From 42796d37da6ef4fd851dc6d5d0387baf7e2b0c3c Mon Sep 17 00:00:00 2001 From: eric miao Date: Mon, 14 Apr 2008 09:35:08 +0100 Subject: [ARM] pxa: add generic PWM backlight driver Patch mostly from Eric Miao, with minor edits by rmk to convert Eric's driver to a generic PWM-based backlight driver. Signed-off-by: eric miao Signed-off-by: Russell King --- drivers/video/backlight/pwm_bl.c | 160 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 160 insertions(+) create mode 100644 drivers/video/backlight/pwm_bl.c (limited to 'drivers/video/backlight/pwm_bl.c') diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c new file mode 100644 index 00000000000..9637f5e08cb --- /dev/null +++ b/drivers/video/backlight/pwm_bl.c @@ -0,0 +1,160 @@ +/* + * linux/drivers/video/backlight/pwm_bl.c + * + * simple PWM based backlight control, board code has to setup + * 1) pin configuration so PWM waveforms can output + * 2) platform_data casts to the PWM id (0/1/2/3 on PXA) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +struct pwm_bl_data { + struct pwm_device *pwm; + unsigned int period; +}; + +static int pwm_backlight_update_status(struct backlight_device *bl) +{ + struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev); + int brightness = bl->props.brightness; + int max = bl->props.max_brightness; + + if (bl->props.power != FB_BLANK_UNBLANK) + brightness = 0; + + if (bl->props.fb_blank != FB_BLANK_UNBLANK) + brightness = 0; + + if (brightness == 0) { + pwm_config(pb->pwm, 0, pb->period); + pwm_disable(pb->pwm); + } else { + pwm_config(pb->pwm, brightness * pb->period / max, pb->period); + pwm_enable(pb->pwm); + } + return 0; +} + +static int pwm_backlight_get_brightness(struct backlight_device *bl) +{ + return bl->props.brightness; +} + +static struct backlight_ops pwm_backlight_ops = { + .update_status = pwm_backlight_update_status, + .get_brightness = pwm_backlight_get_brightness, +}; + +static int pwm_backlight_probe(struct platform_device *pdev) +{ + struct platform_pwm_backlight_data *data = pdev->dev.platform_data; + struct backlight_device *bl; + struct pwm_bl_data *pb; + + if (!data) + return -EINVAL; + + pb = kzalloc(sizeof(*pb), GFP_KERNEL); + if (!pb) + return -ENOMEM; + + pb->period = data->pwm_period_ns; + + pb->pwm = pwm_request(data->pwm_id, "backlight"); + if (pb->pwm == NULL) { + dev_err(&pdev->dev, "unable to request PWM for backlight\n"); + kfree(pb); + return -EBUSY; + } + + bl = backlight_device_register(pdev->name, &pdev->dev, + pb, &pwm_backlight_ops); + if (IS_ERR(bl)) { + dev_err(&pdev->dev, "failed to register backlight\n"); + pwm_free(pb->pwm); + kfree(pb); + return PTR_ERR(bl); + } + + bl->props.max_brightness = data->max_brightness; + bl->props.brightness = data->dft_brightness; + backlight_update_status(bl); + + platform_set_drvdata(pdev, bl); + return 0; +} + +static int pwm_backlight_remove(struct platform_device *pdev) +{ + struct backlight_device *bl = platform_get_drvdata(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_free(pb->pwm); + kfree(pb); + return 0; +} + +#ifdef CONFIG_PM +static int pwm_backlight_suspend(struct platform_device *pdev, + pm_message_t state) +{ + struct backlight_device *bl = platform_get_drvdata(pdev); + struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev); + + pwm_config(pb->pwm, 0, pb->period); + pwm_disable(pb->pwm); + return 0; +} + +static int pwm_backlight_resume(struct platform_device *pdev) +{ + struct backlight_device *bl = platform_get_drvdata(pdev); + + backlight_update_status(bl); + return 0; +} +#else +#define pwm_backlight_suspend NULL +#define pwm_backlight_resume NULL +#endif + +static struct platform_driver pwm_backlight_driver = { + .driver = { + .name = "pwm-backlight", + .owner = THIS_MODULE, + }, + .probe = pwm_backlight_probe, + .remove = pwm_backlight_remove, + .suspend = pwm_backlight_suspend, + .resume = pwm_backlight_resume, +}; + +static int __init pwm_backlight_init(void) +{ + return platform_driver_register(&pwm_backlight_driver); +} +module_init(pwm_backlight_init); + +static void __exit pwm_backlight_exit(void) +{ + platform_driver_unregister(&pwm_backlight_driver); +} +module_exit(pwm_backlight_exit); + +MODULE_DESCRIPTION("PWM based Backlight Driver"); +MODULE_LICENSE("GPL"); -- cgit v1.2.3-70-g09d2 From 3b73125af69f93972625f4b655675f42ca4274eb Mon Sep 17 00:00:00 2001 From: Philipp Zabel Date: Thu, 22 May 2008 14:18:40 +0100 Subject: [ARM] 5044/1: pwm_bl: add init/notify/exit callbacks This allows platform code to manipulate GPIOs and brightness level as needed. Signed-off-by: Philipp Zabel Signed-off-by: Russell King --- drivers/video/backlight/pwm_bl.c | 39 ++++++++++++++++++++++++++++++++------- include/linux/pwm_backlight.h | 3 +++ 2 files changed, 35 