Re: [PWM 04/10] Implements PWM-based LED control

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On Fri, Oct 01, 2010 at 10:17:45AM -0500, Bill Gatliff wrote:
> Signed-off-by: Bill Gatliff <bgat@xxxxxxxxxxxxxxx>

Ditto on comment and patch title

> ---
>  drivers/leds/Kconfig        |   19 +++-
>  drivers/leds/leds-pwm.c     |  224 +++++++++++++++++++++++-------------------
>  include/linux/pwm/pwm-led.h |   33 +++++++
>  3 files changed, 169 insertions(+), 107 deletions(-)
>  create mode 100644 include/linux/pwm/pwm-led.h
> 
> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
> index e411262..3af2cde 100644
> --- a/drivers/leds/Kconfig
> +++ b/drivers/leds/Kconfig
> @@ -26,12 +26,19 @@ config LEDS_88PM860X
>  	  This option enables support for on-chip LED drivers found on Marvell
>  	  Semiconductor 88PM8606 PMIC.
>  
> -config LEDS_ATMEL_PWM
> -	tristate "LED Support using Atmel PWM outputs"
> -	depends on ATMEL_PWM
> -	help
> -	  This option enables support for LEDs driven using outputs
> -	  of the dedicated PWM controller found on newer Atmel SOCs.
> +config LEDS_PWM
> +       tristate "Support for LEDs connected to Generic PWM channels"
> +       depends on LEDS_CLASS && GENERIC_PWM
> +       help
> +         Enables support for LEDs connected to PWM devices that

Inconsistent whitespace indentation

> +	 conform to the Generic PWM API.  This API allows drivers
> +	 to adjust the brightness of the LED by varying the duty
> +	 cycle of the signal at the PWM channel output, using PWM API
> +	 commands, rather than merely turning them on and off.
> +
> +	 If your platform has devices with drivers that implement
> +	 the Generic PWM API, and those devices have outputs that
> +	 are connected to LEDs, then you probably want to say 'Y' here.
>  
>  config LEDS_LOCOMO
>  	tristate "LED Support for Locomo device"
> diff --git a/drivers/leds/leds-pwm.c b/drivers/leds/leds-pwm.c
> index da3fa8d..ab064ac 100644
> --- a/drivers/leds/leds-pwm.c
> +++ b/drivers/leds/leds-pwm.c
> @@ -1,153 +1,175 @@
>  /*
> - * linux/drivers/leds-pwm.c
> + * drivers/leds/leds-pwm.c
>   *
> - * simple PWM based LED control
> + * Copyright (C) 2010 Bill Gatliff <bgat@xxxxxxxxxxxxxxx>
> + * Copyright (C) 2009 Loutao Fu, Pengutronix <l.fu@xxxxxxxxxxxxxx>
>   *
> - * Copyright 2009 Luotao Fu @ Pengutronix (l.fu@xxxxxxxxxxxxxx)
> + * Based on leds-gpio.c by Raphael Assenat <raph@xxxxxx>
>   *
> - * based on leds-gpio.c by Raphael Assenat <raph@xxxxxx>
> - *
> - * 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
> + * This program is Free Software.  You may redistribute and/or modify
> + * it under the terms of the GNU General Public License version 2, as
>   * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful, but
> + * WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
> + * USA
>   */
> -
> -#include <linux/module.h>
>  #include <linux/kernel.h>
> -#include <linux/init.h>
>  #include <linux/platform_device.h>
> -#include <linux/fb.h>
> -#include <linux/leds.h>
> -#include <linux/err.h>
> -#include <linux/pwm.h>
> -#include <linux/leds_pwm.h>
>  #include <linux/slab.h>
> -
> -struct led_pwm_data {
> -	struct led_classdev	cdev;
> -	struct pwm_device	*pwm;
> -	unsigned int 		active_low;
> -	unsigned int		period;
> +#include <linux/leds.h>
> +#include <linux/io.h>
> +#include <linux/pwm/pwm.h>
> +#include <linux/pwm/pwm-led.h>
> +
> +struct led_pwm {
> +	struct led_classdev	led;
> +	struct pwm_channel	*pwm;
> +	int percent;
>  };

Looks to be gratuitous modification.  Changing the name of the
structure (led_pwm_data --> led_pwm) and changing cdev --> led makes
this diff very large for no good reason.  If you really want to change
the names, then do it in a separate cleanup patch without functional
changes.

>  
> -static void led_pwm_set(struct led_classdev *led_cdev,
> -	enum led_brightness brightness)

Ditto here.  Reformatting and renaming the function name just makes
the patch hard to review.  Please repost without the unnecessary
rework (or at least split into a separate patch).

