Re: [PATCH 2/2] input: cros_ec_keyb: Add non-matrix buttons and switches

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

On Fri, Jan 20, 2017 at 11:14:15AM +0100, Enric Balletbo i Serra wrote:
> From: Douglas Anderson <dianders@chromium.org>
> 
> On some newer boards using mkbp we're hooking up non-matrix buttons and
> switches to the EC but NOT to the main application processor.
> 
> Let's add kernel support to handle this.  Rather than creating a whole
> new input driver, we'll continue to use cros_ec_keyb and just report the
> new keys.
> 
> Signed-off-by: Douglas Anderson <dianders@chromium.org>
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>

Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

> ---
>  drivers/input/keyboard/cros_ec_keyb.c | 447 ++++++++++++++++++++++++++++++----
>  1 file changed, 402 insertions(+), 45 deletions(-)
> 
> diff --git a/drivers/input/keyboard/cros_ec_keyb.c b/drivers/input/keyboard/cros_ec_keyb.c
> index 25943e9..ad74ebc 100644
> --- a/drivers/input/keyboard/cros_ec_keyb.c
> +++ b/drivers/input/keyboard/cros_ec_keyb.c
> @@ -34,6 +34,8 @@
>  #include <linux/mfd/cros_ec.h>
>  #include <linux/mfd/cros_ec_commands.h>
>  
> +#include <asm/unaligned.h>
> +
>  /*
>   * @rows: Number of rows in the keypad
>   * @cols: Number of columns in the keypad
> @@ -43,8 +45,9 @@
>   * @valid_keys: bitmap of existing keys for each matrix column
>   * @old_kb_state: bitmap of keys pressed last scan
>   * @dev: Device pointer
> - * @idev: Input device
>   * @ec: Top level ChromeOS device to use to talk to EC
> + * @idev: The input device for the matrix keys.
> + * @bs_idev: The input device for non-matrix buttons and switches (or NULL).
>   * @notifier: interrupt event notifier for transport devices
>   */
>  struct cros_ec_keyb {
> @@ -57,12 +60,59 @@ struct cros_ec_keyb {
>  	uint8_t *old_kb_state;
>  
>  	struct device *dev;
> -	struct input_dev *idev;
>  	struct cros_ec_device *ec;
> +
> +	struct input_dev *idev;
> +	struct input_dev *bs_idev;
>  	struct notifier_block notifier;
>  };
>  
>  
> +/**
> + * cros_ec_bs_map - Struct mapping Linux keycodes to EC button/switch bitmap
> + * #defines
> + *
> + * @ev_type: The type of the input event to generate (e.g., EV_KEY).
> + * @code: A linux keycode
> + * @bit: A #define like EC_MKBP_POWER_BUTTON or EC_MKBP_LID_OPEN
> + * @inverted: If the #define and EV_SW have opposite meanings, this is true.
> + *            Only applicable to switches.
> + */
> +struct cros_ec_bs_map {
> +	unsigned int ev_type;
> +	unsigned int code;
> +	u8 bit;
> +	bool inverted;
> +};
> +
> +/* cros_ec_keyb_bs - Map EC button/switch #defines into kernel ones */
> +static const struct cros_ec_bs_map cros_ec_keyb_bs[] = {
> +	/* Buttons */
> +	{
> +		.ev_type	= EV_KEY,
> +		.code		= KEY_POWER,
> +		.bit		= EC_MKBP_POWER_BUTTON,
> +	},
> +	{
> +		.ev_type	= EV_KEY,
> +		.code		= KEY_VOLUMEUP,
> +		.bit		= EC_MKBP_VOL_UP,
> +	},
> +	{
> +		.ev_type	= EV_KEY,
> +		.code		= KEY_VOLUMEDOWN,
> +		.bit		= EC_MKBP_VOL_DOWN,
> +	},
> +
> +	/* Switches */
> +	{
> +		.ev_type	= EV_SW,
> +		.code		= SW_LID,
> +		.bit		= EC_MKBP_LID_OPEN,
> +		.inverted	= true,
> +	},
> +};
> +
>  /*
>   * Returns true when there is at least one combination of pressed keys that
>   * results in ghosting.
> @@ -149,20 +199,33 @@ static void cros_ec_keyb_process(struct cros_ec_keyb *ckdev,
>  	input_sync(ckdev->idev);
>  }
>  
> -static int cros_ec_keyb_open(struct input_dev *dev)
> +/**
> + * cros_ec_keyb_report_bs - Report non-matrixed buttons or switches
> + *
> + * This takes a bitmap of buttons or switches from the EC and reports events,
> + * syncing at the end.
