linux-kernel - Re: [PATCH v2 3/7] Input: synaptics-rmi4

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Date:   Fri, 2 Dec 2016 16:33:56 -0800
From:   Andrew Duggan <aduggan@...aptics.com>
To:     Benjamin Tissoires <benjamin.tissoires@...hat.com>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Jiri Kosina <jikos@...nel.org>,
        Lyude Paul <thatslyude@...il.com>,
        Nick Dyer <nick@...anahar.org>,
        Dennis Wassenberg <dennis.wassenberg@...unet.com>
CC:     <linux-input@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 3/7] Input: synaptics-rmi4 - allow to add attention
 data

On 12/02/2016 03:41 AM, Benjamin Tissoires wrote:
> The HID implementation of RMI4 provides the data during
> the interrupt (in the input report). We need to provide
> a way for this transport driver to provide the attention
> data while calling an IRQ.
>
> We use a fifo in rmi_core to not lose any incoming event.
>
> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@...hat.com>

Reviewed-by: Andrew Duggan <aduggan@...aptics.com>

> ---
>
> no changes in v2
> ---
>   drivers/input/rmi4/rmi_driver.c | 49 +++++++++++++++++++++++++++++++++++++++--
>   include/linux/rmi.h             | 11 +++++++++
>   2 files changed, 58 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/input/rmi4/rmi_driver.c b/drivers/input/rmi4/rmi_driver.c
> index a718e51..85062e4 100644
> --- a/drivers/input/rmi4/rmi_driver.c
> +++ b/drivers/input/rmi4/rmi_driver.c
> @@ -191,16 +191,53 @@ static int rmi_process_interrupt_requests(struct rmi_device *rmi_dev)
>   	return 0;
>   }
>   
> +void rmi_set_attn_data(struct rmi_device *rmi_dev, unsigned long irq_status,
> +		       void *data, size_t size)
> +{
> +	struct rmi_driver_data *drvdata = dev_get_drvdata(&rmi_dev->dev);
> +	struct rmi4_attn_data attn_data;
> +	void *fifo_data;
> +
> +	if (!drvdata->enabled)
> +		return;
> +
> +	fifo_data = kmemdup(data, size, GFP_ATOMIC);
> +	if (!fifo_data)
> +		return;
> +
> +	attn_data.irq_status = irq_status;
> +	attn_data.size = size;
> +	attn_data.data = fifo_data;
> +
> +	kfifo_put(&drvdata->attn_fifo, attn_data);
> +}
> +EXPORT_SYMBOL_GPL(rmi_set_attn_data);
> +
>   static irqreturn_t rmi_irq_fn(int irq, void *dev_id)
>   {
>   	struct rmi_device *rmi_dev = dev_id;
> -	int ret;
> +	struct rmi_driver_data *drvdata = dev_get_drvdata(&rmi_dev->dev);
> +	struct rmi4_attn_data attn_data = {0};
> +	int ret, count;
> +
> +	count = kfifo_get(&drvdata->attn_fifo, &attn_data);
> +	if (count) {
> +		*(drvdata->irq_status) = attn_data.irq_status;
> +		rmi_dev->xport->attn_data = attn_data.data;
> +		rmi_dev->xport->attn_size = attn_data.size;
> +	}
>   
>   	ret = rmi_process_interrupt_requests(rmi_dev);
>   	if (ret)
>   		rmi_dbg(RMI_DEBUG_CORE, &rmi_dev->dev,
>   			"Failed to process interrupt request: %d\n", ret);
>   
> +	if (count)
> +		kfree(attn_data.data);
> +
> +	if (!kfifo_is_empty(&drvdata->attn_fifo))
> +		return rmi_irq_fn(irq, dev_id);
> +
>   	return IRQ_HANDLED;
>   }
>   
> @@ -880,8 +917,9 @@ void rmi_disable_irq(struct rmi_device *rmi_dev, bool enable_wake)
>   {
>   	struct rmi_device_platform_data *pdata = rmi_get_platform_data(rmi_dev);
>   	struct rmi_driver_data *data = dev_get_drvdata(&rmi_dev->dev);
> +	struct rmi4_attn_data attn_data = {0};
>   	int irq = pdata->irq;
> -	int retval;
> +	int retval, count;
>   
>   	mutex_lock(&data->enabled_mutex);
>   
> @@ -898,6 +936,13 @@ void rmi_disable_irq(struct rmi_device *rmi_dev, bool enable_wake)
>   				 retval);
>   	}
>   
> +	/* make sure the fifo is clean */
> +	while (!kfifo_is_empty(&data->attn_fifo)) {
> +		count = kfifo_get(&data->attn_fifo, &attn_data);
> +		if (count)
> +			kfree(attn_data.data);
> +	}
> +
>   out:
>   	mutex_unlock(&data->enabled_mutex);
>   }
> diff --git a/include/linux/rmi.h b/include/linux/rmi.h
> index 7780e40..1d48656 100644
> --- a/include/linux/rmi.h
> +++ b/include/linux/rmi.h
> @@ -13,6 +13,7 @@
>   #include <linux/device.h>
>   #include <linux/interrupt.h>
>   #include <linux/input.h>
> +#include <linux/kfifo.h>
>   #include <linux/list.h>
>   #include <linux/module.h>
>   #include <linux/types.h>
> @@ -331,6 +332,12 @@ struct rmi_device {
>   
>   };
>   
> +struct rmi4_attn_data {
> +	unsigned long irq_status;
> +	size_t size;
> +	void *data;
> +};
> +
>   struct rmi_driver_data {
>   	struct list_head function_list;
>   
> @@ -357,11 +364,15 @@ struct rmi_driver_data {
>   
>   	bool enabled;
>   	struct mutex enabled_mutex;
> +	DECLARE_KFIFO(attn_fifo, struct rmi4_attn_data, 16);
>   };
>   
>   int rmi_register_transport_device(struct rmi_transport_dev *xport);
>   void rmi_unregister_transport_device(struct rmi_transport_dev *xport);
>   
> +void rmi_set_attn_data(struct rmi_device *rmi_dev, unsigned long irq_status,
> +		       void *data, size_t size);
> +
>   int rmi_driver_suspend(struct rmi_device *rmi_dev, bool enable_wake);
>   int rmi_driver_resume(struct rmi_device *rmi_dev, bool clear_wake);
>   #endif