> +static inline struct led_pwm *to_led_pwm(const struct led_classdev *c)
> +{
> +	return container_of(c, struct led_pwm, led);
> +}
> +
> +static void
> +led_pwm_brightness_set(struct led_classdev *c,
> +		       enum led_brightness b)
> +{
> +	struct led_pwm *led = to_led_pwm(c);
> +	int percent;
> +
> +	percent = (b * 100) / (LED_FULL - LED_OFF);
> +	led->percent = percent;
> +	pwm_set_duty_percent(led->pwm, percent);
> +}
> +
> +static enum led_brightness
> +led_pwm_brightness_get(struct led_classdev *c)
>  {
> -	struct led_pwm_data *led_dat =
> -		container_of(led_cdev, struct led_pwm_data, cdev);
> -	unsigned int max = led_dat->cdev.max_brightness;
> -	unsigned int period =  led_dat->period;
> -
> -	if (brightness == 0) {
> -		pwm_config(led_dat->pwm, 0, period);
> -		pwm_disable(led_dat->pwm);
> -	} else {
> -		pwm_config(led_dat->pwm, brightness * period / max, period);
> -		pwm_enable(led_dat->pwm);
> +	struct led_pwm *led = to_led_pwm(c);
> +	return led->percent;
> +}
> +
> +static int
> +led_pwm_blink_set(struct led_classdev *c,
> +		  unsigned long *on_ms,
> +		  unsigned long *off_ms)
> +{
> +	struct led_pwm *led = to_led_pwm(c);
> +	struct pwm_channel_config cfg;
> +
> +	if (*on_ms == 0 && *off_ms == 0) {
> +		*on_ms = 1000UL;
> +		*off_ms = 1000UL;
>  	}
> +
> +	cfg.config_mask = PWM_CONFIG_DUTY_NS
> +		| PWM_CONFIG_PERIOD_NS;
> +
> +	cfg.duty_ns = *on_ms * 1000000UL;
> +	cfg.period_ns = (*on_ms + *off_ms) * 1000000UL;
> +
> +	return pwm_config(led->pwm, &cfg);
>  }
>  
> -static int led_pwm_probe(struct platform_device *pdev)
> +static int __devinit
> +led_pwm_probe(struct platform_device *pdev)
>  {
> -	struct led_pwm_platform_data *pdata = pdev->dev.platform_data;
> -	struct led_pwm *cur_led;
> -	struct led_pwm_data *leds_data, *led_dat;
> -	int i, ret = 0;
> +	struct pwm_led_platform_data *pdata = pdev->dev.platform_data;
> +	struct led_pwm *led;
> +	int ret;
>  
> -	if (!pdata)
> -		return -EBUSY;
> +	if (!pdata || !pdata->led_info)
> +		return -EINVAL;
>  
> -	leds_data = kzalloc(sizeof(struct led_pwm_data) * pdata->num_leds,
> -				GFP_KERNEL);
> -	if (!leds_data)
> +	led = kzalloc(sizeof(*led), GFP_KERNEL);
> +	if (!led)
>  		return -ENOMEM;
>  
> -	for (i = 0; i < pdata->num_leds; i++) {
> -		cur_led = &pdata->leds[i];
> -		led_dat = &leds_data[i];
> -
> -		led_dat->pwm = pwm_request(cur_led->pwm_id,
> -				cur_led->name);
> -		if (IS_ERR(led_dat->pwm)) {
> -			dev_err(&pdev->dev, "unable to request PWM %d\n",
> -					cur_led->pwm_id);
> -			goto err;
> -		}
> -
> -		led_dat->cdev.name = cur_led->name;
> -		led_dat->cdev.default_trigger = cur_led->default_trigger;
> -		led_dat->active_low = cur_led->active_low;
> -		led_dat->period = cur_led->pwm_period_ns;
> -		led_dat->cdev.brightness_set = led_pwm_set;
> -		led_dat->cdev.brightness = LED_OFF;
> -		led_dat->cdev.max_brightness = cur_led->max_brightness;
> -		led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
> -
> -		ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
> -		if (ret < 0) {
> -			pwm_free(led_dat->pwm);
> -			goto err;
> -		}
> +	led->pwm = pwm_request(pdata->bus_id, pdata->chan,
> +			       pdata->led_info->name);
> +	if (!led->pwm) {
> +		ret = -EINVAL;
> +		goto err_pwm_request;
>  	}
>  
> -	platform_set_drvdata(pdev, leds_data);
> +	platform_set_drvdata(pdev, led);
>  
> -	return 0;
> +	led->led.name = pdata->led_info->name;
> +	led->led.default_trigger = pdata->led_info->default_trigger;
