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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 | // SPDX-License-Identifier: GPL-2.0-only /* * Driver for the Cirrus EP93xx lcd backlight * * Copyright (c) 2010 H Hartley Sweeten <hsweeten@visionengravers.com> * * This driver controls the pulse width modulated brightness control output, * BRIGHT, on the Cirrus EP9307, EP9312, and EP9315 processors. */ #include <linux/module.h> #include <linux/platform_device.h> #include <linux/io.h> #include <linux/fb.h> #include <linux/backlight.h> #define EP93XX_MAX_COUNT 255 #define EP93XX_MAX_BRIGHT 255 #define EP93XX_DEF_BRIGHT 128 struct ep93xxbl { void __iomem *mmio; int brightness; }; static int ep93xxbl_set(struct backlight_device *bl, int brightness) { struct ep93xxbl *ep93xxbl = bl_get_data(bl); writel((brightness << 8) | EP93XX_MAX_COUNT, ep93xxbl->mmio); ep93xxbl->brightness = brightness; return 0; } static int ep93xxbl_update_status(struct backlight_device *bl) { return ep93xxbl_set(bl, backlight_get_brightness(bl)); } static int ep93xxbl_get_brightness(struct backlight_device *bl) { struct ep93xxbl *ep93xxbl = bl_get_data(bl); return ep93xxbl->brightness; } static const struct backlight_ops ep93xxbl_ops = { .update_status = ep93xxbl_update_status, .get_brightness = ep93xxbl_get_brightness, }; static int ep93xxbl_probe(struct platform_device *dev) { struct ep93xxbl *ep93xxbl; struct backlight_device *bl; struct backlight_properties props; struct resource *res; ep93xxbl = devm_kzalloc(&dev->dev, sizeof(*ep93xxbl), GFP_KERNEL); if (!ep93xxbl) return -ENOMEM; res = platform_get_resource(dev, IORESOURCE_MEM, 0); if (!res) return -ENXIO; /* * FIXME - We don't do a request_mem_region here because we are * sharing the register space with the framebuffer driver (see * drivers/video/ep93xx-fb.c) and doing so will cause the second * loaded driver to return -EBUSY. * * NOTE: No locking is required; the framebuffer does not touch * this register. */ ep93xxbl->mmio = devm_ioremap(&dev->dev, res->start, resource_size(res)); if (!ep93xxbl->mmio) return -ENXIO; memset(&props, 0, sizeof(struct backlight_properties)); props.type = BACKLIGHT_RAW; props.max_brightness = EP93XX_MAX_BRIGHT; bl = devm_backlight_device_register(&dev->dev, dev->name, &dev->dev, ep93xxbl, &ep93xxbl_ops, &props); if (IS_ERR(bl)) return PTR_ERR(bl); bl->props.brightness = EP93XX_DEF_BRIGHT; platform_set_drvdata(dev, bl); ep93xxbl_update_status(bl); return 0; } #ifdef CONFIG_PM_SLEEP static int ep93xxbl_suspend(struct device *dev) { struct backlight_device *bl = dev_get_drvdata(dev); return ep93xxbl_set(bl, 0); } static int ep93xxbl_resume(struct device *dev) { struct backlight_device *bl = dev_get_drvdata(dev); backlight_update_status(bl); return 0; } #endif static SIMPLE_DEV_PM_OPS(ep93xxbl_pm_ops, ep93xxbl_suspend, ep93xxbl_resume); static struct platform_driver ep93xxbl_driver = { .driver = { .name = "ep93xx-bl", .pm = &ep93xxbl_pm_ops, }, .probe = ep93xxbl_probe, }; module_platform_driver(ep93xxbl_driver); MODULE_DESCRIPTION("EP93xx Backlight Driver"); MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>"); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:ep93xx-bl"); |