Re: [PATCH v2 2/4] Input: misc: Add haptic driver on max77693

Dmitry Torokhov
2014-09-04T17:00:10Z

Hi Jaewon,

On Fri, Sep 05, 2014 at 12:01:29AM +0900, Jaewon Kim wrote:
> This patch add max77693-haptic device driver to support the haptic controller
> on MAX77693. The MAX77693 is a Multifunction device with PMIC, CHARGER, LED,
> MUIC, HAPTIC and the patch is haptic device driver in the MAX77693. This driver
> support external pwm and LRA(Linear Resonant Actuator) motor. User can control
> the haptic driver by using force feedback framework.
>
> Signed-off-by: Jaewon Kim <jaewon02.kim@samsung.com>
> Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
> ---
> drivers/input/misc/Kconfig | 12 ++
> drivers/input/misc/Makefile | 1 +
> drivers/input/misc/max77693-haptic.c | 333 ++++++++++++++++++++++++++++++++++
> include/linux/mfd/max77693-private.h | 9 +
> 4 files changed, 355 insertions(+)
> create mode 100644 drivers/input/misc/max77693-haptic.c
>
> diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
> index 2ff4425..c597c52 100644
> --- a/drivers/input/misc/Kconfig
> +++ b/drivers/input/misc/Kconfig
> @@ -144,6 +144,18 @@ config INPUT_M68K_BEEP
> tristate "M68k Beeper support"
> depends on M68K
>
> +config INPUT_MAX77693_HAPTIC
> + tristate "MAXIM MAX77693 haptic controller support"
> + depends on MFD_MAX77693 && PWM
> + select INPUT_FF_MEMLESS
> + help
> + This option enables device driver support for the haptic controller
> + on MAXIM MAX77693 chip. This driver supports ff-memless interface
> + from input framework.
> +
> + To compile this driver as module, choose M here: the
> + module will be called max77693-haptic.
> +
> config INPUT_MAX8925_ONKEY
> tristate "MAX8925 ONKEY support"
> depends on MFD_MAX8925
> diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile
> index 4955ad3..b28570c 100644
> --- a/drivers/input/misc/Makefile
> +++ b/drivers/input/misc/Makefile
> @@ -35,6 +35,7 @@ obj-$(CONFIG_INPUT_IXP4XX_BEEPER) += ixp4xx-beeper.o
> obj-$(CONFIG_INPUT_KEYSPAN_REMOTE) += keyspan_remote.o
> obj-$(CONFIG_INPUT_KXTJ9) += kxtj9.o
> obj-$(CONFIG_INPUT_M68K_BEEP) += m68kspkr.o
> +obj-$(CONFIG_INPUT_MAX77693_HAPTIC) += max77693-haptic.o
> obj-$(CONFIG_INPUT_MAX8925_ONKEY) += max8925_onkey.o
> obj-$(CONFIG_INPUT_MAX8997_HAPTIC) += max8997_haptic.o
> obj-$(CONFIG_INPUT_MC13783_PWRBUTTON) += mc13783-pwrbutton.o
> diff --git a/drivers/input/misc/max77693-haptic.c b/drivers/input/misc/max77693-haptic.c
> new file mode 100644
> index 0000000..2a69496
> --- /dev/null
> +++ b/drivers/input/misc/max77693-haptic.c
> @@ -0,0 +1,333 @@
> +/*
> + * max77693-haptic.c - MAXIM MAX77693 Haptic device driver
> + *
> + * Copyright (C) 2014 Samsung Electronics
> + * Jaewon Kim <jaewon02.kim@samsung.com>
> + *
> + * This program is not provided / owned by Maxim Integrated Products.
> + *
> + * 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.
> + */
> +
> +#include <linux/err.h>
> +#include <linux/init.h>
> +#include <linux/i2c.h>
> +#include <linux/regmap.h>
> +#include <linux/input.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/pwm.h>
> +#include <linux/slab.h>
> +#include <linux/workqueue.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/mfd/max77693.h>
> +#include <linux/mfd/max77693-private.h>
> +
