linux-kernel - Re: [PATCH] Input: elan_i2c - Add i2c_reset in sysfs for ELAN touchpad recovery

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Date:   Tue, 26 Mar 2019 21:34:23 -0700
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     KT Liao <kt.liao@....com.tw>
Cc:     linux-kernel@...r.kernel.org, linux-input@...r.kernel.org,
        ulrik.debie-os@...ig.org, Roger.Whittaker@...e.com
Subject: Re: [PATCH] Input: elan_i2c - Add i2c_reset in sysfs for ELAN
 touchpad recovery

Hi KT,

On Sat, Feb 02, 2019 at 03:54:56PM +0800, KT Liao wrote:
> Roger from SUSE reported the touchpad on Lenovo yoga2 crush sometimes.
> He found that rmmod/modprobe elan_i2c will recover the issue.
> He add the workaround on SUSE and solve the problem.
> Recently, the workaround fails in kernel 4.20 becasue IRQ mismatch.
> genirq: Flags mismatch irq 0. 00002002 (ELAN0600:00) vs. 00015a00 (timer)
> I can't reproduce the issue in SUSE with the same kernel.
> And it's a 5 years old laptop, ELAN can't find the module for testing.
> Instead of IRQ debugging IRQ, I tried another approach.
> I added i2c_reset in sysfs to avoid IRQ requesting in probe.

How will users discover this flag? I do not think this is the best
approach. Can we detect that the touchpad firmware crashed from the
kernel and reset automatically?

Thanks.

> 
> Signed-off-by: KT Liao <kt.liao@....com.tw>
> Acked-by: Roger Whittaker <Roger.Whittaker@...e.com>
> ---
>  drivers/input/mouse/elan_i2c_core.c | 25 +++++++++++++++++++++++++
>  1 file changed, 25 insertions(+)
> 
> diff --git a/drivers/input/mouse/elan_i2c_core.c b/drivers/input/mouse/elan_i2c_core.c
> index 2690a4b..388b1f0 100644
> --- a/drivers/input/mouse/elan_i2c_core.c
> +++ b/drivers/input/mouse/elan_i2c_core.c
> @@ -670,6 +670,29 @@ static ssize_t calibrate_store(struct device *dev,
>  	return retval ?: count;
>  }
>  
> +static ssize_t i2c_reset_store(struct device *dev,
> +			       struct device_attribute *attr,
> +			       const char *buf, size_t count)
> +{
> +	struct i2c_client *client = to_i2c_client(dev);
> +	struct elan_tp_data *data = i2c_get_clientdata(client);
> +	int retval;
> +
> +	retval = mutex_lock_interruptible(&data->sysfs_mutex);
> +	if (retval)
> +		return retval;
> +
> +	disable_irq(client->irq);
> +
> +	retval = elan_initialize(data);
> +	if (retval)
> +		dev_err(dev, "failed to re-initialize touchpad: %d\n", retval);
> +
> +	enable_irq(client->irq);
> +	mutex_unlock(&data->sysfs_mutex);
> +	return retval ?: count;
> +}
> +
>  static ssize_t elan_sysfs_read_mode(struct device *dev,
>  				    struct device_attribute *attr,
>  				    char *buf)
> @@ -702,6 +725,7 @@ static DEVICE_ATTR(mode, S_IRUGO, elan_sysfs_read_mode, NULL);
>  static DEVICE_ATTR(update_fw, S_IWUSR, NULL, elan_sysfs_update_fw);
>  
>  static DEVICE_ATTR_WO(calibrate);
> +static DEVICE_ATTR_WO(i2c_reset);
>  
>  static struct attribute *elan_sysfs_entries[] = {
>  	&dev_attr_product_id.attr,
> @@ -710,6 +734,7 @@ static struct attribute *elan_sysfs_entries[] = {
>  	&dev_attr_iap_version.attr,
>  	&dev_attr_fw_checksum.attr,
>  	&dev_attr_calibrate.attr,
> +	&dev_attr_i2c_reset.attr,
>  	&dev_attr_mode.attr,
>  	&dev_attr_update_fw.attr,
>  	NULL,
> -- 
> 2.7.4
> 

-- 
Dmitry