Date: Fri, 25 Jul 2014 23:25:17 -0400
From: Benjamin Tissoires <benjamin.tissoires@redhat.com>
To: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Jiri Kosina <jkosina@suse.cz>, Ping Cheng <pinglinux@gmail.com>,
        Jason Gerecke <killertofu@gmail.com>, Przemo Firszt <przemo@firszt.eu>,
        linux-kernel@vger.kernel.org, linux-input@vger.kernel.org
Subject: Re: [PATCH v2 06/10] Input - wacom: prepare the driver to include BT
 devices
Message-ID: <20140726032517.GC2279@mail.corp.redhat.com>
References: <1406225645-32141-1-git-send-email-benjamin.tissoires@redhat.com>
 <1406225645-32141-7-git-send-email-benjamin.tissoires@redhat.com>
 <20140726003909.GA16900@core.coreip.homeip.net>
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In-Reply-To: <20140726003909.GA16900@core.coreip.homeip.net>
Sender: linux-kernel-owner@vger.kernel.org

On Jul 25 2014 or thereabouts, Dmitry Torokhov wrote:
> Hi Benjamin,
> 
> On Thu, Jul 24, 2014 at 02:14:01PM -0400, Benjamin Tissoires wrote:
> > Now that wacom is a hid driver, there is no point in having a separate
> > driver for bluetooth devices.
> > This patch prepares the common paths of Bluetooth devices in the
> > common wacom driver.
> > It also adds the sysfs file "speed" used by Bluetooth devices.
> > 
> > Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
> > ---
> > 
> > new in v2
> > 
> >  drivers/hid/wacom_sys.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++---
> >  drivers/hid/wacom_wac.h |  2 ++
> >  2 files changed, 69 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/hid/wacom_sys.c b/drivers/hid/wacom_sys.c
> > index d0d06b8..add76ec 100644
> > --- a/drivers/hid/wacom_sys.c
> > +++ b/drivers/hid/wacom_sys.c
> > @@ -262,6 +262,12 @@ static int wacom_set_device_mode(struct hid_device *hdev, int report_id,
> >  	return error < 0 ? error : 0;
> >  }
> >  
> > +static int wacom_bt_query_tablet_data(struct hid_device *hdev, u8 speed,
> > +		struct wacom_features *features)
> > +{
> > +	return 0;
> > +}
> > +
> >  /*
> >   * Switch the tablet into its most-capable mode. Wacom tablets are
> >   * typically configured to power-up in a mode which sends mouse-like
> > @@ -272,6 +278,9 @@ static int wacom_set_device_mode(struct hid_device *hdev, int report_id,
> >  static int wacom_query_tablet_data(struct hid_device *hdev,
> >  		struct wacom_features *features)
> >  {
> > +	if (hdev->bus == BUS_BLUETOOTH)
> > +		return wacom_bt_query_tablet_data(hdev, 1, features);
> > +
> >  	if (features->device_type == BTN_TOOL_FINGER) {
> >  		if (features->type > TABLETPC) {
> >  			/* MT Tablet PC touch */
> > @@ -890,6 +899,38 @@ static void wacom_destroy_battery(struct wacom *wacom)
> >  	}
> >  }
> >  
> > +static ssize_t wacom_show_speed(struct device *dev,
> > +				struct device_attribute
> > +				*attr, char *buf)
> > +{
> > +	struct hid_device *hdev = container_of(dev, struct hid_device, dev);
> > +	struct wacom *wacom = hid_get_drvdata(hdev);
> > +
> > +	return snprintf(buf, PAGE_SIZE, "%i\n", wacom->wacom_wac.bt_high_speed);
> > +}
> > +
> > +static ssize_t wacom_store_speed(struct device *dev,
> > +				struct device_attribute *attr,
> > +				const char *buf, size_t count)
> > +{
> > +	struct hid_device *hdev = container_of(dev, struct hid_device, dev);
> > +	struct wacom *wacom = hid_get_drvdata(hdev);
> > +	int new_speed;
> > +
> > +	if (sscanf(buf, "%1d", &new_speed ) != 1)
> 
> Checkpach is unhappy with ')' placement and I agree with it.
> 

ouch

> > +		return -EINVAL;
> 
> kstrtou8?

re-ouch

> 
> > +
> > +	if (new_speed == 0 || new_speed == 1) {
> > +		wacom_bt_query_tablet_data(hdev, new_speed,
> > +				&wacom->wacom_wac.features);
> > +		return strnlen(buf, PAGE_SIZE);
> 
> This is weird. Normally you want to return count since you should refuse
> input with excessive data.

indeed

> 
> > +	} else
> > +		return -EINVAL;
> 
> Need braces on both branches.
> 

Grmblmbl. I should not have blinded copied the code from one driver to
one other. I will send a v3 of the rest of the series on top of your
wacom branch, at some point next week. Other people can still try to
find out other mistakes meanwhile ;)

Thanks for the review.

Cheers,
Benjamin

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