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SubjectRe: [PATCH v2 5/6] input: atc260x: Add onkey driver for ATC260x PMICs
Hi Cristian,

On Fri, Sep 18, 2020 at 01:35:03PM +0300, Cristian Ciocaltea wrote:
> Hi Dmitry,
>
> Thanks for the review!
>
> On Mon, Sep 14, 2020 at 02:09:41PM -0700, Dmitry Torokhov wrote:
> > Hi Cristian,
> >
> > On Sat, Aug 22, 2020 at 01:19:51AM +0300, Cristian Ciocaltea wrote:
> > > The Actions Semi ATC260x PMICs are able to manage an onkey button.
> > > This driver exposes the ATC260x onkey as an input device. It can also
> > > be configured to force a system reset on a long key-press with an
> > > adjustable duration.
> > >
> > > The currently supported chip variants are ATC2603C and ATC2609A.
> > >
> > > Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@gmail.com>
> > > ---
> > > drivers/input/misc/Kconfig | 11 ++
> > > drivers/input/misc/Makefile | 2 +-
> > > drivers/input/misc/atc260x-onkey.c | 304 +++++++++++++++++++++++++++++
> > > 3 files changed, 316 insertions(+), 1 deletion(-)
> > > create mode 100644 drivers/input/misc/atc260x-onkey.c
> > >
> > > diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
> > > index 362e8a01980c..9e297ebdea57 100644
> > > --- a/drivers/input/misc/Kconfig
> > > +++ b/drivers/input/misc/Kconfig
> > > @@ -83,6 +83,17 @@ config INPUT_ARIZONA_HAPTICS
> > > To compile this driver as a module, choose M here: the
> > > module will be called arizona-haptics.
> > >
> > > +config INPUT_ATC260X_ONKEY
> > > + tristate "Actions Semi ATC260x PMIC ONKEY"
> > > + depends on MFD_ATC260X
> > > + help
> > > + Support the ONKEY of ATC260x PMICs as an input device reporting
> > > + power button status. ONKEY can be used to wakeup from low power
> > > + modes and force a reset on long press.
> > > +
> > > + To compile this driver as a module, choose M here: the
> > > + module will be called atc260x-onkey.
> > > +
> > > config INPUT_ATMEL_CAPTOUCH
> > > tristate "Atmel Capacitive Touch Button Driver"
> > > depends on OF || COMPILE_TEST
> > > diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile
> > > index a48e5f2d859d..7f854c6ecefa 100644
> > > --- a/drivers/input/misc/Makefile
> > > +++ b/drivers/input/misc/Makefile
> > > @@ -16,6 +16,7 @@ obj-$(CONFIG_INPUT_ADXL34X_I2C) += adxl34x-i2c.o
> > > obj-$(CONFIG_INPUT_ADXL34X_SPI) += adxl34x-spi.o
> > > obj-$(CONFIG_INPUT_APANEL) += apanel.o
> > > obj-$(CONFIG_INPUT_ARIZONA_HAPTICS) += arizona-haptics.o
> > > +obj-$(CONFIG_INPUT_ATC260X_ONKEY) += atc260x-onkey.o
> > > obj-$(CONFIG_INPUT_ATI_REMOTE2) += ati_remote2.o
> > > obj-$(CONFIG_INPUT_ATLAS_BTNS) += atlas_btns.o
> > > obj-$(CONFIG_INPUT_ATMEL_CAPTOUCH) += atmel_captouch.o
> > > @@ -84,4 +85,3 @@ obj-$(CONFIG_INPUT_WM831X_ON) += wm831x-on.o
> > > obj-$(CONFIG_INPUT_XEN_KBDDEV_FRONTEND) += xen-kbdfront.o
> > > obj-$(CONFIG_INPUT_YEALINK) += yealink.o
> > > obj-$(CONFIG_INPUT_IDEAPAD_SLIDEBAR) += ideapad_slidebar.o
> > > -
> > > diff --git a/drivers/input/misc/atc260x-onkey.c b/drivers/input/misc/atc260x-onkey.c
> > > new file mode 100644
> > > index 000000000000..7caec7d6f9ac
> > > --- /dev/null
> > > +++ b/drivers/input/misc/atc260x-onkey.c
> > > @@ -0,0 +1,304 @@
> > > +// SPDX-License-Identifier: GPL-2.0+
> > > +/*
> > > + * Onkey driver for Actions Semi ATC260x PMICs.
> > > + *
