From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 20085C433ED for ; Fri, 23 Apr 2021 21:55:55 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id DF10D61168 for ; Fri, 23 Apr 2021 21:55:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DF10D61168 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 4F5926EC9C; Fri, 23 Apr 2021 21:55:50 +0000 (UTC) Received: from alexa-out.qualcomm.com (alexa-out.qualcomm.com [129.46.98.28]) by gabe.freedesktop.org (Postfix) with ESMTPS id 517A76EC95; Fri, 23 Apr 2021 21:55:48 +0000 (UTC) Received: from ironmsg08-lv.qualcomm.com ([10.47.202.152]) by alexa-out.qualcomm.com with ESMTP; 23 Apr 2021 14:55:48 -0700 X-QCInternal: smtphost Received: from ironmsg02-blr.qualcomm.com ([10.86.208.131]) by ironmsg08-lv.qualcomm.com with ESMTP/TLS/AES256-SHA; 23 Apr 2021 14:55:47 -0700 X-QCInternal: smtphost Received: from rajeevny-linux.qualcomm.com ([10.204.66.121]) by ironmsg02-blr.qualcomm.com with ESMTP; 24 Apr 2021 03:25:17 +0530 Received: by rajeevny-linux.qualcomm.com (Postfix, from userid 2363605) id 0D722212C3; Sat, 24 Apr 2021 03:25:15 +0530 (IST) From: Rajeev Nandan To: dri-devel@lists.freedesktop.org, linux-arm-msm@vger.kernel.org, freedreno@lists.freedesktop.org, devicetree@vger.kernel.org Subject: [v2 2/2] backlight: Add DisplayPort aux backlight driver Date: Sat, 24 Apr 2021 03:25:04 +0530 Message-Id: <1619214904-10218-3-git-send-email-rajeevny@codeaurora.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1619214904-10218-1-git-send-email-rajeevny@codeaurora.org> References: <1619214904-10218-1-git-send-email-rajeevny@codeaurora.org> X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mkrishn@codeaurora.org, Rajeev Nandan , linux-kernel@vger.kernel.org, abhinavk@codeaurora.org, dianders@chromium.org, seanpaul@chromium.org, kalyan_t@codeaurora.org, hoegsberg@chromium.org MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Add backlight driver for the panels supporting backlight control using DPCD registers on the DisplayPort aux channel. Changes in v2: - New (most of the code reused from drm_dp_aux_backlight.c of v1) Signed-off-by: Rajeev Nandan --- drivers/video/backlight/Kconfig | 7 + drivers/video/backlight/Makefile | 1 + drivers/video/backlight/dp_aux_backlight.c | 245 +++++++++++++++++++++++++++++ 3 files changed, 253 insertions(+) create mode 100644 drivers/video/backlight/dp_aux_backlight.c diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig index d83c87b..82c88f0 100644 --- a/drivers/video/backlight/Kconfig +++ b/drivers/video/backlight/Kconfig @@ -456,6 +456,13 @@ config BACKLIGHT_LED If you have a LCD backlight adjustable by LED class driver, say Y to enable this driver. +config BACKLIGHT_DP_AUX + tristate "DisplayPort aux backlight driver" + depends on DRM && DRM_KMS_HELPER + help + If you have a panel backlight controlled by DPCD registers + on the DisplayPort aux channel, say Y to enable this driver. + endif # BACKLIGHT_CLASS_DEVICE endmenu diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile index 685f3f1..ba23c7c 100644 --- a/drivers/video/backlight/Makefile +++ b/drivers/video/backlight/Makefile @@ -57,3 +57,4 @@ obj-$(CONFIG_BACKLIGHT_WM831X) += wm831x_bl.o obj-$(CONFIG_BACKLIGHT_ARCXCNN) += arcxcnn_bl.o obj-$(CONFIG_BACKLIGHT_RAVE_SP) += rave-sp-backlight.o obj-$(CONFIG_BACKLIGHT_LED) += led_bl.o +obj-$(CONFIG_BACKLIGHT_DP_AUX) += dp_aux_backlight.o diff --git a/drivers/video/backlight/dp_aux_backlight.c b/drivers/video/backlight/dp_aux_backlight.c new file mode 100644 index 00000000..235fb42 --- /dev/null +++ b/drivers/video/backlight/dp_aux_backlight.c @@ -0,0 +1,245 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Backlight driver to control the brightness over DisplayPort aux channel. + */ + +#include +#include +#include +#include +#include +#include +#include + +#define DP_AUX_MAX_BRIGHTNESS 0xffff + +/** + * struct dp_aux_backlight - DisplayPort aux backlight data + * @dev: pointer to our device. + * @aux: the DisplayPort aux channel. + * @enable_gpio: the backlight enable gpio. + * @enabled: true if backlight is enabled else false. + */ +struct dp_aux_backlight { + struct device *dev; + struct drm_dp_aux *aux; + struct gpio_desc *enable_gpio; + bool enabled; +}; + +static struct drm_dp_aux *i2c_to_aux(struct i2c_adapter *i2c) +{ + return container_of(i2c, struct drm_dp_aux, ddc); +} + +static int dp_aux_backlight_enable(struct dp_aux_backlight *aux_bl) +{ + u8 val = 0; + int ret; + + if (aux_bl->enabled) + return 0; + + /* Set backlight control mode */ + ret = drm_dp_dpcd_readb(aux_bl->aux, DP_EDP_BACKLIGHT_MODE_SET_REGISTER, + &val); + if (ret < 0) + return ret; + + val &= ~DP_EDP_BACKLIGHT_CONTROL_MODE_MASK; + val |= DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD; + ret = drm_dp_dpcd_writeb(aux_bl->aux, DP_EDP_BACKLIGHT_MODE_SET_REGISTER, + val); + if (ret < 0) + return ret; + + /* Enable backlight */ + ret = drm_dp_dpcd_readb(aux_bl->aux, DP_EDP_DISPLAY_CONTROL_REGISTER, + &val); + if (ret < 0) + return ret; + + val |= DP_EDP_BACKLIGHT_ENABLE; + ret = drm_dp_dpcd_writeb(aux_bl->aux, DP_EDP_DISPLAY_CONTROL_REGISTER, + val); + if (ret < 0) + return ret; + + if (aux_bl->enable_gpio) + gpiod_set_value(aux_bl->enable_gpio, 1); + + aux_bl->enabled = true; + + return 0; +} + +static int dp_aux_backlight_disable(struct dp_aux_backlight *aux_bl) +{ + u8 val = 0; + int ret; + + if (!aux_bl->enabled) + return 0; + + if (aux_bl->enable_gpio) + gpiod_set_value(aux_bl->enable_gpio, 0); + + ret = drm_dp_dpcd_readb(aux_bl->aux, DP_EDP_DISPLAY_CONTROL_REGISTER, + &val); + if (ret < 0) + return ret; + + val &= ~DP_EDP_BACKLIGHT_ENABLE; + ret = drm_dp_dpcd_writeb(aux_bl->aux, DP_EDP_DISPLAY_CONTROL_REGISTER, + val); + if (ret < 0) + return ret; + + aux_bl->enabled = false; + + return 0; +} + +static int dp_aux_backlight_update_status(struct backlight_device *bd) +{ + struct dp_aux_backlight *aux_bl = bl_get_data(bd); + u16 brightness = backlight_get_brightness(bd); + u8 val[2] = { 0x0 }; + int ret = 0; + + if (brightness > 0) { + val[0] = brightness >> 8; + val[1] = brightness & 0xff; + ret = drm_dp_dpcd_write(aux_bl->aux, DP_EDP_BACKLIGHT_BRIGHTNESS_MSB, + val, sizeof(val)); + if (ret < 0) + return