Re: [PATCH 1/2] Input: add regulator haptic driver

From: Dan Murphy
Date: Thu Nov 20 2014 - 10:09:55 EST

Hi

On 11/20/2014 08:33 AM, Pankaj Dubey wrote:
> Hi Jaewon,
>
> On 20 November 2014 19:01, Jaewon Kim <jaewon02.kim@xxxxxxxxxxx> wrote:
>> This patch adds support for haptic driver controlled by
>> voltage of regulator. And this driver support for
>> Force Feedback interface from input framework
>>
>> Signed-off-by: Jaewon Kim <jaewon02.kim@xxxxxxxxxxx>
>> Signed-off-by: Hyunhee Kim <hyunhee.kim@xxxxxxxxxxx>
>> Acked-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
>> ---
>> .../devicetree/bindings/input/regulator-haptic.txt | 24 ++
>> drivers/input/misc/Kconfig | 11 +
>> drivers/input/misc/Makefile | 1 +
>> drivers/input/misc/regulator-haptic.c | 241 ++++++++++++++++++++
>> 4 files changed, 277 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/input/regulator-haptic.txt
>> create mode 100644 drivers/input/misc/regulator-haptic.c
>>
>> diff --git a/Documentation/devicetree/bindings/input/regulator-haptic.txt b/Documentation/devicetree/bindings/input/regulator-haptic.txt
>> new file mode 100644
>> index 0000000..9f60e17
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/input/regulator-haptic.txt
>> @@ -0,0 +1,24 @@
>> +* Requlator Haptic Device Tree Bindings
>> +
>> +The regulator haptic driver controlled by voltage of regulator.
>> +This driver implemented via Force Feedback interface.
>> +
>> +Required Properties:
>> + - compatible : Should be "regulator-haptic"
>> + - haptic-supply : Power supply for the haptic motor.
>> + [*] refer Documentation/devicetree/bindings/regulator/regulator.txt
>> +
>> + - max-microvolt : The maximum voltage value supplied to haptic motor.
>> + [The unit of the voltage is a micro]
>> +
>> + - min-microvolt : The minimum voltage value in which haptic motor reacts.
>> + [The unit of the voltage is a micro]
>> +
>> +Example:
>> +
>> + regulator-haptic {

Should this be more about the function and not the driver name?
Somehting like

haptics {

>> + compatible = "regulator-haptic";
>> + haptic-supply = <&motor_regulator>;
>> + max-microvolt = <2700000>;
>> + min-microvolt = <1100000>;
>> + };
>> diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
>> index 23297ab..e5e556d 100644
>> --- a/drivers/input/misc/Kconfig
>> +++ b/drivers/input/misc/Kconfig
>> @@ -394,6 +394,17 @@ config INPUT_CM109
>> To compile this driver as a module, choose M here: the module will be
>> called cm109.
>>
>> +config INPUT_REGULATOR_HAPTIC
>> + tristate "regulator haptics support"
>> + select INPUT_FF_MEMLESS
>> + help
>> + This option enables device driver support for the haptic controlled
>> + by regulator. This driver supports ff-memless interface
>> + from input framework.
>> +
>> + To compile this driver as a module, choose M here: the
>> + module will be called regulator-haptic.
>> +
>> config INPUT_RETU_PWRBUTTON
>> tristate "Retu Power button Driver"
>> depends on MFD_RETU
>> diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile
>> index 19c7603..1f135af 100644
>> --- a/drivers/input/misc/Makefile
>> +++ b/drivers/input/misc/Makefile
>> @@ -53,6 +53,7 @@ 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_RB532_BUTTON) += rb532_button.o
>> +obj-$(CONFIG_INPUT_REGULATOR_HAPTIC) += regulator-haptic.o
>> obj-$(CONFIG_INPUT_RETU_PWRBUTTON) += retu-pwrbutton.o
>> obj-$(CONFIG_INPUT_GPIO_ROTARY_ENCODER) += rotary_encoder.o
>> obj-$(CONFIG_INPUT_SGI_BTNS) += sgi_btns.o
>> diff --git a/drivers/input/misc/regulator-haptic.c b/drivers/input/misc/regulator-haptic.c
>> new file mode 100644
>> index 0000000..1a83ecb
>> --- /dev/null
>> +++ b/drivers/input/misc/regulator-haptic.c
>> @@ -0,0 +1,241 @@
>> +/*
>> + * Regulator haptic driver
>> + *
>> + * Copyright (c) 2014 Samsung Electronics Co., Ltd.
>> + * Author: Jaewon Kim <jaewon02.kim@xxxxxxxxxxx>
>> + * Author: Hyunhee Kim <hyunhee.kim@xxxxxxxxxxx>
>> + *
>> + * 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/platform_device.h>
>> +#include <linux/input.h>
>> +#include <linux/slab.h>
>> +#include <linux/regulator/consumer.h>
>> +#include <linux/of.h>
>> +
>> +#define MAX_MAGNITUDE_SHIFT 16
>> +
>> +struct regulator_haptic {
>> + struct device *dev;
>> + struct input_dev *input_dev;
>> + struct regulator *regulator;
>> + struct work_struct work;
>> +
>> + bool enabled;
>> + bool suspend_state;