> > > + * Copyright (c) 2020 Cristian Ciocaltea <cristian.ciocaltea@gmail.com>
> > > + */
> > > +
> > > +#include <linux/bitfield.h>
> > > +#include <linux/input.h>
> > > +#include <linux/interrupt.h>
> > > +#include <linux/mfd/atc260x/core.h>
> > > +#include <linux/module.h>
> > > +#include <linux/of.h>
> > > +#include <linux/platform_device.h>
> > > +#include <linux/regmap.h>
> > > +
> > > +/* <2s for short press, >2s for long press */
> > > +#define KEY_PRESS_TIME_SEC 2
> > > +
> > > +/* Driver internals */
> > > +enum atc260x_onkey_reset_status {
> > > + KEY_RESET_HW_DEFAULT,
> > > + KEY_RESET_DISABLED,
> > > + KEY_RESET_USER_SEL,
> > > +};
> > > +
> > > +struct atc260x_onkey_params {
> > > + u32 reg_int_ctl;
> > > + u32 kdwn_state_bm;
> > > + u32 long_int_pnd_bm;
> > > + u32 short_int_pnd_bm;
> > > + u32 kdwn_int_pnd_bm;
> > > + u32 press_int_en_bm;
> > > + u32 kdwn_int_en_bm;
> > > + u32 press_time_bm;
> > > + u32 reset_en_bm;
> > > + u32 reset_time_bm;
> > > +};
> > > +
> > > +struct atc260x_onkey {
> > > + struct atc260x *atc260x;
> > > + const struct atc260x_onkey_params *params;
> > > + struct input_dev *input_dev;
> > > + struct delayed_work work;
> > > +};
> > > +
> > > +static const struct atc260x_onkey_params atc2603c_onkey_params = {
> > > + .reg_int_ctl = ATC2603C_PMU_SYS_CTL2,
> > > + .long_int_pnd_bm = ATC2603C_PMU_SYS_CTL2_ONOFF_LONG_PRESS,
> > > + .short_int_pnd_bm = ATC2603C_PMU_SYS_CTL2_ONOFF_SHORT_PRESS,
> > > + .kdwn_int_pnd_bm = ATC2603C_PMU_SYS_CTL2_ONOFF_PRESS_PD,
> > > + .press_int_en_bm = ATC2603C_PMU_SYS_CTL2_ONOFF_INT_EN,
> > > + .kdwn_int_en_bm = ATC2603C_PMU_SYS_CTL2_ONOFF_PRESS_INT_EN,
> > > + .kdwn_state_bm = ATC2603C_PMU_SYS_CTL2_ONOFF_PRESS,
> > > + .press_time_bm = ATC2603C_PMU_SYS_CTL2_ONOFF_PRESS_TIME,
> > > + .reset_en_bm = ATC2603C_PMU_SYS_CTL2_ONOFF_PRESS_RESET_EN,
> > > + .reset_time_bm = ATC2603C_PMU_SYS_CTL2_ONOFF_RESET_TIME_SEL,
> > > +};
> > > +
> > > +static const struct atc260x_onkey_params atc2609a_onkey_params = {
> > > + .reg_int_ctl = ATC2609A_PMU_SYS_CTL2,
> > > + .long_int_pnd_bm = ATC2609A_PMU_SYS_CTL2_ONOFF_LONG_PRESS,
> > > + .short_int_pnd_bm = ATC2609A_PMU_SYS_CTL2_ONOFF_SHORT_PRESS,
> > > + .kdwn_int_pnd_bm = ATC2609A_PMU_SYS_CTL2_ONOFF_PRESS_PD,
> > > + .press_int_en_bm = ATC2609A_PMU_SYS_CTL2_ONOFF_LSP_INT_EN,
> > > + .kdwn_int_en_bm = ATC2609A_PMU_SYS_CTL2_ONOFF_PRESS_INT_EN,
> > > + .kdwn_state_bm = ATC2609A_PMU_SYS_CTL2_ONOFF_PRESS,
> > > + .press_time_bm = ATC2609A_PMU_SYS_CTL2_ONOFF_PRESS_TIME,
> > > + .reset_en_bm = ATC2609A_PMU_SYS_CTL2_ONOFF_RESET_EN,
> > > + .reset_time_bm = ATC2609A_PMU_SYS_CTL2_ONOFF_RESET_TIME_SEL,
> > > +};
> > > +
> > > +static int atc2603x_onkey_hw_init(struct atc260x_onkey *onkey,
> > > + enum atc260x_onkey_reset_status reset_status,
> > > + u32 reset_time, u32 press_time)
> > > +{
> > > + u32 reg_bm, reg_val;
> > > +
> > > + reg_bm = onkey->params->long_int_pnd_bm |
> > > + onkey->params->short_int_pnd_bm |
> > > + onkey->params->kdwn_int_pnd_bm |
> > > + onkey->params->press_int_en_bm |
> > > + onkey->params->kdwn_int_en_bm;
> > > +
> > > + reg_val = reg_bm | press_time;
> > > + reg_bm |= onkey->params->press_time_bm;
> > > +
> > > + if (reset_status == KEY_RESET_DISABLED) {
> > > + reg_bm |= onkey->params->reset_en_bm;
> > > + } else if (reset_status == KEY_RESET_USER_SEL) {