> +#define MAX_MAGNITUDE_SHIFT 16
> +
> +enum max77693_haptic_motor_type {
> + MAX77693_HAPTIC_ERM = 0,
> + MAX77693_HAPTIC_LRA,
> +};
> +
> +enum max77693_haptic_pulse_mode {
> + MAX77693_HAPTIC_EXTERNAL_MODE = 0,
> + MAX77693_HAPTIC_INTERNAL_MODE,
> +};
> +
> +enum max77693_haptic_pwm_divisor {
> + MAX77693_HAPTIC_PWM_DIVISOR_32 = 0,
> + MAX77693_HAPTIC_PWM_DIVISOR_64,
> + MAX77693_HAPTIC_PWM_DIVISOR_128,
> + MAX77693_HAPTIC_PWM_DIVISOR_256,
> +};
> +
> +struct max77693_haptic {
> + struct regmap *regmap_pmic;
> + struct regmap *regmap_haptic;
> + struct device *dev;
> + struct input_dev *input_dev;
> + struct pwm_device *pwm_dev;
> + struct regulator *motor_reg;
> +
> + bool enabled;
> + unsigned int magnitude;
> + enum max77693_haptic_motor_type type;
> + enum max77693_haptic_pulse_mode mode;
> + enum max77693_haptic_pwm_divisor pwm_divisor;
> +
> + struct mutex mutex;
> + struct work_struct work;
> +};
> +
> +static int max77693_haptic_set_duty_cycle(struct max77693_haptic *haptic,
> + unsigned int pwm_duty)
> +{
> + int ret;
> + int delta = (haptic->pwm_dev->period + pwm_duty)/2;
> +
> + ret = pwm_config(haptic->pwm_dev, delta, haptic->pwm_dev->period);
> + if (ret) {
> + dev_err(haptic->dev, "cannot configuration pwm\n");
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static int max77693_haptic_configure(struct max77693_haptic *haptic,
> + unsigned int enable)
> +{
> + int ret;
> + unsigned int value = 0;
> +
> + value = ((haptic->type << MAX77693_CONFIG2_MODE) |
> + (enable << MAX77693_CONFIG2_MEN) |
> + (haptic->mode << MAX77693_CONFIG2_HTYP) |
> + (haptic->pwm_divisor));
> +
> + ret = regmap_write(haptic->regmap_haptic,
> + MAX77693_HAPTIC_REG_CONFIG2, value);
> + if (ret) {
> + dev_err(haptic->dev, "cannot write haptic regmap\n");
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static int max77693_haptic_lowsys(struct max77693_haptic *haptic,
> + unsigned int enable)
> +{
> + int ret;
> +
> + ret = regmap_update_bits(haptic->regmap_pmic,
> + MAX77693_PMIC_REG_LSCNFG,
> + MAX77693_PMIC_LOW_SYS_MASK,
> + enable << MAX77693_PMIC_LOW_SYS_SHIFT);
> + if (ret) {
> + dev_err(haptic->dev, "cannot update pmic regmap\n");
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static void max77693_haptic_enable(struct max77693_haptic *haptic)
> +{
> + int ret;
> +
> + if (haptic->enabled)
> + return;
> +
> + ret = pwm_enable(haptic->pwm_dev);
> + if (ret < 0) {
> + dev_err(haptic->dev, "cannot enable haptic pwm device");
> + return;
> + }
> +
> + ret = regulator_enable(haptic->motor_reg);
> + if (ret) {
> + dev_err(haptic->dev, "cannot enable haptic regulator\n");
> + goto err_pwm_enable;
> + }
> +
> + ret = max77693_haptic_lowsys(haptic, 1);
> + if (ret)
> + goto err_enable_lowsys;
> +
> + ret = max77693_haptic_configure(haptic, 1);
> + if (ret < 0)
> + goto err_enable_config;
> +
> + haptic->enabled = true;
> +
> + return;
> +
> +err_enable_config:
> + max77693_haptic_lowsys(haptic, 0);
> +err_enable_lowsys:
> + regulator_disable(haptic->motor_reg);
> +err_pwm_enable:
> + pwm_disable(haptic->pwm_dev);
> +}
> +
> +static void max77693_haptic_disable(struct max77693_haptic *haptic)
> +{
> + int ret;
> +
> + if (!haptic->enabled)
> + return;
> +
> + ret = max77693_haptic_configure(haptic, 0);
> + if (ret < 0)