I don't understand what you are tracking here. You only set it and unset
this value but never do any checking

>> + unsigned int max_volt;
>> + unsigned int min_volt;
>> + unsigned int intensity;
>> + unsigned int magnitude;
>> +};
>> +
>> +static void regulator_haptic_enable(struct regulator_haptic *haptic)
>> +{
>> + int error;
>> +
>> + if (haptic->enabled)
>> + return;
>> +
>> + error = regulator_enable(haptic->regulator);
>> + if (error) {
>> + dev_err(haptic->dev, "cannot enable regulator\n");
>> + return;
>> + }
>> +
>> + haptic->enabled = true;
>> +}
>> +
>> +static void regulator_haptic_disable(struct regulator_haptic *haptic)
>> +{
>> + int error;
>> +
>> + if (!haptic->enabled)
>> + return;
>> +
>> + error = regulator_disable(haptic->regulator);
>> + if (error) {
>> + dev_err(haptic->dev, "cannot disable regulator\n");
>> + return;
>> + }
>> +
>> + haptic->enabled = false;
>> +}

Can the enable/disable just be one function with an argument?
Then you can centralize the check and reduce the code footprint.

>> +
>> +static void regulator_haptic_work(struct work_struct *work)
>> +{
>> + struct regulator_haptic *haptic = container_of(work,
>> + struct regulator_haptic, work);
>> + int error;
>> +
>> + error = regulator_set_voltage(haptic->regulator,
>> + haptic->intensity + haptic->min_volt, haptic->max_volt);
>> + if (error) {
>> + dev_err(haptic->dev, "cannot set regulator voltage\n");
>> + return;
>> + }
>> +
>> + if (haptic->magnitude)
>> + regulator_haptic_enable(haptic);
>> + else
>> + regulator_haptic_disable(haptic);
>> +}
>> +
>> +static int regulator_haptic_play_effect(struct input_dev *input, void *data,
>> + struct ff_effect *effect)
>> +{
>> + struct regulator_haptic *haptic = input_get_drvdata(input);
>> + u64 volt_mag_multi;
>> +
>> + haptic->magnitude = effect->u.rumble.strong_magnitude;
>> + if (!haptic->magnitude)
>> + haptic->magnitude = effect->u.rumble.weak_magnitude;
>> +
>> +
>> + volt_mag_multi = (u64)(haptic->max_volt - haptic->min_volt) *
>> + haptic->magnitude;
>> + haptic->intensity = (unsigned int)(volt_mag_multi >>
>> + MAX_MAGNITUDE_SHIFT);
>> +
>> + schedule_work(&haptic->work);
>> +
>> + return 0;
>> +}
>> +
>> +static void regulator_haptic_close(struct input_dev *input)
>> +{
>> + struct regulator_haptic *haptic = input_get_drvdata(input);
>> +
>> + cancel_work_sync(&haptic->work);
>> + regulator_haptic_disable(haptic);
>> +}
>> +
>> +static int regulator_haptic_parse_dt(struct regulator_haptic *haptic)
>> +{
>> + struct device_node *node = haptic->dev->of_node;
>> + int error;
>> +
>> + error = of_property_read_u32(node, "max-microvolt", &haptic->max_volt);
>> + if (error) {
>> + dev_err(haptic->dev, "cannot parse max-microvolt\n");
>> + return error;
>> + }
>> +
>> + error = of_property_read_u32(node, "min-microvolt", &haptic->min_volt);
>> + if (error) {
>> + dev_err(haptic->dev, "cannot parse min-microvolt\n");
>> + return error;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static int regulator_haptic_probe(struct platform_device *pdev)
>> +{
>> + struct regulator_haptic *haptic;
>> + struct input_dev *input_dev;
>> + int error;
>> +
>> + haptic = devm_kzalloc(&pdev->dev, sizeof(*haptic), GFP_KERNEL);
>> + if (!haptic)
>> + return -ENOMEM;
>> +
>> + haptic->dev = &pdev->dev;
>> + haptic->enabled = false;
>> + haptic->suspend_state = false;
>> + INIT_WORK(&haptic->work, regulator_haptic_work);
>> +
>> + error = regulator_haptic_parse_dt(haptic);

Do you need platform data support for platforms that do not currently support
dt?