> > > + reg_bm |= onkey->params->reset_en_bm |
> > > + onkey->params->reset_time_bm;
> > > + reg_val |= onkey->params->reset_en_bm | reset_time;
> > > + }
> > > +
> > > + return regmap_update_bits(onkey->atc260x->regmap,
> > > + onkey->params->reg_int_ctl, reg_bm, reg_val);
> > > +}
> > > +
> > > +static void atc260x_onkey_query(struct atc260x_onkey *onkey)
> > > +{
> > > + u32 reg_bits;
> > > + int ret, key_down;
> > > +
> > > + ret = regmap_read(onkey->atc260x->regmap,
> > > + onkey->params->reg_int_ctl, &key_down);
> > > + if (ret) {
> > > + key_down = 1;
> > > + dev_err(onkey->atc260x->dev,
> > > + "Failed to read onkey status: %d\n", ret);
> > > + } else {
> > > + key_down &= onkey->params->kdwn_state_bm;
> > > + }
> > > +
> > > + /*
> > > + * The hardware generates interrupt only when the onkey pin is
> > > + * asserted. Hence, the deassertion of the pin is simulated through
> > > + * work queue.
> > > + */
> > > + if (key_down) {
> > > + schedule_delayed_work(&onkey->work, msecs_to_jiffies(200));
> > > + return;
> > > + }
> > > +
> > > + /*
> > > + * The key-down status bit is cleared when the On/Off button
> > > + * is released.
> > > + */
> > > + input_report_key(onkey->input_dev, KEY_POWER, 0);
> > > + input_sync(onkey->input_dev);
> > > +
> > > + reg_bits = onkey->params->long_int_pnd_bm |
> > > + onkey->params->short_int_pnd_bm |
> > > + onkey->params->kdwn_int_pnd_bm |
> > > + onkey->params->press_int_en_bm |
> > > + onkey->params->kdwn_int_en_bm;
> > > +
> > > + /* Clear key press pending events and enable key press interrupts. */
> > > + regmap_update_bits(onkey->atc260x->regmap, onkey->params->reg_int_ctl,
> > > + reg_bits, reg_bits);
> > > +}
> > > +
> > > +static void atc260x_onkey_work(struct work_struct *work)
> > > +{
> > > + struct atc260x_onkey *onkey = container_of(work, struct atc260x_onkey,
> > > + work.work);
> > > + atc260x_onkey_query(onkey);
> > > +}
> > > +
> > > +static irqreturn_t atc260x_onkey_irq(int irq, void *data)
> > > +{
> > > + struct atc260x_onkey *onkey = data;
> > > + int ret;
> > > +
> > > + /* Disable key press interrupts. */
> > > + ret = regmap_update_bits(onkey->atc260x->regmap,
> > > + onkey->params->reg_int_ctl,
> > > + onkey->params->press_int_en_bm |
> > > + onkey->params->kdwn_int_en_bm, 0);
> > > + if (ret)
> > > + dev_err(onkey->atc260x->dev,
> > > + "Failed to disable interrupts: %d\n", ret);
> > > +
> > > + input_report_key(onkey->input_dev, KEY_POWER, 1);
> > > + input_sync(onkey->input_dev);
> > > +
> > > + atc260x_onkey_query(onkey);
> > > +
> > > + return IRQ_HANDLED;
> > > +}
> > > +
> > > +static int atc260x_onkey_probe(struct platform_device *pdev)
> > > +{
> > > + struct atc260x *atc260x = dev_get_drvdata(pdev->dev.parent);
> > > + struct atc260x_onkey *onkey;
> > > + struct input_dev *input_dev;
> > > + enum atc260x_onkey_reset_status reset_status;
> > > + u32 press_time = KEY_PRESS_TIME_SEC, reset_time = 0;
> > > + int val, irq, ret;
> > > +
> > > + if (!pdev->dev.of_node)
> > > + return -ENXIO;
> >
> > Why is this needed?
>
> The idea was to allow the user enable/disable the ONKEY functionality
> of the MFD device via the 'onkey' DTS node. So if this node is not
> present, the driver will not be loaded.
>
> Is there a better/recommended way to handle this scenario?

