mirror of
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2025-08-20 06:20:41 +00:00
ea45d216dd
Add driver for backlight controllers attached via Apple DWI 2-wire interface, which is found on some Apple iPhones, iPads and iPod touches with a LCD display. Although there is an existing apple_bl driver, it is for backlight controllers on Intel Macs attached via PCI, which is completely different from the Samsung-derived DWI block. Reviewed-by: "Daniel Thompson (RISCstar)" <danielt@kernel.org> Signed-off-by: Nick Chan <towinchenmi@gmail.com> Reviewed-by: Neal Gompa <neal@gompa.dev> Link: https://lore.kernel.org/r/20250214040306.16312-3-towinchenmi@gmail.com Signed-off-by: Lee Jones <lee@kernel.org>
123 lines
3 KiB
C
123 lines
3 KiB
C
// SPDX-License-Identifier: GPL-2.0 OR MIT
|
|
/*
|
|
* Driver for backlight controllers attached via Apple DWI 2-wire interface
|
|
*
|
|
* Copyright (c) 2024 Nick Chan <towinchenmi@gmail.com>
|
|
*/
|
|
|
|
#include <linux/backlight.h>
|
|
#include <linux/bitfield.h>
|
|
#include <linux/device.h>
|
|
#include <linux/io.h>
|
|
#include <linux/module.h>
|
|
#include <linux/platform_device.h>
|
|
|
|
#define DWI_BL_CTL 0x0
|
|
#define DWI_BL_CTL_SEND1 BIT(0)
|
|
#define DWI_BL_CTL_SEND2 BIT(4)
|
|
#define DWI_BL_CTL_SEND3 BIT(5)
|
|
#define DWI_BL_CTL_LE_DATA BIT(6)
|
|
/* Only used on Apple A9 and later */
|
|
#define DWI_BL_CTL_SEND4 BIT(12)
|
|
|
|
#define DWI_BL_CMD 0x4
|
|
#define DWI_BL_CMD_TYPE GENMASK(31, 28)
|
|
#define DWI_BL_CMD_TYPE_SET_BRIGHTNESS 0xa
|
|
#define DWI_BL_CMD_DATA GENMASK(10, 0)
|
|
|
|
#define DWI_BL_CTL_SEND (DWI_BL_CTL_SEND1 | \
|
|
DWI_BL_CTL_SEND2 | \
|
|
DWI_BL_CTL_SEND3 | \
|
|
DWI_BL_CTL_LE_DATA | \
|
|
DWI_BL_CTL_SEND4)
|
|
|
|
#define DWI_BL_MAX_BRIGHTNESS 2047
|
|
|
|
struct apple_dwi_bl {
|
|
void __iomem *base;
|
|
};
|
|
|
|
static int dwi_bl_update_status(struct backlight_device *bl)
|
|
{
|
|
struct apple_dwi_bl *dwi_bl = bl_get_data(bl);
|
|
|
|
int brightness = backlight_get_brightness(bl);
|
|
|
|
u32 cmd = 0;
|
|
|
|
cmd |= FIELD_PREP(DWI_BL_CMD_DATA, brightness);
|
|
cmd |= FIELD_PREP(DWI_BL_CMD_TYPE, DWI_BL_CMD_TYPE_SET_BRIGHTNESS);
|
|
|
|
writel(cmd, dwi_bl->base + DWI_BL_CMD);
|
|
writel(DWI_BL_CTL_SEND, dwi_bl->base + DWI_BL_CTL);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int dwi_bl_get_brightness(struct backlight_device *bl)
|
|
{
|
|
struct apple_dwi_bl *dwi_bl = bl_get_data(bl);
|
|
|
|
u32 cmd = readl(dwi_bl->base + DWI_BL_CMD);
|
|
|
|
return FIELD_GET(DWI_BL_CMD_DATA, cmd);
|
|
}
|
|
|
|
static const struct backlight_ops dwi_bl_ops = {
|
|
.options = BL_CORE_SUSPENDRESUME,
|
|
.get_brightness = dwi_bl_get_brightness,
|
|
.update_status = dwi_bl_update_status
|
|
};
|
|
|
|
static int dwi_bl_probe(struct platform_device *dev)
|
|
{
|
|
struct apple_dwi_bl *dwi_bl;
|
|
struct backlight_device *bl;
|
|
struct backlight_properties props;
|
|
struct resource *res;
|
|
|
|
dwi_bl = devm_kzalloc(&dev->dev, sizeof(*dwi_bl), GFP_KERNEL);
|
|
if (!dwi_bl)
|
|
return -ENOMEM;
|
|
|
|
dwi_bl->base = devm_platform_get_and_ioremap_resource(dev, 0, &res);
|
|
if (IS_ERR(dwi_bl->base))
|
|
return PTR_ERR(dwi_bl->base);
|
|
|
|
memset(&props, 0, sizeof(struct backlight_properties));
|
|
props.type = BACKLIGHT_PLATFORM;
|
|
props.max_brightness = DWI_BL_MAX_BRIGHTNESS;
|
|
props.scale = BACKLIGHT_SCALE_LINEAR;
|
|
|
|
bl = devm_backlight_device_register(&dev->dev, dev->name, &dev->dev,
|
|
dwi_bl, &dwi_bl_ops, &props);
|
|
if (IS_ERR(bl))
|
|
return PTR_ERR(bl);
|
|
|
|
platform_set_drvdata(dev, dwi_bl);
|
|
|
|
bl->props.brightness = dwi_bl_get_brightness(bl);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct of_device_id dwi_bl_of_match[] = {
|
|
{ .compatible = "apple,dwi-bl" },
|
|
{},
|
|
};
|
|
|
|
MODULE_DEVICE_TABLE(of, dwi_bl_of_match);
|
|
|
|
static struct platform_driver dwi_bl_driver = {
|
|
.driver = {
|
|
.name = "apple-dwi-bl",
|
|
.of_match_table = dwi_bl_of_match
|
|
},
|
|
.probe = dwi_bl_probe,
|
|
};
|
|
|
|
module_platform_driver(dwi_bl_driver);
|
|
|
|
MODULE_DESCRIPTION("Apple DWI Backlight Driver");
|
|
MODULE_AUTHOR("Nick Chan <towinchenmi@gmail.com>");
|
|
MODULE_LICENSE("Dual MIT/GPL");
|