>> + if (error) {
>> + dev_err(&pdev->dev, "failed to parse device tree\n");
>> + return error;
>> + }
>> +
>> + haptic->regulator = devm_regulator_get(&pdev->dev, "haptic");
>> + if (IS_ERR(haptic->regulator)) {
>> + dev_err(&pdev->dev, "failed to get regulator\n");
>> + return PTR_ERR(haptic->regulator);
>> + }
>> +
>> + input_dev = devm_input_allocate_device(&pdev->dev);
>> + if (!input_dev)
>> + return -ENOMEM;
>> +
>> + haptic->input_dev = input_dev;
>> + haptic->input_dev->name = "regulator-haptic";
>> + haptic->input_dev->dev.parent = &pdev->dev;
>> + haptic->input_dev->close = regulator_haptic_close;
>> + input_set_drvdata(haptic->input_dev, haptic);
>> + input_set_capability(haptic->input_dev, EV_FF, FF_RUMBLE);
>> +
>> + error = input_ff_create_memless(input_dev, NULL,
>> + regulator_haptic_play_effect);
>> + if (error) {
>> + dev_err(&pdev->dev, "failed to create force-feedback\n");
>> + return error;
>> + }
>> +
>> + error = input_register_device(haptic->input_dev);
>> + if (error) {
>> + dev_err(&pdev->dev, "failed to register input device\n");
>> + return error;
>> + }
>> +
>> + platform_set_drvdata(pdev, haptic);
>> +
>> + return 0;
>> +}
>> +
>> +static int __maybe_unused regulator_haptic_suspend(struct device *dev)
>> +{
>> + struct platform_device *pdev = to_platform_device(dev);
>> + struct regulator_haptic *haptic = platform_get_drvdata(pdev);
>> +
>> + if (haptic->enabled) {
>> + regulator_haptic_disable(haptic);
>> + haptic->suspend_state = true;



>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static int __maybe_unused regulator_haptic_resume(struct device *dev)
>> +{
>> + struct platform_device *pdev = to_platform_device(dev);
>> + struct regulator_haptic *haptic = platform_get_drvdata(pdev);
>> +
>> + if (haptic->enabled) {
>> + regulator_haptic_enable(haptic);

We enable the regulator when we do the haptics work if magnitude is > 0.
And during suspend haptic->enabled may get set to false if it is true
so wouldn't haptic->enabled always be false here?

Plus do we want to continue the haptic response when coming out of suspend state?

>> + haptic->suspend_state = false;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static SIMPLE_DEV_PM_OPS(regulator_haptic_pm_ops,
>> + regulator_haptic_suspend, regulator_haptic_resume);
>> +
>> +static struct of_device_id regulator_haptic_dt_match[] = {
>> + { .compatible = "regulator-haptic" },
>> + {},
>> +};
>> +
>> +static struct platform_driver regulator_haptic_driver = {
>> + .probe = regulator_haptic_probe,
>> + .driver = {
>> + .name = "regulator-haptic",
>> + .owner = THIS_MODULE,
> .owner is no more required for drivers using module_platform_driver()
>
> Thanks,
> Pankaj Dubey
>
>> + .of_match_table = regulator_haptic_dt_match,
>> + .pm = &regulator_haptic_pm_ops,
>> + },
>> +};
>> +module_platform_driver(regulator_haptic_driver);
>> +
>> +MODULE_AUTHOR("Jaewon Kim <jaewon02.kim@xxxxxxxxxxx>");
>> +MODULE_AUTHOR("Hyunhee Kim <hyunhee.kim@xxxxxxxxxxx>");
>> +MODULE_ALIAS("platform:regulator-haptic");
>> +MODULE_DESCRIPTION("Regulator haptic driver");
>> +MODULE_LICENSE("GPL");
>> --
>> 1.7.9.5
>>
>> --
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--
------------------
Dan Murphy

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