB_BLANK_UNBLANK;
0122     backlight_update_status(bd);
0123
0124     printk("nvidia: Backlight initialized (%s)\n", name);
0125
0126 error:
0127     return;
0128 }
0129
0130 void nvidia_bl_exit(struct nvidia_par *par)
0131 {
0132     struct fb_info *info = pci_get_drvdata(par->pci_dev);
0133     struct backlight_device *bd = info->bl_dev;
0134
0135     backlight_device_unregister(bd);
0136     printk("nvidia: Backlight unloaded\n");
0137 }