I believe the best way is not to create correspnding platform device if
functionality is disabled. So the logic shoudl go into MFD piece.

>
> > > +
> > > + onkey = devm_kzalloc(&pdev->dev, sizeof(*onkey), GFP_KERNEL);
> > > + if (!onkey)
> > > + return -ENOMEM;
> > > +
> > > + ret = device_property_read_u32(&pdev->dev,
> > > + "actions,reset-time-sec", &val);
> >
> > Call this "error" please.
>
> Would something like bellow suffice?
>
> if (ret) {
> dev_err(&pdev->dev, "Failed to read actions,reset-time-sec\n");
> return ret;
> }


I meant

error = device_property_read_u32(&pdev->dev,
"actions,reset-time-sec", &val);
if (error) {
reset_status = KEY_RESET_HW_DEFAULT;
}


>
> > > + if (ret) {
> > > + reset_status = KEY_RESET_HW_DEFAULT;
> > > + } else if (val) {
> > > + if (val < 6 || val > 12) {
> > > + dev_err(&pdev->dev, "actions,reset-time-sec out of range\n");
> > > + return -EINVAL;
> > > + }
> > > +
> > > + reset_status = KEY_RESET_USER_SEL;
> > > + reset_time = (val - 6) / 2;
> > > + } else {
> > > + reset_status = KEY_RESET_DISABLED;
> > > + dev_info(&pdev->dev, "Disabled reset on long-press\n");

dev_dbg();