ret; + + dp_aux_backlight_enable(aux_bl); + } else { + dp_aux_backlight_disable(aux_bl); + } + + return 0; +} + +static int dp_aux_backlight_get_brightness(struct backlight_device *bd) +{ + struct dp_aux_backlight *aux_bl = bl_get_data(bd); + u8 val[2] = { 0x0 }; + int ret = 0; + + if (backlight_is_blank(bd)) + return 0; + + ret = drm_dp_dpcd_read(aux_bl->aux, DP_EDP_BACKLIGHT_BRIGHTNESS_MSB, + &val, sizeof(val)); + if (ret < 0) + return ret; + + return (val[0] << 8 | val[1]); +} + +static const struct backlight_ops aux_bl_ops = { + .update_status = dp_aux_backlight_update_status, + .get_brightness = dp_aux_backlight_get_brightness, +}; + + +static int dp_aux_backlight_probe(struct platform_device *pdev) +{ + struct dp_aux_backlight *aux_bl; + struct backlight_device *bd; + struct backlight_properties bl_props = { 0 }; + struct device_node *np; + struct i2c_adapter *ddc; + int ret = 0; + u32 val; + + aux_bl = devm_kzalloc(&pdev->dev, sizeof(*aux_bl), GFP_KERNEL); + if (!aux_bl) + return -ENOMEM; + + aux_bl->dev = &pdev->dev; + + np = of_parse_phandle(pdev->dev.of_node, "ddc-i2c-bus", 0); + if (!np) { + dev_err(&pdev->dev, "failed to get aux ddc I2C bus\n"); + return -ENODEV; + } + + ddc = of_find_i2c_adapter_by_node(np); + of_node_put(np); + if (!ddc) + return -EPROBE_DEFER; + + aux_bl->aux = i2c_to_aux(ddc); + dev_dbg(&pdev->dev, "using dp aux %s\n", aux_bl->aux->name); + + aux_bl->enable_gpio = devm_gpiod_get_optional(&pdev->dev, "enable", + GPIOD_OUT_LOW); + if (IS_ERR(aux_bl->enable_gpio)) { + ret = PTR_ERR(aux_bl->enable_gpio); + goto free_ddc; + } + + val = DP_AUX_MAX_BRIGHTNESS; + of_property_read_u32(pdev->dev.of_node, "max-brightness", &val); + if (val > DP_AUX_MAX_BRIGHTNESS) + val = DP_AUX_MAX_BRIGHTNESS; + + bl_props.max_brightness = val; + bl_props.brightness = val; + bl_props.type = BACKLIGHT_RAW; + bd = devm_backlight_device_register(&pdev->dev, dev_name(&pdev->dev), + &pdev->dev, aux_bl, + &aux_bl_ops, &bl_props); + if (IS_ERR(bd)) { + ret = PTR_ERR(bd); + dev_err(&pdev->dev, + "failed to register backlight (%d)\n", ret); + goto free_ddc; + } + + platform_set_drvdata(pdev, bd); + + return 0; + +free_ddc: + if (ddc) + put_device(&ddc->dev); + + return ret; +} + +static int dp_aux_backlight_remove(struct platform_device *pdev) +{ + struct backlight_device *bd = platform_get_drvdata(pdev); + struct dp_aux_backlight *aux_bl = bl_get_data(bd); + struct i2c_adapter *ddc = &aux_bl->aux->ddc; + + if (ddc) + put_device(&ddc->dev); + + return 0; +} + +static const struct of_device_id dp_aux_bl_of_match_table[] = { + { .compatible = "dp-aux-backlight"}, + {}, +} +MODULE_DEVICE_TABLE(of, dp_aux_bl_of_match_table); + +static struct platform_driver dp_aux_backlight_driver = { + .driver = { + .name = "dp-aux-backlight", + .of_match_table = dp_aux_bl_of_match_table, + }, + .probe = dp_aux_backlight_probe, + .remove = dp_aux_backlight_remove, + +}; +module_platform_driver(dp_aux_backlight_driver); + +MODULE_DESCRIPTION("DisplayPort aux backlight driver"); +MODULE_LICENSE("GPL v2"); -- 2.7.4 _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel