RE: [PATCH] Input: elan_i2c - Add i2c_reset in sysfs for ELAN touchpad recovery

[廖崇榮 <kt.liao@emc.com.tw>]

Hi Dmitry,

-----Original Message-----
From: Dmitry Torokhov [mailto:dmitry.torokhov@gmail.com] 
Sent: Wednesday, March 27, 2019 12:34 PM
To: KT Liao
Cc: linux-kernel@vger.kernel.org; linux-input@vger.kernel.org;
ulrik.debie-os@e2big.org; Roger.Whittaker@suse.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?
Agree your better idea.
I will modify the driver for Roger's testing.
Will upstream after his testing.

Thanks.

> 
> Signed-off-by: KT Liao <kt.liao@emc.com.tw>
> Acked-by: Roger Whittaker <Roger.Whittaker@suse.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