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Mon, 09 Dec 2024 02:08:01 -0800 (PST) Received: from [192.168.0.115] ([59.188.211.160]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-725d9b98eb2sm3567122b3a.148.2024.12.09.02.07.57 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 09 Dec 2024 02:08:00 -0800 (PST) Message-ID: <551941de-b9a4-4353-8bb2-0bfc3304ef87@gmail.com> Date: Mon, 9 Dec 2024 18:07:55 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 2/3] backlight: dwi_bl: Add Apple DWI backlight driver To: Krzysztof Kozlowski , y@krzk-bin Cc: Lee Jones , Daniel Thompson , Jingoo Han , Pavel Machek , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Helge Deller , Hector Martin , Sven Peter , Alyssa Rosenzweig , dri-devel@lists.freedesktop.org, linux-leds@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fbdev@vger.kernel.org, asahi@lists.linux.dev, linux-arm-kernel@lists.infradead.org References: <20241207130433.30351-1-towinchenmi@gmail.com> <20241207130433.30351-3-towinchenmi@gmail.com> Content-Language: en-US From: Nick Chan In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Krzysztof Kozlowski 於 2024/12/9 下午5:22 寫道: > On Sat, Dec 07, 2024 at 09:03:15PM +0800, Nick Chan wrote: >> 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. >> >> Signed-off-by: Nick Chan >> --- >> drivers/video/backlight/Kconfig | 12 +++ >> drivers/video/backlight/Makefile | 1 + >> drivers/video/backlight/dwi_bl.c | 124 +++++++++++++++++++++++++++++++ >> 3 files changed, 137 insertions(+) >> create mode 100644 drivers/video/backlight/dwi_bl.c >> >> diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig >> index 3614a5d29c71..e64cc3d51ac5 100644 >> --- a/drivers/video/backlight/Kconfig >> +++ b/drivers/video/backlight/Kconfig >> @@ -166,6 +166,18 @@ config BACKLIGHT_EP93XX >> To compile this driver as a module, choose M here: the module will >> be called ep93xx_bl. >> >> +config BACKLIGHT_APPLE_DWI >> + tristate "Apple DWI 2-Wire Interface Backlight Driver" >> + depends on ARCH_APPLE || COMPILE_TEST >> + default y >> + help >> + Say Y to enable the backlight driver for backlight controllers >> + attached via the Apple DWI 2-wire interface which is found in some >> + Apple iPhones, iPads and iPod touches. > > Mixed/messed indentation. Some spaces? Ack. Will be fixed for v4. > >> + >> + To compile this driver as a module, choose M here: the module will >> + be called dwi_bl. >> + >> config BACKLIGHT_IPAQ_MICRO >> tristate "iPAQ microcontroller backlight driver" >> depends on MFD_IPAQ_MICRO >> diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile >> index 8fc98f760a8a..0a569d7f0210 100644 >> --- a/drivers/video/backlight/Makefile >> +++ b/drivers/video/backlight/Makefile >> @@ -28,6 +28,7 @@ obj-$(CONFIG_BACKLIGHT_BD6107) += bd6107.o >> obj-$(CONFIG_BACKLIGHT_CLASS_DEVICE) += backlight.o >> obj-$(CONFIG_BACKLIGHT_DA903X) += da903x_bl.o >> obj-$(CONFIG_BACKLIGHT_DA9052) += da9052_bl.o >> +obj-$(CONFIG_BACKLIGHT_APPLE_DWI) += dwi_bl.o > > Please do not introduce other sorting way - it is sorted by config name. > Which will also point you to apple_bl.o and need of explaining the > differences, e.g. why this cannot be one driver. apple_bl is a driver backlight controllers on a PCI bus on Intel Macs, which is completely different from the Samsung-derived DWI block this driver deals with. This will be explained in the commit message for v4. > > >> obj-$(CONFIG_BACKLIGHT_EP93XX) += ep93xx_bl.o >> obj-$(CONFIG_BACKLIGHT_GPIO) += gpio_backlight.o >> obj-$(CONFIG_BACKLIGHT_HP680) += hp680_bl.o >> diff --git a/drivers/video/backlight/dwi_bl.c b/drivers/video/backlight/dwi_bl.c >> new file mode 100644 >> index 000000000000..d4bfd74b3129 >> --- /dev/null >> +++ b/drivers/video/backlight/dwi_bl.c >> @@ -0,0 +1,124 @@ >> +// SPDX-License-Identifier: GPL-2.0 OR MIT >> +/* >> + * Driver for backlight controllers attached via Apple DWI 2-wire interface >> + * >> + * Copyright (c) 2024 Nick Chan >> + */ >> + >> +#include >> +#include >> +#include >> +#include >> + >> +#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(struct apple_dwi_bl), GFP_KERNEL); > > sizeof(*) > >> + if (!dwi_bl) >> + return -ENOMEM; >> + >> + res = platform_get_resource(dev, IORESOURCE_MEM, 0); >> + if (!res) >> + return -ENXIO; >> + >> + dwi_bl->base = devm_ioremap_resource(&dev->dev, res); > > Use helper for these two, devm_platform_get_and_ioremap_resource() or > similar. Ack. Will be fixed for v4. > > Best regards, > Krzysztof > Nick Chan