Re: [PATCH v5 1/3] hwmon: (ads7871) Fix endianness bug in 16-bit register reads

[Guenter Roeck]

On Fri, May 01, 2026 at 08:05:28AM +0530, Tabrez Ahmed wrote:
> The ads7871_read_reg16() function relies on spi_w8r16() to read the
> 16-bit sensor output. The ADS7871 device transmits the Least Significant
> Byte (LSB) first.
> 
> On Little-Endian architectures, spi_w8r16() correctly reconstructs the
> 16-bit value. However, on Big-Endian architectures, the byte swapping
> causes the first received byte (LSB) to be placed in the most significant
> byte of the u16, resulting in corrupted voltage readings.
> 
> Replace spi_w8r16() with a manual spi_write_then_read() into a byte array,
> and safely reconstruct the integer using get_unaligned_le16() to ensure
> correct behavior across all architectures. Additionally, use a u8
> variable for the command byte to ensure the correct instruction is
> transmitted on Big-Endian systems.
> 
> Reported-by: Sashiko <sashiko-bot@xxxxxxxxxx>
> Closes: https://sashiko.dev/#/patchset/20260418034601.90226-1-tabreztalks@xxxxxxxxx
> Signed-off-by: Tabrez Ahmed <tabreztalks@xxxxxxxxx>

Applied.

Thanks,
Guenter