> + *
> + * @ckdev: The keyboard device.
> + * @ev_type: The input event type (e.g., EV_KEY).
> + * @mask: A bitmap of buttons from the EC.
> + */
> +static void cros_ec_keyb_report_bs(struct cros_ec_keyb *ckdev,
> +				   unsigned int ev_type, u32 mask)
> +
>  {
> -	struct cros_ec_keyb *ckdev = input_get_drvdata(dev);
> +	struct input_dev *idev = ckdev->bs_idev;
> +	int i;
>  
> -	return blocking_notifier_chain_register(&ckdev->ec->event_notifier,
> -						&ckdev->notifier);
> -}
> +	for (i = 0; i < ARRAY_SIZE(cros_ec_keyb_bs); i++) {
> +		const struct cros_ec_bs_map *map = &cros_ec_keyb_bs[i];
>  
> -static void cros_ec_keyb_close(struct input_dev *dev)
> -{
> -	struct cros_ec_keyb *ckdev = input_get_drvdata(dev);
> +		if (map->ev_type != ev_type)
> +			continue;
>  
> -	blocking_notifier_chain_unregister(&ckdev->ec->event_notifier,
> -					   &ckdev->notifier);
> +		input_event(idev, ev_type, map->code,
> +			    !!(mask & BIT(map->bit)) ^ map->inverted);
> +	}
> +	input_sync(idev);
>  }
>  
>  static int cros_ec_keyb_work(struct notifier_block *nb,
> @@ -170,22 +233,54 @@ static int cros_ec_keyb_work(struct notifier_block *nb,
>  {
>  	struct cros_ec_keyb *ckdev = container_of(nb, struct cros_ec_keyb,
>  						  notifier);
> +	u32 val;
> +	unsigned int ev_type;
> +
> +	switch (ckdev->ec->event_data.event_type) {
> +	case EC_MKBP_EVENT_KEY_MATRIX:
> +		/*
> +		 * If EC is not the wake source, discard key state changes
> +		 * during suspend.
> +		 */
> +		if (queued_during_suspend)
> +			return NOTIFY_OK;
> +
> +		if (ckdev->ec->event_size != ckdev->cols) {
> +			dev_err(ckdev->dev,
> +				"Discarded incomplete key matrix event.\n");
> +			return NOTIFY_OK;
> +		}
> +		cros_ec_keyb_process(ckdev,
> +				     ckdev->ec->event_data.data.key_matrix,
> +				     ckdev->ec->event_size);
> +		break;
> +
> +	case EC_MKBP_EVENT_BUTTON:
> +	case EC_MKBP_EVENT_SWITCH:
> +		/*
> +		 * If EC is not the wake source, discard key state
> +		 * changes during suspend. Switches will be re-checked in
> +		 * cros_ec_keyb_resume() to be sure nothing is lost.
> +		 */
> +		if (queued_during_suspend)
> +			return NOTIFY_OK;
> +
> +		if (ckdev->ec->event_data.event_type == EC_MKBP_EVENT_BUTTON) {
> +			val = get_unaligned_le32(
> +					&ckdev->ec->event_data.data.buttons);
> +			ev_type = EV_KEY;
> +		} else {
> +			val = get_unaligned_le32(
> +					&ckdev->ec->event_data.data.switches);
> +			ev_type = EV_SW;
> +		}
> +		cros_ec_keyb_report_bs(ckdev, ev_type, val);
> +		break;
>  
> -	if (ckdev->ec->event_data.event_type != EC_MKBP_EVENT_KEY_MATRIX)
> +	default:
>  		return NOTIFY_DONE;
> -	/*
> -	 * If EC is not the wake source, discard key state changes during
> -	 * suspend.
> -	 */
> -	if (queued_during_suspend)
> -		return NOTIFY_OK;
> -	if (ckdev->ec->event_size != ckdev->cols) {
> -		dev_err(ckdev->dev,
> -			"Discarded incomplete key matrix event.\n");
> -		return NOTIFY_OK;
>  	}
> -	cros_ec_keyb_process(ckdev, ckdev->ec->event_data.data.key_matrix,
> -			     ckdev->ec->event_size);
> +
>  	return NOTIFY_OK;
>  }
>  
> @@ -213,22 +308,228 @@ static void cros_ec_keyb_compute_valid_keys(struct cros_ec_keyb *ckdev)
>  	}
>  }
>  
> -static int cros_ec_keyb_probe(struct platform_device *pdev)
> +/**
> + * cros_ec_keyb_info - Wrap the EC command EC_CMD_MKBP_INFO
> + *
> + * This wraps the EC_CMD_MKBP_INFO, abstracting out all of the marshalling and
> + * unmarshalling and different version nonsense into something simple.