> +	led->led.brightness_set = led_pwm_brightness_set;
> +	led->led.brightness_get = led_pwm_brightness_get;
> +	led->led.blink_set = led_pwm_blink_set;
> +	led->led.brightness = LED_OFF;
>  
> -err:
> -	if (i > 0) {
> -		for (i = i - 1; i >= 0; i--) {
> -			led_classdev_unregister(&leds_data[i].cdev);
> -			pwm_free(leds_data[i].pwm);
> -		}
> -	}
> +	ret = pwm_config(led->pwm, pdata->config);
> +	if (ret)
> +		goto err_pwm_config;
> +	pwm_start(led->pwm);
> +
> +	ret = led_classdev_register(&pdev->dev, &led->led);
> +	if (ret < 0)
> +		goto err_classdev_register;
>  
> -	kfree(leds_data);
> +	return 0;
> +
> +err_classdev_register:
> +	pwm_stop(led->pwm);
> +err_pwm_config:
> +	pwm_release(led->pwm);
> +err_pwm_request:
> +	kfree(led);
>  
>  	return ret;
>  }
>  
> -static int __devexit led_pwm_remove(struct platform_device *pdev)
> +static int __devexit
> +led_pwm_remove(struct platform_device *pdev)
>  {
> -	int i;
> -	struct led_pwm_platform_data *pdata = pdev->dev.platform_data;
> -	struct led_pwm_data *leds_data;
> +	struct led_pwm *led = platform_get_drvdata(pdev);
>  
> -	leds_data = platform_get_drvdata(pdev);
> +	led_classdev_unregister(&led->led);
>  
> -	for (i = 0; i < pdata->num_leds; i++) {
> -		led_classdev_unregister(&leds_data[i].cdev);
> -		pwm_free(leds_data[i].pwm);
> +	if (led->pwm) {
> +		pwm_stop(led->pwm);
> +		pwm_release(led->pwm);
>  	}
>  
> -	kfree(leds_data);
> +	kfree(led);
>  
>  	return 0;
>  }
>  
>  static struct platform_driver led_pwm_driver = {
> -	.probe		= led_pwm_probe,
> -	.remove		= __devexit_p(led_pwm_remove),
> -	.driver		= {
> -		.name	= "leds_pwm",
> -		.owner	= THIS_MODULE,
> +	.driver = {
> +		.name =		"leds-pwm",
> +		.owner =	THIS_MODULE,
>  	},
> +	.probe = led_pwm_probe,
> +	.remove = led_pwm_remove,
>  };
>  
> -static int __init led_pwm_init(void)
> +static int __init led_pwm_modinit(void)
>  {
>  	return platform_driver_register(&led_pwm_driver);
>  }
> +module_init(led_pwm_modinit);
>  
> -static void __exit led_pwm_exit(void)
> +static void __exit led_pwm_modexit(void)
>  {
>  	platform_driver_unregister(&led_pwm_driver);
>  }
> +module_exit(led_pwm_modexit);
>  
> -module_init(led_pwm_init);
> -module_exit(led_pwm_exit);
> -
> -MODULE_AUTHOR("Luotao Fu <l.fu@xxxxxxxxxxxxxx>");
> -MODULE_DESCRIPTION("PWM LED driver for PXA");
> +MODULE_AUTHOR("Bill Gatliff <bgat@xxxxxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("Driver for LEDs with PWM-controlled brightness");
>  MODULE_LICENSE("GPL");
>  MODULE_ALIAS("platform:leds-pwm");
> diff --git a/include/linux/pwm/pwm-led.h b/include/linux/pwm/pwm-led.h
> new file mode 100644
> index 0000000..8ffeecc
> --- /dev/null
> +++ b/include/linux/pwm/pwm-led.h
> @@ -0,0 +1,33 @@
> +/*
> + * include/linux/pwm-led.h
> + *
> + * Copyright (C) 2008 Bill Gatliff <bgat@xxxxxxxxxxxxxxx>
> + *
> + * This program is free software; you may redistribute and/or modify
> + * it under the terms of the GNU General Public License version 2, as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
> + * USA
> + */
> +#ifndef __LINUX_PWM_LED_H
> +#define __LINUX_PWM_LED_H
> +
> +struct led_info;
> +struct pwm_channel_config;
> +
> +struct pwm_led_platform_data {
> +	const char *bus_id;
> +	int chan;
> +	struct pwm_channel_config *config;
> +	struct led_info *led_info;
> +};
> +
> +#endif /* __LINUX_PWM_LED_H */
> -- 
> 1.7.1
> 
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