iio: adc: mcp3422: fix locking scope (3f1093d8) · Commits · 戴 / test

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: ("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>

drivers/iio/adc/mcp3422.c

+7 −5

Original line number	Diff line number	Diff line
		@@ -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,

Admin message