insertions(+), 7 deletions(-) (limited to 'drivers/video/backlight/pwm_bl.c') diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c index 9637f5e08cb..8346dfc01cf 100644 --- a/drivers/video/backlight/pwm_bl.c +++ b/drivers/video/backlight/pwm_bl.c @@ -23,6 +23,7 @@ struct pwm_bl_data { struct pwm_device *pwm; unsigned int period; + int (*notify)(int brightness); }; static int pwm_backlight_update_status(struct backlight_device *bl) @@ -37,6 +38,9 @@ static int pwm_backlight_update_status(struct backlight_device *bl) if (bl->props.fb_blank != FB_BLANK_UNBLANK) brightness = 0; + if (pb->notify) + brightness = pb->notify(brightness); + if (brightness == 0) { pwm_config(pb->pwm, 0, pb->period); pwm_disable(pb->pwm); @@ -62,30 +66,39 @@ static int pwm_backlight_probe(struct platform_device *pdev) struct platform_pwm_backlight_data *data = pdev->dev.platform_data; struct backlight_device *bl; struct pwm_bl_data *pb; + int ret; if (!data) return -EINVAL; + if (data->init) { + ret = data->init(&pdev->dev); + if (ret < 0) + return ret; + } + pb = kzalloc(sizeof(*pb), GFP_KERNEL); - if (!pb) - return -ENOMEM; + if (!pb) { + ret = -ENOMEM; + goto err_alloc; + } pb->period = data->pwm_period_ns; + pb->notify = data->notify; pb->pwm = pwm_request(data->pwm_id, "backlight"); if (pb->pwm == NULL) { dev_err(&pdev->dev, "unable to request PWM for backlight\n"); - kfree(pb); - return -EBUSY; + ret = -EBUSY; + goto err_pwm; } bl = backlight_device_register(pdev->name, &pdev->dev, pb, &pwm_backlight_ops); if (IS_ERR(bl)) { dev_err(&pdev->dev, "failed to register backlight\n"); - pwm_free(pb->pwm); - kfree(pb); - return PTR_ERR(bl); + ret = PTR_ERR(bl); + goto err_bl; } bl->props.max_brightness = data->max_brightness; @@ -94,10 +107,20 @@ static int pwm_backlight_probe(struct platform_device *pdev) platform_set_drvdata(pdev, bl); return 0; + +err_bl: + pwm_free(pb->pwm); +err_pwm: + kfree(pb); +err_alloc: + if (data->exit) + data->exit(&pdev->dev); + return ret; } static int pwm_backlight_remove(struct platform_device *pdev) { + struct platform_pwm_backlight_data *data = pdev->dev.platform_data; struct backlight_device *bl = platform_get_drvdata(pdev); struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev); @@ -106,6 +129,8 @@ static int pwm_backlight_remove(struct platform_device *pdev) pwm_disable(pb->pwm); pwm_free(pb->pwm); kfree(pb); + if (data->exit) + data->exit(&pdev->dev); return 0; } diff --git a/include/linux/pwm_backlight.h b/include/linux/pwm_backlight.h index aeeffedbe82..7a9754c9677 100644 --- a/include/linux/pwm_backlight.h +++ b/include/linux/pwm_backlight.h @@ -9,6 +9,9 @@ struct platform_pwm_backlight_data { unsigned int max_brightness; unsigned int dft_brightness; unsigned int pwm_period_ns; + int (*init)(struct device *dev); + int (*notify)(int brightness); + void (*exit)(struct device *dev); }; #endif -- cgit v1.2.3-70-g09d2 From 43bda1a6d218744382547a2f8be3240d1c3a151b Mon Sep 17 00:00:00 2001 From: Ben Dooks Date: Tue, 1 Jul 2008 14:18:27 +0100 Subject: [ARM] 5141/1: PWM: pwm_request() should return an PTR_ERR() instead of NULL. Make the return of pwm_request() be more informative than just being NULL on error by using PTR_ERR() to respond with an approriate error. Signed-off-by: Ben Dooks Signed-off-by: Russell King --- arch/arm/mach-pxa/pwm.c | 16 +++++++++++----- drivers/video/backlight/pwm_bl.c | 4 ++-- 2 files changed, 13 insertions(+), 7 deletions(-) (limited to 'drivers/video/backlight/pwm_bl.c') diff --git a/arch/arm/mach-pxa/pwm.c b/arch/arm/mach-pxa/pwm.c index 7c86dd1d108..ce28cd9fed1 100644 --- a/arch/arm/mach-pxa/pwm.c +++ b/arch/arm/mach-pxa/pwm.c @@ -119,17 +119,23 @@ struct pwm_device *pwm_request(int pwm_id, const char *label) mutex_lock(&pwm_lock); list_for_each_entry(pwm, &pwm_list, node) { - if (pwm->pwm_id == pwm_id && pwm->use_count == 0) { - pwm->use_count++; - pwm->label = label; + if (pwm->pwm_id == pwm_id) { found = 1; break; } } - mutex_unlock(&pwm_lock); + if (found) { + if (pwm->use_count == 0) { + pwm->use_count++; + pwm->label = label; + } else + pwm = ERR_PTR(-EBUSY); + } else + pwm = ERR_PTR(-ENOENT); - return (found) ? pwm : NULL; + mutex_unlock(&pwm_lock); + return pwm; } EXPORT_SYMBOL(pwm_request); diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c index 8346dfc01cf..6338d0e2fe0 100644 --- a/drivers/video/backlight/pwm_bl.c +++ b/drivers/video/backlight/pwm_bl.c @@ -87,9 +87,9 @@ static int pwm_backlight_probe(struct platform_device *pdev) pb->notify = data->notify; pb->pwm = pwm_request(data->pwm_id, "backlight"); - if (pb->pwm == NULL) { + if (IS_ERR(pb->pwm)) { dev_err(&pdev->dev, "unable to request PWM for backlight\n"); - ret = -EBUSY; + ret = PTR_ERR(pb->pwm); goto err_pwm; } -- cgit v1.2.3-70-g09d2