Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-12-03 17:41:22 +00:00
Code Issues Packages Projects Releases Wiki Activity

iio: adc: mcp3422: fix locking scope

Browse Source 
Locking should be held for the entire reading sequence involving setting
the channel, waiting for the channel switch and reading from the
channel.
If not, reading from a channel can result mixing with the reading from
another channel.

Fixes: 07914c84ba ("iio: adc: Add driver for Microchip MCP3422/3/4 high resolution ADC")
Signed-off-by: Angelo Compagnucci <angelo.compagnucci@gmail.com>
Link: https://lore.kernel.org/r/20200819075525.1395248-1-angelo.compagnucci@gmail.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Angelo Compagnucci 2020-08-19 09:55:25 +02:00 committed by Jonathan Cameron
parent d53bfdf2f0
commit 3f1093d83d
1 changed files with 7 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
drivers/iio/adc/mcp3422.c
View File

@ -96,16 +96,12 @@ static int mcp3422_update_config(struct mcp3422 *adc, u8 newconfig)
{
int ret;
mutex_lock(&adc->lock);
ret = i2c_master_send(adc->i2c, &newconfig, 1);
if (ret > 0) {
adc->config = newconfig;
ret = 0;
}
mutex_unlock(&adc->lock);
return ret;
}
@ -138,6 +134,8 @@ static int mcp3422_read_channel(struct mcp3422 *adc,
u8 config;
u8 req_channel = channel->channel;
mutex_lock(&adc->lock);
if (req_channel != MCP3422_CHANNEL(adc->config)) {
config = adc->config;
config &= ~MCP3422_CHANNEL_MASK;
@ -150,7 +148,11 @@ static int mcp3422_read_channel(struct mcp3422 *adc,
msleep(mcp3422_read_times[MCP3422_SAMPLE_RATE(adc->config)]);
}
return mcp3422_read(adc, value, &config);
ret = mcp3422_read(adc, value, &config);
mutex_unlock(&adc->lock);
return ret;
}
static int mcp3422_read_raw(struct iio_dev *iio,