Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933119Ab3ICU3J (ORCPT ); Tue, 3 Sep 2013 16:29:09 -0400 Received: from smtp1.newsguy.com ([74.209.136.71]:59597 "EHLO smtp1.newsguy.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932929Ab3ICU3G (ORCPT ); Tue, 3 Sep 2013 16:29:06 -0400 X-Greylist: delayed 3658 seconds by postgrey-1.27 at vger.kernel.org; Tue, 03 Sep 2013 16:29:05 EDT From: Mike Dunn To: thierry.reding@gmail.com Cc: Mike Dunn , Richard Purdie , Jingoo Han , Jean-Christophe Plagniol-Villard , Tomi Valkeinen , Grant Likely , Rob Herring , linux-pwm@vger.kernel.org, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, Robert Jarzmik , Marek Vasut Subject: [PATCH] pwm-backlight: add support for device tree gpio control Date: Tue, 3 Sep 2013 12:26:12 -0700 Message-Id: <1378236372-15711-1-git-send-email-mikedunn@newsguy.com> X-Mailer: git-send-email 1.8.1.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7925 Lines: 261 This patch adds support for controlling an arbitrary number of gpios to the pwm-backlight driver. This was left as a TODO when initial device tree support was added by Thierry a while back. This functionality replaces the callbacks that are passed in the platform data for non-DT cases. Users can avail themselves of this feature by adding a 'gpios' property to the 'backlight' node. When the update_status() callback in backlight_ops runs, the gpios listed in the property are asserted/deasserted if the specified brightness is non-zero/zero. Tested on a pxa270-based Palm Treo 680. Signed-off-by: Mike Dunn --- Thanks for looking! .../bindings/video/backlight/pwm-backlight.txt | 4 + drivers/video/backlight/pwm_bl.c | 128 ++++++++++++++++++--- 2 files changed, 113 insertions(+), 19 deletions(-) diff --git a/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt b/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt index 1e4fc72..4583e68 100644 --- a/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt +++ b/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt @@ -14,6 +14,9 @@ Required properties: Optional properties: - pwm-names: a list of names for the PWM devices specified in the "pwms" property (see PWM binding[0]) + - gpios: An arbitrary number of gpios that must be asserted when the + backlight is on, and de-asserted when off. They will be asserted + in the order they appear, and de-asserted in reverse order. [0]: Documentation/devicetree/bindings/pwm/pwm.txt @@ -25,4 +28,5 @@ Example: brightness-levels = <0 4 8 16 32 64 128 255>; default-brightness-level = <6>; + gpios = <&gpio 77 0>, <&gpio 25 1>; /* gpio 25 is active low */ }; diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c index 1fea627..1e2ab52 100644 --- a/drivers/video/backlight/pwm_bl.c +++ b/drivers/video/backlight/pwm_bl.c @@ -20,6 +20,12 @@ #include #include #include +#include + +struct pwm_bl_gpio { + unsigned int gpio; + enum of_gpio_flags flags; +}; struct pwm_bl_data { struct pwm_device *pwm; @@ -27,6 +33,8 @@ struct pwm_bl_data { unsigned int period; unsigned int lth_brightness; unsigned int *levels; + unsigned int num_gpios; + struct pwm_bl_gpio *gpios; int (*notify)(struct device *, int brightness); void (*notify_after)(struct device *, @@ -94,14 +102,77 @@ static const struct backlight_ops pwm_backlight_ops = { }; #ifdef CONFIG_OF +static int pwm_backlight_dt_notify(struct device *dev, int brightness) +{ + struct backlight_device *bl = dev_get_drvdata(dev); + struct pwm_bl_data *pb = bl_get_data(bl); + int i; + + if (brightness) { + for (i = 0; i < pb->num_gpios; i++) { + if (pb->gpios[i].flags == OF_GPIO_ACTIVE_LOW) + gpio_set_value(pb->gpios[i].gpio, 0); + else + gpio_set_value(pb->gpios[i].gpio, 1); + } + return 0; + } + + /* de-assert gpios in reverse order, in case this is important */ + for (i = pb->num_gpios - 1; i >= 0; i--) { + if (pb->gpios[i].flags == OF_GPIO_ACTIVE_LOW) + gpio_set_value(pb->gpios[i].gpio, 1); + else + gpio_set_value(pb->gpios[i].gpio, 0); + } + return 0; +} + +static void pwm_backlight_dt_exit(struct pwm_bl_data *pb) +{ + int i; + + for (i = 0; i < pb->num_gpios; i++) + gpio_free(pb->gpios[i].gpio); +} + +static int pwm_backlight_dt_init(struct device *dev, struct pwm_bl_data *pb) +{ + int i, j, ret; + + /* request gpios and drive in the inactive state */ + for (i = 0; i < pb->num_gpios; i++) { + char gpio_name[32]; + unsigned long flags; + if (pb->gpios[i].flags == OF_GPIO_ACTIVE_LOW) + flags = GPIOF_OUT_INIT_LOW; + else + flags = GPIOF_OUT_INIT_HIGH; + snprintf(gpio_name, 32, "%s.