> + *
> + * @ec_dev: The EC device
> + * @info_type: Either EC_MKBP_INFO_SUPPORTED or EC_MKBP_INFO_CURRENT.
> + * @event_type: Either EC_MKBP_EVENT_BUTTON or EC_MKBP_EVENT_SWITCH.  Actually
> + *              in some cases this could be EC_MKBP_EVENT_KEY_MATRIX or
> + *              EC_MKBP_EVENT_HOST_EVENT too but we don't use in this driver.
> + * @result: Where we'll store the result; a union
> + * @result_size: The size of the result.  Expected to be the size of one of
> + *               the elements in the union.
> + *
> + * Returns 0 if no error or -error upon error.
> + */
> +static int cros_ec_keyb_info(struct cros_ec_device *ec_dev,
> +			     enum ec_mkbp_info_type info_type,
> +			     enum ec_mkbp_event event_type,
> +			     union ec_response_get_next_data *result,
> +			     size_t result_size)
>  {
> -	struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
> -	struct device *dev = &pdev->dev;
> -	struct cros_ec_keyb *ckdev;
> +	struct ec_params_mkbp_info *params;
> +	struct cros_ec_command *msg;
> +	int ret;
> +
> +	msg = kzalloc(sizeof(*msg) + max_t(size_t, result_size,
> +					   sizeof(*params)), GFP_KERNEL);
> +	if (!msg)
> +		return -ENOMEM;
> +
> +	msg->command = EC_CMD_MKBP_INFO;
> +	msg->version = 1;
> +	msg->outsize = sizeof(*params);
> +	msg->insize = result_size;
> +	params = (struct ec_params_mkbp_info *)msg->data;
> +	params->info_type = info_type;
> +	params->event_type = event_type;
> +
> +	ret = cros_ec_cmd_xfer(ec_dev, msg);
> +	if (ret < 0) {
> +		dev_warn(ec_dev->dev, "Transfer error %d/%d: %d\n",
> +			 (int)info_type, (int)event_type, ret);
> +	} else if (msg->result == EC_RES_INVALID_VERSION) {
> +		/* With older ECs we just return 0 for everything */
> +		memset(result, 0, result_size);
> +		ret = 0;
> +	} else if (msg->result != EC_RES_SUCCESS) {
> +		dev_warn(ec_dev->dev, "Error getting info %d/%d: %d\n",
> +			 (int)info_type, (int)event_type, msg->result);
> +		ret = -EPROTO;
> +	} else if (ret != result_size) {
> +		dev_warn(ec_dev->dev, "Wrong size %d/%d: %d != %zu\n",
> +			 (int)info_type, (int)event_type,
> +			 ret, result_size);
> +		ret = -EPROTO;
> +	} else {
> +		memcpy(result, msg->data, result_size);
> +		ret = 0;
> +	}
> +
> +	kfree(msg);
> +
> +	return ret;
> +}
> +
> +/**
> + * cros_ec_keyb_query_switches - Query the state of switches and report
> + *
> + * This will ask the EC about the current state of switches and report to the
> + * kernel.  Note that we don't query for buttons because they are more
> + * transitory and we'll get an update on the next release / press.
> + *
> + * @ckdev: The keyboard device
> + *
> + * Returns 0 if no error or -error upon error.
> + */
> +static int cros_ec_keyb_query_switches(struct cros_ec_keyb *ckdev)
> +{
> +	struct cros_ec_device *ec_dev = ckdev->ec;
> +	union ec_response_get_next_data event_data = {};
> +	int ret;
> +
> +	ret = cros_ec_keyb_info(ec_dev, EC_MKBP_INFO_CURRENT,
> +				EC_MKBP_EVENT_SWITCH, &event_data,
> +				sizeof(event_data.switches));
> +	if (ret)
> +		return ret;
> +
> +	cros_ec_keyb_report_bs(ckdev, EV_SW,
> +			       get_unaligned_le32(&event_data.switches));
> +
> +	return 0;
> +}
> +
> +/**
> + * cros_ec_keyb_resume - Resume the keyboard
> + *
> + * We use the resume notification as a chance to query the EC for switches.
> + *
> + * @dev: The keyboard device
> + *
> + * Returns 0 if no error or -error upon error.
