6.6-stable review patch. If anyone has any objections, please let me know.
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From: David Lechner dlechner@baylibre.com
[ Upstream commit ae5bc07ec9f73a41734270ef3f800c5c8a7e0ad3 ]
Replace using stack-allocated buffers with a DMA-safe buffer for use with spi_read(). This allows the driver to be safely used with DMA-enabled SPI controllers.
The buffer array is also converted to a struct with a union to make the usage of the memory in the buffer more clear and ensure proper alignment.
Fixes: 1f25ca11d84a ("iio: temperature: add support for Maxim thermocouple chips") Signed-off-by: David Lechner dlechner@baylibre.com Reviewed-by: Nuno Sá nuno.sa@analog.com Link: https://patch.msgid.link/20250721-iio-use-more-iio_declare_buffer_with_ts-3-... Cc: Stable@vger.kernel.org Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com [ iio_push_to_buffers_with_ts() => iio_push_to_buffers_with_timestamp() ] Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/iio/temperature/maxim_thermocouple.c | 26 ++++++++++++++++---------- 1 file changed, 16 insertions(+), 10 deletions(-)
--- a/drivers/iio/temperature/maxim_thermocouple.c +++ b/drivers/iio/temperature/maxim_thermocouple.c @@ -12,6 +12,7 @@ #include <linux/mutex.h> #include <linux/err.h> #include <linux/spi/spi.h> +#include <linux/types.h> #include <linux/iio/iio.h> #include <linux/iio/sysfs.h> #include <linux/iio/trigger.h> @@ -122,8 +123,15 @@ struct maxim_thermocouple_data { struct spi_device *spi; const struct maxim_thermocouple_chip *chip; char tc_type; - - u8 buffer[16] __aligned(IIO_DMA_MINALIGN); + /* Buffer for reading up to 2 hardware channels. */ + struct { + union { + __be16 raw16; + __be32 raw32; + __be16 raw[2]; + }; + aligned_s64 timestamp; + } buffer __aligned(IIO_DMA_MINALIGN); };
static int maxim_thermocouple_read(struct maxim_thermocouple_data *data, @@ -131,18 +139,16 @@ static int maxim_thermocouple_read(struc { unsigned int storage_bytes = data->chip->read_size; unsigned int shift = chan->scan_type.shift + (chan->address * 8); - __be16 buf16; - __be32 buf32; int ret;
switch (storage_bytes) { case 2: - ret = spi_read(data->spi, (void *)&buf16, storage_bytes); - *val = be16_to_cpu(buf16); + ret = spi_read(data->spi, &data->buffer.raw16, storage_bytes); + *val = be16_to_cpu(data->buffer.raw16); break; case 4: - ret = spi_read(data->spi, (void *)&buf32, storage_bytes); - *val = be32_to_cpu(buf32); + ret = spi_read(data->spi, &data->buffer.raw32, storage_bytes); + *val = be32_to_cpu(data->buffer.raw32); break; default: ret = -EINVAL; @@ -167,9 +173,9 @@ static irqreturn_t maxim_thermocouple_tr struct maxim_thermocouple_data *data = iio_priv(indio_dev); int ret;
- ret = spi_read(data->spi, data->buffer, data->chip->read_size); + ret = spi_read(data->spi, data->buffer.raw, data->chip->read_size); if (!ret) { - iio_push_to_buffers_with_timestamp(indio_dev, data->buffer, + iio_push_to_buffers_with_timestamp(indio_dev, &data->buffer, iio_get_time_ns(indio_dev)); }