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Date: Sat, 21 Jul 2012 02:48:49 +0800
From: Bryan Wu <bryan.wu@...onical.com>
To: shuahkhan@...il.com,
Mark Brown <broonie@...nsource.wolfsonmicro.com>
Cc: "Kim, Milo" <Milo.Kim@...com>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] leds: add new lp8788 led driver
On Fri, Jul 20, 2012 at 11:49 PM, Shuah Khan <shuahkhan@...il.com> wrote:
> On Fri, 2012-07-20 at 08:43 +0000, Kim, Milo wrote:
>> TI LP8788 PMU has the current sink as the keyboard led driver.
>> The brightness is controlled by the i2c commands.
>> Configurable parameters can be defined in the platform side.
>>
>> Patch v2.
>> (a) use workqueue on changing the brightness
>>
>> (b) use mutex_lock/unlock when the brightness is set
>> and the led block of lp8788 device is enabled
>>
>> (c) remove err_dev on _probe()
>> : just return as returned value if any errors
>>
>> (d) replace module_init/exit() with module_platform_driver()
>>
>> (e) add led configuration structure and loading them by default
>> if platform data is null
>>
>> Signed-off-by: Milo(Woogyom) Kim <milo.kim@...com>
>> ---
>> drivers/leds/Kconfig | 7 ++
>> drivers/leds/Makefile | 1 +
>> drivers/leds/leds-lp8788.c | 192 ++++++++++++++++++++++++++++++++++++++++++++
>> 3 files changed, 200 insertions(+), 0 deletions(-)
>> create mode 100644 drivers/leds/leds-lp8788.c
>>
>> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
>> index f028f03..a498deb 100644
>> --- a/drivers/leds/Kconfig
>> +++ b/drivers/leds/Kconfig
>> @@ -200,6 +200,13 @@ config LEDS_LP5523
>> Driver provides direct control via LED class and interface for
>> programming the engines.
>>
>> +config LEDS_LP8788
>> + tristate "LED support for the TI LP8788 PMIC"
>> + depends on LEDS_CLASS
>> + depends on MFD_LP8788
>> + help
>> + This option enables support for the Keyboard LEDs on the LP8788 PMIC.
>> +
>> config LEDS_CLEVO_MAIL
>> tristate "Mail LED on Clevo notebook"
>> depends on LEDS_CLASS
>> diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
>> index 5eebd7b..f156193 100644
>> --- a/drivers/leds/Makefile
>> +++ b/drivers/leds/Makefile
>> @@ -24,6 +24,7 @@ obj-$(CONFIG_LEDS_GPIO) += leds-gpio.o
>> obj-$(CONFIG_LEDS_LP3944) += leds-lp3944.o
>> obj-$(CONFIG_LEDS_LP5521) += leds-lp5521.o
>> obj-$(CONFIG_LEDS_LP5523) += leds-lp5523.o
>> +obj-$(CONFIG_LEDS_LP8788) += leds-lp8788.o
>> obj-$(CONFIG_LEDS_TCA6507) += leds-tca6507.o
>> obj-$(CONFIG_LEDS_CLEVO_MAIL) += leds-clevo-mail.o
>> obj-$(CONFIG_LEDS_HP6XX) += leds-hp6xx.o
>> diff --git a/drivers/leds/leds-lp8788.c b/drivers/leds/leds-lp8788.c
>> new file mode 100644
>> index 0000000..574b49f
>> --- /dev/null
>> +++ b/drivers/leds/leds-lp8788.c
>> @@ -0,0 +1,192 @@
>> +/*
>> + * TI LP8788 MFD - keyled driver
>> + *
>> + * Copyright 2012 Texas Instruments
>> + *
>> + * Author: Milo(Woogyom) Kim <milo.kim@...com>
>> + *
>> + * 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 <linux/module.h>
>> +#include <linux/slab.h>
>> +#include <linux/err.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/leds.h>
>> +#include <linux/mutex.h>
>> +#include <linux/mfd/lp8788.h>
>> +#include <linux/mfd/lp8788-isink.h>
>> +
>> +#define MAX_BRIGHTNESS LP8788_ISINK_MAX_PWM
>> +#define DEFAULT_LED_NAME "keyboard-backlight"
>> +
>> +struct lp8788_led {
>> + struct lp8788 *lp;
>> + struct mutex lock;
>> + struct work_struct work;
>> + struct led_classdev led_dev;
>> + enum lp8788_isink_number isink_num;
>> + enum led_brightness brightness;
>> + int on;
>> +};
>> +
>> +struct lp8788_led_config {
>> + enum lp8788_isink_scale scale;
>> + enum lp8788_isink_number num;
>> + int iout;
>> +};
>> +
>> +static struct lp8788_led_config default_led_config = {
>> + .scale = LP8788_ISINK_SCALE_100mA,
>> + .num = LP8788_ISINK_3,
>> + .iout = 0,
>> +};
>> +
>> +static int lp8788_led_init_device(struct lp8788_led *led,
>> + struct lp8788_led_platform_data *pdata)
>> +{
>> + struct lp8788_led_config *cfg = &default_led_config;
>> + u8 addr, mask, val;
>> + int ret;
>> +
>> + if (pdata) {
>> + cfg->scale = pdata->scale;
>> + cfg->num = pdata->num;
>> + cfg->iout = pdata->iout_code;
>> + }
>> +
>> + led->isink_num = cfg->num;
>> +
>> + /* scale configuration */
>> + addr = LP8788_ISINK_CTRL;