> > > + }
> > > +
> > > + switch (atc260x->ic_type) {
> > > + case ATC2603C:
> > > + onkey->params = &atc2603c_onkey_params;
> > > + press_time = FIELD_PREP(ATC2603C_PMU_SYS_CTL2_ONOFF_PRESS_TIME,
> > > + press_time);
> > > + reset_time = FIELD_PREP(ATC2603C_PMU_SYS_CTL2_ONOFF_RESET_TIME_SEL,
> > > + reset_time);
> > > + break;
> > > + case ATC2609A:
> > > + onkey->params = &atc2609a_onkey_params;
> > > + press_time = FIELD_PREP(ATC2609A_PMU_SYS_CTL2_ONOFF_PRESS_TIME,
> > > + press_time);
> > > + reset_time = FIELD_PREP(ATC2609A_PMU_SYS_CTL2_ONOFF_RESET_TIME_SEL,
> > > + reset_time);
> > > + break;
> > > + default:
> > > + dev_err(&pdev->dev,
> > > + "OnKey not supported for ATC260x PMIC type: %u\n",
> > > + atc260x->ic_type);
> > > + return -EINVAL;
> > > + }
> > > +
> > > + input_dev = devm_input_allocate_device(&pdev->dev);
> > > + if (!input_dev) {
> > > + dev_err(&pdev->dev, "Failed to allocate input device\n");
> > > + return -ENOMEM;
> > > + }
> > > +
> > > + onkey->input_dev = input_dev;
> > > + onkey->atc260x = atc260x;
> > > +
> > > + input_dev->name = "atc260x-onkey";
> > > + input_dev->phys = "atc260x-onkey/input0";
> > > + input_dev->evbit[0] = BIT_MASK(EV_KEY);
> >
> > Not needed.
>
> Done.
>
> > > + input_set_capability(input_dev, EV_KEY, KEY_POWER);
> > > +
> > > + INIT_DELAYED_WORK(&onkey->work, atc260x_onkey_work);
> > > +
> > > + irq = platform_get_irq(pdev, 0);
> > > + if (irq < 0)
> > > + return irq;
> > > +
> > > + ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
> > > + atc260x_onkey_irq,
> > > + IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
> >
> > Do we need to force the trigger type? Can we rely on the parent to
> > configure it as needed?
>
> Done, I removed the trigger type enforcement.
>
> > > + dev_name(&pdev->dev), onkey);
> > > + if (ret) {
> > > + dev_err(&pdev->dev,
> > > + "Failed to register IRQ %d: %d\n", irq, ret);
> > > + return ret;
> > > + }
> > > +
> > > + ret = input_register_device(input_dev);
> > > + if (ret) {
> > > + dev_err(&pdev->dev,
> > > + "Failed to register input device: %d\n", ret);
> > > + return ret;
> > > + }
> > > +
> > > + ret = atc2603x_onkey_hw_init(onkey, reset_status,
> > > + reset_time, press_time);
> > > + if (ret)
> > > + return ret;
> > > +
> > > + platform_set_drvdata(pdev, onkey);
> > > + device_init_wakeup(&pdev->dev, true);
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +static int atc260x_onkey_remove(struct platform_device *pdev)
> > > +{
> > > + struct atc260x_onkey *onkey = platform_get_drvdata(pdev);
> > > +
> > > + cancel_delayed_work_sync(&onkey->work);
> >
> > This is racy. Past this point the interrupts are not disabled, so if key
> > happens to be pressed you will re-schedule the work and it will go BOOM.
> >
> > You are using threaded interrupt. Maybe consider sleeping and
> > re-checking the key status right there.
>
> I've seen this approach in a few drivers: da9055_onkey.c,
> palmas-pwrbutton.c, wm831x-on.c
>
> I noticed they also call 'free_irq()' right before
> 'cancel_delayed_work_sync()'. Would this help mitigate the racing issue?

Yes, but this messes up with devm releasing resources.

Another option is to implement open/close and call enable_irq() in open
and disable_irq/cancel_work_sync in close.

Thanks.

--
Dmitry

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