Messages in this thread Patch in this message | | | Date | Tue, 10 Apr 2012 00:17:02 -0700 | From | Dmitry Torokhov <> | Subject | Re: [PATCH RESEND] LEDS-One-Shot-Timer-Trigger-implementation |
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On Mon, Apr 09, 2012 at 04:40:29PM -0600, Shuah Khan wrote: > On Mon, 2012-04-09 at 13:42 -0700, Dmitry Torokhov wrote: > > On Mon, Apr 09, 2012 at 02:20:47PM -0600, Shuah Khan wrote: > > > On Mon, 2012-04-09 at 11:45 -0700, Dmitry Torokhov wrote: > > > > On Mon, Apr 09, 2012 at 12:16:05PM -0600, Shuah Khan wrote: > > > > > On Mon, 2012-04-09 at 10:37 -0700, Dmitry Torokhov wrote: > > > > > > On Mon, Apr 09, 2012 at 10:55:49AM -0600, Shuah Khan wrote: > > > > > > > On Sat, 2012-04-07 at 14:56 -0700, Dmitry Torokhov wrote: > > > > > > > > Hi Shuah, > > > > > > > > > > > > > > > > On Sat, Apr 07, 2012 at 08:13:44AM -0600, Shuah Khan wrote: > > > > > > > > > > > > > > > > > > > > +This feature will help implement vibrate functionality which requires one > > > > > > > > > > > +time activation of vibrate mode without a continuous vibrate on/off cycles. > > > > > > > > > > > > > > > > > > > > They make vibrating LED? ;) > > > > > > > > > > > > > > > > > > > > What's going on here? You're proposing to repurpose the LEDs code to > > > > > > > > > > drive vibration devices? Or some devices couple a LED with a vibration > > > > > > > > > > device? > > > > > > > > > > > > > > > > > > I owe you filling in the blanks type explanation. Let me describe the > > > > > > > > > use-case I am trying to address first. Vibrater function on phones is > > > > > > > > > implemented using PWM pins on SoC or PMIC. When there is no such > > > > > > > > > hardware present, a software solution is needed. Currently two drivers > > > > > > > > > timed-gpio and timed-output (under staging/android in Linux 3.3) > > > > > > > > > together implement the software vibrate feature. The main functionality > > > > > > > > > it implements is the one time enables of timer to prevent user space > > > > > > > > > crashes leaving the phone in vibrate mode causing the battery to drain. > > > > > > > > > leds as it is implemented currently, is not suitable to address this > > > > > > > > > use-case as it doesn't support one time enables. > > > > > > > > > > > > > > > > So why do not you use memoryless force feedback framework that other > > > > > > > > devices use (see drivers/input/misc/*vibra.c drivers). > > > > > > > > > > > > > > > > > > > > > > Dimitry, > > > > > > > > > > > > > > I took a look at these vibra* drivers. The three vibrate drivers are > > > > > > > chip-set specific. The use-case I have is a non-chip set approach to > > > > > > > address the use-case when vibrate hardware is not present. Are you > > > > > > > envisioning a generic approach using ff-memoryless infrastructure? > > > > > > > > > > > > Shuah, > > > > > > > > > > > > I guess I am confused now. You need some form of hardware to make your > > > > > > device to vibrate. > > > > > > > > > > > > What exactly are you trying to do? Are you trying to: > > > > > > > > > > > > 1. activate vibration on devices that can actually do it using LED > > > > > > interface, or > > > > > > > > > > > > 2. use LEDs as an alternative to vibrate on devices that can't > > > > > > physically vibrate? > > > > > > > > > > > > Thanks. > > > > > > > > > > What I meant by generic approach is a higher level interface that is not > > > > > tied too closely to the underlying hardware. Similar to the leds-pwm.c > > > > > and leds-gpio.c handle gpio and pwm based leds. The vibrate hardware in > > > > > my sue-case is a gpio based and could pwm based on some phones. > > > > > > > > Ok, so you need to add drivers/input/misc/gpio-vibrate.c and pwm-vibrate.c > > > > and then use FF to activate them. This way we have all vibrate > > > > implementation use one subsystem instead of splitting between > > > > input/led/whatever else people could come up with. > > > > > > > > Thanks. > > > > > > > > > > Dmitry, > > > > > > It is unfortunate that we have these two infrastructures evolve that has > > > a lot of overlap. Let me summarize the two alternatives first so we get > > > a feel for the work involved to address this use-case using ff and leds > > > frameworks: > > > > > > Alternative 1: using leds infrastructure > > > > > > Add new kernel interface to support one time enables. This will enable > > > existing gpio and pwm drivers to be used to implement vibrate. > > > > > > Alternative 2: using ff infrastructure > > > > > > Add new drivers gpio and pwm that use existing one time enable to > > > implement vibrate in a generic way. > > > > > > Does this sound right? From a quick glance it sounds like we can get to > > > the end goal quicker and in a simpler way with Alternative 1. However, I > > > might be missing longterm view. Any other alternatives we could explore? > > > > > > > For 1 you are forgetting "persuade current users of mainline vibrator > > drivers in kernel to adopt their drivers and userpace to LED framework" > > because we should try to provide single interface for a given function. > > > > Thanks. > > > > Dmitry, > > I can't argue against the user-space angle. Let me give more thought to > Alternative 2 and see if it indeed turns out to be more work. Thanks for > a good discussion.