Why sometimes you test for negative errors and sometimes for != 0 from the same
MFD core? Can you settle on one, preferably 0/!0, in which case please also call
local local variables holding the result 'error' so that you have sequences:

error = action();
if (error)
handle_error;

> + return;
> +
> + ret = max77693_haptic_lowsys(haptic, 0);
> + if (ret)
> + goto err_disable_lowsys;
> +
> + ret = regulator_disable(haptic->motor_reg);
> + if (ret) {
> + dev_err(haptic->dev, "cannot disable haptic regulator\n");
> + goto err_reg_disable;
> + }
> +
> + pwm_disable(haptic->pwm_dev);
> + haptic->enabled = false;
> +
> + return;
> +
> +err_reg_disable:
> + max77693_haptic_lowsys(haptic, 1);
> +err_disable_lowsys:
> + max77693_haptic_configure(haptic, 1);
> +}
> +
> +static void max77693_haptic_play_work(struct work_struct *work)
> +{
> + struct max77693_haptic *haptic =
> + container_of(work, struct max77693_haptic, work);
> +
> + mutex_lock(&haptic->mutex);

Workqueues are not reentrant by default, you do not need this mutex.

> + if (haptic->magnitude)
> + max77693_haptic_enable(haptic);
> + else
> + max77693_haptic_disable(haptic);

Hmm, do you really want to bounce regulator on and off on every buzz? I guess
it may save some power...

> + mutex_unlock(&haptic->mutex);
> +}
> +
> +static int max77693_haptic_play_effect(struct input_dev *dev, void *data,
> + struct ff_effect *effect)
> +{
> + struct max77693_haptic *haptic = input_get_drvdata(dev);
> + uint64_t period_mag_multi;
> + unsigned int pwm_duty;
> + int ret;
> +
> + haptic->magnitude = effect->u.rumble.strong_magnitude;
> + if (!haptic->magnitude)
> + haptic->magnitude = effect->u.rumble.weak_magnitude;
> +
> + /*
> + * The magnitude comes from force-feedback interface.
> + * The formula convert magnitude to pwm_duty as following:
> + * - pwm_duty = (magnitude * pwm_period) / MAX_MAGNITUDE(0xFFFF)
> + */
> + period_mag_multi = (int64_t)(haptic->pwm_dev->period *
> + haptic->magnitude);
> + pwm_duty = (unsigned int)(period_mag_multi >> MAX_MAGNITUDE_SHIFT);
> + ret = max77693_haptic_set_duty_cycle(haptic, pwm_duty);

Why is this done here and not in max77693_haptic_play_work? Is it even safe to
access the device here (you are running under a spinlock with interrupts off).

