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Sat, 02 May 2026 11:23:47 -0700 (PDT) Sender: Guenter Roeck Date: Sat, 2 May 2026 11:23:47 -0700 From: Guenter Roeck To: Tabrez Ahmed Cc: linux-hwmon@vger.kernel.org, linux-kernel@vger.kernel.org, david.laight.linux@gmail.com, me@brighamcampbell.com, shuah@kernel.org Subject: Re: [PATCH v6 3/3] hwmon: (ads7871) Use DMA-safe buffer for SPI writes Message-ID: <8f4363a4-b05a-4e42-8868-e7b611fd0dda@roeck-us.net> References: <20260502020844.110038-1-tabreztalks@gmail.com> <20260502020844.110038-4-tabreztalks@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260502020844.110038-4-tabreztalks@gmail.com> On Sat, May 02, 2026 at 07:38:44AM +0530, Tabrez Ahmed wrote: > The driver currently passes a stack-allocated buffer to spi_write(), > which is incompatible with DMA on systems with CONFIG_VMAP_STACK > enabled. > > Move the transfer buffer into the driver's private data structure > to ensure it is DMA-safe. Since this shared buffer now requires > serialization, this change depends on the previous commit which > migrated the driver to the hwmon 'with_info' API. > > While moving the logic, also: > - Corrected the sign extension for 14-bit data by casting to s16. > - Scaled the output to millivolts (2500mV full scale > ) to comply with the hwmon ABI. > > Signed-off-by: Tabrez Ahmed Applied. Thanks, Guenter