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@xxxxxxxxx>
> Cc: Daniel Baluta <daniel.baluta@xxxxxxxxx>
> ---
> 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
>
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