From patchwork Sat Jun 12 12:07:58 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Rajeev Nandan X-Patchwork-Id: 12317029 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=-16.8 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 3482FC49EA3 for ; Sat, 12 Jun 2021 12:09:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2BA1E613BC for ; Sat, 12 Jun 2021 12:09:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231295AbhFLMLL (ORCPT ); Sat, 12 Jun 2021 08:11:11 -0400 Received: from alexa-out.qualcomm.com ([129.46.98.28]:7932 "EHLO alexa-out.qualcomm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230191AbhFLMLJ (ORCPT ); Sat, 12 Jun 2021 08:11:09 -0400 Received: from ironmsg09-lv.qualcomm.com ([10.47.202.153]) by alexa-out.qualcomm.com with ESMTP; 12 Jun 2021 05:09:09 -0700 X-QCInternal: smtphost Received: from ironmsg02-blr.qualcomm.com ([10.86.208.131]) by ironmsg09-lv.qualcomm.com with ESMTP/TLS/AES256-SHA; 12 Jun 2021 05:09:08 -0700 X-QCInternal: smtphost Received: from rajeevny-linux.qualcomm.com ([10.204.66.121]) by ironmsg02-blr.qualcomm.com with ESMTP; 12 Jun 2021 17:38:24 +0530 Received: by rajeevny-linux.qualcomm.com (Postfix, from userid 2363605) id 36D9D21465; Sat, 12 Jun 2021 17:38:23 +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 Cc: Rajeev Nandan , linux-kernel@vger.kernel.org, thierry.reding@gmail.com, sam@ravnborg.org, robdclark@gmail.com, dianders@chromium.org, lyude@redhat.com, jani.nikula@intel.com, robh@kernel.org, laurent.pinchart@ideasonboard.com, a.hajda@samsung.com, daniel.thompson@linaro.org, hoegsberg@chromium.org, abhinavk@codeaurora.org, seanpaul@chromium.org, kalyan_t@codeaurora.org, mkrishn@codeaurora.org, lee.jones@linaro.org, jingoohan1@gmail.com, linux-fbdev@vger.kernel.org Subject: [v6 1/5] drm/panel: add basic DP AUX backlight support Date: Sat, 12 Jun 2021 17:37:58 +0530 Message-Id: <1623499682-2140-2-git-send-email-rajeevny@codeaurora.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1623499682-2140-1-git-send-email-rajeevny@codeaurora.org> References: <1623499682-2140-1-git-send-email-rajeevny@codeaurora.org> Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org Some panels support backlight control over DP AUX channel using VESA's standard backlight control interface. Using new DRM eDP backlight helpers, add support to create and register a backlight for those panels in drm_panel to simplify the panel drivers. The panel driver with access to "struct drm_dp_aux" can create and register a backlight device using following code snippet in its probe() function: err = drm_panel_dp_aux_backlight(panel, aux); if (err) return err; Then drm_panel will handle backlight_(enable|disable) calls similar to the case when drm_panel_of_backlight() is used. Currently, we are not supporting one feature where the source device can combine the backlight brightness levels set through DP AUX and the BL_PWM_DIM eDP connector pin. Since it's not required for the basic backlight controls, it can be added later. Signed-off-by: Rajeev Nandan Reviewed-by: Douglas Anderson Reviewed-by: Lyude Paul --- Changes in v5: - New Changes in v6: - Fixed ordering of memory allocation (Douglas) - Updated word wrapping in a comment (Douglas) drivers/gpu/drm/drm_panel.c | 108 ++++++++++++++++++++++++++++++++++++++++++++ include/drm/drm_panel.h | 15 ++++-- 2 files changed, 119 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c index f634371..9e65342 100644 --- a/drivers/gpu/drm/drm_panel.c +++ b/drivers/gpu/drm/drm_panel.c @@ -26,12 +26,20 @@ #include #include +#include #include #include static DEFINE_MUTEX(panel_lock); static LIST_HEAD(panel_list); +struct dp_aux_backlight { + struct backlight_device *base; + struct drm_dp_aux *aux; + struct drm_edp_backlight_info info; + bool enabled; +}; + /** * DOC: drm panel * @@ -342,6 +350,106 @@ int drm_panel_of_backlight(struct drm_panel *panel) return 0; } EXPORT_SYMBOL(drm_panel_of_backlight); + +static int dp_aux_backlight_update_status(struct backlight_device *bd) +{ + struct dp_aux_backlight *bl = bl_get_data(bd); + u16 brightness = backlight_get_brightness(bd); + int ret = 0; + + if (brightness > 0) { + if (!bl->enabled) { + drm_edp_backlight_enable(bl->aux, &bl->info, brightness); + bl->enabled = true; + return 0; + } + ret = drm_edp_backlight_set_level(bl->aux, &bl->info, brightness); + } else { + if (bl->enabled) { + drm_edp_backlight_disable(bl->aux, &bl->info); + bl->enabled = false; + } + } + + return ret; +} + +static const struct backlight_ops dp_aux_bl_ops = { + .update_status = dp_aux_backlight_update_status, +}; + +/** + * drm_panel_dp_aux_backlight - create and use DP AUX backlight + * @panel: DRM panel + * @aux: The DP AUX channel to use + * + * Use this function to create and handle backlight if your panel + * supports backlight control over DP AUX channel using DPCD + * registers as per VESA's standard backlight control interface. + * + * When the panel is enabled backlight will be enabled after a + * successful call to &drm_panel_funcs.enable() + * + * When the panel is disabled backlight will be disabled before the + * call to &drm_panel_funcs.disable(). + * + * A typical implementation for a panel driver supporting backlight + * control over DP AUX will call this function at probe time. + * Backlight will then be handled transparently without requiring + * any intervention from the driver. + * + * drm_panel_dp_aux_backlight() must be called after the call to drm_panel_init(). + * + * Return: 0 on success or a negative error code on failure. + */ +int drm_panel_dp_aux_backlight(struct drm_panel *panel, struct drm_dp_aux *aux) +{ + struct dp_aux_backlight *bl; + struct backlight_properties props = { 0 }; + u16 current_level; + u8 current_mode; + u8 edp_dpcd[EDP_DISPLAY_CTL_CAP_SIZE]; + int ret; + + if (!panel || !panel->dev || !aux) + return -EINVAL; + + ret = drm_dp_dpcd_read(aux, DP_EDP_DPCD_REV, edp_dpcd, + EDP_DISPLAY_CTL_CAP_SIZE); + if (ret < 0) + return ret; + + if (!drm_edp_backlight_supported(edp_dpcd)) { + DRM_DEV_INFO(panel->dev, "DP AUX backlight is not supported\n"); + return 0; + } + + bl = devm_kzalloc(panel->dev, sizeof(*bl), GFP_KERNEL); + if (!bl) + return -ENOMEM; + + bl->aux = aux; + + ret = drm_edp_backlight_init(aux, &bl->info, 0, edp_dpcd, + ¤t_level, ¤t_mode); + if (ret < 0) + return ret; + + props.type = BACKLIGHT_RAW; + props.brightness = current_level; + props.max_brightness = bl->info.max; + + bl->base = devm_backlight_device_register(panel->dev, "dp_aux_backlight", + panel->dev, bl, + &dp_aux_bl_ops, &props); + if (IS_ERR(bl->base)) + return PTR_ERR(bl->base); + + panel->backlight = bl->base; + + return 0; +} +EXPORT_SYMBOL(drm_panel_dp_aux_backlight); #endif MODULE_AUTHOR("Thierry Reding "); diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h index 33605c3..3ebfaa6 100644 --- a/include/drm/drm_panel.h +++ b/include/drm/drm_panel.h @@ -32,6 +32,7 @@ struct backlight_device; struct device_node; struct drm_connector; struct drm_device; +struct drm_dp_aux; struct drm_panel; struct display_timing; @@ -64,8 +65,8 @@ enum drm_panel_orientation; * the panel. This is the job of the .unprepare() function. * * Backlight can be handled automatically if configured using - * drm_panel_of_backlight(). Then the driver does not need to implement the - * functionality to enable/disable backlight. + * drm_panel_of_backlight() or drm_panel_dp_aux_backlight(). Then the driver + * does not need to implement the functionality to enable/disable backlight. */ struct drm_panel_funcs { /** @@ -144,8 +145,8 @@ struct drm_panel { * Backlight device, used to turn on backlight after the call * to enable(), and to turn off backlight before the call to * disable(). - * backlight is set by drm_panel_of_backlight() and drivers - * shall not assign it. + * backlight is set by drm_panel_of_backlight() or + * drm_panel_dp_aux_backlight() and drivers shall not assign it. */ struct backlight_device *backlight; @@ -208,11 +209,17 @@ static inline int of_drm_get_panel_orientation(const struct device_node *np, #if IS_ENABLED(CONFIG_DRM_PANEL) && (IS_BUILTIN(CONFIG_BACKLIGHT_CLASS_DEVICE) || \ (IS_MODULE(CONFIG_DRM) && IS_MODULE(CONFIG_BACKLIGHT_CLASS_DEVICE))) int drm_panel_of_backlight(struct drm_panel *panel); +int drm_panel_dp_aux_backlight(struct drm_panel *panel, struct drm_dp_aux *aux); #else static inline int drm_panel_of_backlight(struct drm_panel *panel) { return 0; } +static inline int drm_panel_dp_aux_backlight(struct drm_panel *panel, + struct drm_dp_aux *aux) +{ + return 0; +} #endif #endif