From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753303Ab2HaLdT (ORCPT ); Fri, 31 Aug 2012 07:33:19 -0400 Received: from hqemgate04.nvidia.com ([216.228.121.35]:8823 "EHLO hqemgate04.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752246Ab2HaLdN (ORCPT ); Fri, 31 Aug 2012 07:33:13 -0400 X-PGP-Universal: processed; by hqnvupgp05.nvidia.com on Fri, 31 Aug 2012 04:32:32 -0700 From: Alexandre Courbot To: Stephen Warren , Thierry Reding , Simon Glass , Grant Likely , Rob Herring , Mark Brown , Anton Vorontsov , David Woodhouse , Arnd Bergmann CC: Leela Krishna Amudala , , , , , , , Alexandre Courbot Subject: [PATCH v5 2/4] pwm_backlight: use power sequences Date: Fri, 31 Aug 2012 20:34:04 +0900 Message-ID: <1346412846-17102-3-git-send-email-acourbot@nvidia.com> X-Mailer: git-send-email 1.7.12 In-Reply-To: <1346412846-17102-1-git-send-email-acourbot@nvidia.com> References: <1346412846-17102-1-git-send-email-acourbot@nvidia.com> X-NVConfidentiality: public MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Make use of the power sequences specified in the device tree or platform data to control how the backlight is powered on and off. Signed-off-by: Alexandre Courbot --- .../bindings/video/backlight/pwm-backlight.txt | 67 +++++++- drivers/video/backlight/Kconfig | 1 + drivers/video/backlight/pwm_bl.c | 179 +++++++++++++++------ include/linux/pwm_backlight.h | 15 +- 4 files changed, 208 insertions(+), 54 deletions(-) diff --git a/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt b/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt index 1e4fc72..873b993 100644 --- a/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt +++ b/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt @@ -2,7 +2,8 @@ pwm-backlight bindings Required properties: - compatible: "pwm-backlight" - - pwms: OF device-tree PWM specification (see PWM binding[0]) + - pwms: OF device-tree PWM specification (see PWM binding[0]). Exactly one PWM + must be specified - brightness-levels: Array of distinct brightness levels. Typically these are in the range from 0 to 255, but any range starting at 0 will do. The actual brightness level (PWM duty cycle) will be interpolated @@ -12,17 +13,73 @@ Required properties: array defined by the "brightness-levels" property) Optional properties: - - pwm-names: a list of names for the PWM devices specified in the - "pwms" property (see PWM binding[0]) + - pwm-names: name for the PWM device specified in the "pwms" property (see PWM + binding[0]). Necessary if power sequences are used + - power-sequences: Power sequences (see Power sequences[1]) used to bring the + backlight on and off. If this property is present, then two power + sequences named "power-on" and "power-off" must be defined to control how + the backlight is to be powered on and off. These sequences must reference + the PWM specified in the pwms property by its name, and can also reference + other resources supported by the power sequences mechanism [0]: Documentation/devicetree/bindings/pwm/pwm.txt +[1]: Documentation/devicetree/bindings/power_seq/power_seq.txt Example: backlight { compatible = "pwm-backlight"; - pwms = <&pwm 0 5000000>; - brightness-levels = <0 4 8 16 32 64 128 255>; default-brightness-level = <6>; + + /* resources used by the sequences */ + pwms = <&pwm 2 5000000>; + pwm-names = "backlight"; + power-supply = <&backlight_reg>; + + power-sequences { + power-on { + step0 { + type = "regulator"; + id = "power"; + enable; + }; + step1 { + type = "delay"; + delay_us = <10000>; + }; + step2 { + type = "pwm"; + id = "backlight"; + enable; + }; + step3 { + type = "gpio"; + number = <&gpio 28 0>; + enable; + }; + }; + + power-off { + step0 { + type = "gpio"; + number = <&gpio 28 0>; + disable; + }; + step1 { + type = "pwm"; + id = "backlight"; + disable; + }; + step2 { + type = "delay"; + delay_us = <10000>; + }; + step3 { + type = "regulator"; + id = "power"; + disable; + }; + }; + }; }; diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig index cf28276..6fb8aa3 100644 --- a/drivers/video/backlight/Kconfig +++ b/drivers/video/backlight/Kconfig @@ -246,6 +246,7 @@ config BACKLIGHT_CARILLO_RANCH config BACKLIGHT_PWM tristate "Generic PWM based Backlight Driver" depends on PWM + select POWER_SEQ help If you have a LCD backlight adjustable by PWM, say Y to enable this driver. diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c index 995f016..45d6edd 100644 --- a/drivers/video/backlight/pwm_bl.c +++ b/drivers/video/backlight/pwm_bl.c @@ -27,6 +27,12 @@ struct pwm_bl_data { unsigned int period; unsigned int lth_brightness; unsigned int *levels; + bool enabled; + bool use_power_seqs; + struct power_seq *power_on_seq; + struct power_seq *power_off_seq; + + /* Legacy callbacks */ int (*notify)(struct device *, int brightness); void (*notify_after)(struct device *, @@ -35,6 +41,49 @@ struct pwm_bl_data { void (*exit)(struct device *); }; +static void pwm_backlight_on(struct backlight_device *bl) +{ + struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev); + int ret; + + if (pb->enabled) + return; + + /* Legacy framework? */ + if (!pb->use_power_seqs) { + pwm_config(pb->pwm, 0, pb->period); + pwm_disable(pb->pwm); + return; + } + + ret = power_seq_run(pb->power_on_seq); + if (ret < 0) + dev_err(&bl->dev, "cannot run power on sequence\n"); + + pb->enabled = true; +} + +static void pwm_backlight_off(struct backlight_device *bl) +{ + struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev); + int ret; + + if (!pb->enabled) + return; + + /* Legacy framework? */ + if (!pb->use_power_seqs) { + pwm_enable(pb->pwm); + return; + } + + ret = power_seq_run(pb->power_off_seq); + if (ret < 0) + dev_err(&bl->dev, "cannot run power off sequence\n"); + + pb->enabled = false; +} + static int pwm_backlight_update_status(struct backlight_device *bl) { struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev); @@ -51,8 +100,7 @@ static int pwm_backlight_update_status(struct backlight_device *bl) brightness = pb->notify(pb->dev, brightness); if (brightness == 0) { - pwm_config(pb->pwm, 0, pb->period); - pwm_disable(pb->pwm); + pwm_backlight_off(bl); } else { int duty_cycle; @@ -66,7 +114,7 @@ static int pwm_backlight_update_status(struct backlight_device *bl) duty_cycle = pb->lth_brightness + (duty_cycle * (pb->period - pb->lth_brightness) / max); pwm_config(pb->pwm, duty_cycle, pb->period); - pwm_enable(pb->pwm); + pwm_backlight_on(bl); } if (pb->notify_after) @@ -145,11 +193,10 @@ 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. - */ + /* parse power sequences and extract those we will use */ + data->power_seqs = devm_of_parse_power_seq_set(dev); + if (IS_ERR(data->power_seqs)) + return PTR_ERR(data->power_seqs); return 0; } @@ -172,33 +219,96 @@ static int pwm_backlight_probe(struct platform_device *pdev) { struct platform_pwm_backlight_data *data = pdev->dev.platform_data; struct platform_pwm_backlight_data defdata; + struct power_seq_resource *res; struct backlight_properties props; struct backlight_device *bl; struct pwm_bl_data *pb; + bool use_dt = false; 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; + } + + /* using new interface or device tree */ if (!data) { + /* build platform data from device tree */ ret = pwm_backlight_parse_dt(&pdev->dev, &defdata); - if (ret < 0) { + if (ret == -EPROBE_DEFER) { + return ret; + } else if (ret < 0) { dev_err(&pdev->dev, "failed to find platform data\n"); return ret; } - data = &defdata; + use_dt = true; + } + + /* using legacy interface? */ + if (!data->power_seqs) { + pb->pwm = devm_pwm_get(&pdev->dev, NULL); + if (IS_ERR(pb->pwm)) { + dev_err(&pdev->dev, + "unable to request PWM, trying legacy API\n"); + + pb->pwm = pwm_request(data->pwm_id, "pwm-backlight"); + if (IS_ERR(pb->pwm)) { + dev_err(&pdev->dev, + "unable to request legacy PWM\n"); + return PTR_ERR(pb->pwm); + } + } + + /* + * The DT case will set the pwm_period_ns field to 0 and store + * the