Re: [PATCH v5 7/7] input: keyboard: support i.MX95 BBM module

[Cristian Marussi]

On Fri, Jun 21, 2024 at 03:04:42PM +0800, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan@xxxxxxx>
> 
> The BBM module provides BUTTON feature. To i.MX95, this module
> is managed by System Manager and exported using System Management
> Control Interface(SCMI). Linux could use i.MX SCMI BBM Extension
> protocol to use BUTTON feature.

Hi Peng,

one remarks down below.

> 
> This driver is to use SCMI interface to enable pwrkey.
> 
> Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
> ---
>  drivers/input/keyboard/Kconfig          |  11 ++
>  drivers/input/keyboard/Makefile         |   1 +
>  drivers/input/keyboard/imx-sm-bbm-key.c | 225 ++++++++++++++++++++++++++++++++
>  3 files changed, 237 insertions(+)
> 
> diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
> index 1d0c5f4c0f99..1c3fef7d34af 100644
> --- a/drivers/input/keyboard/Kconfig
> +++ b/drivers/input/keyboard/Kconfig
> @@ -466,6 +466,17 @@ config KEYBOARD_IMX
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called imx_keypad.
>  
> +config KEYBOARD_IMX_BBM_SCMI
> +	tristate "IMX BBM SCMI Key Driver"
> +	depends on IMX_SCMI_BBM_EXT || COMPILE_TEST
> +	default y if ARCH_MXC
> +	help
> +	  This is the BBM key driver for NXP i.MX SoCs managed through
> +	  SCMI protocol.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called scmi-imx-bbm-key.
> +
>  config KEYBOARD_IMX_SC_KEY
>  	tristate "IMX SCU Key Driver"
>  	depends on IMX_SCU
> diff --git a/drivers/input/keyboard/Makefile b/drivers/input/keyboard/Makefile
> index aecef00c5d09..624c90adde89 100644
> --- a/drivers/input/keyboard/Makefile
> +++ b/drivers/input/keyboard/Makefile
> @@ -31,6 +31,7 @@ obj-$(CONFIG_KEYBOARD_IPAQ_MICRO)	+= ipaq-micro-keys.o
>  obj-$(CONFIG_KEYBOARD_IQS62X)		+= iqs62x-keys.o
>  obj-$(CONFIG_KEYBOARD_IMX)		+= imx_keypad.o
>  obj-$(CONFIG_KEYBOARD_IMX_SC_KEY)	+= imx_sc_key.o
> +obj-$(CONFIG_KEYBOARD_IMX_BBM_SCMI)	+= imx-sm-bbm-key.o
>  obj-$(CONFIG_KEYBOARD_HP6XX)		+= jornada680_kbd.o
>  obj-$(CONFIG_KEYBOARD_HP7XX)		+= jornada720_kbd.o
>  obj-$(CONFIG_KEYBOARD_LKKBD)		+= lkkbd.o
> diff --git a/drivers/input/keyboard/imx-sm-bbm-key.c b/drivers/input/keyboard/imx-sm-bbm-key.c
> new file mode 100644
> index 000000000000..907dad383b8f
> --- /dev/null
> +++ b/drivers/input/keyboard/imx-sm-bbm-key.c
> @@ -0,0 +1,225 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright 2024 NXP.
> + */
> +
> +#include <linux/input.h>
> +#include <linux/jiffies.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/rtc.h>
> +#include <linux/scmi_protocol.h>
> +#include <linux/scmi_imx_protocol.h>
> +#include <linux/suspend.h>
> +
> +#define DEBOUNCE_TIME		30
> +#define REPEAT_INTERVAL		60
> +
> +struct scmi_imx_bbm {
> +	struct scmi_protocol_handle *ph;
> +	const struct scmi_imx_bbm_proto_ops *ops;
> +	struct notifier_block nb;
> +	int keycode;
> +	int keystate;  /* 1:pressed */
> +	bool suspended;
> +	struct delayed_work check_work;
> +	struct input_dev *input;