> + */
> +static __maybe_unused int cros_ec_keyb_resume(struct device *dev)
> +{
> +	struct cros_ec_keyb *ckdev = dev_get_drvdata(dev);
> +
> +	if (ckdev->bs_idev)
> +		return cros_ec_keyb_query_switches(ckdev);
> +
> +	return 0;
> +}
> +
> +/**
> + * cros_ec_keyb_register_bs - Register non-matrix buttons/switches
> + *
> + * Handles all the bits of the keyboard driver related to non-matrix buttons
> + * and switches, including asking the EC about which are present and telling
> + * the kernel to expect them.
> + *
> + * If this device has no support for buttons and switches we'll return no error
> + * but the ckdev->bs_idev will remain NULL when this function exits.
> + *
> + * @ckdev: The keyboard device
> + *
> + * Returns 0 if no error or -error upon error.
> + */
> +static int cros_ec_keyb_register_bs(struct cros_ec_keyb *ckdev)
> +{
> +	struct cros_ec_device *ec_dev = ckdev->ec;
> +	struct device *dev = ckdev->dev;
>  	struct input_dev *idev;
> -	struct device_node *np;
> -	int err;
> +	union ec_response_get_next_data event_data = {};
> +	const char *phys;
> +	u32 buttons;
> +	u32 switches;
> +	int ret;
> +	int i;
> +
> +	ret = cros_ec_keyb_info(ec_dev, EC_MKBP_INFO_SUPPORTED,
> +				EC_MKBP_EVENT_BUTTON, &event_data,
> +				sizeof(event_data.buttons));
> +	if (ret)
> +		return ret;
> +	buttons = get_unaligned_le32(&event_data.buttons);
> +
> +	ret = cros_ec_keyb_info(ec_dev, EC_MKBP_INFO_SUPPORTED,
> +				EC_MKBP_EVENT_SWITCH, &event_data,
> +				sizeof(event_data.switches));
> +	if (ret)
> +		return ret;
> +	switches = get_unaligned_le32(&event_data.switches);
> +
> +	if (!buttons && !switches)
> +		return 0;
>  
> -	np = pdev->dev.of_node;
> -	if (!np)
> -		return -ENODEV;
> +	/*
> +	 * We call the non-matrix buttons/switches 'input1', if present.
> +	 * Allocate phys before input dev, to ensure correct tear-down
> +	 * ordering.
> +	 */
> +	phys = devm_kasprintf(dev, GFP_KERNEL, "%s/input1", ec_dev->phys_name);
> +	if (!phys)
> +		return -ENOMEM;
>  
> -	ckdev = devm_kzalloc(dev, sizeof(*ckdev), GFP_KERNEL);
> -	if (!ckdev)
> +	idev = devm_input_allocate_device(dev);
> +	if (!idev)
>  		return -ENOMEM;
> +
> +	idev->name = "cros_ec_buttons";
> +	idev->phys = phys;
> +	__set_bit(EV_REP, idev->evbit);
> +
> +	idev->id.bustype = BUS_VIRTUAL;
> +	idev->id.version = 1;
> +	idev->id.product = 0;
> +	idev->dev.parent = dev;
> +
> +	input_set_drvdata(idev, ckdev);
> +	ckdev->bs_idev = idev;
> +
> +	for (i = 0; i < ARRAY_SIZE(cros_ec_keyb_bs); i++) {
> +		const struct cros_ec_bs_map *map = &cros_ec_keyb_bs[i];
> +
> +		if (buttons & BIT(map->bit))
> +			input_set_capability(idev, map->ev_type, map->code);
> +	}
> +
> +	ret = cros_ec_keyb_query_switches(ckdev);
> +	if (ret) {
> +		dev_err(dev, "cannot query switches\n");
> +		return ret;
> +	}
> +
> +	ret = input_register_device(ckdev->bs_idev);
> +	if (ret) {
> +		dev_err(dev, "cannot register input device\n");
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +/**
> + * cros_ec_keyb_register_bs - Register matrix keys
> + *
> + * Handles all the bits of the keyboard driver related to matrix keys.
> + *
> + * @ckdev: The keyboard device
> + *
> + * Returns 0 if no error or -error upon error.
> + */
> +static int cros_ec_keyb_register_matrix(struct cros_ec_keyb *ckdev)
> +{
> +	struct cros_ec_device *ec_dev = ckdev->ec;
> +	struct device *dev = ckdev->dev;
> +	struct input_dev *idev;
> +	const char *phys;
> +	int err;
> +
>  	err = matrix_keypad_parse_of_params(dev, &ckdev->rows, &ckdev->cols);
>  	if (err)
>  		return err;
> @@ -241,27 +542,28 @@ static int cros_ec_keyb_probe(struct platform_device *pdev)
>  	if (!ckdev->old_kb_state)
>  		return -ENOMEM;
>  
> +	/*
> +	 * We call the keyboard matrix 'input0'. Allocate phys before input
> +	 * dev, to ensure correct tear-down ordering.
