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From: Andi Shyti <andi.shyti@samsung.com>
To: Sean Young <sean@mess.org>
Cc: Mauro Carvalho Chehab <mchehab@osg.samsung.com>,
	linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
	Andi Shyti <andi@etezian.org>
Subject: Re: [RFC 7/7] [media] rc: add support for IR LEDs driven through SPI
Date: Thu, 21 Jul 2016 10:09:26 +0900	[thread overview]
Message-ID: <20160721010926.GG23521@samsunx.samsung> (raw)
In-Reply-To: <20160719231122.GA25146@gofer.mess.org>

Hi Sean,

> > +	int ret;
> > +	struct ir_spi_data *idata = (struct ir_spi_data *) dev->priv;
> 
> No cast needed.

yes, thanks.

> > +	ret = regulator_enable(idata->regulator);
> > +	if (ret)
> > +		return ret;
> > +
> > +	mutex_lock(&idata->mutex);
> > +	idata->xfer.len = n;
> > +	idata->xfer.tx_buf = buffer;
> > +	mutex_unlock(&idata->mutex);
> 
> I'm not convinced the locking works here. You want to guard against 
> someone modifying xfer while you are sending (so in spi_sync_transfer), 
> which this locking is not doing. You could declare a 
> local "struct spi_transfer xfer" and avoid the mutex altogether.

I cannot declare xfer locally because the spi framework needs
a statically allocated xfer, so that either I dynamically
allocate it in the function or I declare it global in idata.

With the mutex I would like to prevent different tasks to change
the value at the same time, it's an easy case, it shouldn't make
much difference.

There are checkpatch issues, in the next patchset I will fix
them.

Thanks a lot for your review,
Andi

  reply	other threads:[~2016-07-21  1:09 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-19 15:56 [RFC 0/7] Add support for IR transmitters Andi Shyti
2016-07-19 15:56 ` [RFC 1/7] [media] rc-main: assign driver type during allocation Andi Shyti
2016-07-19 22:04   ` Sean Young
2016-07-21  0:19     ` Andi Shyti
2016-07-19 15:56 ` [RFC 2/7] [media] rc-main: split setup and unregister functions Andi Shyti
2016-07-19 15:56 ` [RFC 3/7] [media] rc-core: add support for IR raw transmitters Andi Shyti
2016-07-19 22:10   ` Sean Young
2016-07-21  0:44     ` Andi Shyti
2016-07-19 15:56 ` [RFC 4/7] [media] rc-ir-raw: do not generate any receiving thread for " Andi Shyti
2016-07-19 15:56 ` [RFC 5/7] [media] ir-lirc-codec: do not handle any buffer " Andi Shyti
2016-07-19 22:16   ` Sean Young
2016-07-21  0:48     ` Andi Shyti
2016-07-21 14:43       ` Sean Young
2016-07-19 15:56 ` [RFC 6/7] Documentation: bindings: add documentation for ir-spi device driver Andi Shyti
2016-07-19 15:56 ` [RFC 7/7] [media] rc: add support for IR LEDs driven through SPI Andi Shyti
2016-07-19 23:11   ` Sean Young
2016-07-21  1:09     ` Andi Shyti [this message]
2016-07-21 10:22       ` Sean Young
2016-07-21 14:57         ` Andi Shyti

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