From: Alison Schofield <amsfield22@gmail.com>
To: jic23@kernel.org
Cc: mranostay@gmail.com, knaack.h@gmx.de, lars@metafoo.de,
pmeerw@pmeerw.net, linux-iio@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] iio: humidity: hdc100x: move lock on config updates to single function
Date: Fri, 15 Jul 2016 22:23:42 -0700 [thread overview]
Message-ID: <20160716052341.GA1872@d830.WORKGROUP> (raw)
In-Reply-To: <634a2c91a91bdbbe3e79872fffb4fbf2d804a59e.1468180067.git.amsfield22@gmail.com>
On Sun, Jul 10, 2016 at 02:30:01PM -0700, Alison Schofield wrote:
> Move the config register locking to the config update function. This
> continues to protect updates to heater and integration times. It puts
> the lock in one place, right where it needs to occur.
Since creating this patch, I've learned that it is a design choice in
kernel drivers to keep the locking at a higher level - ie point of entry.
This patch goes against that design, so, I get that it's not do-able.
alisons
>
> Add the checkpatch required comment on this lock declaration.
>
> Signed-off-by: Alison Schofield <amsfield22@gmail.com>
> Cc: Daniel Baluta <daniel.baluta@gmail.com>
> ---
> drivers/iio/humidity/hdc100x.c | 16 ++++++----------
> 1 file changed, 6 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/iio/humidity/hdc100x.c b/drivers/iio/humidity/hdc100x.c
> index a03832a..ad5a12a 100644
> --- a/drivers/iio/humidity/hdc100x.c
> +++ b/drivers/iio/humidity/hdc100x.c
> @@ -31,7 +31,7 @@
>
> struct hdc100x_data {
> struct i2c_client *client;
> - struct mutex lock;
> + struct mutex lock; /* protect config updates & raw measurements */
> u16 config;
>
> /* integration time of the sensor */
> @@ -108,10 +108,12 @@ static int hdc100x_update_config(struct hdc100x_data *data, int mask, int val)
> int tmp = (~mask & data->config) | val;
> int ret;
>
> + mutex_lock(&data->lock);
> ret = i2c_smbus_write_word_swapped(data->client,
> HDC100X_REG_CONFIG, tmp);
> if (!ret)
> data->config = tmp;
> + mutex_unlock(&data->lock);
>
> return ret;
> }
> @@ -234,26 +236,20 @@ static int hdc100x_write_raw(struct iio_dev *indio_dev,
> int val, int val2, long mask)
> {
> struct hdc100x_data *data = iio_priv(indio_dev);
> - int ret = -EINVAL;
>
> switch (mask) {
> case IIO_CHAN_INFO_INT_TIME:
> if (val != 0)
> return -EINVAL;
>
> - mutex_lock(&data->lock);
> - ret = hdc100x_set_it_time(data, chan->address, val2);
> - mutex_unlock(&data->lock);
> - return ret;
> + return hdc100x_set_it_time(data, chan->address, val2);
> +
> case IIO_CHAN_INFO_RAW:
> if (chan->type != IIO_CURRENT || val2 != 0)
> return -EINVAL;
>
> - mutex_lock(&data->lock);
> - ret = hdc100x_update_config(data, HDC100X_REG_CONFIG_HEATER_EN,
> + return hdc100x_update_config(data, HDC100X_REG_CONFIG_HEATER_EN,
> val ? HDC100X_REG_CONFIG_HEATER_EN : 0);
> - mutex_unlock(&data->lock);
> - return ret;
> default:
> return -EINVAL;
> }
> --
> 2.1.4
>
next prev parent reply other threads:[~2016-07-16 5:23 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-10 21:29 [PATCH 0/2] iio: humidity: hdc100x: update driver locking Alison Schofield
2016-07-10 21:30 ` [PATCH 1/2] iio: humidity: hdc100x: move lock on config updates to single function Alison Schofield
2016-07-16 5:23 ` Alison Schofield [this message]
2016-07-10 21:31 ` [PATCH 2/2] iio: humidity: hdc100x: remove lock on heater configuration read Alison Schofield
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