%d", dev_name(dev), i); + ret = gpio_request_one(pb->gpios[i].gpio, flags, gpio_name); + if (ret) { + dev_err(dev, "gpio #%d request failed\n", i); + goto gpio_err; + } + } + return 0; + + gpio_err: + for (j = 0; j < i; j++) + gpio_free(pb->gpios[j].gpio); + return ret; +} + static int pwm_backlight_parse_dt(struct device *dev, - struct platform_pwm_backlight_data *data) + struct platform_pwm_backlight_data *data, + struct pwm_bl_data *pb) { struct device_node *node = dev->of_node; struct property *prop; int length; u32 value; - int ret; + int ret, i, num_gpios; + size_t gpiosize; if (!node) return -ENODEV; @@ -138,13 +209,29 @@ static int pwm_backlight_parse_dt(struct device *dev, data->max_brightness--; } - /* - * TODO: Most users of this driver use a number of GPIOs to control - * backlight power. Support for specifying these needs to be - * added. - */ + /* read gpios from DT property */ + num_gpios = of_gpio_count(node); + if (num_gpios == -ENOENT) + return 0; /* no 'gpios' property present */ + if (num_gpios < 0) { + dev_err(dev, "invalid DT node: gpios\n"); + return -EINVAL; + } + gpiosize = sizeof(struct pwm_bl_gpio) * num_gpios; + pb->gpios = devm_kzalloc(dev, gpiosize, GFP_KERNEL); + if (!pb->gpios) + return -ENOMEM; + for (i = 0; i < num_gpios; i++) { + int gpio; + enum of_gpio_flags flags; + gpio = of_get_gpio_flags(node, i, &flags); + pb->gpios[i].gpio = (unsigned int)gpio; + pb->gpios[i].flags = flags; + } + pb->num_gpios = (unsigned int)num_gpios; + pb->notify = pwm_backlight_dt_notify; - return 0; + return pwm_backlight_dt_init(dev, pb); } static struct of_device_id pwm_backlight_of_match[] = { @@ -155,10 +242,12 @@ static struct of_device_id pwm_backlight_of_match[] = { MODULE_DEVICE_TABLE(of, pwm_backlight_of_match); #else static int pwm_backlight_parse_dt(struct device *dev, - struct platform_pwm_backlight_data *data) + struct platform_pwm_backlight_data *data, + struct pwm_bl_data *pb) { return -ENODEV; } +static void pwm_backlight_dt_exit(struct pwm_bl_data *pb) {} #endif static int pwm_backlight_probe(struct platform_device *pdev) @@ -171,8 +260,14 @@ static int pwm_backlight_probe(struct platform_device *pdev) unsigned int max; int ret; + pb = devm_kzalloc(&pdev->dev, sizeof(*pb), GFP_KERNEL); + if (!pb) { + dev_err(&pdev->dev, "no memory for state\n"); + return -ENOMEM; + } + if (!data) { - ret = pwm_backlight_parse_dt(&pdev->dev, &defdata); + ret = pwm_backlight_parse_dt(&pdev->dev, &defdata, pb); if (ret < 0) { dev_err(&pdev->dev, "failed to find platform data\n"); return ret; @@ -187,20 +282,14 @@ static int pwm_backlight_probe(struct platform_device *pdev) return ret; } - pb = devm_kzalloc(&pdev->dev, sizeof(*pb), GFP_KERNEL); - if (!pb) { - dev_err(&pdev->dev, "no memory for state\n"); - ret = -ENOMEM; - goto err_alloc; - } - if (data->levels) { max = data->levels[data->max_brightness]; pb->levels = data->levels; } else max = data->max_brightness; - pb->notify = data->notify; + if (pb->notify == NULL) /* not using DT and its built-in notify() */ + pb->notify = data->notify; pb->notify_after = data->notify_after; pb->check_fb = data->check_fb; pb->exit = data->exit; @@ -250,9 +339,9 @@ static int pwm_backlight_probe(struct platform_device *pdev) } bl->props.brightness = data->dft_brightness; + platform_set_drvdata(pdev, bl); backlight_update_status(bl); - platform_set_drvdata(pdev, bl); return 0; err_alloc: @@ -271,6 +360,7 @@ static int pwm_backlight_remove(struct platform_device *pdev) pwm_disable(pb->pwm); if (pb->exit) pb->exit(&pdev->dev); + pwm_backlight_dt_exit(pb); return 0; } -- 1.8.1.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/