> +	 */
> +	phys = devm_kasprintf(dev, GFP_KERNEL, "%s/input0", ec_dev->phys_name);
> +	if (!phys)
> +		return -ENOMEM;
> +
>  	idev = devm_input_allocate_device(dev);
>  	if (!idev)
>  		return -ENOMEM;
>  
> -	ckdev->ec = ec;
> -	ckdev->notifier.notifier_call = cros_ec_keyb_work;
> -	ckdev->dev = dev;
> -	dev_set_drvdata(dev, ckdev);
> -
>  	idev->name = CROS_EC_DEV_NAME;
> -	idev->phys = ec->phys_name;
> +	idev->phys = phys;
>  	__set_bit(EV_REP, idev->evbit);
>  
>  	idev->id.bustype = BUS_VIRTUAL;
>  	idev->id.version = 1;
>  	idev->id.product = 0;
>  	idev->dev.parent = dev;
> -	idev->open = cros_ec_keyb_open;
> -	idev->close = cros_ec_keyb_close;
>  
> -	ckdev->ghost_filter = of_property_read_bool(np,
> +	ckdev->ghost_filter = of_property_read_bool(dev->of_node,
>  					"google,needs-ghost-filter");
>  
>  	err = matrix_keypad_build_keymap(NULL, NULL, ckdev->rows, ckdev->cols,
> @@ -287,6 +589,57 @@ static int cros_ec_keyb_probe(struct platform_device *pdev)
>  	return 0;
>  }
>  
> +static int cros_ec_keyb_probe(struct platform_device *pdev)
> +{
> +	struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
> +	struct device *dev = &pdev->dev;
> +	struct cros_ec_keyb *ckdev;
> +	int err;
> +
> +	if (!dev->of_node)
> +		return -ENODEV;
> +
> +	ckdev = devm_kzalloc(dev, sizeof(*ckdev), GFP_KERNEL);
> +	if (!ckdev)
> +		return -ENOMEM;
> +
> +	ckdev->ec = ec;
> +	ckdev->dev = dev;
> +	dev_set_drvdata(dev, ckdev);
> +
> +	err = cros_ec_keyb_register_matrix(ckdev);
> +	if (err) {
> +		dev_err(dev, "cannot register matrix inputs: %d\n", err);
> +		return err;
> +	}
> +
> +	err = cros_ec_keyb_register_bs(ckdev);
> +	if (err) {
> +		dev_err(dev, "cannot register non-matrix inputs: %d\n", err);
> +		return err;
> +	}
> +
> +	ckdev->notifier.notifier_call = cros_ec_keyb_work;
> +	err = blocking_notifier_chain_register(&ckdev->ec->event_notifier,
> +					       &ckdev->notifier);
> +	if (err) {
> +		dev_err(dev, "cannot register notifier: %d\n", err);
> +		return err;
> +	}
> +
> +	return 0;
> +}
> +
> +static int cros_ec_keyb_remove(struct platform_device *pdev)
> +{
> +	struct cros_ec_keyb *ckdev = dev_get_drvdata(&pdev->dev);
> +
> +	blocking_notifier_chain_unregister(&ckdev->ec->event_notifier,
> +					   &ckdev->notifier);
> +
> +	return 0;
> +}
> +
>  #ifdef CONFIG_OF
>  static const struct of_device_id cros_ec_keyb_of_match[] = {
>  	{ .compatible = "google,cros-ec-keyb" },
> @@ -295,11 +648,15 @@ static const struct of_device_id cros_ec_keyb_of_match[] = {
>  MODULE_DEVICE_TABLE(of, cros_ec_keyb_of_match);
>  #endif
>  
> +static const SIMPLE_DEV_PM_OPS(cros_ec_keyb_pm_ops, NULL, cros_ec_keyb_resume);
> +
>  static struct platform_driver cros_ec_keyb_driver = {
>  	.probe = cros_ec_keyb_probe,
> +	.remove = cros_ec_keyb_remove,
>  	.driver = {
>  		.name = "cros-ec-keyb",
>  		.of_match_table = of_match_ptr(cros_ec_keyb_of_match),
> +		.pm = &cros_ec_keyb_pm_ops,
>  	},
>  };
>  
> -- 
> 2.9.3
> 

-- 
Dmitry