> + if (ret)
> + return ret;
> +
> + schedule_work(&haptic->work);
> +
> + return 0;
> +}
> +
> +static void max77693_haptic_close(struct input_dev *dev)
> +{
> + struct max77693_haptic *haptic = input_get_drvdata(dev);
> +
> + cancel_work_sync(&haptic->work);
> + max77693_haptic_disable(haptic);
> +}
> +
> +static int max77693_haptic_probe(struct platform_device *pdev)
> +{
> + struct max77693_dev *max77693 = dev_get_drvdata(pdev->dev.parent);
> + struct max77693_haptic *haptic;
> + int ret = 0;
> +
> + haptic = devm_kzalloc(&pdev->dev, sizeof(*haptic), GFP_KERNEL);
> + if (!haptic)
> + return -ENOMEM;
> +
> + haptic->regmap_pmic = max77693->regmap;
> + haptic->regmap_haptic = max77693->regmap_haptic;
> + haptic->dev = &pdev->dev;
> + haptic->type = MAX77693_HAPTIC_LRA;
> + haptic->mode = MAX77693_HAPTIC_EXTERNAL_MODE;
> + haptic->pwm_divisor = MAX77693_HAPTIC_PWM_DIVISOR_128;
> + mutex_init(&haptic->mutex);
> +
> + /* Get pwm and regulatot for haptic device */
> + haptic->pwm_dev = devm_pwm_get(&pdev->dev, NULL);
> + if (IS_ERR(haptic->pwm_dev)) {
> + dev_err(&pdev->dev, "failed to get pwm device\n");
> + return PTR_ERR(haptic->pwm_dev);
> + }
> +
> + haptic->motor_reg = devm_regulator_get(&pdev->dev, "haptic");
> + if (IS_ERR(haptic->motor_reg)) {
> + dev_err(&pdev->dev, "failed to get regulator\n");
> + return PTR_ERR(haptic->motor_reg);
> + }
> +
> + /* Initialize input device for haptic device */
> + haptic->input_dev = devm_input_allocate_device(&pdev->dev);
> + if (!haptic->input_dev) {
> + dev_err(&pdev->dev, "failed to allocate input device\n");
> + return -ENOMEM;
> + }
> +
> + haptic->input_dev->name = "max77693-haptic";
> + haptic->input_dev->id.version = 1;
> + haptic->input_dev->dev.parent = &pdev->dev;
> + haptic->input_dev->close = max77693_haptic_close;
> + input_set_drvdata(haptic->input_dev, haptic);
> + input_set_capability(haptic->input_dev, EV_FF, FF_RUMBLE);
> +
> + ret = input_ff_create_memless(haptic->input_dev, NULL,
> + max77693_haptic_play_effect);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to create force-feedback\n");
> + return ret;
> + }
> +
> + ret = input_register_device(haptic->input_dev);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to register input device\n");
> + goto err_input_device;
> + }
> +
> + INIT_WORK(&haptic->work, max77693_haptic_play_work);
> +
> + platform_set_drvdata(pdev, haptic);
> +
> + return 0;
> +
> +err_input_device:
> + input_ff_destroy(haptic->input_dev);

No need to call, will be done automatically.

> +
> + return ret;
> +}
> +
> +static int max77693_haptic_remove(struct platform_device *pdev)
> +{
> + struct max77693_haptic *haptic = platform_get_drvdata(pdev);
> +
> + max77693_haptic_disable(haptic);

It is done in close() so no need to cal here.

> + input_unregister_device(haptic->input_dev);

You are using devm so no need to call it either. Just remove
max77693_haptic_remove() altogether.

What you need I think is suspend/resume to make sure the device is shut off
when system is suspending.

> +
> + return 0;
> +}
> +
> +static struct platform_driver max77693_haptic_driver = {
> + .driver = {
> + .name = "max77693-haptic",
> + .owner = THIS_MODULE,
> + },
> + .probe = max77693_haptic_probe,
> + .remove = max77693_haptic_remove,
> +};
> +module_platform_driver(max77693_haptic_driver);
> +
> +MODULE_AUTHOR("Jaewon Kim <jaewon02.kim@samsung.com>");
> +MODULE_DESCRIPTION("MAXIM MAX77693 Haptic driver");
> +MODULE_ALIAS("platform:max77693-haptic");
> +MODULE_LICENSE("GPL");
> diff --git a/include/linux/mfd/max77693-private.h b/include/linux/mfd/max77693-private.h
> index c466ff3..d0e578f 100644
> --- a/include/linux/mfd/max77693-private.h
> +++ b/include/linux/mfd/max77693-private.h
> @@ -251,6 +251,15 @@ enum max77693_haptic_reg {
> MAX77693_HAPTIC_REG_END,
> };
>
> +/* max77693-pmic LSCNFG configuraton register */
> +#define MAX77693_PMIC_LOW_SYS_MASK 0x80
> +#define MAX77693_PMIC_LOW_SYS_SHIFT 7
> +
> +/* max77693-haptic configuration register */
> +#define MAX77693_CONFIG2_MODE 7
> +#define MAX77693_CONFIG2_MEN 6
> +#define MAX77693_CONFIG2_HTYP 5
> +
> enum max77693_irq_source {
> LED_INT = 0,
> TOPSYS_INT,
> --
> 1.7.9.5
>

Thanks.

--
Dmitry