> +};
> +
> +static void scmi_imx_bbm_pwrkey_check_for_events(struct work_struct *work)
> +{
> +	struct scmi_imx_bbm *bbnsm = container_of(to_delayed_work(work),
> +						  struct scmi_imx_bbm, check_work);
> +	struct scmi_protocol_handle *ph = bbnsm->ph;
> +	struct input_dev *input = bbnsm->input;
> +	u32 state = 0;
> +	int ret;
> +
> +	ret = bbnsm->ops->button_get(ph, &state);
> +	if (ret) {
> +		pr_err("%s: %d\n", __func__, ret);
> +		return;
> +	}
> +
> +	pr_debug("%s: state: %d, keystate %d\n", __func__, state, bbnsm->keystate);
> +
> +	/* only report new event if status changed */
> +	if (state ^ bbnsm->keystate) {
> +		bbnsm->keystate = state;
> +		input_event(input, EV_KEY, bbnsm->keycode, state);
> +		input_sync(input);
> +		pm_relax(bbnsm->input->dev.parent);
> +		pr_debug("EV_KEY: %x\n", bbnsm->keycode);
> +	}
> +
> +	/* repeat check if pressed long */
> +	if (state)
> +		schedule_delayed_work(&bbnsm->check_work, msecs_to_jiffies(REPEAT_INTERVAL));
> +}
> +
> +static int scmi_imx_bbm_pwrkey_event(struct scmi_imx_bbm *bbnsm)
> +{
> +	struct input_dev *input = bbnsm->input;
> +
> +	pm_wakeup_event(input->dev.parent, 0);
> +
> +	schedule_delayed_work(&bbnsm->check_work, msecs_to_jiffies(DEBOUNCE_TIME));
> +
> +	/*
> +	 * Directly report key event after resume to make no key press
> +	 * event is missed.
> +	 */
> +	if (READ_ONCE(bbnsm->suspended)) {
> +		bbnsm->keystate = 1;
> +		input_event(input, EV_KEY, bbnsm->keycode, 1);
> +		input_sync(input);
> +		WRITE_ONCE(bbnsm->suspended, false);
> +	}
> +
> +	return 0;
> +}
> +
> +static void scmi_imx_bbm_pwrkey_act(void *pdata)
> +{
> +	struct scmi_imx_bbm *bbnsm = pdata;
> +
> +	cancel_delayed_work_sync(&bbnsm->check_work);
> +}
> +
> +static int scmi_imx_bbm_key_notifier(struct notifier_block *nb, unsigned long event, void *data)
> +{
> +	struct scmi_imx_bbm *bbnsm = container_of(nb, struct scmi_imx_bbm, nb);
> +	struct scmi_imx_bbm_notif_report *r = data;
> +
> +	if (r->is_button) {
> +		pr_debug("BBM Button Power key pressed\n");
> +		scmi_imx_bbm_pwrkey_event(bbnsm);
> +	} else {
> +		/* Should never reach here */
> +		pr_err("Unexpected BBM event: %s\n", __func__);
> +	}
> +
> +	return 0;
> +}
> +
> +static int scmi_imx_bbm_pwrkey_init(struct scmi_device *sdev)
> +{
> +	const struct scmi_handle *handle = sdev->handle;
> +	struct device *dev = &sdev->dev;
> +	struct scmi_imx_bbm *bbnsm = dev_get_drvdata(dev);
> +	struct input_dev *input;
> +	int ret;
> +
> +	if (device_property_read_u32(dev, "linux,code", &bbnsm->keycode)) {
> +		bbnsm->keycode = KEY_POWER;
> +		dev_warn(dev, "key code is not specified, using default KEY_POWER\n");
> +	}
> +
> +	INIT_DELAYED_WORK(&bbnsm->check_work, scmi_imx_bbm_pwrkey_check_for_events);

To stay on the safe side I would issue a cancel_delayed_work_sync()
somewhere along the remove() path of this driver...just to be sure
there is not an  actively scheduled deleayed work queued while we are
shutting down.....I maybe overly paranoic...but seems a safe thing to do O_o

Thanks,
Cristian