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Sun, 15 Nov 2026 00:58:40 -0800 (PST) Received: from xeon ([188.163.112.62]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-c5095a5c4b7sm287613266b.1.2026.11.15.00.58.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 15 Nov 2026 00:58:39 -0800 (PST) From: Svyatoslav Ryhel To: Lee Jones , Pavel Machek , Griffin Kroah-Hartman , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Liam Girdwood , Mark Brown , Daniel Thompson , Jingoo Han , Svyatoslav Ryhel Cc: linux-leds@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, mfd@lists.linux.dev, dri-devel@lists.freedesktop.org Subject: [PATCH v7 2/4] backlight: aat2870: Derive brightness steps from max current Date: Sun, 15 Nov 2026 10:58:23 +0200 Message-ID: <20261115085826.89641-3-clamor95@gmail.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261115085826.89641-1-clamor95@gmail.com> References: <20261115085826.89641-1-clamor95@gmail.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The AAT2870 allows only 32 steps of brightness, with this amount defined by the maximum supported current. Remove the need for max_brightness by calculating the allowed number of steps from the maximum current. Reviewed-by: Daniel Thompson (RISCstar) Reviewed-by: Griffin Kroah-Hartman Signed-off-by: Svyatoslav Ryhel --- drivers/video/backlight/aat2870_bl.c | 35 +++++++++------------------- 1 file changed, 11 insertions(+), 24 deletions(-) diff --git a/drivers/video/backlight/aat2870_bl.c b/drivers/video/backlight/aat2870_bl.c index 5af36d3784f11..ea955b55bca18 100644 --- a/drivers/video/backlight/aat2870_bl.c +++ b/drivers/video/backlight/aat2870_bl.c @@ -20,22 +20,9 @@ struct aat2870_bl_driver_data { struct backlight_device *bd; int channels; - int max_current; int brightness; /* current brightness */ }; -static inline int aat2870_brightness(struct aat2870_bl_driver_data *aat2870_bl, - int brightness) -{ - struct backlight_device *bd = aat2870_bl->bd; - int val; - - val = brightness * (aat2870_bl->max_current - 1); - val /= bd->props.max_brightness; - - return val; -} - static inline int aat2870_bl_enable(struct aat2870_bl_driver_data *aat2870_bl) { struct aat2870_data *aat2870 @@ -69,10 +56,11 @@ static int aat2870_bl_update_status(struct backlight_device *bd) dev_dbg(&bd->dev, "brightness=%d, power=%d, state=%d\n", bd->props.brightness, bd->props.power, bd->props.state); - ret = aat2870->write(aat2870, AAT2870_BLM, - (u8)aat2870_brightness(aat2870_bl, brightness)); - if (ret < 0) - return ret; + if (brightness) { + ret = aat2870->write(aat2870, AAT2870_BLM, (u8)brightness - 1); + if (ret < 0) + return ret; + } if (brightness == 0) { ret = aat2870_bl_disable(aat2870_bl); @@ -143,15 +131,14 @@ static int aat2870_bl_probe(struct platform_device *pdev) else aat2870_bl->channels = AAT2870_BL_CH_ALL; + /* + * The maximum number of brightness steps is determined by the max current. + * The aat2870_current enum maps directly to the allowed brightness steps. + */ if (pdata->max_current > 0) - aat2870_bl->max_current = pdata->max_current; - else - aat2870_bl->max_current = AAT2870_CURRENT_27_9; - - if (pdata->max_brightness > 0) - bd->props.max_brightness = pdata->max_brightness; + bd->props.max_brightness = pdata->max_current; else - bd->props.max_brightness = 255; + bd->props.max_brightness = AAT2870_CURRENT_27_9; aat2870_bl->brightness = 0; bd->props.power = BACKLIGHT_POWER_ON; -- 2.53.0