period, parsed from the DT, in the PWM device. For the + * non-DT case, set the period from platform data. + */ + if (data->pwm_period_ns > 0) + pwm_set_period(pb->pwm, data->pwm_period_ns); + } else { + /* build power sequences from platform data */ + struct power_seq_set *seqs; + + seqs = devm_power_seq_set_build(&pdev->dev, data->power_seqs); + if (IS_ERR(seqs)) + return PTR_ERR(seqs); + + if (use_dt) + devm_platform_power_seq_set_free(&pdev->dev, + data->power_seqs); + + pb->power_on_seq = power_seq_lookup(seqs, "power-on"); + pb->power_off_seq = power_seq_lookup(seqs, "power-off"); + + /* we must have exactly one PWM for this driver */ + power_seq_for_each_resource(res, seqs) { + if (res->pdata->type != POWER_SEQ_PWM) + continue; + if (pb->pwm) { + dev_err(&pdev->dev, "more than one PWM used\n"); + return -EINVAL; + } + /* keep the pwm at hand */ + pb->pwm = res->pwm; + } + + pb->use_power_seqs = true; } if (data->init) { ret = data->init(&pdev->dev); if (ret < 0) - return ret; + goto err; } - 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; + /* from here we should have a PWM */ + if (!pb->pwm) { + dev_err(&pdev->dev, "no PWM defined!\n"); + return -EINVAL; } if (data->levels) { @@ -213,28 +323,6 @@ static int pwm_backlight_probe(struct platform_device *pdev) pb->exit = data->exit; pb->dev = &pdev->dev; - pb->pwm = pwm_get(&pdev->dev, NULL); - if (IS_ERR(pb->pwm)) { - dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n"); - - pb->pwm = pwm_request(data->pwm_id, "pwm-backlight"); - if (IS_ERR(pb->pwm)) { - dev_err(&pdev->dev, "unable to request legacy PWM\n"); - ret = PTR_ERR(pb->pwm); - goto err_alloc; - } - } - - dev_dbg(&pdev->dev, "got pwm for backlight\n"); - - /* - * The DT case will set the pwm_period_ns field to 0 and store the - * period, parsed from the DT, in the PWM device. For the non-DT case, - * set the period from platform data. - */ - if (data->pwm_period_ns > 0) - pwm_set_period(pb->pwm, data->pwm_period_ns); - pb->period = pwm_get_period(pb->pwm); pb->lth_brightness = data->lth_brightness * (pb->period / max); @@ -246,18 +334,17 @@ static int pwm_backlight_probe(struct platform_device *pdev) if (IS_ERR(bl)) { dev_err(&pdev->dev, "failed to register backlight\n"); ret = PTR_ERR(bl); - goto err_bl; + goto err; } bl->props.brightness = data->dft_brightness; backlight_update_status(bl); platform_set_drvdata(pdev, bl); + return 0; -err_bl: - pwm_put(pb->pwm); -err_alloc: +err: if (data->exit) data->exit(&pdev->dev); return ret; @@ -269,9 +356,8 @@ static int pwm_backlight_remove(struct platform_device *pdev) struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev); backlight_device_unregister(bl); - pwm_config(pb->pwm, 0, pb->period); - pwm_disable(pb->pwm); - pwm_put(pb->pwm); + pwm_backlight_off(bl); + if (pb->exit) pb->exit(&pdev->dev); return 0; @@ -285,8 +371,7 @@ static int pwm_backlight_suspend(struct device *dev) if (pb->notify) pb->notify(pb->dev, 0); - pwm_config(pb->pwm, 0, pb->period); - pwm_disable(pb->pwm); + pwm_backlight_off(bl); if (pb->notify_after) pb->notify_after(pb->dev, 0); return 0; diff --git a/include/linux/pwm_backlight.h b/include/linux/pwm_backlight.h index 56f4a86..70d22f2 100644 --- a/include/linux/pwm_backlight.h +++ b/include/linux/pwm_backlight.h @@ -5,14 +5,25 @@ #define __LINUX_PWM_BACKLIGHT_H #include +#include struct platform_pwm_backlight_data { - int pwm_id; unsigned int max_brightness; unsigned int dft_brightness; unsigned int lth_brightness; - unsigned int pwm_period_ns; unsigned int *levels; + /* + * New interface using power sequences + */ + struct platform_power_seq_set *power_seqs; + /* + * Legacy interface - use power sequences instead! + * + * pwm_id and pwm_period_ns need only be specified + * if get_pwm(dev, NULL) would return NULL. + */ + int pwm_id; + unsigned int pwm_period_ns; int (*init)(struct device *dev); int (*notify)(struct device *dev, int brightness); void (*notify_after)(struct device *dev, int brightness); -- 1.7.12