>> + mask = 1 << (cfg->num + LP8788_ISINK_SCALE_OFFSET);
>> + val = cfg->scale << cfg->num;
>> + ret = lp8788_update_bits(led->lp, addr, mask, val);
>> + if (ret)
>> + return ret;
>> +
>> + /* current configuration */
>> + addr = lp8788_iout_addr[cfg->num];
>> + mask = lp8788_iout_mask[cfg->num];
>> + val = cfg->iout;
>> +
>> + return lp8788_update_bits(led->lp, addr, mask, val);
>> +}
>> +
>> +static void lp8788_led_enable(struct lp8788_led *led,
>> + enum lp8788_isink_number num, int on)
>> +{
>> + u8 mask = 1 << num;
>> + u8 val = on << num;
>> +
>> + if (lp8788_update_bits(led->lp, LP8788_ISINK_CTRL, mask, val))
>> + return;
>> +
>> + led->on = on;
>> +}
>> +
>> +static void lp8788_led_work(struct work_struct *work)
>> +{
>> + struct lp8788_led *led = container_of(work, struct lp8788_led, work);
>> + enum lp8788_isink_number num = led->isink_num;
>> + int enable;
>> + u8 val = led->brightness;
>> +
>> + mutex_lock(&led->lock);
>> +
>> + switch (num) {
>> + case LP8788_ISINK_1:
>> + case LP8788_ISINK_2:
>> + case LP8788_ISINK_3:
>> + lp8788_write_byte(led->lp, lp8788_pwm_addr[num], val);
>> + break;
>> + default:
>> + return;
>> + }
>> +
>> + enable = (val > 0) ? 1 : 0;
>> + if (enable != led->on)
>> + lp8788_led_enable(led, num, enable);
>> +
>> + mutex_unlock(&led->lock);
>> +}
>> +
>> +static void lp8788_brightness_set(struct led_classdev *led_cdev,
>> + enum led_brightness brt_val)
>> +{
>> + struct lp8788_led *led =
>> + container_of(led_cdev, struct lp8788_led, led_dev);
>> +
>> + led->brightness = brt_val;
>> + schedule_work(&led->work);
>> +}
>> +
>> +static __devinit int lp8788_led_probe(struct platform_device *pdev)
>> +{
>> + struct lp8788 *lp = dev_get_drvdata(pdev->dev.parent);
>> + struct lp8788_led_platform_data *led_pdata;
>> + struct lp8788_led *led;
>> + int ret;
>> +
>> + led = devm_kzalloc(lp->dev, sizeof(struct lp8788_led), GFP_KERNEL);
>> + if (!led)
>> + return -ENOMEM;
>> +
>> + led->lp = lp;
>> + led->led_dev.max_brightness = MAX_BRIGHTNESS;
>> + led->led_dev.brightness_set = lp8788_brightness_set;
>> +
>> + led_pdata = lp->pdata ? lp->pdata->led_pdata : NULL;
>> +
>> + if (!led_pdata || !led_pdata->name)
>> + led->led_dev.name = DEFAULT_LED_NAME;
>> + else
>> + led->led_dev.name = led_pdata->name;
>> +
>> + mutex_init(&led->lock);
>> + INIT_WORK(&led->work, lp8788_led_work);
>> +
>> + platform_set_drvdata(pdev, led);
>> +
>> + ret = lp8788_led_init_device(led, led_pdata);
>> + if (ret) {
>> + dev_err(lp->dev, "led init device err: %d\n", ret);
>> + return ret;
>> + }
>> +
>> + ret = led_classdev_register(lp->dev, &led->led_dev);
>> + if (ret) {
>> + dev_err(lp->dev, "led register err: %d\n", ret);
>> + return ret;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static int __devexit lp8788_led_remove(struct platform_device *pdev)
>> +{
>> + struct lp8788_led *led = platform_get_drvdata(pdev);
>> +
>> + led_classdev_unregister(&led->led_dev);
>> + flush_work_sync(&led->work);
>
> Is flush_work_sync() sufficient or cancel_work_sync() is a better
> choice. I see some led drivers using cancel_work_sync() and some using
> flush_work_sync(). I do see that flush_work_sync() doesn't do any
> del_timer_sync() calls to cancel timers if any running.
>
Actually cancel_work_sync() is quite similar to flush_work_sync()
here. For the timer thing, in fact it is NULL when cancel_work_sync()
call __cancel_work_timer().
And Mark, do you have any advice about the flush_work_sync() and
cancel_work_sync(). I saw you use flush in the
drivers/leds/leds-wm8350.c.
Thanks a lot,
-Bryan
>> +
>> + return 0;
>> +}
>> +
>> +static struct platform_driver lp8788_led_driver = {
>> + .probe = lp8788_led_probe,
>> + .remove = __devexit_p(lp8788_led_remove),
>> + .driver = {
>> + .name = LP8788_DEV_KEYLED,
>> + .owner = THIS_MODULE,
>> + },
>> +};
>> +module_platform_driver(lp8788_led_driver);
>> +
>> +MODULE_DESCRIPTION("Texas Instruments LP8788 Keyboard LED Driver");
>> +MODULE_AUTHOR("Milo Kim");
>> +MODULE_LICENSE("GPL");
>> +MODULE_ALIAS("platform:lp8788-keyled");
>
>
--
Bryan Wu <bryan.wu@...onical.com>
Kernel Developer +86.186-168-78255 Mobile
Canonical Ltd. www.canonical.com
Ubuntu - Linux for human beings | www.ubuntu.com
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