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([103.218.174.23]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2a2f3d6ec6bsm296003075ad.87.2025.12.30.05.02.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 30 Dec 2025 05:03:00 -0800 (PST) From: Sudarshan Shetty To: andersson@kernel.org, konradybcio@kernel.org Cc: robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Sudarshan Shetty Subject: [PATCH v10 3/5] backlight: gpio: add support for multiple GPIOs for backlight control Date: Tue, 30 Dec 2025 18:32:25 +0530 Message-Id: <20251230130227.3503590-4-tessolveupstream@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20251230130227.3503590-1-tessolveupstream@gmail.com> References: <20251230130227.3503590-1-tessolveupstream@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Extend the gpio-backlight driver to handle multiple GPIOs instead of a single one. This allows panels that require driving several enable pins to be controlled by the backlight framework. Signed-off-by: Sudarshan Shetty --- drivers/video/backlight/gpio_backlight.c | 61 +++++++++++++++++------- 1 file changed, 45 insertions(+), 16 deletions(-) diff --git a/drivers/video/backlight/gpio_backlight.c b/drivers/video/backlight/gpio_backlight.c index 728a546904b0..037e1c111e48 100644 --- a/drivers/video/backlight/gpio_backlight.c +++ b/drivers/video/backlight/gpio_backlight.c @@ -17,14 +17,18 @@ struct gpio_backlight { struct device *dev; - struct gpio_desc *gpiod; + struct gpio_desc **gpiods; + unsigned int num_gpios; }; static int gpio_backlight_update_status(struct backlight_device *bl) { struct gpio_backlight *gbl = bl_get_data(bl); + unsigned int i; + int br = backlight_get_brightness(bl); - gpiod_set_value_cansleep(gbl->gpiod, backlight_get_brightness(bl)); + for (i = 0; i < gbl->num_gpios; i++) + gpiod_set_value_cansleep(gbl->gpiods[i], br); return 0; } @@ -52,6 +56,7 @@ static int gpio_backlight_probe(struct platform_device *pdev) struct backlight_device *bl; struct gpio_backlight *gbl; int ret, init_brightness, def_value; + unsigned int i; gbl = devm_kzalloc(dev, sizeof(*gbl), GFP_KERNEL); if (gbl == NULL) @@ -62,10 +67,22 @@ static int gpio_backlight_probe(struct platform_device *pdev) def_value = device_property_read_bool(dev, "default-on"); - gbl->gpiod = devm_gpiod_get(dev, NULL, GPIOD_ASIS); - if (IS_ERR(gbl->gpiod)) - return dev_err_probe(dev, PTR_ERR(gbl->gpiod), - "The gpios parameter is missing or invalid\n"); + gbl->num_gpios = gpiod_count(dev, NULL); + if (gbl->num_gpios == 0) + return dev_err_probe(dev, -EINVAL, + "The gpios parameter is missing or invalid\n"); + gbl->gpiods = devm_kcalloc(dev, gbl->num_gpios, sizeof(*gbl->gpiods), + GFP_KERNEL); + if (!gbl->gpiods) + return -ENOMEM; + + for (i = 0; i < gbl->num_gpios; i++) { + gbl->gpiods[i] = + devm_gpiod_get_index(dev, NULL, i, GPIOD_ASIS); + if (IS_ERR(gbl->gpiods[i])) + return dev_err_probe(dev, PTR_ERR(gbl->gpiods[i]), + "Failed to get GPIO at index %u\n", i); + } memset(&props, 0, sizeof(props)); props.type = BACKLIGHT_RAW; @@ -78,22 +95,34 @@ static int gpio_backlight_probe(struct platform_device *pdev) } /* Set the initial power state */ - if (!of_node || !of_node->phandle) + if (!of_node || !of_node->phandle) { /* Not booted with device tree or no phandle link to the node */ bl->props.power = def_value ? BACKLIGHT_POWER_ON - : BACKLIGHT_POWER_OFF; - else if (gpiod_get_value_cansleep(gbl->gpiod) == 0) - bl->props.power = BACKLIGHT_POWER_OFF; - else - bl->props.power = BACKLIGHT_POWER_ON; + : BACKLIGHT_POWER_OFF; + } else { + bool all_high = true; + + for (i = 0; i < gbl->num_gpios; i++) { + if (gpiod_get_value_cansleep(gbl->gpiods[i]) != 0) { + all_high = false; + break; + } + } + + bl->props.power = + all_high ? BACKLIGHT_POWER_ON : BACKLIGHT_POWER_OFF; + } bl->props.brightness = 1; init_brightness = backlight_get_brightness(bl); - ret = gpiod_direction_output(gbl->gpiod, init_brightness); - if (ret) { - dev_err(dev, "failed to set initial brightness\n"); - return ret; + + for (i = 0; i < gbl->num_gpios; i++) { + ret = gpiod_direction_output(gbl->gpiods[i], init_brightness); + if (ret) + return dev_err_probe(dev, ret, + "failed to set gpio %u direction\n", + i); } platform_set_drvdata(pdev, bl); -- 2.34.1