See if the following patch will make the decision a bit easier ;) It might need some love as I do not actually have the hardware.
-- Dmitry
Input: add support for PWM-based vibrators
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru> ---
drivers/input/misc/Kconfig | 11 ++ drivers/input/misc/Makefile | 1 drivers/input/misc/pwm-vibrator.c | 213 ++++++++++++++++++++++++++++++++++++ include/linux/input/pwm-vibrator.h | 13 ++ 4 files changed, 238 insertions(+), 0 deletions(-) create mode 100644 drivers/input/misc/pwm-vibrator.c create mode 100644 include/linux/input/pwm-vibrator.h
diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig index ee077a4..913bdb8 100644 --- a/drivers/input/misc/Kconfig +++ b/drivers/input/misc/Kconfig @@ -451,6 +451,17 @@ config INPUT_PWM_BEEPER To compile this driver as a module, choose M here: the module will be called pwm-beeper. +config INPUT_PWM_VIBRATOR + tristate "PWM vibrator support" + depends on HAVE_PWM + help + Say Y here to get support for PWM based vibrator devices. + + If unsure, say N. + + To compile this driver as a module, choose M here: the module will be + called pwm-vibrator. + config INPUT_GPIO_ROTARY_ENCODER tristate "Rotary encoders connected to GPIO pins" depends on GPIOLIB && GENERIC_GPIO diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile index f55cdf4..e8b7643 100644 --- a/drivers/input/misc/Makefile +++ b/drivers/input/misc/Makefile @@ -43,6 +43,7 @@ obj-$(CONFIG_INPUT_PM8XXX_VIBRATOR) += pm8xxx-vibrator.o obj-$(CONFIG_INPUT_PMIC8XXX_PWRKEY) += pmic8xxx-pwrkey.o obj-$(CONFIG_INPUT_POWERMATE) += powermate.o obj-$(CONFIG_INPUT_PWM_BEEPER) += pwm-beeper.o +obj-$(CONFIG_INPUT_PWM_VIBRATOR) += pwm-vibrator.o obj-$(CONFIG_INPUT_RB532_BUTTON) += rb532_button.o obj-$(CONFIG_INPUT_GPIO_ROTARY_ENCODER) += rotary_encoder.o obj-$(CONFIG_INPUT_SGI_BTNS) += sgi_btns.o diff --git a/drivers/input/misc/pwm-vibrator.c b/drivers/input/misc/pwm-vibrator.c new file mode 100644 index 0000000..c72bac9 --- /dev/null +++ b/drivers/input/misc/pwm-vibrator.c @@ -0,0 +1,213 @@ +/* + * PWM vibrator driver + * + * Copyright (C) 2012 Dmitry Torokhov <dmitry.torokhov@gmail.com> + * + * Based on PWM beeper driver: + * Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2 of the License, or (at your + * option) any later version. + * + * 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., + * 675 Mass Ave, Cambridge, MA 02139, USA. + * + */ + +#include <linux/input.h> +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/platform_device.h> +#include <linux/pwm.h> +#include <linux/slab.h> +#include <linux/input/pwm-vibrator.h> + +struct pwm_vibrator { + struct input_dev *input; + struct pwm_device *pwm; + unsigned int pwm_period; + unsigned int level; +}; + +static int pwm_vibrator_start(struct pwm_vibrator *vibrator) +{ + unsigned int duty = vibrator->pwm_period * vibrator->level / 100; + int error; + + error = pwm_config(vibrator->pwm, duty, vibrator->pwm_period); + if (error < 0) + return error; + + error = pwm_enable(vibrator->pwm); + if (error < 0) + return error; + + return 0; +} + +static void pwm_vibrator_stop(struct pwm_vibrator *vibrator) +{ + pwm_config(vibrator->pwm, 0, 0); + pwm_disable(vibrator->pwm); +} + +static int pwm_vibrator_play_effect(struct input_dev *dev, void *data, + struct ff_effect *effect) +{ + struct pwm_vibrator *vibrator = input_get_drvdata(dev); + int error; + + vibrator->level = effect->u.rumble.strong_magnitude; + if (!vibrator->level) + vibrator->level = effect->u.rumble.weak_magnitude; + + if (vibrator->level) { + error = pwm_vibrator_start(vibrator); + if (error) { + dev_err(vibrator->input->dev.parent, + "%s: pwm_vibrator_start failed, error: %d\n", + __func__, error); + return error; + } + } else { + pwm_vibrator_stop(vibrator); + } + + return 0; +} + + +static int __devinit pwm_vibrator_probe(struct platform_device *pdev) +{ + const struct pwm_vibrator_platform_data *pdata; + struct pwm_vibrator *vibrator; + struct input_dev *input; + int error; + + pdata = pdev->dev.platform_data; + if (!pdata) { + dev_err(&pdev->dev, "Missing platform dat\n"); + return -EINVAL; + } + + vibrator = kzalloc(sizeof(*vibrator), GFP_KERNEL); + input = input_allocate_device(); + if (!vibrator || !input) { + error = -ENOMEM; + goto err_mem_free; + } + + vibrator->input = input; + vibrator->pwm_period = pdata->pwm_period; + + vibrator->pwm = pwm_request(pdata->pwm_id, "pwm vibrator"); + if (IS_ERR(vibrator->pwm)) { + error = PTR_ERR(vibrator->pwm); + dev_err(&pdev->dev, "Failed to request pwm device: %d\n", error); + goto err_mem_free; + } + + input->name = "pwm-vibrator"; + input->id.bustype = BUS_HOST; + input->dev.parent = &pdev->dev; + + input_set_drvdata(input, vibrator); + input_set_capability(input, EV_FF, FF_RUMBLE); + + error = input_ff_create_memless(input, NULL, + pwm_vibrator_play_effect); + if (error) { + dev_err(&pdev->dev, + "Unable to create FF device, error: %d\n", + error); + goto err_pwm_free; + } + + error = input_register_device(input); + if (error) { + dev_err(&pdev->dev, "Failed to register input device: %d\n", error); + goto err_pwm_free; + } + + platform_set_drvdata(pdev, vibrator); + + return 0; + +err_pwm_free: + pwm_free(vibrator->pwm); +err_mem_free: + input_free_device(vibrator->input); + kfree(vibrator); + + return error; +} + +static int __devexit pwm_vibrator_remove(struct platform_device *pdev) +{ + struct pwm_vibrator *vibrator = platform_get_drvdata(pdev); + + platform_set_drvdata(pdev, NULL); + + input_unregister_device(vibrator->input); + + pwm_disable(vibrator->pwm); + pwm_free(vibrator->pwm); + + kfree(vibrator); + + return 0; +} + +#ifdef CONFIG_PM_SLEEP +static int pwm_vibrator_suspend(struct device *dev) +{ + struct platform_device *pdev = to_platform_device(dev); + struct pwm_vibrator *vibrator = platform_get_drvdata(pdev); + struct input_dev *input = vibrator->input; + unsigned long flags; + + spin_lock_irqsave(&input->event_lock, flags); + if (vibrator->level) + pwm_vibrator_stop(vibrator); + spin_unlock_irqrestore(&input->event_lock, flags); + + return 0; +} + +static int pwm_vibrator_resume(struct device *dev) +{ + struct platform_device *pdev = to_platform_device(dev); + struct pwm_vibrator *vibrator = platform_get_drvdata(pdev); + struct input_dev *input = vibrator->input; + unsigned long flags; + + spin_lock_irqsave(&input->event_lock, flags); + if (vibrator->level) + pwm_vibrator_start(vibrator); + spin_unlock_irqrestore(&input->event_lock, flags); + + return 0; +} +#endif + +static SIMPLE_DEV_PM_OPS(pwm_vibrator_pm_ops, + pwm_vibrator_suspend, pwm_vibrator_resume); + +static struct platform_driver pwm_vibrator_driver = { + .probe = pwm_vibrator_probe, + .remove = __devexit_p(pwm_vibrator_remove), + .driver = { + .name = "pwm-vibrator", + .owner = THIS_MODULE, + .pm = &pwm_vibrator_pm_ops, + }, +}; +module_platform_driver(pwm_vibrator_driver); + +MODULE_AUTHOR("Dmitry Torokhov <dmitry.torokhov@gmail.com>"); +MODULE_DESCRIPTION("PWM vibrator driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:pwm-vibrator"); diff --git a/include/linux/input/pwm-vibrator.h b/include/linux/input/pwm-vibrator.h new file mode 100644 index 0000000..efe1f72 --- /dev/null +++ b/include/linux/input/pwm-vibrator.h @@ -0,0 +1,13 @@ +#ifndef __INPUT_PWM_VIBRATOR_H +#define __INPUT_PWM_VIBRATOR_H + +/* + * PWM vibrator driver data + */ + +struct pwm_vibrator_platform_data { + unsigned int pwm_id; + unsigned int pwm_period; +}; + +#endif
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